diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..e989503
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,14 @@
+[run]
+branch = True
+source =
+   OpenSSL
+   tests/
+
+[paths]
+source =
+   src/OpenSSL
+   .tox/*/lib/python*/site-packages/OpenSSL
+   .tox/pypy/site-packages/OpenSSL
+
+[report]
+show_missing = True
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..2040b80
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,13 @@
+build
+dist
+*.egg-info
+*.pyc
+*.pyo
+__pycache__
+.tox
+doc/_build/
+.coverage*
+.eggs
+examples/simple/*.cert
+examples/simple/*.pkey
+.cache
diff --git a/.mention-bot b/.mention-bot
new file mode 100644
index 0000000..9a20eb3
--- /dev/null
+++ b/.mention-bot
@@ -0,0 +1,3 @@
+{
+    "userBlacklist": ["exarkun"]
+}
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..52131e8
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,148 @@
+dist: trusty
+sudo: false
+language: python
+
+cache:
+  directories:
+    - $HOME/.cache/pip
+
+env:
+  global:
+    - LC_ALL=en_US.UTF-8
+
+matrix:
+  include:
+  - language: generic
+    os: osx
+    osx_image: xcode10.1
+    env: TOXENV=py27
+  - language: generic
+    os: osx
+    osx_image: xcode10.1
+    env: TOXENV=py27 OPENSSL=1.1.0
+  - python: "2.7" # these are just to make travis's UI a bit prettier
+    env: TOXENV=py27
+  - python: "3.4"
+    env: TOXENV=py34
+  - python: "3.5"
+    env: TOXENV=py35
+  - python: "3.6"
+    env: TOXENV=py36
+  - python: "3.7"
+    env: TOXENV=py37
+    dist: xenial
+    sudo: true
+  - python: "pypy"
+    env: TOXENV=pypy
+  - python: "pypy3"
+    env: TOXENV=pypy3
+
+  # Also run the tests against cryptography master.
+  - python: "2.7"
+    env: TOXENV=py27-cryptographyMaster
+  - python: "3.4"
+    env: TOXENV=py34-cryptographyMaster
+  - python: "3.5"
+    env: TOXENV=py35-cryptographyMaster
+  - python: "3.6"
+    env: TOXENV=py36-cryptographyMaster
+  - python: "3.7"
+    env: TOXENV=py37-cryptographyMaster
+    dist: xenial
+    sudo: true
+  - python: "pypy"
+    env: TOXENV=pypy-cryptographyMaster
+  - python: "pypy3"
+    env: TOXENV=pypy3-cryptographyMaster
+
+  # And current minimum cryptography version.
+  - python: "2.7"
+    env: TOXENV=py27-cryptographyMinimum
+  - python: "3.4"
+    env: TOXENV=py34-cryptographyMinimum
+  - python: "3.5"
+    env: TOXENV=py35-cryptographyMinimum
+  - python: "3.6"
+    env: TOXENV=py36-cryptographyMinimum
+  - python: "3.7"
+    env: TOXENV=py37-cryptographyMinimum
+    dist: xenial
+    sudo: true
+  - python: "pypy"
+    env: TOXENV=pypy-cryptographyMinimum
+  - python: "pypy3"
+    env: TOXENV=pypy3-cryptographyMinimum
+
+
+  # Make sure we don't break Twisted or urllib3
+  - python: "2.7"
+    env: TOXENV=py27-twistedMaster
+  - python: "3.5"
+    env: TOXENV=py35-urllib3Master
+
+
+  # Meta
+  - python: "2.7"
+    env: TOXENV=check-manifest
+
+  - python: "2.7"
+    env: TOXENV=pypi-readme
+
+  - python: "2.7"
+    env: TOXENV=flake8
+
+  - python: "2.7"
+    env: TOXENV=docs
+
+  # Let the cryptography master builds fail because they might be caused by
+  # cryptography changes that are beyond our control.
+  allow_failures:
+  - env: TOXENV=py27-cryptographyMaster
+  - env: TOXENV=py34-cryptographyMaster
+  - env: TOXENV=py35-cryptographyMaster
+  - env: TOXENV=py36-cryptographyMaster
+  - env: TOXENV=py37-cryptographyMaster
+  - env: TOXENV=pypy-cryptographyMaster
+  - env: TOXENV=pypy3-cryptographyMaster
+
+
+install:
+  - |
+    if [[ "$(uname -s)" == 'Darwin' ]]; then
+      brew update
+      if [[ "${OPENSSL}" == "1.1.0" ]]; then
+        brew upgrade openssl@1.1
+      else
+        brew upgrade openssl
+      fi
+      curl -O https://bootstrap.pypa.io/get-pip.py
+      python get-pip.py --user
+      python -m pip install --user virtualenv
+    else
+      pip install virtualenv
+    fi
+    python -m virtualenv ~/.venv
+    ~/.venv/bin/pip install tox coverage
+
+script:
+  - |
+    if [[ "$(uname -s)" == 'Darwin' ]]; then
+      # set our flags to use homebrew openssl
+      if [[ "${OPENSSL}"  == "1.1.0" ]]; then
+        export LDFLAGS="-L/usr/local/opt/openssl@1.1/lib"
+        export CFLAGS="-I/usr/local/opt/openssl@1.1/include"
+        export PATH="/usr/local/opt/openssl@1.1/bin:$PATH"
+      else
+        export LDFLAGS="-L/usr/local/opt/openssl/lib"
+        export CFLAGS="-I/usr/local/opt/openssl/include"
+        export PATH="/usr/local/opt/openssl/bin:$PATH"
+      fi
+    fi
+    openssl version
+    ~/.venv/bin/tox -v
+
+after_script:
+  - ./.travis/upload_coverage.sh
+
+notifications:
+  email: false
diff --git a/.travis/install_urllib3.sh b/.travis/install_urllib3.sh
new file mode 100755
index 0000000..1324ded
--- /dev/null
+++ b/.travis/install_urllib3.sh
@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -e
+set -x
+
+git clone --depth 1 https://github.com/shazow/urllib3.git
+pip install -r ./urllib3/dev-requirements.txt
+pip install ./urllib3[socks]
diff --git a/.travis/upload_coverage.sh b/.travis/upload_coverage.sh
new file mode 100755
index 0000000..02ea5f4
--- /dev/null
+++ b/.travis/upload_coverage.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -e
+set -x
+
+NO_COVERAGE_TOXENVS=(pypy docs check-manifest pypi-readme flake8)
+if ! [[ "${NO_COVERAGE_TOXENVS[*]}" =~ "${TOXENV}" ]]; then
+    source ~/.venv/bin/activate
+    coverage combine
+    bash <(curl -s https://codecov.io/bash) -e TRAVIS_OS_NAME,TOXENV,OPENSSL
+fi
diff --git a/CHANGELOG.rst b/CHANGELOG.rst
new file mode 100644
index 0000000..2dda0d2
--- /dev/null
+++ b/CHANGELOG.rst
@@ -0,0 +1,390 @@
+Changelog
+=========
+
+Versions are year-based with a strict backward-compatibility policy.
+The third digit is only for regressions.
+
+19.0.0 (2019-01-21)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- ``X509Store.add_cert`` no longer raises an error if you add a duplicate cert.
+  `#787 <https://github.com/pyca/pyopenssl/pull/787>`_
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+*none*
+
+
+Changes:
+^^^^^^^^
+
+- pyOpenSSL now works with OpenSSL 1.1.1.
+  `#805 <https://github.com/pyca/pyopenssl/pull/805>`_
+- pyOpenSSL now handles NUL bytes in ``X509Name.get_components()``
+  `#804 <https://github.com/pyca/pyopenssl/pull/804>`_
+
+
+
+----
+
+18.0.0 (2018-05-16)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- The minimum ``cryptography`` version is now 2.2.1.
+- Support for Python 2.6 has been dropped.
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+*none*
+
+
+Changes:
+^^^^^^^^
+
+- Added ``Connection.get_certificate`` to retrieve the local certificate.
+  `#733 <https://github.com/pyca/pyopenssl/pull/733>`_
+- ``OpenSSL.SSL.Connection`` now sets ``SSL_MODE_AUTO_RETRY`` by default.
+  `#753 <https://github.com/pyca/pyopenssl/pull/753>`_
+- Added ``Context.set_tlsext_use_srtp`` to enable negotiation of SRTP keying material.
+  `#734 <https://github.com/pyca/pyopenssl/pull/734>`_
+
+
+----
+
+17.5.0 (2017-11-30)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- The minimum ``cryptography`` version is now 2.1.4.
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+*none*
+
+
+Changes:
+^^^^^^^^
+
+- Fixed a potential use-after-free in the verify callback and resolved a memory leak when loading PKCS12 files with ``cacerts``.
+  `#723 <https://github.com/pyca/pyopenssl/pull/723>`_
+- Added ``Connection.export_keying_material`` for RFC 5705 compatible export of keying material.
+  `#725 <https://github.com/pyca/pyopenssl/pull/725>`_
+
+----
+
+
+
+17.4.0 (2017-11-21)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*none*
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+*none*
+
+
+Changes:
+^^^^^^^^
+
+
+- Re-added a subset of the ``OpenSSL.rand`` module.
+  This subset allows conscientious users to reseed the OpenSSL CSPRNG after fork.
+  `#708 <https://github.com/pyca/pyopenssl/pull/708>`_
+- Corrected a use-after-free when reusing an issuer or subject from an ``X509`` object after the underlying object has been mutated.
+  `#709 <https://github.com/pyca/pyopenssl/pull/709>`_
+
+----
+
+
+17.3.0 (2017-09-14)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- Dropped support for Python 3.3.
+  `#677 <https://github.com/pyca/pyopenssl/pull/677>`_
+- Removed the deprecated ``OpenSSL.rand`` module.
+  This is being done ahead of our normal deprecation schedule due to its lack of use and the fact that it was becoming a maintenance burden.
+  ``os.urandom()`` should be used instead.
+  `#675 <https://github.com/pyca/pyopenssl/pull/675>`_
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+- Deprecated ``OpenSSL.tsafe``.
+  `#673 <https://github.com/pyca/pyopenssl/pull/673>`_
+
+Changes:
+^^^^^^^^
+
+- Fixed a memory leak in ``OpenSSL.crypto.CRL``.
+  `#690 <https://github.com/pyca/pyopenssl/pull/690>`_
+- Fixed a memory leak when verifying certificates with ``OpenSSL.crypto.X509StoreContext``.
+  `#691 <https://github.com/pyca/pyopenssl/pull/691>`_
+
+
+----
+
+
+17.2.0 (2017-07-20)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*none*
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+- Deprecated ``OpenSSL.rand`` - callers should use ``os.urandom()`` instead.
+  `#658 <https://github.com/pyca/pyopenssl/pull/658>`_
+
+
+Changes:
+^^^^^^^^
+
+- Fixed a bug causing ``Context.set_default_verify_paths()`` to not work with cryptography ``manylinux1`` wheels on Python 3.x.
+  `#665 <https://github.com/pyca/pyopenssl/pull/665>`_
+- Fixed a crash with (EC)DSA signatures in some cases.
+  `#670 <https://github.com/pyca/pyopenssl/pull/670>`_
+
+
+----
+
+
+17.1.0 (2017-06-30)
+-------------------
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- Removed the deprecated ``OpenSSL.rand.egd()`` function.
+  Applications should prefer ``os.urandom()`` for random number generation.
+  `#630 <https://github.com/pyca/pyopenssl/pull/630>`_
+- Removed the deprecated default ``digest`` argument to ``OpenSSL.crypto.CRL.export()``.
+  Callers must now always pass an explicit ``digest``.
+  `#652 <https://github.com/pyca/pyopenssl/pull/652>`_
+- Fixed a bug with ``ASN1_TIME`` casting in ``X509.set_notBefore()``,
+  ``X509.set_notAfter()``, ``Revoked.set_rev_date()``, ``Revoked.set_nextUpdate()``,
+  and ``Revoked.set_lastUpdate()``. You must now pass times in the form
+  ``YYYYMMDDhhmmssZ``. ``YYYYMMDDhhmmss+hhmm`` and ``YYYYMMDDhhmmss-hhmm``
+  will no longer work. `#612 <https://github.com/pyca/pyopenssl/pull/612>`_
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+
+- Deprecated the legacy "Type" aliases: ``ContextType``, ``ConnectionType``, ``PKeyType``, ``X509NameType``, ``X509ExtensionType``, ``X509ReqType``, ``X509Type``, ``X509StoreType``, ``CRLType``, ``PKCS7Type``, ``PKCS12Type``, ``NetscapeSPKIType``.
+  The names without the "Type"-suffix should be used instead.
+
+
+Changes:
+^^^^^^^^
+
+- Added ``OpenSSL.crypto.X509.from_cryptography()`` and ``OpenSSL.crypto.X509.to_cryptography()`` for converting X.509 certificate to and from pyca/cryptography objects.
+  `#640 <https://github.com/pyca/pyopenssl/pull/640>`_
+- Added ``OpenSSL.crypto.X509Req.from_cryptography()``, ``OpenSSL.crypto.X509Req.to_cryptography()``, ``OpenSSL.crypto.CRL.from_cryptography()``, and ``OpenSSL.crypto.CRL.to_cryptography()`` for converting X.509 CSRs and CRLs to and from pyca/cryptography objects.
+  `#645 <https://github.com/pyca/pyopenssl/pull/645>`_
+- Added ``OpenSSL.debug`` that allows to get an overview of used library versions (including linked OpenSSL) and other useful runtime information using ``python -m OpenSSL.debug``.
+  `#620 <https://github.com/pyca/pyopenssl/pull/620>`_
+- Added a fallback path to ``Context.set_default_verify_paths()`` to accommodate the upcoming release of ``cryptography`` ``manylinux1`` wheels.
+  `#633 <https://github.com/pyca/pyopenssl/pull/633>`_
+
+
+----
+
+
+17.0.0 (2017-04-20)
+-------------------
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*none*
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+*none*
+
+
+Changes:
+^^^^^^^^
+
+- Added ``OpenSSL.X509Store.set_time()`` to set a custom verification time when verifying certificate chains.
+  `#567 <https://github.com/pyca/pyopenssl/pull/567>`_
+- Added a collection of functions for working with OCSP stapling.
+  None of these functions make it possible to validate OCSP assertions, only to staple them into the handshake and to retrieve the stapled assertion if provided.
+  Users will need to write their own code to handle OCSP assertions.
+  We specifically added: ``Context.set_ocsp_server_callback()``, ``Context.set_ocsp_client_callback()``, and ``Connection.request_ocsp()``.
+  `#580 <https://github.com/pyca/pyopenssl/pull/580>`_
+- Changed the ``SSL`` module's memory allocation policy to avoid zeroing memory it allocates when unnecessary.
+  This reduces CPU usage and memory allocation time by an amount proportional to the size of the allocation.
+  For applications that process a lot of TLS data or that use very lage allocations this can provide considerable performance improvements.
+  `#578 <https://github.com/pyca/pyopenssl/pull/578>`_
+- Automatically set ``SSL_CTX_set_ecdh_auto()`` on ``OpenSSL.SSL.Context``.
+  `#575 <https://github.com/pyca/pyopenssl/pull/575>`_
+- Fix empty exceptions from ``OpenSSL.crypto.load_privatekey()``.
+  `#581 <https://github.com/pyca/pyopenssl/pull/581>`_
+
+
+----
+
+
+16.2.0 (2016-10-15)
+-------------------
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*none*
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+*none*
+
+
+Changes:
+^^^^^^^^
+
+- Fixed compatibility errors with OpenSSL 1.1.0.
+- Fixed an issue that caused failures with subinterpreters and embedded Pythons.
+  `#552 <https://github.com/pyca/pyopenssl/pull/552>`_
+
+
+----
+
+
+16.1.0 (2016-08-26)
+-------------------
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+*none*
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+- Dropped support for OpenSSL 0.9.8.
+
+
+Changes:
+^^^^^^^^
+
+- Fix memory leak in ``OpenSSL.crypto.dump_privatekey()`` with ``FILETYPE_TEXT``.
+  `#496 <https://github.com/pyca/pyopenssl/pull/496>`_
+- Enable use of CRL (and more) in verify context.
+  `#483 <https://github.com/pyca/pyopenssl/pull/483>`_
+- ``OpenSSL.crypto.PKey`` can now be constructed from ``cryptography`` objects and also exported as such.
+  `#439 <https://github.com/pyca/pyopenssl/pull/439>`_
+- Support newer versions of ``cryptography`` which use opaque structs for OpenSSL 1.1.0 compatibility.
+
+
+----
+
+
+16.0.0 (2016-03-19)
+-------------------
+
+This is the first release under full stewardship of PyCA.
+We have made *many* changes to make local development more pleasing.
+The test suite now passes both on Linux and OS X with OpenSSL 0.9.8, 1.0.1, and 1.0.2.
+It has been moved to `pytest <https://docs.pytest.org/>`_, all CI test runs are part of `tox <https://tox.readthedocs.io/>`_ and the source code has been made fully `flake8 <https://flake8.readthedocs.io/>`_ compliant.
+
+We hope to have lowered the barrier for contributions significantly but are open to hear about any remaining frustrations.
+
+
+Backward-incompatible changes:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+- Python 3.2 support has been dropped.
+  It never had significant real world usage and has been dropped by our main dependency ``cryptography``.
+  Affected users should upgrade to Python 3.3 or later.
+
+
+Deprecations:
+^^^^^^^^^^^^^
+
+- The support for EGD has been removed.
+  The only affected function ``OpenSSL.rand.egd()`` now uses ``os.urandom()`` to seed the internal PRNG instead.
+  Please see `pyca/cryptography#1636 <https://github.com/pyca/cryptography/pull/1636>`_ for more background information on this decision.
+  In accordance with our backward compatibility policy ``OpenSSL.rand.egd()`` will be *removed* no sooner than a year from the release of 16.0.0.
+
+  Please note that you should `use urandom <https://sockpuppet.org/blog/2014/02/25/safely-generate-random-numbers/>`_ for all your secure random number needs.
+- Python 2.6 support has been deprecated.
+  Our main dependency ``cryptography`` deprecated 2.6 in version 0.9 (2015-05-14) with no time table for actually dropping it.
+  pyOpenSSL will drop Python 2.6 support once ``cryptography`` does.
+
+
+Changes:
+^^^^^^^^
+
+- Fixed ``OpenSSL.SSL.Context.set_session_id``, ``OpenSSL.SSL.Connection.renegotiate``, ``OpenSSL.SSL.Connection.renegotiate_pending``, and ``OpenSSL.SSL.Context.load_client_ca``.
+  They were lacking an implementation since 0.14.
+  `#422 <https://github.com/pyca/pyopenssl/pull/422>`_
+- Fixed segmentation fault when using keys larger than 4096-bit to sign data.
+  `#428 <https://github.com/pyca/pyopenssl/pull/428>`_
+- Fixed ``AttributeError`` when ``OpenSSL.SSL.Connection.get_app_data()`` was called before setting any app data.
+  `#304 <https://github.com/pyca/pyopenssl/pull/304>`_
+- Added ``OpenSSL.crypto.dump_publickey()`` to dump ``OpenSSL.crypto.PKey`` objects that represent public keys, and ``OpenSSL.crypto.load_publickey()`` to load such objects from serialized representations.
+  `#382 <https://github.com/pyca/pyopenssl/pull/382>`_
+- Added ``OpenSSL.crypto.dump_crl()`` to dump a certificate revocation list out to a string buffer.
+  `#368 <https://github.com/pyca/pyopenssl/pull/368>`_
+- Added ``OpenSSL.SSL.Connection.get_state_string()`` using the OpenSSL binding ``state_string_long``.
+  `#358 <https://github.com/pyca/pyopenssl/pull/358>`_
+- Added support for the ``socket.MSG_PEEK`` flag to ``OpenSSL.SSL.Connection.recv()`` and ``OpenSSL.SSL.Connection.recv_into()``.
+  `#294 <https://github.com/pyca/pyopenssl/pull/294>`_
+- Added ``OpenSSL.SSL.Connection.get_protocol_version()`` and ``OpenSSL.SSL.Connection.get_protocol_version_name()``.
+  `#244 <https://github.com/pyca/pyopenssl/pull/244>`_
+- Switched to ``utf8string`` mask by default.
+  OpenSSL formerly defaulted to a ``T61String`` if there were UTF-8 characters present.
+  This was changed to default to ``UTF8String`` in the config around 2005, but the actual code didn't change it until late last year.
+  This will default us to the setting that actually works.
+  To revert this you can call ``OpenSSL.crypto._lib.ASN1_STRING_set_default_mask_asc(b"default")``.
+  `#234 <https://github.com/pyca/pyopenssl/pull/234>`_
+
+
+----
+
+
+Older Changelog Entries
+-----------------------
+
+The changes from before release 16.0.0 are preserved in the `repository <https://github.com/pyca/pyopenssl/blob/master/doc/ChangeLog_old.txt>`_.
diff --git a/CODE_OF_CONDUCT.rst b/CODE_OF_CONDUCT.rst
new file mode 100644
index 0000000..dd50c33
--- /dev/null
+++ b/CODE_OF_CONDUCT.rst
@@ -0,0 +1,55 @@
+Contributor Covenant Code of Conduct
+====================================
+
+Our Pledge
+----------
+
+In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to making participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
+
+Our Standards
+-------------
+
+Examples of behavior that contributes to creating a positive environment include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a professional setting
+
+Our Responsibilities
+--------------------
+
+Project maintainers are responsible for clarifying the standards of acceptable behavior and are expected to take appropriate and fair corrective action in response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors that they deem inappropriate, threatening, offensive, or harmful.
+
+Scope
+-----
+
+This Code of Conduct applies both within project spaces and in public spaces when an individual is representing the project or its community.
+Examples of representing a project or community include using an official project e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event.
+Representation of a project may be further defined and clarified by project maintainers.
+
+Enforcement
+-----------
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by contacting either the project maintainer Hynek Schlawack at hs@ox.cx or -- e.g. in case of a conflict of interest -- Amber Brown at hawkowl@atleastfornow.net.
+All complaints will be reviewed and investigated and will result in a response that is deemed necessary and appropriate to the circumstances.
+The project team is obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
+
+Attribution
+-----------
+
+This Code of Conduct is adapted from the `Contributor Covenant <http://contributor-covenant.org>`_, version 1.4, available at http://contributor-covenant.org/version/1/4.
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
new file mode 100644
index 0000000..ad10137
--- /dev/null
+++ b/CONTRIBUTING.rst
@@ -0,0 +1,120 @@
+Contributing
+============
+
+First of all, thank you for your interest in contributing to pyOpenSSL!
+This project has no company backing its development therefore we're dependent on help by the community.
+
+
+Filing bug reports
+------------------
+
+Bug reports are very welcome.
+Please file them on the `GitHub issue tracker`_.
+Good bug reports come with extensive descriptions of the error and how to reproduce it.
+Reporters are strongly encouraged to include an `short, self contained, correct example <http://www.sscce.org/>`_.
+
+
+Patches
+-------
+
+All patches to pyOpenSSL should be submitted in the form of pull requests to the main pyOpenSSL repository, `pyca/pyopenssl`_.
+These pull requests should satisfy the following properties:
+
+
+Code
+^^^^
+
+- The pull request should focus on one particular improvement to pyOpenSSL.
+  Create different pull requests for unrelated features or bugfixes.
+- Code should follow `PEP 8`_, especially in the "do what code around you does" sense.
+  Follow OpenSSL naming for callables whenever possible is preferred.
+- Pull requests that introduce code must test all new behavior they introduce as well as for previously untested or poorly tested behavior that they touch.
+- Pull requests are not allowed to break existing tests.
+  We usually don't comment on pull requests that are breaking the CI because we consider them work in progress.
+  Please note that not having 100% code coverage for the code you wrote/touched also causes our CI to fail.
+
+
+Documentation
+^^^^^^^^^^^^^
+
+When introducing new functionality, please remember to write documentation.
+
+- New functions and methods should have a docstring describing what they do, what parameters they takes, what types those parameters are, and what they return.
+
+  .. code-block:: python
+
+     def dump_publickey(type, pkey):
+         """
+         Dump a public key to a buffer.
+
+         :param type: The file type (one of :data:`FILETYPE_PEM` or
+             :data:`FILETYPE_ASN1`).
+         :param PKey pkey: The PKey to dump.
+
+         :return: The buffer with the dumped key in it.
+         :rtype: bytes
+         """
+
+
+  Don't forget to add an ``.. auto(function|class|method)::`` statement to the relevant API document found in ``doc/api/`` to actually add your function to the Sphinx documentation.
+- Do *not* use ``:py:`` prefixes when cross-linking (Python is default).
+  Do *not* use the generic ``:data:`` or ``:obj:``.
+  Instead use more specific types like ``:class:``, ``:func:`` or ``:meth:`` if applicable.
+- Pull requests that introduce features or fix bugs should note those changes in the CHANGELOG.rst_ file.
+  Please add new entries to the *top* of the *current* Changes section followed by a line linking to the relevant pull request:
+
+  .. code-block:: rst
+
+     - Added ``OpenSSL.crypto.some_func()`` to do something awesome.
+       [`#1 <https://github.com/pyca/pyopenssl/pull/1>`_]
+
+
+- Use `semantic newlines`_ in reStructuredText_ files (files ending in ``.rst``).
+
+
+Review
+------
+
+Finally, pull requests must be reviewed before merging.
+This process mirrors the `cryptography code review process`_.
+Everyone can perform reviews; this is a very valuable way to contribute, and is highly encouraged.
+
+Pull requests are merged by `members of PyCA`_.
+They should, of course, keep all the requirements detailed in this document as well as the ``pyca/cryptography`` merge requirements in mind.
+
+The final responsibility for the reviewing of merged code lies with the person merging it.
+Since pyOpenSSL is a sensitive project from a security perspective, reviewers are strongly encouraged to take this review and merge process very seriously.
+
+
+Finding Help
+------------
+
+If you need any help with the contribution process, you'll find us hanging out at ``#cryptography-dev`` on Freenode_ IRC.
+You can also ask questions on our `mailing list`_.
+
+Please note that this project is released with a Contributor `Code of Conduct`_.
+By participating in this project you agree to abide by its terms.
+
+
+Security
+--------
+
+If you feel that you found a security-relevant bug that you would prefer to discuss in private, please send us a GPG_-encrypted e-mail.
+
+The maintainer can be reached at hs@ox.cx and his GPG key ID is ``0xAE2536227F69F181`` (Fingerprint: ``C2A0 4F86 ACE2 8ADC F817  DBB7 AE25 3622 7F69 F181``).
+Feel free to cross-check this information with Keybase_.
+
+
+.. _GitHub issue tracker: https://github.com/pyca/pyopenssl/issues
+.. _GPG: https://en.wikipedia.org/wiki/GNU_Privacy_Guard
+.. _Keybase: https://keybase.io/hynek
+.. _pyca/pyopenssl: https://github.com/pyca/pyopenssl
+.. _PEP 8: https://www.python.org/dev/peps/pep-0008/
+.. _cryptography code review process: https://cryptography.io/en/latest/development/reviewing-patches/
+.. _freenode: https://freenode.net
+.. _mailing list: https://mail.python.org/mailman/listinfo/cryptography-dev
+.. _members of PyCA: https://github.com/orgs/pyca/people
+.. _semantic newlines: http://rhodesmill.org/brandon/2012/one-sentence-per-line/
+.. _reStructuredText: http://sphinx-doc.org/rest.html
+.. _CHANGELOG.rst: https://github.com/pyca/pyopenssl/blob/master/CHANGELOG.rst
+.. _`Code of Conduct`: https://github.com/pyca/pyopenssl/blob/master/CODE_OF_CONDUCT.rst
diff --git a/INSTALL.rst b/INSTALL.rst
new file mode 100644
index 0000000..71fe1ed
--- /dev/null
+++ b/INSTALL.rst
@@ -0,0 +1,46 @@
+Installation
+============
+
+To install pyOpenSSL::
+
+  $ pip install pyopenssl
+
+If you are installing in order to *develop* on pyOpenSSL, move to the root directory of a pyOpenSSL checkout, and run::
+
+  $ pip install -e .
+
+
+.. warning::
+
+   As of 0.14, pyOpenSSL is a pure-Python project.
+   That means that if you encounter *any* kind of compiler errors, pyOpenSSL's bugtracker is the **wrong** place to report them because we *cannot* help you.
+
+   Please take the time to read the errors and report them/ask help from the appropriate project.
+   The most likely culprit being `cryptography <https://cryptography.io/>`_ that contains OpenSSL's library bindings.
+
+
+Supported OpenSSL Versions
+--------------------------
+
+pyOpenSSL supports the same platforms and releases as the upstream cryptography project `does <https://cryptography.io/en/latest/installation/#supported-platforms>`_.
+Currently that means:
+
+- 1.0.1
+- 1.0.2
+- 1.1.0
+
+If you need support for older releases, the following pinned versions will work:
+
+- **OpenSSL 0.9.8**: ``'pyOpenSSL<17.0' 'cryptography<1.4'``
+- **OpenSSL 1.0.0**: ``'pyOpenSSL<17.1' 'cryptography<1.7'``
+
+You can always find out the versions of pyOpenSSL, cryptography, and the linked OpenSSL by running ``python -m OpenSSL.debug``.
+
+
+Documentation
+-------------
+
+The documentation is written in reStructuredText and built using Sphinx::
+
+  $ cd doc
+  $ make html
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..d645695
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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+      (c) You must retain, in the Source form of any Derivative Works
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+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
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+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
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+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
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+      Work (including but not limited to damages for loss of goodwill,
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+      other commercial damages or losses), even if such Contributor
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+   9. Accepting Warranty or Additional Liability. While redistributing
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+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
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+
+   END OF TERMS AND CONDITIONS
+
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+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
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+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
diff --git a/MANIFEST.in b/MANIFEST.in
new file mode 100644
index 0000000..036bcdb
--- /dev/null
+++ b/MANIFEST.in
@@ -0,0 +1,11 @@
+include             LICENSE MANIFEST.in *.rst tox.ini .coveragerc
+exclude             leakcheck codecov.yml
+recursive-include   tests           *.py
+recursive-include   doc             *
+recursive-include   examples        *
+recursive-include   rpm             *
+recursive-exclude   leakcheck       *.py *.pem
+recursive-exclude   examples/simple *.cert *.pkey
+prune               doc/_build
+prune               .travis
+prune               .mention-bot
diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..ec746ee
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,17 @@
+name: "pyopenssl"
+description:
+    "A Python wrapper around the OpenSSL library"
+
+third_party {
+  url {
+    type: HOMEPAGE
+    value: "https://pyopenssl.org/en/stable/"
+  }
+  url {
+    type: GIT
+    value: "https://github.com/pyca/pyopenssl"
+  }
+  version: "19.0.0 "
+  last_upgrade_date { year: 2019 month: 2 day: 26 }
+  license_type: NOTICE
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/NOTICE b/NOTICE
new file mode 120000
index 0000000..7a694c9
--- /dev/null
+++ b/NOTICE
@@ -0,0 +1 @@
+LICENSE
\ No newline at end of file
diff --git a/README.rst b/README.rst
new file mode 100644
index 0000000..ed078d4
--- /dev/null
+++ b/README.rst
@@ -0,0 +1,47 @@
+========================================================
+pyOpenSSL -- A Python wrapper around the OpenSSL library
+========================================================
+
+.. image:: https://readthedocs.org/projects/pyopenssl/badge/?version=stable
+   :target: https://pyopenssl.org/en/stable/
+   :alt: Stable Docs
+
+.. image:: https://travis-ci.org/pyca/pyopenssl.svg?branch=master
+   :target: https://travis-ci.org/pyca/pyopenssl
+   :alt: Build status
+
+.. image:: https://codecov.io/github/pyca/pyopenssl/branch/master/graph/badge.svg
+   :target: https://codecov.io/github/pyca/pyopenssl
+   :alt: Test coverage
+
+**Note:** The Python Cryptographic Authority **strongly suggests** the use of `pyca/cryptography`_
+where possible. If you are using pyOpenSSL for anything other than making a TLS connection 
+**you should move to cryptography and drop your pyOpenSSL dependency**.
+
+High-level wrapper around a subset of the OpenSSL library. Includes
+
+* ``SSL.Connection`` objects, wrapping the methods of Python's portable sockets
+* Callbacks written in Python
+* Extensive error-handling mechanism, mirroring OpenSSL's error codes
+
+... and much more.
+
+You can find more information in the documentation_.
+Development takes place on GitHub_.
+
+
+Discussion
+==========
+
+If you run into bugs, you can file them in our `issue tracker`_.
+
+We maintain a cryptography-dev_ mailing list for both user and development discussions.
+
+You can also join ``#cryptography-dev`` on Freenode to ask questions or get involved.
+
+
+.. _documentation: https://pyopenssl.org/
+.. _`issue tracker`: https://github.com/pyca/pyopenssl/issues
+.. _cryptography-dev: https://mail.python.org/mailman/listinfo/cryptography-dev
+.. _GitHub: https://github.com/pyca/pyopenssl
+.. _`pyca/cryptography`: https://github.com/pyca/cryptography
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000..69cb760
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1 @@
+comment: false
diff --git a/doc/ChangeLog_old.txt b/doc/ChangeLog_old.txt
new file mode 100644
index 0000000..1a16d72
--- /dev/null
+++ b/doc/ChangeLog_old.txt
@@ -0,0 +1,833 @@
+This file only contains the changes up to release 0.15.1.  Newer changes can be
+found at <https://pyopenssl.readthedocs.io/en/latest/changelog.html>.
+
+***
+
+2015-04-14  Hynek Schlawack  <hs@ox.cx>
+
+	* Release 0.15.1
+
+2015-04-14  Glyph Lefkowitz  <glyph@twistedmatrix.com>
+
+	* OpenSSL/SSL.py, OpenSSL/test/test_ssl.py: Fix a regression
+	  present in 0.15, where when an error occurs and no errno() is set,
+	  a KeyError is raised.  This happens, for example, if
+	  Connection.shutdown() is called when the underlying transport has
+	  gone away.
+
+2015-04-14  Hynek Schlawack  <hs@ox.cx>
+
+	* Release 0.15
+
+2015-04-12  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/rand.py, OpenSSL/SSL.py: APIs which previously accepted
+	  filenames only as bytes now accept them as either bytes or
+	  unicode (and respect sys.getfilesystemencoding()).
+
+2015-03-23  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/SSL.py: Add Cory Benfield's next-protocol-negotiation
+	  (NPN) bindings.
+
+2015-03-15  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/SSL.py: Add ``Connection.recv_into``, mirroring the
+	  builtin ``socket.recv_into``.  Based on work from Cory Benfield.
+	* OpenSSL/test/test_ssl.py: Add tests for ``recv_into``.
+
+2015-01-30  Stephen Holsapple <sholsapp@gmail.com>
+
+	* OpenSSL/crypto.py: Expose ``X509StoreContext`` for verifying certificates.
+	* OpenSSL/test/test_crypto.py: Add intermediate certificates for
+
+2015-01-08  Paul Aurich <paul@darkrain42.org>
+
+	* OpenSSL/SSL.py: ``Connection.shutdown`` now propagates errors from the
+	  underlying socket.
+
+2014-12-11  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/SSL.py: Fixed a regression ``Context.check_privatekey``
+	  causing it to always succeed - even if it should fail.
+
+2014-08-21  Alex Gaynor  <alex.gaynor@gmail.com>
+
+	* OpenSSL/crypto.py: Fixed a regression where calling ``load_pkcs7_data``
+	  with ``FILETYPE_ASN1`` would fail with a ``NameError``.
+
+2014-05-05  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/SSL.py: Fix a regression in which the first argument of
+	  the "verify" callback was incorrectly passed a ``Context`` instance
+	  instead of the ``Connection`` instance.
+	* OpenSSL/test/test_ssl.py: Add a test for the value passed as the
+	  first argument of the "verify" callback.
+
+2014-04-19  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto.py: Based on work from Alex Gaynor, Andrew
+	  Lutomirski, Tobias Oberstein, Laurens Van Houtven, and Hynek
+	  Schlawack, add ``get_elliptic_curve`` and ``get_elliptic_curves``
+	  to support TLS ECDHE modes.
+	* OpenSSL/SSL.py: Add ``Context.set_tmp_ecdh`` to configure a TLS
+	  context with a particular elliptic curve for ECDHE modes.
+
+2014-04-19  Markus Unterwaditzer <markus@unterwaditzer.net>
+
+	* OpenSSL/SSL.py: ``Connection.send`` and ``Connection.sendall``
+	  now also accept the ``buffer`` type as data.
+
+2014-04-05  Stephen Holsapple <sholsapp@gmail.com>
+
+	* OpenSSL/crypto.py: Make ``load_pkcs12`` backwards compatible with
+	  pyOpenSSL 0.13 by making passphrase optional.
+
+2014-03-30  Fedor Brunner  <fedor.brunner@azet.sk>
+
+	* OpenSSL/SSL.py: Add ``get_finished``, ``get_peer_finished``
+	  methods to ``Connection``. If you use these methods to
+	  implement TLS channel binding (RFC 5929) disable session
+	  resumption because triple handshake attacks against TLS.
+	  <https://www.ietf.org/mail-archive/web/tls/current/msg11337.html>
+	  <https://secure-resumption.com/tlsauth.pdf>
+
+2014-03-29  Fedor Brunner  <fedor.brunner@azet.sk>
+
+	* OpenSSL/SSL.py: Add ``get_cipher_name``, ``get_cipher_bits``,
+	  and ``get_cipher_version`` to ``Connection``.
+
+2014-03-28  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/tsafe.py: Replace the use of ``apply`` (which has been
+	  removed in Python 3) with the equivalent syntax.
+
+2014-03-28  Jonathan Giannuzzi  <jonathan@giannuzzi.be>
+
+	* OpenSSL/crypto.py: Fix memory leak in _X509_REVOKED_dup.
+	* leakcheck/crypto.py: Add checks for _X509_REVOKED_dup, CRL.add_revoked
+	  and CRL.get_revoked.
+	* setup.py: Require cryptography 0.3 to have the ASN1_TIME_free binding.
+
+2014-03-02  Stephen Holsapple  <sholsapp@gmail.com>
+
+	* OpenSSL/crypto.py: Add ``get_extensions`` method to ``X509Req``.
+
+2014-02-23  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.14
+
+2014-01-09  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL: Port to the cffi-based OpenSSL bindings provided by
+	  <https://github.com/pyca/cryptography>
+
+2013-10-06  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/ssl/context.c: Add support for negotiating TLS v1.1 or
+	  v1.2.
+
+2013-10-03  Christian Heimes  <christian@python.org>
+
+	* OpenSSL/crypto/x509.c: Fix an inconsistency in memory management
+	  in X509.get_serial_number which leads to crashes on some runtimes
+	  (certain Windows/Python 3.3 environments, at least).
+
+2013-08-11  Christian Heimes  <christian@python.org>
+
+	* OpenSSL/crypto/x509ext.c: Fix handling of NULL bytes inside
+	  subjectAltName general names when formatting an X509 extension
+	  as a string.
+	* OpenSSL/crypto/x509.c: Fix memory leak in get_extension().
+
+2012-04-03  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/pkey.c: Release the GIL around RSA and DSA key
+	  generation, based on code from INADA Naoki.
+
+2012-02-13  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/ssl/ssl.c: Add session cache related constants for use
+	  with the new Context.set_session_cache_mode method.
+
+	* OpenSSL/ssl/context.c: Add new Context methods
+	  set_session_cache_mode and get_session_cache_mode.
+
+2011-11-01  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/pkey.c: Raise TypeError when trying to check a
+	  PKey instance which has no private component, instead of crashing.
+	  Based on fix by <lp:~dataway>.
+
+2011-09-14  Žiga Seilnacht <lp:ziga-seilnacht>
+
+	* OpenSSL/crypto/crypto.c: Allow exceptions from passphrase
+	  callbacks to propagate up out of load_privatekey
+	* OpenSSL/crypto/crypto.c: Raise an exception when a too-long
+	  passphrase is returned from a passphrase callback, instead of
+	  silently truncating it.
+	* OpenSSL/crypto/crypto.c: Fix a memory leak when a passphrase
+	  callback returns the wrong type.
+
+2011-09-13  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/crl.c: Add error handling for the use of
+	  X509_CRL_sign.
+
+2011-09-11  Jonathan Ballet  <lp:multani>
+
+	* doc/: Convert the LaTeX documentation to Sphinx-using ReST.
+	* OpenSSL/: Convert the epytext API documentation to Sphinx-using ReST.
+
+2011-09-08  Guillermo Gonzalez  <guillermo.gonzalez@canonical.com>
+
+	* OpenSSL/ssl/context.c: Add Context.set_mode method.
+	* OpenSSL/ssl/ssl.c: Add MODE_RELEASE_BUFFERS and OP_NO_COMPRESSION
+	  constants.
+
+2011-09-02  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.13
+
+2011-06-12  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/pkey.c: Add the PKey.check method, mostly
+	  implemented by Rick Dean, to verify the internal consistency of a
+	  PKey instance.
+
+2011-06-12  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/crypto.c: Fix the sign and verify functions so
+	  they handle data with embedded NULs.  Fix by David Brodsky
+	  <lp:~lihalla>.
+
+2011-05-20  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/ssl/connection.c, OpenSSL/test/test_ssl.py: Add a new
+          method to the Connection type, get_peer_cert_chain, for retrieving
+          the peer's certificate chain.
+
+2011-05-19  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/x509.c, OpenSSL/test/test_crypto.py: Add a new
+          method to the X509 type, get_signature_algorithm, for inspecting
+          the signature algorithm field of the certificate.  Based on a
+          patch from <lp:~okuda>.
+
+2011-05-10  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/crypto.h: Work around a Windows/OpenSSL 1.0 issue
+	  explicitly including a Windows header before any OpenSSL headers.
+
+	* OpenSSL/crypto/pkcs12.c: Work around an OpenSSL 1.0 issue by
+	  explicitly flushing errors known to be uninteresting after calling
+	  PKCS12_parse.
+
+	* OpenSSL/ssl/context.c: Remove SSLv2 support if the underlying
+	  OpenSSL library does not provide it.
+
+	* OpenSSL/test/test_crypto.py: Support an OpenSSL 1.0 change from
+	  MD5 to SHA1 by allowing either hash algorithm's result as the
+	  return value of X509.subject_name_hash.
+
+	* OpenSSL/test/test_ssl.py: Support an OpenSSL 1.0 change from MD5
+	  to SHA1 by constructing certificate files named using both hash
+	  algorithms' results when testing Context.load_verify_locations.
+
+	* Support OpenSSL 1.0.0a.
+
+2011-04-15  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/ssl/ssl.c: Add OPENSSL_VERSION_NUMBER, SSLeay_version
+	  and related constants for retrieving version information about the
+	  underlying OpenSSL library.
+
+2011-04-07  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.12
+
+2011-04-06  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/x509.c: Add get_extension_count and get_extension
+	  to the X509 type, allowing read access to certificate extensions.
+
+	* OpenSSL/crypto/x509ext.c: Add get_short_name and get_data to the
+	  X509Extension type, allowing read access to the contents of an
+	  extension.
+
+2011-03-21  Olivier Hervieu <lp:~ohe>
+
+	* OpenSSL/ssl/ssl.c: Expose a number of symbolic constants for
+	  values passed to the connection "info" callback.
+
+2011-01-22  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/ssl/connection.py: Add support for new-style
+	  buffers (primarily memoryviews) to Connection.send and
+	  Connection.sendall.
+
+2010-11-01  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.11
+
+2010-10-07  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Initial support for Python 3.x throughout the codebase.
+
+2010-09-14  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* OpenSSL/crypto/netscape_spki.c: Fix an off-by-one mistake in the
+	  error handling for NetscapeSPKI.verify.  Add additional error
+          checking to NetscapeSPKI.sign to handle the case where there is no
+          private key.
+
+	* OpenSSL/crypto/x509.c: Fix an overflow bug in the subject_name_hash
+	  method of the X509 type which would cause it to return negative
+	  values on 32 bit systems.
+
+	* OpenSSL/crypto/x509req.c: Fix an off-by-one mistake in the error
+	  handling for X509Req.verify.
+
+	* OpenSSL/ssl/context.c: Fix the error handling in the load_tmp_dh
+	  method of the Context type which would cause it to always raise
+	  MemoryError, regardless of the actual error (such as a bad file
+	  name).
+
+	* OpenSSL/test/: Numerous unit tests added, both for above fixes
+	  and for other previously untested code paths.
+
+2010-07-27  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Re-arrange the repository so that the package can be built and
+	  used in-place without requiring installation.
+
+2010-02-27  James Yonan <james@openvpn.net>
+
+	* src/crypto/crypto.c: Added crypto.sign and crypto.verify methods
+	  that wrap EVP_Sign and EVP_Verify function families, using code
+	  derived from Dave Cridland's PyOpenSSL branch.
+
+	* test/test_crypto.py: Added unit tests for crypto.sign and
+	  crypto.verify.
+
+2010-01-27  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/connection.c, src/util.h: Apply patch from Sandro Tosi to
+	  fix misspellings of "compatibility".
+
+2009-11-13  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.10
+
+2009-11-07  Žiga Seilnacht, Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/connection.c, src/ssl/context.c: Add set_client_ca_list,
+	  add_client_ca, and get_client_ca_list to Context for manipulating
+	  the list of certificate authority names which are sent by servers
+	  with the certificate request message.
+	* src/util.h: Add ssize-related defines if the version of Python
+	  being used does not have them.
+	* setup.py: Significant changes to the way Windows builds are done,
+	  particularly the way OpenSSL headers and libraries are found (with
+	  the new --with-openssl argument to build_ext).
+
+2009-08-27  Rick Dean  <rick@fdd.com>, Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/pkcs12.c: Add setters to the PKCS12 type for the
+	  certificate, private key, ca certificate list, and friendly
+	  name, and add a getter for the friendly name.  Also add a method
+	  for exporting a PKCS12 object as a string.
+	* test/test_crypto.py: Add lots of additional tests for the PKCS12
+	  type.
+	* doc/pyOpenSSL.tex: Documentation for the new PKCS12 methods.
+
+2009-07-17  Rick Dean  <rick@fdd.com>, Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509ext.c: Add subject and issuer parameters to
+	  X509Extension, allowing creation of extensions which require that
+	  information.  Fixes LP#322813.
+
+2009-07-16  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* test/util.py: Changed the base TestCase's tearDown to assert that
+	  no errors were left in the OpenSSL error queue by the test.
+	* src/crypto/crypto.c: Add a private helper in support of the
+	  TestCase.tearDown change.
+	* src/crypto/x509name.c: Changed X509Name's getattr implementation
+	  to clean up the error queue.  Fixes LP#314814.
+	* test/util.c: Changed flush_error_queue to avoid a reference
+	  counting bug caused by macro expansion.
+
+2009-07-16  Rick Dean  <rick@fdd.com>
+
+	* src/rand.c: Added OpenSSL.rand.bytes to get random bytes directly.
+	* src/util.c: Added generic exceptions_from_error_queue to replace
+	  the various other implementations of this function.  Also updated
+	  the rest of the codebase to use this version instead.
+
+2009-07-05  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* test/util.py, test/test_ssl.py, test/test_crypto.py: Fold the
+	  Python 2.3 compatibility TestCase mixin into the TestCase defined
+	  in util.py.
+
+2009-07-05  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* test/util.py, test/test_ssl.py, test/test_crypto.py: Stop trying
+	  to use Twisted's TestCase even when it's available.  Instead,
+	  always use the stdlib TestCase with a few enhancements.
+
+2009-07-04  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Changed most extension types so that they can be instantiated
+	  using the type object rather than a factory function.  The old
+	  factory functions are now aliases for the type objects.
+	  Fixes LP#312786.
+
+2009-05-27  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Changed all docstrings in extension modules to be friendlier
+	  towards Python programmers.  Fixes LP#312787.
+
+2009-05-27  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509ext.c: Correctly deallocate the new Extension
+	  instance when there is an error initializing it and it is not
+	  going to be returned.  Resolves LP#368043.
+
+2009-05-11  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* test/test_crypto.py: Use binary mode for the pipe to talk to the
+	  external openssl binary.  The data being transported over this
+	  pipe is indeed binary, so previously it would often be truncated
+	  or otherwise mangled.
+
+	* src/ssl/connection.h, src/ssl/connection.c, test/test_ssl.py:
+	  Extend the Connection class with support for in-memory BIOs.  This
+	  allows SSL to be run without a real socket, useful for
+	  implementing EAP-TLS or using SSL with Windows IO completion
+	  ports, for example.  Based heavily on contributions from Rick
+	  Dean.
+
+2009-04-25  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.9
+
+2009-04-01  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+            Samuele Pedroni  <pedronis@openend.se>
+
+	* src/util.h: Delete the TLS key before trying to set a new value
+	  for it in case the current thread identifier is a recycled one (if
+	  it is recycled, the key won't be set because there is already a
+	  value from the previous thread to have this identifier and to use
+	  the pyOpenSSL API).
+
+2009-04-01  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/crypto.c: Add FILETYPE_TEXT for dumping keys and
+	  certificates and certificate signature requests to a text format.
+
+2008-12-31  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509ext.c, test/test_crypto.py: Add the get_short_name
+	  method to X509Extension based on patch from Alex Stapleton.
+
+2008-12-31  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509ext.c, test/test_crypto.py: Fix X509Extension so
+	  that it is possible to instantiate extensions which use s2i or r2i
+	  instead of v2i (an extremely obscure extension implementation
+	  detail).
+
+2008-12-30  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* MANIFEST.in, src/crypto/crypto.c, src/crypto/x509.c,
+	  src/crypto/x509name.c, src/rand/rand.c, src/ssl/context.c: Changes
+	  which eliminate compiler warnings but should not change any
+	  behavior.
+
+2008-12-28  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* test/test_ssl.py, src/ssl/ssl.c: Expose DTLS-related constants,
+	  OP_NO_QUERY_MTU, OP_COOKIE_EXCHANGE, and OP_NO_TICKET.
+
+2008-12-28  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/context.c: Add a capath parameter to
+	  Context.load_verify_locations to allow Python code to specify
+	  either or both arguments to the underlying
+	  SSL_CTX_load_verify_locations API.
+	* src/ssl/context.c: Add Context.set_default_verify_paths, a wrapper
+	  around SSL_CTX_set_default_verify_paths.
+
+2008-12-28  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* test/test_crypto.py, src/crypto/x509req.c: Added get_version and
+	  set_version_methods to X509ReqType based on patch from Wouter van
+	  Bommel.  Resolves LP#274418.
+
+2008-09-22  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.8
+
+2008-10-19  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* tsafe.py: Revert the deprecation of the thread-safe Connection
+	  wrapper.  The Connection class should not segfault if used from
+	  multiple threads now, but it generally cannot be relied on to
+	  produce correct results if used without the thread-safe wrapper.
+	* doc/pyOpenSSL.tex: Correct the documentation for the set_passwd_cb
+	  callback parameter so that it accurately describes the required
+	  signature.
+
+2008-09-22  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.8a1
+
+2008-09-21  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/ssl.h, src/ssl/ssl.c: Add a thread-local storage key
+	  which will be used to store and retrieve PyThreadState pointers
+	  whenever it is necessary to release or re-acquire the GIL.
+
+	* src/ssl/context.c: Change global_verify_callback so that it
+	  unconditionally manipulates the Python threadstate, rather than
+	  checking the tstate field which is now always NULL.
+
+2008-04-26  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/context.c: Change global_passphrase_callback and
+	  global_info_callback so that they acquire the GIL before
+	  invoking any CPython APIs and do not release it until after they
+	  are finished invoking all of them (based heavily on on patch
+	  from Dan Williams).
+	* src/ssl/crypto.c: Initialize OpenSSL thread support so that it
+	  is valid to use OpenSSL APIs from more than one thread (based on
+	  patch from Dan Williams).
+	* test/test_crypto.py: Add tests for load_privatekey and
+	  dump_privatekey when a passphrase or a passphrase callback is
+	  supplied.
+	* test/test_ssl.py: Add tests for Context.set_passwd_cb and
+	  Context.set_info_callback.
+
+2008-04-11  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Release 0.7
+
+2008-03-26  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509name.c: Add X509Name.get_components
+
+2008-03-25  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509name.c: Add hash and der methods to X509Name.
+	* src/crypto/x509.c: Fix a bug in X509.get_notBefore and
+	  X509.get_notAfter preventing UTCTIME format timestamps from
+	  working.
+
+2008-03-12  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* Fix coding problems in examples/.  Remove keys and certificates
+	  and add a note about how to generate new ones.
+
+2008-03-09  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509.c: Add getters and setters for the notBefore and
+	  notAfter attributes of X509s.
+	* src/crypto/pkey.h, src/crypto/pkey.c, src/crypto/x509req.c,
+	  src/crypto/x509.c: Track the initialized and public/private state
+	  of EVP_PKEY structures underlying the crypto_PKeyObj type and
+	  reject X509Req signature operations on keys not suitable for the
+	  task.
+
+2008-03-06  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/x509name.c: Fix tp_compare so it only returns -1, 0, or
+	  1.  This eliminates a RuntimeWarning emitted by Python.
+	* src/crypto/x509req.c: Fix reference counting for X509Name returned
+	  by X509Req.get_subject.  This removes a segfault when the subject
+	  name outlives the request object.
+	* src/crypto/x509.c: Change get_serial_number and set_serial_number
+	  to accept Python longs.
+	* doc/pyOpenSSL.tex: A number of minor corrections.
+
+2008-03-03  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/crypto/crypto.c: Expose X509_verify_cert_error_string. (patch
+	  from Victor Stinner)
+
+2008-02-22  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/connection.c src/ssl/context.c src/ssl/ssl.c: Fix
+	  compilation on Windows.  (patch from Michael Schneider)
+
+2008-02-21  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/connection.c: Expose SSL_get_shutdown and
+	  SSL_set_shutdown. (patch from James Knight)
+	* src/ssl/ssl.c: Expose SSL_SENT_SHUTDOWN and SSL_RECEIVED_SHUTDOWN.
+	  (patch from James Knight)
+
+2008-02-19  Jean-Paul Calderone  <exarkun@twistedmatrix.com>
+
+	* src/ssl/context.c: Expose SSL_CTX_add_extra_chain_cert.
+	* src/crypto/x509name.c: Fix memory leaks in __getattr__ and
+	  __setattr_ implementations.
+	* src/crypto/x509.c: Fix memory leak in X509.get_pubkey().
+	* leakcheck/: An attempt at a systematic approach to leak
+	  elimination.
+
+2004-08-13  Martin Sjögren  <msjogren@gmail.com>
+
+	* Released version 0.6.
+
+2004-08-11  Martin Sjögren  <msjogren@gmail.com>
+
+	* doc/pyOpenSSL.tex: Updates to the docs.
+
+2004-08-10  Martin Sjögren  <msjogren@gmail.com>
+
+	* src/crypto/x509.c: Add X509.add_extensions based on a patch
+	  from Han S. Lee.
+	* src/ssl/ssl.c: Add more SSL_OP_ constants. Patch from Mihai
+	  Ibanescu.
+
+2004-08-09  Martin Sjögren  <msjogren@gmail.com>
+
+	* setup.py src/crypto/: Add support for Netscape SPKI extensions
+	  based on a patch from Tollef Fog Heen.
+	* src/crypto/crypto.c: Add support for python passphrase callbacks
+	  based on a patch from Robert Olson.
+
+2004-08-03  Martin Sjögren  <msjogren@gmail.com>
+
+	* src/ssl/context.c: Applied patch from Frederic Peters to add
+	  Context.use_certificate_chain_file.
+	* src/crypto/x509.c: Applid patch from Tollef Fog Heen to add
+	  X509.subject_name_hash and X509.digest.
+
+2004-08-02  Martin Sjögren  <msjogren@gmail.com>
+
+	* src/crypto/crypto.c src/ssl/ssl.c: Applied patch from Bastian
+	  Kleineidam to fix full names of exceptions.
+
+2004-07-19  Martin Sjögren  <msjogren@gmail.com>
+
+	* doc/pyOpenSSL.tex: Fix the errors regarding X509Name's field names.
+
+2004-07-18  Martin Sjögren  <msjogren@gmail.com>
+
+	* examples/certgen.py: Fixed wrong attributes in doc string, thanks
+	  Remy. (SFbug#913315)
+	* __init__.py, setup.py, version.py: Add __version__, as suggested by
+	  Ronald Oussoren in SFbug#888729.
+	* examples/proxy.py: Fix typos, thanks Mihai Ibanescu. (SFpatch#895820)
+
+2003-01-09  Martin Sjögren  <martin@strakt.com>
+
+	* Use cyclic GC protocol in SSL.Connection, SSL.Context, crypto.PKCS12
+	  and crypto.X509Name.
+
+2002-12-02  Martin Sjögren  <martin@strakt.com>
+
+	* tsafe.py: Add some missing methods.
+
+2002-10-06  Martin Sjögren  <martin@strakt.com>
+
+	* __init__.py: Import tsafe too!
+
+2002-10-05  Martin Sjögren  <martin@strakt.com>
+
+	* src/crypto/x509name.c: Use unicode strings instead of ordinary
+	  strings in getattr/setattr. Note that plain ascii strings should
+	  still work.
+
+2002-09-17  Martin Sjögren  <martin@strakt.com>
+
+	* Released version 0.5.1.
+
+2002-09-09  Martin Sjögren  <martin@strakt.com>
+
+	* setup.cfg: Fixed build requirements for rpms.
+
+2002-09-07  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/connection.c: Fix sendall() method. It segfaulted because
+	  it was too generous about giving away the GIL.
+	* Added SecureXMLRPCServer example, contributed by Michal Wallace.
+
+2002-09-06  Martin Sjögren  <martin@strakt.com>
+
+	* setup.cfg: Updated the build requirements.
+	* src/ssl/connection.c: Fix includes for AIX.
+
+2002-09-04  Anders Hammarquist  <iko@strakt.com>
+
+	* Added type checks in all the other places where we expect
+	  specific types of objects passed.
+
+2002-09-04  Martin Sjögren  <martin@strakt.com>
+
+	* src/crypto/crypto.c: Added an explicit type check in the dump_*
+	  functions, so that they won't die when e.g. None is passed in.
+
+2002-08-25  Martin Sjögren  <martin@strakt.com>
+
+	* doc/pyOpenSSL.tex: Docs for PKCS12.
+
+2002-08-24  Martin Sjögren  <martin@strakt.com>
+
+	* src/crypto: Added basic PKCS12 support, thanks to Mark Welch
+	  <mark@collab.net>
+
+2002-08-16  Martin Sjögren  <martin@strakt.com>
+
+	* D'oh! Fixes for python 1.5 and python 2.1.
+
+2002-08-15  Martin Sjögren  <martin@strakt.com>
+
+	* Version 0.5. Yay!
+
+2002-07-25  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/context.c: Added set_options method.
+	* src/ssl/ssl.c: Added constants for Context.set_options method.
+
+2002-07-23  Martin Sjögren  <martin@strakt.com>
+
+	* Updated docs
+	* src/ssl/connection.c: Changed the get_cipher_list method to actually
+	  return a list! WARNING: This change makes the API incompatible with
+	  earlier versions!
+
+2002-07-15  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/connection.[ch]: Removed the fileno method, it uses the
+	  transport object's fileno instead.
+
+2002-07-09  Martin Sjögren  <martin@strakt.com>
+
+	* src/crypto/x509.c src/crypto/x509name.c: Fixed segfault bug where
+	  you used an X509Name after its X509 had been destroyed.
+	* src/crypto/crypto.[ch] src/crypto/x509req.c src/crypto/x509ext.[ch]:
+	  Added X509 Extension support. Thanks to maas-Maarten Zeeman
+	  <maas@awanim.com>
+	* src/crypto/pkey.c: Added bits() and type() methods.
+
+2002-07-08  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/connection.c: Moved the contents of setup_ssl into the
+	  constructor, thereby fixing some segfault bugs :)
+	* src/ssl/connection.c: Added connect_ex and sendall methods.
+	* src/crypto/x509name.c: Cleaned up comparisons and NID lookup.
+	  Thank you Maas-Maarten Zeeman <maas@awanim.com>
+	* src/rand/rand.c: Fix RAND_screen import.
+	* src/crypto/crypto.c src/crypto/pkcs7.[ch]: Added PKCS7 management,
+	  courtesy of Maas-Maarten Zeeman <maas@awanim.com>
+	* src/crypto/x509req.c: Added verify method.
+
+2002-06-17  Martin Sjögren  <martin@strakt.com>
+
+	* rpm/, setup.cfg: Added improved RPM-building stuff, thanks to
+	  Mihai Ibanescu <misa@redhat.com>
+
+2002-06-14  Martin Sjögren  <martin@strakt.com>
+
+	* examples/proxy.py: Example code for using OpenSSL through a proxy
+	  contributed by Mihai Ibanescu <misa@redhat.com>
+	* Updated installation instruction and added them to the TeX manual.
+
+2002-06-13  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/context.c: Changed global_verify_callback so that it uses
+	  PyObject_IsTrue instead of requiring ints.
+	* Added pymemcompat.h to make the memory management uniform and
+	  backwards-compatible.
+	* src/util.h: Added conditional definition of PyModule_AddObject and
+	  PyModule_AddIntConstant
+	* src/ssl/connection.c: Socket methods are no longer explicitly
+	  wrapped. fileno() is the only method the transport layer object HAS
+	  to support, but if you want to use connect, accept or sock_shutdown,
+	  then the transport layer object has to supply connect, accept
+	  and shutdown respectively.
+
+2002-06-12  Martin Sjögren  <martin@strakt.com>
+
+	* Changed comments to docstrings that are visible in Python.
+	* src/ssl/connection.c: Added set_connect_state and set_accept_state
+	  methods. Thanks to Mark Welch <mark@collab.net> for this.
+
+2002-06-11  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/connection.c: accept and connect now use SSL_set_accept_state
+	  and SSL_set_connect_state respectively, instead of SSL_accept and
+	  SSL_connect.
+	* src/ssl/connection.c: Added want_read and want_write methods.
+
+2002-06-05  Martin Sjögren  <martin@strakt.com>
+
+	* src/ssl/connection.c: Added error messages for windows. The code is
+	  copied from Python's socketmodule.c. Ick.
+	* src/ssl/connection.c: Changed the parameters to the SysCallError. It
+	  always has a tuple (number, string) now, even though the number
+	  might not always be useful.
+
+2002-04-05  Martin Sjögren  <md9ms@mdstud.chalmers.se>
+
+	* Worked more on the Debian packaging, hopefully the packages
+	  are getting into the main Debian archive soon.
+
+2002-01-10  Martin Sjögren  <martin@strakt.com>
+
+	* Worked some more on the Debian packaging, it's turning out real
+	  nice.
+	* Changed format on this file, I'm going to try to be a bit more
+	  verbose about my changes, and this format makes it easier.
+
+2002-01-08  Martin Sjögren  <martin@strakt.com>
+
+	* Version 0.4.1
+	* Added some example code
+	* Added the thread safe Connection object in the 'tsafe' submodule
+	* New Debian packaging
+
+2001-08-09  Martin Sjögren  <martin@strakt.com>
+
+	* Version 0.4
+	* Added a compare function for X509Name structures.
+	* Moved the submodules to separate .so files, with tiny C APIs so they
+	  can communicate
+	* Skeletal OpenSSL/__init__.py
+	* Removed the err submodule, use crypto.Error and SSL.Error instead
+
+2001-08-06  Martin Sjögren  <martin@strakt.com>
+
+	* Version 0.3
+	* Added more types for dealing with certificates (X509Store, X509Req,
+	  PKey)
+	* Functionality to load private keys, certificates and certificate
+	  requests from memory buffers, and store them too
+	* X509 and X509Name objects can now be modified as well, very neat when
+	  creating certificates ;)
+	* Added SSL_MODE_AUTO_RETRY to smooth things for blocking sockets
+	* Added a sock_shutdown() method to the Connection type
+	* I don't understand why, but I can't use Py_InitModule() to create
+	  submodules in Python 2.0, the interpreter segfaults on the cleanup
+	  process when I do. I added a conditional compile on the version
+	  number, falling back to my own routine. It would of course be nice to
+	  investigate what is happening, but I don't have the time to do so
+	* Do INCREF on the type objects before inserting them in the
+	  dictionary, so they will never reach refcount 0 (they are, after all,
+	  statically allocated)
+
+2001-07-30  Martin Sjögren  <martin@strakt.com>
+
+	* Version 0.2
+	* Lots of tweaking and comments in the code
+	* Now uses distutils instead of the stupid Setup file
+	* Hacked doc/tools/mkhowto, html generation should now work
+
+2001-07-16  Martin Sjögren  <martin@strakt.com>
+
+	* Initial release (0.1, don't expect much from this one :-)
+
diff --git a/doc/Makefile b/doc/Makefile
new file mode 100644
index 0000000..4202bee
--- /dev/null
+++ b/doc/Makefile
@@ -0,0 +1,130 @@
+# Makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS    =
+SPHINXBUILD   = sphinx-build
+PAPER         =
+BUILDDIR      = _build
+
+# Internal variables.
+PAPEROPT_a4     = -D latex_paper_size=a4
+PAPEROPT_letter = -D latex_paper_size=letter
+ALLSPHINXOPTS   = -d $(BUILDDIR)/doctrees $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
+
+.PHONY: help clean html dirhtml singlehtml pickle json htmlhelp qthelp devhelp epub latex latexpdf text man changes linkcheck doctest
+
+help:
+	@echo "Please use \`make <target>' where <target> is one of"
+	@echo "  html       to make standalone HTML files"
+	@echo "  dirhtml    to make HTML files named index.html in directories"
+	@echo "  singlehtml to make a single large HTML file"
+	@echo "  pickle     to make pickle files"
+	@echo "  json       to make JSON files"
+	@echo "  htmlhelp   to make HTML files and a HTML help project"
+	@echo "  qthelp     to make HTML files and a qthelp project"
+	@echo "  devhelp    to make HTML files and a Devhelp project"
+	@echo "  epub       to make an epub"
+	@echo "  latex      to make LaTeX files, you can set PAPER=a4 or PAPER=letter"
+	@echo "  latexpdf   to make LaTeX files and run them through pdflatex"
+	@echo "  text       to make text files"
+	@echo "  man        to make manual pages"
+	@echo "  changes    to make an overview of all changed/added/deprecated items"
+	@echo "  linkcheck  to check all external links for integrity"
+	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
+
+clean:
+	-rm -rf $(BUILDDIR)/*
+
+html:
+	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."
+
+dirhtml:
+	$(SPHINXBUILD) -b dirhtml $(ALLSPHINXOPTS) $(BUILDDIR)/dirhtml
+	@echo
+	@echo "Build finished. The HTML pages are in $(BUILDDIR)/dirhtml."
+
+singlehtml:
+	$(SPHINXBUILD) -b singlehtml $(ALLSPHINXOPTS) $(BUILDDIR)/singlehtml
+	@echo
+	@echo "Build finished. The HTML page is in $(BUILDDIR)/singlehtml."
+
+pickle:
+	$(SPHINXBUILD) -b pickle $(ALLSPHINXOPTS) $(BUILDDIR)/pickle
+	@echo
+	@echo "Build finished; now you can process the pickle files."
+
+json:
+	$(SPHINXBUILD) -b json $(ALLSPHINXOPTS) $(BUILDDIR)/json
+	@echo
+	@echo "Build finished; now you can process the JSON files."
+
+htmlhelp:
+	$(SPHINXBUILD) -b htmlhelp $(ALLSPHINXOPTS) $(BUILDDIR)/htmlhelp
+	@echo
+	@echo "Build finished; now you can run HTML Help Workshop with the" \
+	      ".hhp project file in $(BUILDDIR)/htmlhelp."
+
+qthelp:
+	$(SPHINXBUILD) -b qthelp $(ALLSPHINXOPTS) $(BUILDDIR)/qthelp
+	@echo
+	@echo "Build finished; now you can run "qcollectiongenerator" with the" \
+	      ".qhcp project file in $(BUILDDIR)/qthelp, like this:"
+	@echo "# qcollectiongenerator $(BUILDDIR)/qthelp/pyOpenSSL.qhcp"
+	@echo "To view the help file:"
+	@echo "# assistant -collectionFile $(BUILDDIR)/qthelp/pyOpenSSL.qhc"
+
+devhelp:
+	$(SPHINXBUILD) -b devhelp $(ALLSPHINXOPTS) $(BUILDDIR)/devhelp
+	@echo
+	@echo "Build finished."
+	@echo "To view the help file:"
+	@echo "# mkdir -p $$HOME/.local/share/devhelp/pyOpenSSL"
+	@echo "# ln -s $(BUILDDIR)/devhelp $$HOME/.local/share/devhelp/pyOpenSSL"
+	@echo "# devhelp"
+
+epub:
+	$(SPHINXBUILD) -b epub $(ALLSPHINXOPTS) $(BUILDDIR)/epub
+	@echo
+	@echo "Build finished. The epub file is in $(BUILDDIR)/epub."
+
+latex:
+	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+	@echo
+	@echo "Build finished; the LaTeX files are in $(BUILDDIR)/latex."
+	@echo "Run \`make' in that directory to run these through (pdf)latex" \
+	      "(use \`make latexpdf' here to do that automatically)."
+
+latexpdf:
+	$(SPHINXBUILD) -b latex $(ALLSPHINXOPTS) $(BUILDDIR)/latex
+	@echo "Running LaTeX files through pdflatex..."
+	make -C $(BUILDDIR)/latex all-pdf
+	@echo "pdflatex finished; the PDF files are in $(BUILDDIR)/latex."
+
+text:
+	$(SPHINXBUILD) -b text $(ALLSPHINXOPTS) $(BUILDDIR)/text
+	@echo
+	@echo "Build finished. The text files are in $(BUILDDIR)/text."
+
+man:
+	$(SPHINXBUILD) -b man $(ALLSPHINXOPTS) $(BUILDDIR)/man
+	@echo
+	@echo "Build finished. The manual pages are in $(BUILDDIR)/man."
+
+changes:
+	$(SPHINXBUILD) -b changes $(ALLSPHINXOPTS) $(BUILDDIR)/changes
+	@echo
+	@echo "The overview file is in $(BUILDDIR)/changes."
+
+linkcheck:
+	$(SPHINXBUILD) -b linkcheck $(ALLSPHINXOPTS) $(BUILDDIR)/linkcheck
+	@echo
+	@echo "Link check complete; look for any errors in the above output " \
+	      "or in $(BUILDDIR)/linkcheck/output.txt."
+
+doctest:
+	$(SPHINXBUILD) -b doctest $(ALLSPHINXOPTS) $(BUILDDIR)/doctest
+	@echo "Testing of doctests in the sources finished, look at the " \
+	      "results in $(BUILDDIR)/doctest/output.txt."
diff --git a/doc/Quotes b/doc/Quotes
new file mode 100644
index 0000000..b2cdb2d
--- /dev/null
+++ b/doc/Quotes
@@ -0,0 +1,2 @@
+< Screwtape> I like how developing against OpenSSL is like a text adventure game with a maze of twisty passages, all alike.
+%
diff --git a/doc/README b/doc/README
new file mode 100644
index 0000000..2c6359c
--- /dev/null
+++ b/doc/README
@@ -0,0 +1,4 @@
+This is the pyOpenSSL documentation source.  It uses Sphinx.  To build the
+documentation, install Sphinx and run:
+
+    $ make html
diff --git a/doc/api.rst b/doc/api.rst
new file mode 100644
index 0000000..b5ca3f2
--- /dev/null
+++ b/doc/api.rst
@@ -0,0 +1,17 @@
+.. _openssl:
+
+:py:mod:`OpenSSL` --- Python interface to OpenSSL
+=================================================
+
+.. py:module:: OpenSSL
+   :synopsis: Python interface to OpenSSL
+
+
+This package provides a high-level interface to the functions in the
+OpenSSL library. The following modules are defined:
+
+.. toctree::
+   :maxdepth: 2
+
+   api/crypto
+   api/ssl
diff --git a/doc/api/crypto.rst b/doc/api/crypto.rst
new file mode 100644
index 0000000..5cd7fd9
--- /dev/null
+++ b/doc/api/crypto.rst
@@ -0,0 +1,242 @@
+.. _openssl-crypto:
+
+:py:mod:`crypto` --- Generic cryptographic module
+=================================================
+
+.. py:module:: OpenSSL.crypto
+   :synopsis: Generic cryptographic module
+
+.. note::
+
+    `pyca/cryptography`_ is likely a better choice than using this module.
+    It contains a complete set of cryptographic primitives as well as a significantly better and more powerful X509 API.
+    If necessary you can convert to and from cryptography objects using the ``to_cryptography`` and ``from_cryptography`` methods on ``X509``, ``X509Req``, ``CRL``, and ``PKey``.
+
+
+Elliptic curves
+---------------
+
+.. autofunction:: get_elliptic_curves
+
+.. autofunction:: get_elliptic_curve
+
+Serialization and deserialization
+---------------------------------
+
+The following serialization functions take one of these constants to determine the format.
+
+.. py:data:: FILETYPE_PEM
+
+:data:`FILETYPE_PEM` serializes data to a Base64-encoded encoded representation of the underlying ASN.1 data structure. This representation includes delimiters that define what data structure is contained within the Base64-encoded block: for example, for a certificate, the delimiters are ``-----BEGIN CERTIFICATE-----`` and ``-----END CERTIFICATE-----``.
+
+.. py:data:: FILETYPE_ASN1
+
+:data:`FILETYPE_ASN1` serializes data to the underlying ASN.1 data structure. The format used by :data:`FILETYPE_ASN1` is also sometimes referred to as DER.
+
+Certificates
+~~~~~~~~~~~~
+
+.. autofunction:: dump_certificate
+
+.. autofunction:: load_certificate
+
+Certificate signing requests
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autofunction:: dump_certificate_request
+
+.. autofunction:: load_certificate_request
+
+Private keys
+~~~~~~~~~~~~
+
+.. autofunction:: dump_privatekey
+
+.. autofunction:: load_privatekey
+
+Public keys
+~~~~~~~~~~~
+
+.. autofunction:: dump_publickey
+
+.. autofunction:: load_publickey
+
+Certificate revocation lists
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autofunction:: dump_crl
+
+.. autofunction:: load_crl
+
+.. autofunction:: load_pkcs7_data
+
+.. autofunction:: load_pkcs12
+
+Signing and verifying signatures
+--------------------------------
+
+.. autofunction:: sign
+
+.. autofunction:: verify
+
+
+.. _openssl-x509:
+
+X509 objects
+------------
+
+.. autoclass:: X509
+               :members:
+
+.. _openssl-x509name:
+
+X509Name objects
+----------------
+
+.. autoclass:: X509Name
+               :members:
+               :special-members:
+               :exclude-members: __repr__, __getattr__, __weakref__
+
+.. _openssl-x509req:
+
+X509Req objects
+---------------
+
+.. autoclass:: X509Req
+               :members:
+               :special-members:
+               :exclude-members: __weakref__
+
+.. _openssl-x509store:
+
+X509Store objects
+-----------------
+
+.. autoclass:: X509Store
+               :members:
+
+.. _openssl-x509storecontexterror:
+
+X509StoreContextError objects
+-----------------------------
+
+.. autoclass:: X509StoreContextError
+               :members:
+
+.. _openssl-x509storecontext:
+
+X509StoreContext objects
+------------------------
+
+.. autoclass:: X509StoreContext
+               :members:
+
+.. _openssl-pkey:
+
+X509StoreFlags constants
+------------------------
+
+.. autoclass:: X509StoreFlags
+
+    .. data:: CRL_CHECK
+    .. data:: CRL_CHECK_ALL
+    .. data:: IGNORE_CRITICAL
+    .. data:: X509_STRICT
+    .. data:: ALLOW_PROXY_CERTS
+    .. data:: POLICY_CHECK
+    .. data:: EXPLICIT_POLICY
+    .. data:: INHIBIT_MAP
+    .. data:: NOTIFY_POLICY
+    .. data:: CHECK_SS_SIGNATURE
+    .. data:: CB_ISSUER_CHECK
+
+.. _openssl-x509storeflags:
+
+PKey objects
+------------
+
+.. autoclass:: PKey
+               :members:
+
+.. _openssl-pkcs7:
+
+.. py:data:: TYPE_RSA
+             TYPE_DSA
+
+    Key type constants.
+
+PKCS7 objects
+-------------
+
+PKCS7 objects have the following methods:
+
+.. autoclass:: PKCS7
+               :members:
+
+.. _openssl-pkcs12:
+
+PKCS12 objects
+--------------
+
+.. autoclass:: PKCS12
+               :members:
+
+.. _openssl-509ext:
+
+X509Extension objects
+---------------------
+
+.. autoclass:: X509Extension
+               :members:
+               :special-members:
+               :exclude-members: __weakref__
+
+.. _openssl-netscape-spki:
+
+NetscapeSPKI objects
+--------------------
+
+.. autoclass:: NetscapeSPKI
+               :members:
+               :special-members:
+               :exclude-members: __weakref__
+
+.. _crl:
+
+CRL objects
+-----------
+
+.. autoclass:: CRL
+               :members:
+               :special-members:
+               :exclude-members: __weakref__
+
+.. _revoked:
+
+Revoked objects
+---------------
+
+.. autoclass:: Revoked
+               :members:
+
+Exceptions
+----------
+
+.. py:exception:: Error
+
+    Generic exception used in the :py:mod:`.crypto` module.
+
+
+Digest names
+------------
+
+Several of the functions and methods in this module take a digest name.
+These must be strings describing a digest algorithm supported by OpenSSL (by ``EVP_get_digestbyname``, specifically).
+For example, :const:`b"sha256"` or :const:`b"sha384"`.
+
+More information and a list of these digest names can be found in the ``EVP_DigestInit(3)`` man page of your OpenSSL installation.
+This page can be found online for the latest version of OpenSSL:
+https://www.openssl.org/docs/manmaster/man3/EVP_DigestInit.html
+
+.. _`pyca/cryptography`:  https://cryptography.io
diff --git a/doc/api/ssl.rst b/doc/api/ssl.rst
new file mode 100644
index 0000000..c678b28
--- /dev/null
+++ b/doc/api/ssl.rst
@@ -0,0 +1,247 @@
+.. _openssl-ssl:
+
+:py:mod:`SSL` --- An interface to the SSL-specific parts of OpenSSL
+===================================================================
+
+.. py:module:: OpenSSL.SSL
+    :synopsis: An interface to the SSL-specific parts of OpenSSL
+
+
+This module handles things specific to SSL. There are two objects defined:
+Context, Connection.
+
+.. py:data:: SSLv2_METHOD
+             SSLv3_METHOD
+             SSLv23_METHOD
+             TLSv1_METHOD
+             TLSv1_1_METHOD
+             TLSv1_2_METHOD
+
+    These constants represent the different SSL methods to use when creating a
+    context object.  If the underlying OpenSSL build is missing support for any
+    of these protocols, constructing a :py:class:`Context` using the
+    corresponding :py:const:`*_METHOD` will raise an exception.
+
+
+.. py:data:: VERIFY_NONE
+             VERIFY_PEER
+             VERIFY_FAIL_IF_NO_PEER_CERT
+
+    These constants represent the verification mode used by the Context
+    object's :py:meth:`set_verify` method.
+
+
+.. py:data:: FILETYPE_PEM
+             FILETYPE_ASN1
+
+    File type constants used with the :py:meth:`use_certificate_file` and
+    :py:meth:`use_privatekey_file` methods of Context objects.
+
+
+.. py:data:: OP_SINGLE_DH_USE
+             OP_SINGLE_ECDH_USE
+
+    Constants used with :py:meth:`set_options` of Context objects.
+
+    When these options are used, a new key will always be created when using
+    ephemeral (Elliptic curve) Diffie-Hellman.
+
+
+.. py:data:: OP_EPHEMERAL_RSA
+
+    Constant used with :py:meth:`set_options` of Context objects.
+
+    When this option is used, ephemeral RSA keys will always be used when doing
+    RSA operations.
+
+
+.. py:data:: OP_NO_TICKET
+
+    Constant used with :py:meth:`set_options` of Context objects.
+
+    When this option is used, the session ticket extension will not be used.
+
+
+.. py:data:: OP_NO_COMPRESSION
+
+    Constant used with :py:meth:`set_options` of Context objects.
+
+    When this option is used, compression will not be used.
+
+
+.. py:data:: OP_NO_SSLv2
+             OP_NO_SSLv3
+             OP_NO_TLSv1
+             OP_NO_TLSv1_1
+             OP_NO_TLSv1_2
+
+    Constants used with :py:meth:`set_options` of Context objects.
+
+    Each of these options disables one version of the SSL/TLS protocol.  This
+    is interesting if you're using e.g. :py:const:`SSLv23_METHOD` to get an
+    SSLv2-compatible handshake, but don't want to use SSLv2.  If the underlying
+    OpenSSL build is missing support for any of these protocols, the
+    :py:const:`OP_NO_*` constant may be undefined.
+
+
+.. py:data:: SSLEAY_VERSION
+             SSLEAY_CFLAGS
+             SSLEAY_BUILT_ON
+             SSLEAY_PLATFORM
+             SSLEAY_DIR
+
+    Constants used with :py:meth:`SSLeay_version` to specify what OpenSSL version
+    information to retrieve.  See the man page for the :py:func:`SSLeay_version` C
+    API for details.
+
+
+.. py:data:: SESS_CACHE_OFF
+             SESS_CACHE_CLIENT
+             SESS_CACHE_SERVER
+             SESS_CACHE_BOTH
+             SESS_CACHE_NO_AUTO_CLEAR
+             SESS_CACHE_NO_INTERNAL_LOOKUP
+             SESS_CACHE_NO_INTERNAL_STORE
+             SESS_CACHE_NO_INTERNAL
+
+     Constants used with :py:meth:`Context.set_session_cache_mode` to specify
+     the behavior of the session cache and potential session reuse.  See the man
+     page for the :py:func:`SSL_CTX_set_session_cache_mode` C API for details.
+
+     .. versionadded:: 0.14
+
+
+.. py:data:: OPENSSL_VERSION_NUMBER
+
+    An integer giving the version number of the OpenSSL library used to build this
+    version of pyOpenSSL.  See the man page for the :py:func:`SSLeay_version` C API
+    for details.
+
+
+.. autofunction:: SSLeay_version
+
+
+.. py:data:: ContextType
+
+    See :py:class:`Context`.
+
+
+.. autoclass:: Context
+
+.. autoclass:: Session
+
+
+.. py:data:: ConnectionType
+
+    See :py:class:`Connection`.
+
+
+.. py:class:: Connection(context, socket)
+
+    A class representing SSL connections.
+
+    *context* should be an instance of :py:class:`Context` and *socket*
+    should be a socket [#connection-context-socket]_  object.  *socket* may be
+    *None*; in this case, the Connection is created with a memory BIO: see
+    the :py:meth:`bio_read`, :py:meth:`bio_write`, and :py:meth:`bio_shutdown`
+    methods.
+
+.. py:exception:: Error
+
+    This exception is used as a base class for the other SSL-related
+    exceptions, but may also be raised directly.
+
+    Whenever this exception is raised directly, it has a list of error messages
+    from the OpenSSL error queue, where each item is a tuple *(lib, function,
+    reason)*. Here *lib*, *function* and *reason* are all strings, describing
+    where and what the problem is. See :manpage:`err(3)` for more information.
+
+
+.. py:exception:: ZeroReturnError
+
+    This exception matches the error return code
+    :py:data:`SSL_ERROR_ZERO_RETURN`, and is raised when the SSL Connection has
+    been closed. In SSL 3.0 and TLS 1.0, this only occurs if a closure alert has
+    occurred in the protocol, i.e.  the connection has been closed cleanly. Note
+    that this does not necessarily mean that the transport layer (e.g. a socket)
+    has been closed.
+
+    It may seem a little strange that this is an exception, but it does match an
+    :py:data:`SSL_ERROR` code, and is very convenient.
+
+
+.. py:exception:: WantReadError
+
+    The operation did not complete; the same I/O method should be called again
+    later, with the same arguments. Any I/O method can lead to this since new
+    handshakes can occur at any time.
+
+    The wanted read is for **dirty** data sent over the network, not the
+    **clean** data inside the tunnel.  For a socket based SSL connection,
+    **read** means data coming at us over the network.  Until that read
+    succeeds, the attempted :py:meth:`OpenSSL.SSL.Connection.recv`,
+    :py:meth:`OpenSSL.SSL.Connection.send`, or
+    :py:meth:`OpenSSL.SSL.Connection.do_handshake` is prevented or incomplete. You
+    probably want to :py:meth:`select()` on the socket before trying again.
+
+
+.. py:exception:: WantWriteError
+
+    See :py:exc:`WantReadError`.  The socket send buffer may be too full to
+    write more data.
+
+
+.. py:exception:: WantX509LookupError
+
+    The operation did not complete because an application callback has asked to be
+    called again. The I/O method should be called again later, with the same
+    arguments.
+
+    .. note:: This won't occur in this version, as there are no such
+        callbacks in this version.
+
+
+.. py:exception:: SysCallError
+
+    The :py:exc:`SysCallError` occurs when there's an I/O error and OpenSSL's
+    error queue does not contain any information. This can mean two things: An
+    error in the transport protocol, or an end of file that violates the protocol.
+    The parameter to the exception is always a pair *(errnum,
+    errstr)*.
+
+
+
+.. _openssl-context:
+
+Context objects
+---------------
+
+Context objects have the following methods:
+
+.. autoclass:: OpenSSL.SSL.Context
+               :members:
+
+.. _openssl-session:
+
+Session objects
+---------------
+
+Session objects have no methods.
+
+
+.. _openssl-connection:
+
+Connection objects
+------------------
+
+Connection objects have the following methods:
+
+.. autoclass:: OpenSSL.SSL.Connection
+               :members:
+
+
+.. Rubric:: Footnotes
+
+.. [#connection-context-socket] Actually, all that is required is an object that
+    **behaves** like a socket, you could even use files, even though it'd be
+    tricky to get the handshakes right!
diff --git a/doc/backward-compatibility.rst b/doc/backward-compatibility.rst
new file mode 100644
index 0000000..446339b
--- /dev/null
+++ b/doc/backward-compatibility.rst
@@ -0,0 +1,11 @@
+Backward Compatibility
+======================
+
+pyOpenSSL has a very strong backward compatibility policy.
+Generally speaking, you shouldn't ever be afraid of updating.
+
+If breaking changes are needed do be done, they are:
+
+#. …announced in the :doc:`changelog`.
+#. …the old behavior raises a :exc:`DeprecationWarning` for a year.
+#. …are done with another announcement in the :doc:`changelog`.
diff --git a/doc/changelog.rst b/doc/changelog.rst
new file mode 100644
index 0000000..565b052
--- /dev/null
+++ b/doc/changelog.rst
@@ -0,0 +1 @@
+.. include:: ../CHANGELOG.rst
diff --git a/doc/conf.py b/doc/conf.py
new file mode 100644
index 0000000..3940dd2
--- /dev/null
+++ b/doc/conf.py
@@ -0,0 +1,259 @@
+# -*- coding: utf-8 -*-
+#
+# pyOpenSSL documentation build configuration file, created by
+# sphinx-quickstart on Sat Jul 16 07:12:22 2011.
+#
+# This file is execfile()d with the current directory set to its containing dir.
+#
+# Note that not all possible configuration values are present in this
+# autogenerated file.
+#
+# All configuration values have a default; values that are commented out
+# serve to show the default.
+
+import datetime
+import codecs
+import os
+import re
+import sys
+
+
+HERE = os.path.abspath(os.path.dirname(__file__))
+
+
+def read_file(*parts):
+    """
+    Build an absolute path from *parts* and return the contents of the
+    resulting file.  Assume UTF-8 encoding.
+    """
+    with codecs.open(os.path.join(HERE, *parts), "rb", "ascii") as f:
+        return f.read()
+
+
+def find_version(*file_paths):
+    version_file = read_file(*file_paths)
+    version_match = re.search(r"^__version__ = ['\"]([^'\"]*)['\"]",
+                              version_file, re.M)
+    if version_match:
+        return version_match.group(1)
+    raise RuntimeError("Unable to find version string.")
+
+
+DOC_DIR = os.path.abspath(os.path.dirname(__file__))
+sys.path.insert(0, os.path.abspath(os.path.join(DOC_DIR, "..")))
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#sys.path.insert(0, os.path.abspath('.'))
+
+# -- General configuration -----------------------------------------------------
+
+# If your documentation needs a minimal Sphinx version, state it here.
+needs_sphinx = '1.0'
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
+extensions = [
+    "sphinx.ext.autodoc",
+    'sphinx.ext.intersphinx',
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# The suffix of source filenames.
+source_suffix = '.rst'
+
+# The encoding of source files.
+#source_encoding = 'utf-8-sig'
+
+# The master toctree document.
+master_doc = 'index'
+
+# General information about the project.
+project = u'pyOpenSSL'
+authors = u"The pyOpenSSL developers"
+copyright = u"2001 " + authors
+
+# The version info for the project you're documenting, acts as replacement for
+# |version| and |release|, also used in various other places throughout the
+# built documents.
+#
+# The short X.Y version.
+version = find_version("..", "src", "OpenSSL", "version.py")
+# The full version, including alpha/beta/rc tags.
+release = version
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#language = None
+
+# There are two options for replacing |today|: either, you set today to some
+# non-false value, then it is used:
+#today = ''
+# Else, today_fmt is used as the format for a strftime call.
+#today_fmt = '%B %d, %Y'
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+exclude_patterns = ['_build']
+
+# The reST default role (used for this markup: `text`) to use for all documents.
+#default_role = None
+
+# If true, '()' will be appended to :func: etc. cross-reference text.
+#add_function_parentheses = True
+
+# If true, the current module name will be prepended to all description
+# unit titles (such as .. function::).
+#add_module_names = True
+
+# If true, sectionauthor and moduleauthor directives will be shown in the
+# output. They are ignored by default.
+#show_authors = False
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = 'sphinx'
+
+# A list of ignored prefixes for module index sorting.
+#modindex_common_prefix = []
+
+
+# -- Options for HTML output ---------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
+
+if not on_rtd:  # only import and set the theme if we're building docs locally
+    import sphinx_rtd_theme
+    html_theme = 'sphinx_rtd_theme'
+    html_theme_path = [sphinx_rtd_theme.get_html_theme_path()]
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further.  For a list of options available for each theme, see the
+# documentation.
+#html_theme_options = {}
+
+# Add any paths that contain custom themes here, relative to this directory.
+#html_theme_path = []
+
+# The name for this set of Sphinx documents.  If None, it defaults to
+# "<project> v<release> documentation".
+#html_title = None
+
+# A shorter title for the navigation bar.  Default is the same as html_title.
+#html_short_title = None
+
+# The name of an image file (relative to this directory) to place at the top
+# of the sidebar.
+#html_logo = None
+
+# The name of an image file (within the static path) to use as favicon of the
+# docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
+# pixels large.
+#html_favicon = None
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+# html_static_path = ['_static']
+
+# If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
+# using the given strftime format.
+#html_last_updated_fmt = '%b %d, %Y'
+
+# If true, SmartyPants will be used to convert quotes and dashes to
+# typographically correct entities.
+#html_use_smartypants = True
+
+# Custom sidebar templates, maps document names to template names.
+#html_sidebars = {}
+
+# Additional templates that should be rendered to pages, maps page names to
+# template names.
+#html_additional_pages = {}
+
+# If false, no module index is generated.
+#html_domain_indices = True
+
+# If false, no index is generated.
+#html_use_index = True
+
+# If true, the index is split into individual pages for each letter.
+#html_split_index = False
+
+# If true, links to the reST sources are added to the pages.
+#html_show_sourcelink = True
+
+# If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
+#html_show_sphinx = True
+
+# If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
+#html_show_copyright = True
+
+# If true, an OpenSearch description file will be output, and all pages will
+# contain a <link> tag referring to it.  The value of this option must be the
+# base URL from which the finished HTML is served.
+#html_use_opensearch = ''
+
+# This is the file name suffix for HTML files (e.g. ".xhtml").
+#html_file_suffix = None
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = 'pyOpenSSLdoc'
+
+
+# -- Options for LaTeX output --------------------------------------------------
+
+# The paper size ('letter' or 'a4').
+#latex_paper_size = 'letter'
+
+# The font size ('10pt', '11pt' or '12pt').
+#latex_font_size = '10pt'
+
+# Grouping the document tree into LaTeX files. List of tuples
+# (source start file, target name, title, author, documentclass [howto/manual]).
+latex_documents = [
+  ('index', 'pyOpenSSL.tex', u'pyOpenSSL Documentation',
+   authors, 'manual'),
+]
+
+# The name of an image file (relative to this directory) to place at the top of
+# the title page.
+#latex_logo = None
+
+# For "manual" documents, if this is true, then toplevel headings are parts,
+# not chapters.
+#latex_use_parts = False
+
+# If true, show page references after internal links.
+#latex_show_pagerefs = False
+
+# If true, show URL addresses after external links.
+#latex_show_urls = False
+
+# Additional stuff for the LaTeX preamble.
+#latex_preamble = ''
+
+# Documents to append as an appendix to all manuals.
+#latex_appendices = []
+
+# If false, no module index is generated.
+#latex_domain_indices = True
+
+
+# -- Options for manual page output --------------------------------------------
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    ('index', 'pyopenssl', u'pyOpenSSL Documentation',
+     [authors], 1)
+]
+
+intersphinx_mapping = {
+    "https://docs.python.org/3": None,
+    "https://cryptography.io/en/latest/": None,
+}
diff --git a/doc/images/pyopenssl-brand.png b/doc/images/pyopenssl-brand.png
new file mode 100644
index 0000000..9c46185
--- /dev/null
+++ b/doc/images/pyopenssl-brand.png
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diff --git a/doc/images/pyopenssl-icon.png b/doc/images/pyopenssl-icon.png
new file mode 100644
index 0000000..5c0620f
--- /dev/null
+++ b/doc/images/pyopenssl-icon.png
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diff --git a/doc/images/pyopenssl-logo.png b/doc/images/pyopenssl-logo.png
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diff --git a/doc/images/pyopenssl.svg b/doc/images/pyopenssl.svg
new file mode 100644
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diff --git a/doc/index.rst b/doc/index.rst
new file mode 100644
index 0000000..d4c5e2e
--- /dev/null
+++ b/doc/index.rst
@@ -0,0 +1,41 @@
+=====================================
+Welcome to pyOpenSSL's documentation!
+=====================================
+
+Release v\ |release| (:doc:`What's new? <changelog>`).
+
+pyOpenSSL is a rather thin wrapper around (a subset of) the OpenSSL library.
+With thin wrapper we mean that a lot of the object methods do nothing more than
+calling a corresponding function in the OpenSSL library.
+
+
+Contents:
+=========
+
+.. toctree::
+   :maxdepth: 2
+
+   introduction
+   install
+   api
+   internals
+
+There are also `examples in the pyOpenSSL repository <https://github.com/pyca/pyopenssl/tree/master/examples>`_ that may help you getting started.
+
+
+Meta
+----
+
+.. toctree::
+   :maxdepth: 1
+
+   backward-compatibility
+   changelog
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
diff --git a/doc/install.rst b/doc/install.rst
new file mode 100644
index 0000000..a23a75e
--- /dev/null
+++ b/doc/install.rst
@@ -0,0 +1 @@
+.. include:: ../INSTALL.rst
diff --git a/doc/internals.rst b/doc/internals.rst
new file mode 100644
index 0000000..a2a4cdc
--- /dev/null
+++ b/doc/internals.rst
@@ -0,0 +1,69 @@
+.. _internals:
+
+Internals
+=========
+
+We ran into three main problems developing this: Exceptions, callbacks and
+accessing socket methods. This is what this chapter is about.
+
+
+.. _exceptions:
+
+Exceptions
+----------
+
+We realized early that most of the exceptions would be raised by the I/O
+functions of OpenSSL, so it felt natural to mimic OpenSSL's error code system,
+translating them into Python exceptions. This naturally gives us the exceptions
+:py:exc:`.SSL.ZeroReturnError`, :py:exc:`.SSL.WantReadError`,
+:py:exc:`.SSL.WantWriteError`, :py:exc:`.SSL.WantX509LookupError` and
+:py:exc:`.SSL.SysCallError`.
+
+For more information about this, see section :ref:`openssl-ssl`.
+
+
+.. _callbacks:
+
+Callbacks
+---------
+
+Callbacks were more of a problem when pyOpenSSL was written in C.
+Having switched to being written in Python using cffi, callbacks are now straightforward.
+The problems that originally existed no longer do
+(if you are interested in the details you can find descriptions of those problems in the version control history for this document).
+
+.. _socket-methods:
+
+Accessing Socket Methods
+------------------------
+
+We quickly saw the benefit of wrapping socket methods in the
+:py:class:`.SSL.Connection` class, for an easy transition into using SSL. The
+problem here is that the :py:mod:`socket` module lacks a C API, and all the
+methods are declared static. One approach would be to have :py:mod:`.OpenSSL` as
+a submodule to the :py:mod:`socket` module, placing all the code in
+``socketmodule.c``, but this is obviously not a good solution, since you
+might not want to import tonnes of extra stuff you're not going to use when
+importing the :py:mod:`socket` module. The other approach is to somehow get a
+pointer to the method to be called, either the C function, or a callable Python
+object. This is not really a good solution either, since there's a lot of
+lookups involved.
+
+The way it works is that you have to supply a :py:class:`socket`- **like** transport
+object to the :py:class:`.SSL.Connection`. The only requirement of this object is
+that it has a :py:meth:`fileno()` method that returns a file descriptor that's
+valid at the C level (i.e. you can use the system calls read and write). If you
+want to use the :py:meth:`connect()` or :py:meth:`accept()` methods of the
+:py:class:`.SSL.Connection` object, the transport object has to supply such
+methods too. Apart from them, any method lookups in the :py:class:`.SSL.Connection`
+object that fail are passed on to the underlying transport object.
+
+Future changes might be to allow Python-level transport objects, that instead
+of having :py:meth:`fileno()` methods, have :py:meth:`read()` and :py:meth:`write()`
+methods, so more advanced features of Python can be used. This would probably
+entail some sort of OpenSSL **BIOs**, but converting Python strings back and
+forth is expensive, so this shouldn't be used unless necessary. Other nice
+things would be to be able to pass in different transport objects for reading
+and writing, but then the :py:meth:`fileno()` method of :py:class:`.SSL.Connection`
+becomes virtually useless. Also, should the method resolution be used on the
+read-transport or the write-transport?
diff --git a/doc/introduction.rst b/doc/introduction.rst
new file mode 100644
index 0000000..a810fbb
--- /dev/null
+++ b/doc/introduction.rst
@@ -0,0 +1,36 @@
+.. _intro:
+
+============
+Introduction
+============
+
+
+History
+=======
+
+pyOpenSSL was originally created by Martin Sjögren because the SSL support in the standard library in Python 2.1 (the contemporary version of Python when the pyOpenSSL project was begun) was severely limited.
+Other OpenSSL wrappers for Python at the time were also limited, though in different ways.
+
+Later it was maintained by `Jean-Paul Calderone`_ who among other things managed to make pyOpenSSL a pure Python project which the current maintainers are *very* grateful for.
+
+Over the time the standard library's ``ssl`` module improved, never reaching the completeness of pyOpenSSL's API coverage.
+Despite `PEP 466`_ many useful features remain Python 3-only and pyOpenSSL remains the only alternative for full-featured TLS code across all noteworthy Python versions from 2.7 through 3.5 and PyPy_.
+
+
+Development
+===========
+
+pyOpenSSL is collaboratively developed by the Python Cryptography Authority (PyCA_) that also maintains the low-level bindings called cryptography_.
+
+Current maintainer and release manager is `Hynek Schlawack`_.
+
+
+.. include:: ../CONTRIBUTING.rst
+
+
+.. _Jean-Paul Calderone: https://github.com/exarkun
+.. _PyPy: http://pypy.org
+.. _PEP 466: https://www.python.org/dev/peps/pep-0466/
+.. _PyCA: https://github.com/pyca
+.. _cryptography: https://github.com/pyca/cryptography
+.. _Hynek Schlawack: https://hynek.me/
diff --git a/doc/make.bat b/doc/make.bat
new file mode 100644
index 0000000..5ef04de
--- /dev/null
+++ b/doc/make.bat
@@ -0,0 +1,170 @@
+@ECHO OFF
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set BUILDDIR=_build
+set ALLSPHINXOPTS=-d %BUILDDIR%/doctrees %SPHINXOPTS% .
+if NOT "%PAPER%" == "" (
+	set ALLSPHINXOPTS=-D latex_paper_size=%PAPER% %ALLSPHINXOPTS%
+)
+
+if "%1" == "" goto help
+
+if "%1" == "help" (
+	:help
+	echo.Please use `make ^<target^>` where ^<target^> is one of
+	echo.  html       to make standalone HTML files
+	echo.  dirhtml    to make HTML files named index.html in directories
+	echo.  singlehtml to make a single large HTML file
+	echo.  pickle     to make pickle files
+	echo.  json       to make JSON files
+	echo.  htmlhelp   to make HTML files and a HTML help project
+	echo.  qthelp     to make HTML files and a qthelp project
+	echo.  devhelp    to make HTML files and a Devhelp project
+	echo.  epub       to make an epub
+	echo.  latex      to make LaTeX files, you can set PAPER=a4 or PAPER=letter
+	echo.  text       to make text files
+	echo.  man        to make manual pages
+	echo.  changes    to make an overview over all changed/added/deprecated items
+	echo.  linkcheck  to check all external links for integrity
+	echo.  doctest    to run all doctests embedded in the documentation if enabled
+	goto end
+)
+
+if "%1" == "clean" (
+	for /d %%i in (%BUILDDIR%\*) do rmdir /q /s %%i
+	del /q /s %BUILDDIR%\*
+	goto end
+)
+
+if "%1" == "html" (
+	%SPHINXBUILD% -b html %ALLSPHINXOPTS% %BUILDDIR%/html
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished. The HTML pages are in %BUILDDIR%/html.
+	goto end
+)
+
+if "%1" == "dirhtml" (
+	%SPHINXBUILD% -b dirhtml %ALLSPHINXOPTS% %BUILDDIR%/dirhtml
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished. The HTML pages are in %BUILDDIR%/dirhtml.
+	goto end
+)
+
+if "%1" == "singlehtml" (
+	%SPHINXBUILD% -b singlehtml %ALLSPHINXOPTS% %BUILDDIR%/singlehtml
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished. The HTML pages are in %BUILDDIR%/singlehtml.
+	goto end
+)
+
+if "%1" == "pickle" (
+	%SPHINXBUILD% -b pickle %ALLSPHINXOPTS% %BUILDDIR%/pickle
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished; now you can process the pickle files.
+	goto end
+)
+
+if "%1" == "json" (
+	%SPHINXBUILD% -b json %ALLSPHINXOPTS% %BUILDDIR%/json
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished; now you can process the JSON files.
+	goto end
+)
+
+if "%1" == "htmlhelp" (
+	%SPHINXBUILD% -b htmlhelp %ALLSPHINXOPTS% %BUILDDIR%/htmlhelp
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished; now you can run HTML Help Workshop with the ^
+.hhp project file in %BUILDDIR%/htmlhelp.
+	goto end
+)
+
+if "%1" == "qthelp" (
+	%SPHINXBUILD% -b qthelp %ALLSPHINXOPTS% %BUILDDIR%/qthelp
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished; now you can run "qcollectiongenerator" with the ^
+.qhcp project file in %BUILDDIR%/qthelp, like this:
+	echo.^> qcollectiongenerator %BUILDDIR%\qthelp\pyOpenSSL.qhcp
+	echo.To view the help file:
+	echo.^> assistant -collectionFile %BUILDDIR%\qthelp\pyOpenSSL.ghc
+	goto end
+)
+
+if "%1" == "devhelp" (
+	%SPHINXBUILD% -b devhelp %ALLSPHINXOPTS% %BUILDDIR%/devhelp
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished.
+	goto end
+)
+
+if "%1" == "epub" (
+	%SPHINXBUILD% -b epub %ALLSPHINXOPTS% %BUILDDIR%/epub
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished. The epub file is in %BUILDDIR%/epub.
+	goto end
+)
+
+if "%1" == "latex" (
+	%SPHINXBUILD% -b latex %ALLSPHINXOPTS% %BUILDDIR%/latex
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished; the LaTeX files are in %BUILDDIR%/latex.
+	goto end
+)
+
+if "%1" == "text" (
+	%SPHINXBUILD% -b text %ALLSPHINXOPTS% %BUILDDIR%/text
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished. The text files are in %BUILDDIR%/text.
+	goto end
+)
+
+if "%1" == "man" (
+	%SPHINXBUILD% -b man %ALLSPHINXOPTS% %BUILDDIR%/man
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Build finished. The manual pages are in %BUILDDIR%/man.
+	goto end
+)
+
+if "%1" == "changes" (
+	%SPHINXBUILD% -b changes %ALLSPHINXOPTS% %BUILDDIR%/changes
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.The overview file is in %BUILDDIR%/changes.
+	goto end
+)
+
+if "%1" == "linkcheck" (
+	%SPHINXBUILD% -b linkcheck %ALLSPHINXOPTS% %BUILDDIR%/linkcheck
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Link check complete; look for any errors in the above output ^
+or in %BUILDDIR%/linkcheck/output.txt.
+	goto end
+)
+
+if "%1" == "doctest" (
+	%SPHINXBUILD% -b doctest %ALLSPHINXOPTS% %BUILDDIR%/doctest
+	if errorlevel 1 exit /b 1
+	echo.
+	echo.Testing of doctests in the sources finished, look at the ^
+results in %BUILDDIR%/doctest/output.txt.
+	goto end
+)
+
+:end
diff --git a/examples/README.rst b/examples/README.rst
new file mode 100644
index 0000000..1e9116b
--- /dev/null
+++ b/examples/README.rst
@@ -0,0 +1,56 @@
+========
+Examples
+========
+
+
+certgen.py -- Certificate generation module
+===========================================
+
+Example module with three functions:
+
+createKeyPair
+   Create a public/private key pair.
+
+createCertRequest
+   Create a certificate request.
+
+createCertificate
+   Create a certificate given a cert request.
+
+In fact, I created the certificates and keys in the 'simple' directory with the script ``mk_simple_certs.py``.
+
+
+simple -- Simple client/server example
+======================================
+
+Start the server with::
+
+    python server.py PORT
+
+and start clients with::
+
+    python client.py HOST PORT
+
+The server is a simple echo server, anything a client sends, it sends back.
+
+
+proxy.py -- Example of an SSL-enabled proxy
+===========================================
+
+The proxy example demonstrate how to use set_connect_state to start talking SSL over an already connected socket.
+
+Usage::
+
+  python proxy.py server[:port] proxy[:port]
+
+Contributed by Mihai Ibanescu
+
+
+SecureXMLRPCServer.py -- SSL-enabled version of SimpleXMLRPCServer
+==================================================================
+
+Acts exactly like `SimpleXMLRPCServer <https://docs.python.org/3/library/xmlrpc.server.html>`_ from the Python standard library, but uses secure connections.
+The technique and classes should work for any SocketServer style server.
+However, the code has not been extensively tested.
+
+Contributed by Michal Wallace
diff --git a/examples/SecureXMLRPCServer.py b/examples/SecureXMLRPCServer.py
new file mode 100644
index 0000000..56bfaea
--- /dev/null
+++ b/examples/SecureXMLRPCServer.py
@@ -0,0 +1,115 @@
+"""
+SecureXMLRPCServer module using pyOpenSSL 0.5
+Written 0907.2002
+by Michal Wallace
+http://www.sabren.net/
+
+This acts exactly like SimpleXMLRPCServer
+from the standard python library, but
+uses secure connections. The technique
+and classes should work for any SocketServer
+style server. However, the code has not
+been extensively tested.
+
+This code is in the public domain.
+It is provided AS-IS WITH NO WARRANTY WHATSOEVER.
+"""
+
+import SimpleXMLRPCServer
+import SocketServer
+import os
+import socket
+
+from OpenSSL import SSL
+
+
+class SSLWrapper:
+    """
+    This whole class exists just to filter out a parameter
+    passed in to the shutdown() method in SimpleXMLRPC.doPOST()
+    """
+    def __init__(self, conn):
+        """
+        Connection is not yet a new-style class,
+        so I'm making a proxy instead of subclassing.
+        """
+        self.__dict__["conn"] = conn
+
+    def __getattr__(self, name):
+        return getattr(self.__dict__["conn"], name)
+
+    def __setattr__(self, name, value):
+        setattr(self.__dict__["conn"], name, value)
+
+    def shutdown(self, how=1):
+        """
+        SimpleXMLRpcServer.doPOST calls shutdown(1),
+        and Connection.shutdown() doesn't take
+        an argument. So we just discard the argument.
+        """
+        self.__dict__["conn"].shutdown()
+
+    def accept(self):
+        """
+        This is the other part of the shutdown() workaround.
+        Since servers create new sockets, we have to infect
+        them with our magic. :)
+        """
+        c, a = self.__dict__["conn"].accept()
+        return (SSLWrapper(c), a)
+
+
+class SecureTCPServer(SocketServer.TCPServer):
+    """
+    Just like TCPServer, but use a socket.
+    This really ought to let you specify the key and certificate files.
+    """
+    def __init__(self, server_address, RequestHandlerClass):
+        SocketServer.BaseServer.__init__(
+            self, server_address, RequestHandlerClass
+        )
+
+        # Same as normal, but make it secure:
+        ctx = SSL.Context(SSL.SSLv23_METHOD)
+        ctx.set_options(SSL.OP_NO_SSLv2)
+
+        dir = os.curdir
+        ctx.use_privatekey_file(os.path.join(dir, 'server.pkey'))
+        ctx.use_certificate_file(os.path.join(dir, 'server.cert'))
+
+        self.socket = SSLWrapper(
+            SSL.Connection(
+                ctx, socket.socket(self.address_family, self.socket_type)
+            )
+        )
+        self.server_bind()
+        self.server_activate()
+
+
+class SecureXMLRPCRequestHandler(
+        SimpleXMLRPCServer.SimpleXMLRPCRequestHandler):
+    def setup(self):
+        """
+        We need to use socket._fileobject Because SSL.Connection
+        doesn't have a 'dup'. Not exactly sure WHY this is, but
+        this is backed up by comments in socket.py and SSL/connection.c
+        """
+        self.connection = self.request  # for doPOST
+        self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
+        self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)
+
+
+class SecureXMLRPCServer(SimpleXMLRPCServer.SimpleXMLRPCServer,
+                         SecureTCPServer):
+    def __init__(self, addr,
+                 requestHandler=SecureXMLRPCRequestHandler,
+                 logRequests=1):
+        """
+        This is the exact same code as SimpleXMLRPCServer.__init__
+        except it calls SecureTCPServer.__init__ instead of plain
+        old TCPServer.__init__
+        """
+        self.funcs = {}
+        self.logRequests = logRequests
+        self.instance = None
+        SecureTCPServer.__init__(self, addr, requestHandler)
diff --git a/examples/certgen.py b/examples/certgen.py
new file mode 100644
index 0000000..7b70e98
--- /dev/null
+++ b/examples/certgen.py
@@ -0,0 +1,84 @@
+# -*- coding: latin-1 -*-
+#
+# Copyright (C) AB Strakt
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+Certificate generation module.
+"""
+
+from OpenSSL import crypto
+
+TYPE_RSA = crypto.TYPE_RSA
+TYPE_DSA = crypto.TYPE_DSA
+
+
+def createKeyPair(type, bits):
+    """
+    Create a public/private key pair.
+
+    Arguments: type - Key type, must be one of TYPE_RSA and TYPE_DSA
+               bits - Number of bits to use in the key
+    Returns:   The public/private key pair in a PKey object
+    """
+    pkey = crypto.PKey()
+    pkey.generate_key(type, bits)
+    return pkey
+
+
+def createCertRequest(pkey, digest="sha256", **name):
+    """
+    Create a certificate request.
+
+    Arguments: pkey   - The key to associate with the request
+               digest - Digestion method to use for signing, default is sha256
+               **name - The name of the subject of the request, possible
+                        arguments are:
+                          C     - Country name
+                          ST    - State or province name
+                          L     - Locality name
+                          O     - Organization name
+                          OU    - Organizational unit name
+                          CN    - Common name
+                          emailAddress - E-mail address
+    Returns:   The certificate request in an X509Req object
+    """
+    req = crypto.X509Req()
+    subj = req.get_subject()
+
+    for key, value in name.items():
+        setattr(subj, key, value)
+
+    req.set_pubkey(pkey)
+    req.sign(pkey, digest)
+    return req
+
+
+def createCertificate(req, issuerCertKey, serial, validityPeriod,
+                      digest="sha256"):
+    """
+    Generate a certificate given a certificate request.
+
+    Arguments: req        - Certificate request to use
+               issuerCert - The certificate of the issuer
+               issuerKey  - The private key of the issuer
+               serial     - Serial number for the certificate
+               notBefore  - Timestamp (relative to now) when the certificate
+                            starts being valid
+               notAfter   - Timestamp (relative to now) when the certificate
+                            stops being valid
+               digest     - Digest method to use for signing, default is sha256
+    Returns:   The signed certificate in an X509 object
+    """
+    issuerCert, issuerKey = issuerCertKey
+    notBefore, notAfter = validityPeriod
+    cert = crypto.X509()
+    cert.set_serial_number(serial)
+    cert.gmtime_adj_notBefore(notBefore)
+    cert.gmtime_adj_notAfter(notAfter)
+    cert.set_issuer(issuerCert.get_subject())
+    cert.set_subject(req.get_subject())
+    cert.set_pubkey(req.get_pubkey())
+    cert.sign(issuerKey, digest)
+    return cert
diff --git a/examples/mk_simple_certs.py b/examples/mk_simple_certs.py
new file mode 100644
index 0000000..f0416cd
--- /dev/null
+++ b/examples/mk_simple_certs.py
@@ -0,0 +1,50 @@
+"""
+Create certificates and private keys for the 'simple' example.
+"""
+
+from __future__ import print_function
+
+from OpenSSL import crypto
+from certgen import (
+    createKeyPair,
+    createCertRequest,
+    createCertificate,
+)
+
+cakey = createKeyPair(crypto.TYPE_RSA, 2048)
+careq = createCertRequest(cakey, CN='Certificate Authority')
+# CA certificate is valid for five years.
+cacert = createCertificate(careq, (careq, cakey), 0, (0, 60*60*24*365*5))
+
+print('Creating Certificate Authority private key in "simple/CA.pkey"')
+with open('simple/CA.pkey', 'w') as capkey:
+    capkey.write(
+        crypto.dump_privatekey(crypto.FILETYPE_PEM, cakey).decode('utf-8')
+    )
+
+print('Creating Certificate Authority certificate in "simple/CA.cert"')
+with open('simple/CA.cert', 'w') as ca:
+    ca.write(
+        crypto.dump_certificate(crypto.FILETYPE_PEM, cacert).decode('utf-8')
+    )
+
+for (fname, cname) in [('client', 'Simple Client'),
+                       ('server', 'Simple Server')]:
+    pkey = createKeyPair(crypto.TYPE_RSA, 2048)
+    req = createCertRequest(pkey, CN=cname)
+    # Certificates are valid for five years.
+    cert = createCertificate(req, (cacert, cakey), 1, (0, 60*60*24*365*5))
+
+    print('Creating Certificate %s private key in "simple/%s.pkey"'
+          % (fname, fname))
+    with open('simple/%s.pkey' % (fname,), 'w') as leafpkey:
+        leafpkey.write(
+            crypto.dump_privatekey(crypto.FILETYPE_PEM, pkey).decode('utf-8')
+        )
+
+    print('Creating Certificate %s certificate in "simple/%s.cert"'
+          % (fname, fname))
+    with open('simple/%s.cert' % (fname,), 'w') as leafcert:
+        leafcert.write(
+            crypto.dump_certificate(crypto.FILETYPE_PEM, cert).decode('utf-8')
+        )
diff --git a/examples/proxy.py b/examples/proxy.py
new file mode 100644
index 0000000..3be26f9
--- /dev/null
+++ b/examples/proxy.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python
+#
+# This script demonstrates how one can use pyOpenSSL to speak SSL over an HTTP
+# proxy
+# The challenge here is to start talking SSL over an already connected socket
+#
+# Author: Mihai Ibanescu <misa@redhat.com>
+#
+# $Id: proxy.py,v 1.2 2004/07/22 12:01:25 martin Exp $
+
+import sys
+import socket
+import string
+
+from OpenSSL import SSL
+
+
+def usage(exit_code=0):
+    print "Usage: %s server[:port] proxy[:port]" % sys.argv[0]
+    print "  Connects SSL to the specified server (port 443 by default)"
+    print "    using the specified proxy (port 8080 by default)"
+    sys.exit(exit_code)
+
+
+def main():
+    # Command-line processing
+    if len(sys.argv) != 3:
+        usage(-1)
+
+    server, proxy = sys.argv[1:3]
+
+    run(split_host(server, 443), split_host(proxy, 8080))
+
+
+def split_host(hostname, default_port=80):
+    a = string.split(hostname, ':', 1)
+    if len(a) == 1:
+        a.append(default_port)
+    return a[0], int(a[1])
+
+
+# Connects to the server, through the proxy
+def run(server, proxy):
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    try:
+        s.connect(proxy)
+    except socket.error, e:
+        print "Unable to connect to %s:%s %s" % (proxy[0], proxy[1], str(e))
+        sys.exit(-1)
+
+    # Use the CONNECT method to get a connection to the actual server
+    s.send("CONNECT %s:%s HTTP/1.0\n\n" % (server[0], server[1]))
+    print "Proxy response: %s" % string.strip(s.recv(1024))
+
+    ctx = SSL.Context(SSL.SSLv23_METHOD)
+    conn = SSL.Connection(ctx, s)
+
+    # Go to client mode
+    conn.set_connect_state()
+
+    # start using HTTP
+
+    conn.send("HEAD / HTTP/1.0\n\n")
+    print "Sever response:"
+    print "-" * 40
+    while 1:
+        try:
+            buff = conn.recv(4096)
+        except SSL.ZeroReturnError:
+            # we're done
+            break
+
+        print buff,
+
+
+if __name__ == '__main__':
+    main()
diff --git a/examples/simple/README b/examples/simple/README
new file mode 100644
index 0000000..a072998
--- /dev/null
+++ b/examples/simple/README
@@ -0,0 +1,3 @@
+To use this example, first generate keys and certificates for both the
+client and the server.  You can do this with the script in the directory
+above this one, mk_simple_certs.py.
diff --git a/examples/simple/client.py b/examples/simple/client.py
new file mode 100644
index 0000000..5662122
--- /dev/null
+++ b/examples/simple/client.py
@@ -0,0 +1,62 @@
+# -*- coding: latin-1 -*-
+#
+# Copyright (C) AB Strakt
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+Simple SSL client, using blocking I/O
+"""
+
+import os
+import socket
+import sys
+
+from OpenSSL import SSL, crypto
+
+
+def verify_cb(conn, cert, errnum, depth, ok):
+    certsubject = crypto.X509Name(cert.get_subject())
+    commonname = certsubject.commonName
+    print('Got certificate: ' + commonname)
+    return ok
+
+
+if len(sys.argv) < 3:
+    print('Usage: python client.py HOST PORT')
+    sys.exit(1)
+
+
+dir = os.path.dirname(sys.argv[0])
+if dir == '':
+    dir = os.curdir
+
+
+# Initialize context
+ctx = SSL.Context(SSL.SSLv23_METHOD)
+ctx.set_options(SSL.OP_NO_SSLv2)
+ctx.set_options(SSL.OP_NO_SSLv3)
+ctx.set_verify(SSL.VERIFY_PEER, verify_cb)  # Demand a certificate
+ctx.use_privatekey_file(os.path.join(dir, 'client.pkey'))
+ctx.use_certificate_file(os.path.join(dir, 'client.cert'))
+ctx.load_verify_locations(os.path.join(dir, 'CA.cert'))
+
+# Set up client
+sock = SSL.Connection(ctx, socket.socket(socket.AF_INET, socket.SOCK_STREAM))
+sock.connect((sys.argv[1], int(sys.argv[2])))
+
+while 1:
+    line = sys.stdin.readline()
+    if line == '':
+        break
+    try:
+        sock.send(line)
+        sys.stdout.write(sock.recv(1024).decode('utf-8'))
+        sys.stdout.flush()
+    except SSL.Error:
+        print('Connection died unexpectedly')
+        break
+
+
+sock.shutdown()
+sock.close()
diff --git a/examples/simple/server.py b/examples/simple/server.py
new file mode 100644
index 0000000..d25feb1
--- /dev/null
+++ b/examples/simple/server.py
@@ -0,0 +1,119 @@
+# -*- coding: latin-1 -*-
+#
+# Copyright (C) AB Strakt
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+Simple echo server, using nonblocking I/O
+"""
+
+from __future__ import print_function
+
+import os
+import select
+import socket
+import sys
+
+from OpenSSL import SSL, crypto
+
+
+def verify_cb(conn, cert, errnum, depth, ok):
+    certsubject = crypto.X509Name(cert.get_subject())
+    commonname = certsubject.commonName
+    print('Got certificate: ' + commonname)
+    return ok
+
+
+if len(sys.argv) < 2:
+    print('Usage: python server.py PORT')
+    sys.exit(1)
+
+dir = os.path.dirname(sys.argv[0])
+if dir == '':
+    dir = os.curdir
+
+# Initialize context
+ctx = SSL.Context(SSL.SSLv23_METHOD)
+ctx.set_options(SSL.OP_NO_SSLv2)
+ctx.set_options(SSL.OP_NO_SSLv3)
+ctx.set_verify(
+    SSL.VERIFY_PEER | SSL.VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb
+)  # Demand a certificate
+ctx.use_privatekey_file(os.path.join(dir, 'server.pkey'))
+ctx.use_certificate_file(os.path.join(dir, 'server.cert'))
+ctx.load_verify_locations(os.path.join(dir, 'CA.cert'))
+
+# Set up server
+server = SSL.Connection(ctx, socket.socket(socket.AF_INET, socket.SOCK_STREAM))
+server.bind(('', int(sys.argv[1])))
+server.listen(3)
+server.setblocking(0)
+
+clients = {}
+writers = {}
+
+
+def dropClient(cli, errors=None):
+    if errors:
+        print('Client %s left unexpectedly:' % (clients[cli],))
+        print('  ', errors)
+    else:
+        print('Client %s left politely' % (clients[cli],))
+    del clients[cli]
+    if cli in writers:
+        del writers[cli]
+    if not errors:
+        cli.shutdown()
+    cli.close()
+
+
+while 1:
+    try:
+        r, w, _ = select.select(
+            [server] + list(clients.keys()), list(writers.keys()), []
+        )
+    except Exception:
+        break
+
+    for cli in r:
+        if cli == server:
+            cli, addr = server.accept()
+            print('Connection from %s' % (addr,))
+            clients[cli] = addr
+
+        else:
+            try:
+                ret = cli.recv(1024).decode('utf-8')
+            except (SSL.WantReadError,
+                    SSL.WantWriteError,
+                    SSL.WantX509LookupError):
+                pass
+            except SSL.ZeroReturnError:
+                dropClient(cli)
+            except SSL.Error as errors:
+                dropClient(cli, errors)
+            else:
+                if cli not in writers:
+                    writers[cli] = ''
+                writers[cli] = writers[cli] + ret
+
+    for cli in w:
+        try:
+            ret = cli.send(writers[cli])
+        except (SSL.WantReadError,
+                SSL.WantWriteError,
+                SSL.WantX509LookupError):
+            pass
+        except SSL.ZeroReturnError:
+            dropClient(cli)
+        except SSL.Error as errors:
+            dropClient(cli, errors)
+        else:
+            writers[cli] = writers[cli][ret:]
+            if writers[cli] == '':
+                del writers[cli]
+
+for cli in clients.keys():
+    cli.close()
+server.close()
diff --git a/examples/sni/README b/examples/sni/README
new file mode 100644
index 0000000..4c74eb5
--- /dev/null
+++ b/examples/sni/README
@@ -0,0 +1,19 @@
+This directory contains client and server examples for the "Server Name
+Indication" (SNI) feature.
+
+Run server.py with no arguments.  It will accept one client connection and
+then exit.  It has two certificates it can use, one for "example.invalid"
+and another for "another.invalid".  If a client indicates one of these names
+to it, it will use the corresponding certificate for that connection (if a
+client doesn't indicate a name or indicates another name, it won't try to
+use any certificate).
+
+Run client.py with one argument, the server name to indicate.  For example:
+
+  $ python client.py example.invalid
+  Connecting... connected ('127.0.0.1', 8443)
+  Server subject is <X509Name object '/OU=Security/O=pyOpenSSL/CN=example.invalid/ST=New York/C=US/emailAddress=invalid@example.invalid/L=New York'>
+  $
+
+Depending on what hostname is supplied, the server will select a different
+certificate to use and the client output will be different.
diff --git a/examples/sni/another.invalid.crt b/examples/sni/another.invalid.crt
new file mode 100644
index 0000000..995e14c
--- /dev/null
+++ b/examples/sni/another.invalid.crt
@@ -0,0 +1,17 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/examples/sni/another.invalid.key b/examples/sni/another.invalid.key
new file mode 100644
index 0000000..8d955f6
--- /dev/null
+++ b/examples/sni/another.invalid.key
@@ -0,0 +1,15 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
diff --git a/examples/sni/client.py b/examples/sni/client.py
new file mode 100644
index 0000000..428525b
--- /dev/null
+++ b/examples/sni/client.py
@@ -0,0 +1,36 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+from sys import argv, stdout
+from socket import socket
+
+from OpenSSL.SSL import TLSv1_METHOD, Context, Connection
+
+
+def main():
+    """
+    Connect to an SNI-enabled server and request a specific hostname, specified
+    by argv[1], of it.
+    """
+    if len(argv) < 2:
+        print 'Usage: %s <hostname>' % (argv[0],)
+        return 1
+
+    client = socket()
+
+    print 'Connecting...',
+    stdout.flush()
+    client.connect(('127.0.0.1', 8443))
+    print 'connected', client.getpeername()
+
+    client_ssl = Connection(Context(TLSv1_METHOD), client)
+    client_ssl.set_connect_state()
+    client_ssl.set_tlsext_host_name(argv[1])
+    client_ssl.do_handshake()
+    print 'Server subject is', client_ssl.get_peer_certificate().get_subject()
+    client_ssl.close()
+
+
+if __name__ == '__main__':
+    import client
+    raise SystemExit(client.main())
diff --git a/examples/sni/example.invalid.crt b/examples/sni/example.invalid.crt
new file mode 100644
index 0000000..b0cabac
--- /dev/null
+++ b/examples/sni/example.invalid.crt
@@ -0,0 +1,17 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/examples/sni/example.invalid.key b/examples/sni/example.invalid.key
new file mode 100644
index 0000000..192e346
--- /dev/null
+++ b/examples/sni/example.invalid.key
@@ -0,0 +1,15 @@
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
diff --git a/examples/sni/server.py b/examples/sni/server.py
new file mode 100644
index 0000000..e0c159a
--- /dev/null
+++ b/examples/sni/server.py
@@ -0,0 +1,65 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+from sys import stdout
+from socket import SOL_SOCKET, SO_REUSEADDR, socket
+
+from OpenSSL.crypto import FILETYPE_PEM, load_privatekey, load_certificate
+from OpenSSL.SSL import TLSv1_METHOD, Context, Connection
+
+
+def load(domain):
+    crt = open(domain + ".crt")
+    key = open(domain + ".key")
+    result = (
+        load_privatekey(FILETYPE_PEM, key.read()),
+        load_certificate(FILETYPE_PEM, crt.read()))
+    crt.close()
+    key.close()
+    return result
+
+
+def main():
+    """
+    Run an SNI-enabled server which selects between a few certificates in a
+    C{dict} based on the handshake request it receives from a client.
+    """
+    port = socket()
+    port.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
+    port.bind(('', 8443))
+    port.listen(3)
+
+    print 'Accepting...',
+    stdout.flush()
+    server, addr = port.accept()
+    print 'accepted', addr
+
+    server_context = Context(TLSv1_METHOD)
+    server_context.set_tlsext_servername_callback(pick_certificate)
+
+    server_ssl = Connection(server_context, server)
+    server_ssl.set_accept_state()
+    server_ssl.do_handshake()
+    server.close()
+
+
+certificates = {
+    "example.invalid": load("example.invalid"),
+    "another.invalid": load("another.invalid"),
+}
+
+
+def pick_certificate(connection):
+    try:
+        key, cert = certificates[connection.get_servername()]
+    except KeyError:
+        pass
+    else:
+        new_context = Context(TLSv1_METHOD)
+        new_context.use_privatekey(key)
+        new_context.use_certificate(cert)
+        connection.set_context(new_context)
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())
diff --git a/leakcheck/context-info-callback.py b/leakcheck/context-info-callback.py
new file mode 100644
index 0000000..6a3925c
--- /dev/null
+++ b/leakcheck/context-info-callback.py
@@ -0,0 +1,97 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+#
+# Stress tester for thread-related bugs in global_info_callback in
+# src/ssl/context.c.  In 0.7 and earlier, this will somewhat reliably
+# segfault or abort after a few dozen to a few thousand iterations on an SMP
+# machine (generally not on a UP machine) due to uses of Python/C API
+# without holding the GIL.
+
+from itertools import count
+from threading import Thread
+from socket import socket
+
+from OpenSSL.SSL import Context, TLSv1_METHOD, Connection, WantReadError
+from OpenSSL.crypto import FILETYPE_PEM, load_certificate, load_privatekey
+
+cleartextPrivateKeyPEM = (
+    "-----BEGIN RSA PRIVATE KEY-----\n"
+    "MIICXAIBAAKBgQDaemNe1syksAbFFpF3aoOrZ18vB/IQNZrAjFqXPv9iieJm7+Tc\n"
+    "g+lA/v0qmoEKrpT2xfwxXmvZwBNM4ZhyRC3DPIFEyJV7/3IA1p5iuMY/GJI1VIgn\n"
+    "aikQCnrsyxtaRpsMBeZRniaVzcUJ+XnEdFGEjlo+k0xlwfVclDEMwgpXAQIDAQAB\n"
+    "AoGBALi0a7pMQqqgnriVAdpBVJveQtxSDVWi2/gZMKVZfzNheuSnv4amhtaKPKJ+\n"
+    "CMZtHkcazsE2IFvxRN/kgato9H3gJqq8nq2CkdpdLNVKBoxiCtkLfutdY4SQLtoY\n"
+    "USN7exk131pchsAJXYlR6mCW+ZP+E523cNwpPgsyKxVbmXSBAkEA9470fy2W0jFM\n"
+    "taZFslpntKSzbvn6JmdtjtvWrM1bBaeeqFiGBuQFYg46VaCUaeRWYw02jmYAsDYh\n"
+    "ZQavmXThaQJBAOHtlAQ0IJJEiMZr6vtVPH32fmbthSv1AUSYPzKqdlQrUnOXPQXu\n"
+    "z70cFoLG1TvPF5rBxbOkbQ/s8/ka5ZjPfdkCQCeC7YsO36+UpsWnUCBzRXITh4AC\n"
+    "7eYLQ/U1KUJTVF/GrQ/5cQrQgftwgecAxi9Qfmk4xqhbp2h4e0QAmS5I9WECQH02\n"
+    "0QwrX8nxFeTytr8pFGezj4a4KVCdb2B3CL+p3f70K7RIo9d/7b6frJI6ZL/LHQf2\n"
+    "UP4pKRDkgKsVDx7MELECQGm072/Z7vmb03h/uE95IYJOgY4nfmYs0QKA9Is18wUz\n"
+    "DpjfE33p0Ha6GO1VZRIQoqE24F8o5oimy3BEjryFuw4=\n"
+    "-----END RSA PRIVATE KEY-----\n")
+
+
+cleartextCertificatePEM = (
+    "-----BEGIN CERTIFICATE-----\n"
+    "MIICfTCCAeYCAQEwDQYJKoZIhvcNAQEEBQAwgYYxCzAJBgNVBAYTAlVTMRkwFwYD\n"
+    "VQQDExBweW9wZW5zc2wuc2YubmV0MREwDwYDVQQHEwhOZXcgWW9yazESMBAGA1UE\n"
+    "ChMJUHlPcGVuU1NMMREwDwYDVQQIEwhOZXcgWW9yazEQMA4GCSqGSIb3DQEJARYB\n"
+    "IDEQMA4GA1UECxMHVGVzdGluZzAeFw0wODAzMjUxOTA0MTNaFw0wOTAzMjUxOTA0\n"
+    "MTNaMIGGMQswCQYDVQQGEwJVUzEZMBcGA1UEAxMQcHlvcGVuc3NsLnNmLm5ldDER\n"
+    "MA8GA1UEBxMITmV3IFlvcmsxEjAQBgNVBAoTCVB5T3BlblNTTDERMA8GA1UECBMI\n"
+    "TmV3IFlvcmsxEDAOBgkqhkiG9w0BCQEWASAxEDAOBgNVBAsTB1Rlc3RpbmcwgZ8w\n"
+    "DQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBANp6Y17WzKSwBsUWkXdqg6tnXy8H8hA1\n"
+    "msCMWpc+/2KJ4mbv5NyD6UD+/SqagQqulPbF/DFea9nAE0zhmHJELcM8gUTIlXv/\n"
+    "cgDWnmK4xj8YkjVUiCdqKRAKeuzLG1pGmwwF5lGeJpXNxQn5ecR0UYSOWj6TTGXB\n"
+    "9VyUMQzCClcBAgMBAAEwDQYJKoZIhvcNAQEEBQADgYEAmm0Vzvv1O91WLl2LnF2P\n"
+    "q55LJdOnJbCCXIgxLdoVmvYAz1ZJq1eGKgKWI5QLgxiSzJLEU7KK//aVfiZzoCd5\n"
+    "RipBiEEMEV4eAY317bHPwPP+4Bj9t0l8AsDLseC5vLRHgxrLEu3bn08DYx6imB5Q\n"
+    "UBj849/xpszEM7BhwKE0GiQ=\n"
+    "-----END CERTIFICATE-----\n")
+
+count = count()
+def go():
+    port = socket()
+    port.bind(('', 0))
+    port.listen(1)
+
+    called = []
+    def info(conn, where, ret):
+        print count.next()
+        called.append(None)
+    context = Context(TLSv1_METHOD)
+    context.set_info_callback(info)
+    context.use_certificate(
+        load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+    context.use_privatekey(
+        load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+
+    while 1:
+        client = socket()
+        client.setblocking(False)
+        client.connect_ex(port.getsockname())
+
+        clientSSL = Connection(Context(TLSv1_METHOD), client)
+        clientSSL.set_connect_state()
+
+        server, ignored = port.accept()
+        server.setblocking(False)
+
+        serverSSL = Connection(context, server)
+        serverSSL.set_accept_state()
+
+        del called[:]
+        while not called:
+            for ssl in clientSSL, serverSSL:
+                try:
+                    ssl.do_handshake()
+                except WantReadError:
+                    pass
+
+
+threads = [Thread(target=go, args=()) for i in xrange(2)]
+for th in threads:
+    th.start()
+for th in threads:
+    th.join()
diff --git a/leakcheck/context-passphrase-callback.py b/leakcheck/context-passphrase-callback.py
new file mode 100644
index 0000000..ba71655
--- /dev/null
+++ b/leakcheck/context-passphrase-callback.py
@@ -0,0 +1,34 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+#
+# Stress tester for thread-related bugs in global_passphrase_callback in
+# src/ssl/context.c.  In 0.7 and earlier, this will somewhat reliably
+# segfault or abort after a few dozen to a few thousand iterations on an SMP
+# machine (generally not on a UP machine) due to uses of Python/C API
+# without holding the GIL.
+
+from itertools import count
+from threading import Thread
+
+from OpenSSL.SSL import Context, TLSv1_METHOD
+from OpenSSL.crypto import TYPE_RSA, FILETYPE_PEM, PKey, dump_privatekey
+
+k = PKey()
+k.generate_key(TYPE_RSA, 128)
+file('pkey.pem', 'w').write(dump_privatekey(FILETYPE_PEM, k, "blowfish", "foobar"))
+
+count = count()
+def go():
+    def cb(a, b, c):
+        print count.next()
+        return "foobar"
+    c = Context(TLSv1_METHOD)
+    c.set_passwd_cb(cb)
+    while 1:
+        c.use_privatekey_file('pkey.pem')
+
+threads = [Thread(target=go, args=()) for i in xrange(2)]
+for th in threads:
+    th.start()
+for th in threads:
+    th.join()
diff --git a/leakcheck/context-verify-callback.py b/leakcheck/context-verify-callback.py
new file mode 100644
index 0000000..0ae586b
--- /dev/null
+++ b/leakcheck/context-verify-callback.py
@@ -0,0 +1,99 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+#
+# Stress tester for thread-related bugs in global_verify_callback in
+# src/ssl/context.c.  This will reliably segfault if context.c isn't a
+# PyThreadState management technique which is compatible with the approach used
+# by ssl.c.
+
+
+from itertools import count
+from threading import Thread
+from socket import socket
+
+from OpenSSL.SSL import Context, TLSv1_METHOD, VERIFY_PEER, Connection, WantReadError
+from OpenSSL.crypto import FILETYPE_PEM, load_certificate, load_privatekey
+
+cleartextPrivateKeyPEM = (
+    "-----BEGIN RSA PRIVATE KEY-----\n"
+    "MIICXAIBAAKBgQDaemNe1syksAbFFpF3aoOrZ18vB/IQNZrAjFqXPv9iieJm7+Tc\n"
+    "g+lA/v0qmoEKrpT2xfwxXmvZwBNM4ZhyRC3DPIFEyJV7/3IA1p5iuMY/GJI1VIgn\n"
+    "aikQCnrsyxtaRpsMBeZRniaVzcUJ+XnEdFGEjlo+k0xlwfVclDEMwgpXAQIDAQAB\n"
+    "AoGBALi0a7pMQqqgnriVAdpBVJveQtxSDVWi2/gZMKVZfzNheuSnv4amhtaKPKJ+\n"
+    "CMZtHkcazsE2IFvxRN/kgato9H3gJqq8nq2CkdpdLNVKBoxiCtkLfutdY4SQLtoY\n"
+    "USN7exk131pchsAJXYlR6mCW+ZP+E523cNwpPgsyKxVbmXSBAkEA9470fy2W0jFM\n"
+    "taZFslpntKSzbvn6JmdtjtvWrM1bBaeeqFiGBuQFYg46VaCUaeRWYw02jmYAsDYh\n"
+    "ZQavmXThaQJBAOHtlAQ0IJJEiMZr6vtVPH32fmbthSv1AUSYPzKqdlQrUnOXPQXu\n"
+    "z70cFoLG1TvPF5rBxbOkbQ/s8/ka5ZjPfdkCQCeC7YsO36+UpsWnUCBzRXITh4AC\n"
+    "7eYLQ/U1KUJTVF/GrQ/5cQrQgftwgecAxi9Qfmk4xqhbp2h4e0QAmS5I9WECQH02\n"
+    "0QwrX8nxFeTytr8pFGezj4a4KVCdb2B3CL+p3f70K7RIo9d/7b6frJI6ZL/LHQf2\n"
+    "UP4pKRDkgKsVDx7MELECQGm072/Z7vmb03h/uE95IYJOgY4nfmYs0QKA9Is18wUz\n"
+    "DpjfE33p0Ha6GO1VZRIQoqE24F8o5oimy3BEjryFuw4=\n"
+    "-----END RSA PRIVATE KEY-----\n")
+
+
+cleartextCertificatePEM = (
+    "-----BEGIN CERTIFICATE-----\n"
+    "MIICfTCCAeYCAQEwDQYJKoZIhvcNAQEEBQAwgYYxCzAJBgNVBAYTAlVTMRkwFwYD\n"
+    "VQQDExBweW9wZW5zc2wuc2YubmV0MREwDwYDVQQHEwhOZXcgWW9yazESMBAGA1UE\n"
+    "ChMJUHlPcGVuU1NMMREwDwYDVQQIEwhOZXcgWW9yazEQMA4GCSqGSIb3DQEJARYB\n"
+    "IDEQMA4GA1UECxMHVGVzdGluZzAeFw0wODAzMjUxOTA0MTNaFw0wOTAzMjUxOTA0\n"
+    "MTNaMIGGMQswCQYDVQQGEwJVUzEZMBcGA1UEAxMQcHlvcGVuc3NsLnNmLm5ldDER\n"
+    "MA8GA1UEBxMITmV3IFlvcmsxEjAQBgNVBAoTCVB5T3BlblNTTDERMA8GA1UECBMI\n"
+    "TmV3IFlvcmsxEDAOBgkqhkiG9w0BCQEWASAxEDAOBgNVBAsTB1Rlc3RpbmcwgZ8w\n"
+    "DQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBANp6Y17WzKSwBsUWkXdqg6tnXy8H8hA1\n"
+    "msCMWpc+/2KJ4mbv5NyD6UD+/SqagQqulPbF/DFea9nAE0zhmHJELcM8gUTIlXv/\n"
+    "cgDWnmK4xj8YkjVUiCdqKRAKeuzLG1pGmwwF5lGeJpXNxQn5ecR0UYSOWj6TTGXB\n"
+    "9VyUMQzCClcBAgMBAAEwDQYJKoZIhvcNAQEEBQADgYEAmm0Vzvv1O91WLl2LnF2P\n"
+    "q55LJdOnJbCCXIgxLdoVmvYAz1ZJq1eGKgKWI5QLgxiSzJLEU7KK//aVfiZzoCd5\n"
+    "RipBiEEMEV4eAY317bHPwPP+4Bj9t0l8AsDLseC5vLRHgxrLEu3bn08DYx6imB5Q\n"
+    "UBj849/xpszEM7BhwKE0GiQ=\n"
+    "-----END CERTIFICATE-----\n")
+
+count = count()
+def go():
+    port = socket()
+    port.bind(('', 0))
+    port.listen(1)
+
+    called = []
+    def info(*args):
+        print count.next()
+        called.append(None)
+        return 1
+    context = Context(TLSv1_METHOD)
+    context.set_verify(VERIFY_PEER, info)
+    context.use_certificate(
+        load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+    context.use_privatekey(
+        load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+
+    while 1:
+        client = socket()
+        client.setblocking(False)
+        client.connect_ex(port.getsockname())
+
+        clientSSL = Connection(context, client)
+        clientSSL.set_connect_state()
+
+        server, ignored = port.accept()
+        server.setblocking(False)
+
+        serverSSL = Connection(context, server)
+        serverSSL.set_accept_state()
+
+        del called[:]
+        while not called:
+            for ssl in clientSSL, serverSSL:
+                try:
+                    ssl.send('foo')
+                except WantReadError, e:
+                    pass
+
+
+threads = [Thread(target=go, args=()) for i in xrange(2)]
+for th in threads:
+    th.start()
+for th in threads:
+    th.join()
+
diff --git a/leakcheck/crypto.py b/leakcheck/crypto.py
new file mode 100644
index 0000000..ca79b7c
--- /dev/null
+++ b/leakcheck/crypto.py
@@ -0,0 +1,183 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+import sys
+
+from OpenSSL.crypto import (
+    FILETYPE_PEM, TYPE_DSA, Error, PKey, X509, load_privatekey, CRL, Revoked,
+    get_elliptic_curves, _X509_REVOKED_dup)
+
+from OpenSSL._util import lib as _lib
+
+
+
+class BaseChecker(object):
+    def __init__(self, iterations):
+        self.iterations = iterations
+
+
+
+class Checker_X509_get_pubkey(BaseChecker):
+    """
+    Leak checks for L{X509.get_pubkey}.
+    """
+    def check_exception(self):
+        """
+        Call the method repeatedly such that it will raise an exception.
+        """
+        for i in xrange(self.iterations):
+            cert = X509()
+            try:
+                cert.get_pubkey()
+            except Error:
+                pass
+
+
+    def check_success(self):
+        """
+        Call the method repeatedly such that it will return a PKey object.
+        """
+        small = xrange(3)
+        for i in xrange(self.iterations):
+            key = PKey()
+            key.generate_key(TYPE_DSA, 256)
+            for i in small:
+                cert = X509()
+                cert.set_pubkey(key)
+                for i in small:
+                    cert.get_pubkey()
+
+
+
+class Checker_load_privatekey(BaseChecker):
+    """
+    Leak checks for :py:obj:`load_privatekey`.
+    """
+    ENCRYPTED_PEM = """\
+-----BEGIN RSA PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: BF-CBC,3763C340F9B5A1D0
+
+a/DO10mLjHLCAOG8/Hc5Lbuh3pfjvcTZiCexShP+tupkp0VxW2YbZjML8uoXrpA6
+fSPUo7cEC+r96GjV03ZIVhjmsxxesdWMpfkzXRpG8rUbWEW2KcCJWdSX8bEkuNW3
+uvAXdXZwiOrm56ANDo/48gj27GcLwnlA8ld39+ylAzkUJ1tcMVzzTjfcyd6BMFpR
+Yjg23ikseug6iWEsZQormdl0ITdYzmFpM+YYsG7kmmmi4UjCEYfb9zFaqJn+WZT2
+qXxmo2ZPFzmEVkuB46mf5GCqMwLRN2QTbIZX2+Dljj1Hfo5erf5jROewE/yzcTwO
+FCB5K3c2kkTv2KjcCAimjxkE+SBKfHg35W0wB0AWkXpVFO5W/TbHg4tqtkpt/KMn
+/MPnSxvYr/vEqYMfW4Y83c45iqK0Cyr2pwY60lcn8Kk=
+-----END RSA PRIVATE KEY-----
+"""
+    def check_load_privatekey_callback(self):
+        """
+        Call the function with an encrypted PEM and a passphrase callback.
+        """
+        for i in xrange(self.iterations * 10):
+            load_privatekey(
+                FILETYPE_PEM, self.ENCRYPTED_PEM, lambda *args: "hello, secret")
+
+
+    def check_load_privatekey_callback_incorrect(self):
+        """
+        Call the function with an encrypted PEM and a passphrase callback which
+        returns the wrong passphrase.
+        """
+        for i in xrange(self.iterations * 10):
+            try:
+                load_privatekey(
+                    FILETYPE_PEM, self.ENCRYPTED_PEM,
+                    lambda *args: "hello, public")
+            except Error:
+                pass
+
+
+    def check_load_privatekey_callback_wrong_type(self):
+        """
+        Call the function with an encrypted PEM and a passphrase callback which
+        returns a non-string.
+        """
+        for i in xrange(self.iterations * 10):
+            try:
+                load_privatekey(
+                    FILETYPE_PEM, self.ENCRYPTED_PEM,
+                    lambda *args: {})
+            except ValueError:
+                pass
+
+
+
+class Checker_CRL(BaseChecker):
+    """
+    Leak checks for L{CRL.add_revoked} and L{CRL.get_revoked}.
+    """
+    def check_add_revoked(self):
+        """
+        Call the add_revoked method repeatedly on an empty CRL.
+        """
+        for i in xrange(self.iterations * 200):
+            CRL().add_revoked(Revoked())
+
+
+    def check_get_revoked(self):
+        """
+        Create a CRL object with 100 Revoked objects, then call the
+        get_revoked method repeatedly.
+        """
+        crl = CRL()
+        for i in xrange(100):
+            crl.add_revoked(Revoked())
+        for i in xrange(self.iterations):
+            crl.get_revoked()
+
+
+
+class Checker_X509_REVOKED_dup(BaseChecker):
+    """
+    Leak checks for :py:obj:`_X509_REVOKED_dup`.
+    """
+    def check_X509_REVOKED_dup(self):
+        """
+        Copy an empty Revoked object repeatedly. The copy is not garbage
+        collected, therefore it needs to be manually freed.
+        """
+        for i in xrange(self.iterations * 100):
+            revoked_copy = _X509_REVOKED_dup(Revoked()._revoked)
+            _lib.X509_REVOKED_free(revoked_copy)
+
+
+
+class Checker_EllipticCurve(BaseChecker):
+    """
+    Leak checks for :py:obj:`_EllipticCurve`.
+    """
+    def check_to_EC_KEY(self):
+        """
+        Repeatedly create an EC_KEY* from an :py:obj:`_EllipticCurve`.  The
+        structure should be automatically garbage collected.
+        """
+        curves = get_elliptic_curves()
+        if curves:
+            curve = next(iter(curves))
+            for i in xrange(self.iterations * 1000):
+                curve._to_EC_KEY()
+
+
+def vmsize():
+    return [x for x in file('/proc/self/status').readlines() if 'VmSize' in x]
+
+
+def main(iterations='1000'):
+    iterations = int(iterations)
+    for klass in globals():
+        if klass.startswith('Checker_'):
+            klass = globals()[klass]
+            print klass
+            checker = klass(iterations)
+            for meth in dir(checker):
+                if meth.startswith('check_'):
+                    print '\t', meth, vmsize(), '...',
+                    getattr(checker, meth)()
+                    print vmsize()
+
+
+if __name__ == '__main__':
+    main(*sys.argv[1:])
diff --git a/leakcheck/dhparam.pem b/leakcheck/dhparam.pem
new file mode 100644
index 0000000..9d33a4a
--- /dev/null
+++ b/leakcheck/dhparam.pem
@@ -0,0 +1,4 @@
+-----BEGIN DH PARAMETERS-----
+MEYCQQDM2LbvAjF5ahXHOUdDR09Vw/7kxjF/euWhNKBqUQQYT7FDSAMCCMq+Jhno
+BKxWEDhlxR1Q1VZ4H/NVTAGtWai7AgEC
+-----END DH PARAMETERS-----
diff --git a/leakcheck/thread-crash.py b/leakcheck/thread-crash.py
new file mode 100644
index 0000000..a1ebbdd
--- /dev/null
+++ b/leakcheck/thread-crash.py
@@ -0,0 +1,71 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+#
+# Stress tester for thread-related bugs in ssl_Connection_send and
+# ssl_Connection_recv in src/ssl/connection.c for usage of a single
+# Connection object simultaneously in multiple threads.  In 0.7 and earlier,
+# this will somewhat reliably cause Python to abort with a "tstate mix-up"
+# almost immediately, due to the incorrect sharing between threads of the
+# `tstate` field of the connection object.
+
+
+from socket import socket
+from threading import Thread
+
+from OpenSSL.SSL import Connection, Context, TLSv1_METHOD
+
+def send(conn):
+    while 1:
+        for i in xrange(1024 * 32):
+            conn.send('x')
+        print 'Sent 32KB on', hex(id(conn))
+
+
+def recv(conn):
+    while 1:
+        for i in xrange(1024 * 64):
+            conn.recv(1)
+        print 'Received 64KB on', hex(id(conn))
+
+
+def main():
+    port = socket()
+    port.bind(('', 0))
+    port.listen(5)
+
+    client = socket()
+    client.setblocking(False)
+    client.connect_ex(port.getsockname())
+    client.setblocking(True)
+
+    server = port.accept()[0]
+
+    clientCtx = Context(TLSv1_METHOD)
+    clientCtx.set_cipher_list('ALL:ADH')
+    clientCtx.load_tmp_dh('dhparam.pem')
+
+    sslClient = Connection(clientCtx, client)
+    sslClient.set_connect_state()
+
+    serverCtx = Context(TLSv1_METHOD)
+    serverCtx.set_cipher_list('ALL:ADH')
+    serverCtx.load_tmp_dh('dhparam.pem')
+
+    sslServer = Connection(serverCtx, server)
+    sslServer.set_accept_state()
+
+    t1 = Thread(target=send, args=(sslClient,))
+    t2 = Thread(target=send, args=(sslServer,))
+    t3 = Thread(target=recv, args=(sslClient,))
+    t4 = Thread(target=recv, args=(sslServer,))
+
+    t1.start()
+    t2.start()
+    t3.start()
+    t4.start()
+    t1.join()
+    t2.join()
+    t3.join()
+    t4.join()
+
+main()
diff --git a/leakcheck/thread-key-gen.py b/leakcheck/thread-key-gen.py
new file mode 100644
index 0000000..62e1a58
--- /dev/null
+++ b/leakcheck/thread-key-gen.py
@@ -0,0 +1,38 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+#
+# Stress tester for thread-related bugs in RSA and DSA key generation.  0.12 and
+# older held the GIL during these operations.  Subsequent versions release it
+# during them.
+
+from threading import Thread
+
+from OpenSSL.crypto import TYPE_RSA, TYPE_DSA, PKey
+
+def generate_rsa():
+    keys = []
+    for i in range(100):
+        key = PKey()
+        key.generate_key(TYPE_RSA, 1024)
+        keys.append(key)
+
+def generate_dsa():
+    keys = []
+    for i in range(100):
+        key = PKey()
+        key.generate_key(TYPE_DSA, 512)
+        keys.append(key)
+
+
+def main():
+    threads = []
+    for i in range(3):
+        t = Thread(target=generate_rsa, args=())
+        threads.append(t)
+        t = Thread(target=generate_dsa, args=())
+        threads.append(t)
+
+    for t in threads:
+        t.start()
+
+main()
diff --git a/rpm/build_script b/rpm/build_script
new file mode 100644
index 0000000..1b0276b
--- /dev/null
+++ b/rpm/build_script
@@ -0,0 +1 @@
+make -C doc text html
diff --git a/setup.cfg b/setup.cfg
new file mode 100644
index 0000000..138d91c
--- /dev/null
+++ b/setup.cfg
@@ -0,0 +1,21 @@
+[tool:pytest]
+minversion = 3.0.1
+strict = true
+testpaths = tests
+
+[bdist_wheel]
+# We are a pure-Python project so a single wheel is enough.
+universal = 1
+
+[metadata]
+# Ensure LICENSE is included in wheels.
+license_file = LICENSE
+
+# bdist_rpm settings contributed by Mihai Ibanescu <misa@redhat.com>
+# This is currently *not* actively tested.
+[bdist_rpm]
+release = 1
+build-requires = openssl-devel python-devel python-sphinx
+group = Development/Libraries
+build_script = rpm/build_script
+doc-files = doc/_build/html
diff --git a/setup.py b/setup.py
new file mode 100755
index 0000000..5387d2a
--- /dev/null
+++ b/setup.py
@@ -0,0 +1,112 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) Jean-Paul Calderone 2008-2015, All rights reserved
+#
+
+"""
+Installation script for the OpenSSL package.
+"""
+
+import codecs
+import os
+import re
+
+from setuptools import setup, find_packages
+
+
+HERE = os.path.abspath(os.path.dirname(__file__))
+META_PATH = os.path.join("src", "OpenSSL", "version.py")
+
+
+def read_file(*parts):
+    """
+    Build an absolute path from *parts* and and return the contents of the
+    resulting file.  Assume UTF-8 encoding.
+    """
+    with codecs.open(os.path.join(HERE, *parts), "rb", "ascii") as f:
+        return f.read()
+
+
+META_FILE = read_file(META_PATH)
+
+
+def find_meta(meta):
+    """
+    Extract __*meta*__ from META_FILE.
+    """
+    meta_match = re.search(
+        r"^__{meta}__ = ['\"]([^'\"]*)['\"]".format(meta=meta),
+        META_FILE, re.M
+    )
+    if meta_match:
+        return meta_match.group(1)
+    raise RuntimeError("Unable to find __{meta}__ string.".format(meta=meta))
+
+
+URI = find_meta("uri")
+LONG = (
+    read_file("README.rst") + "\n\n" +
+    "Release Information\n" +
+    "===================\n\n" +
+    re.search(r"(\d{2}.\d.\d \(.*?\)\n.*?)\n\n\n----\n",
+              read_file("CHANGELOG.rst"), re.S).group(1) +
+    "\n\n`Full changelog " +
+    "<{uri}en/stable/changelog.html>`_.\n\n"
+).format(uri=URI)
+
+
+if __name__ == "__main__":
+    setup(
+        name=find_meta("title"),
+        version=find_meta("version"),
+        description=find_meta("summary"),
+        long_description=LONG,
+        author=find_meta("author"),
+        author_email=find_meta("email"),
+        maintainer="Hynek Schlawack",
+        maintainer_email="hs@ox.cx",
+        url=URI,
+        license=find_meta("license"),
+        classifiers=[
+            'Development Status :: 6 - Mature',
+            'Intended Audience :: Developers',
+            'License :: OSI Approved :: Apache Software License',
+            'Operating System :: MacOS :: MacOS X',
+            'Operating System :: Microsoft :: Windows',
+            'Operating System :: POSIX',
+
+            'Programming Language :: Python :: 2',
+            'Programming Language :: Python :: 2.7',
+            'Programming Language :: Python :: 3',
+            'Programming Language :: Python :: 3.4',
+            'Programming Language :: Python :: 3.5',
+            'Programming Language :: Python :: 3.6',
+            'Programming Language :: Python :: 3.7',
+
+            'Programming Language :: Python :: Implementation :: CPython',
+            'Programming Language :: Python :: Implementation :: PyPy',
+            'Topic :: Security :: Cryptography',
+            'Topic :: Software Development :: Libraries :: Python Modules',
+            'Topic :: System :: Networking',
+        ],
+
+        packages=find_packages(where="src"),
+        package_dir={"": "src"},
+        install_requires=[
+            # Fix cryptographyMinimum in tox.ini when changing this!
+            "cryptography>=2.3",
+            "six>=1.5.2"
+        ],
+        extras_require={
+            "test": [
+                "flaky",
+                "pretend",
+                "pytest>=3.0.1",
+            ],
+            "docs": [
+                "sphinx",
+                "sphinx_rtd_theme",
+            ]
+        },
+    )
diff --git a/src/OpenSSL/Android.bp b/src/OpenSSL/Android.bp
new file mode 100644
index 0000000..75c431e
--- /dev/null
+++ b/src/OpenSSL/Android.bp
@@ -0,0 +1,33 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+python_library {
+    name: "py-pyopenssl",
+    host_supported: true,
+    srcs: [
+        "*.py",
+    ],
+    version: {
+        py2: {
+            enabled: true,
+        },
+        py3: {
+            enabled: true,
+        },
+    },
+    libs: [
+        "py-cryptography",
+	"py-six",
+    ],
+    pkg_path: "OpenSSL",
+}
diff --git a/src/OpenSSL/SSL.py b/src/OpenSSL/SSL.py
new file mode 100644
index 0000000..0687fc3
--- /dev/null
+++ b/src/OpenSSL/SSL.py
@@ -0,0 +1,2507 @@
+import os
+import socket
+from sys import platform
+from functools import wraps, partial
+from itertools import count, chain
+from weakref import WeakValueDictionary
+from errno import errorcode
+
+from cryptography.utils import deprecated
+
+from six import (
+    binary_type as _binary_type, integer_types as integer_types, int2byte,
+    indexbytes)
+
+from OpenSSL._util import (
+    UNSPECIFIED as _UNSPECIFIED,
+    exception_from_error_queue as _exception_from_error_queue,
+    ffi as _ffi,
+    lib as _lib,
+    make_assert as _make_assert,
+    native as _native,
+    path_string as _path_string,
+    text_to_bytes_and_warn as _text_to_bytes_and_warn,
+    no_zero_allocator as _no_zero_allocator,
+)
+
+from OpenSSL.crypto import (
+    FILETYPE_PEM, _PassphraseHelper, PKey, X509Name, X509, X509Store)
+
+__all__ = [
+    'OPENSSL_VERSION_NUMBER',
+    'SSLEAY_VERSION',
+    'SSLEAY_CFLAGS',
+    'SSLEAY_PLATFORM',
+    'SSLEAY_DIR',
+    'SSLEAY_BUILT_ON',
+    'SENT_SHUTDOWN',
+    'RECEIVED_SHUTDOWN',
+    'SSLv2_METHOD',
+    'SSLv3_METHOD',
+    'SSLv23_METHOD',
+    'TLSv1_METHOD',
+    'TLSv1_1_METHOD',
+    'TLSv1_2_METHOD',
+    'OP_NO_SSLv2',
+    'OP_NO_SSLv3',
+    'OP_NO_TLSv1',
+    'OP_NO_TLSv1_1',
+    'OP_NO_TLSv1_2',
+    'MODE_RELEASE_BUFFERS',
+    'OP_SINGLE_DH_USE',
+    'OP_SINGLE_ECDH_USE',
+    'OP_EPHEMERAL_RSA',
+    'OP_MICROSOFT_SESS_ID_BUG',
+    'OP_NETSCAPE_CHALLENGE_BUG',
+    'OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG',
+    'OP_SSLREF2_REUSE_CERT_TYPE_BUG',
+    'OP_MICROSOFT_BIG_SSLV3_BUFFER',
+    'OP_MSIE_SSLV2_RSA_PADDING',
+    'OP_SSLEAY_080_CLIENT_DH_BUG',
+    'OP_TLS_D5_BUG',
+    'OP_TLS_BLOCK_PADDING_BUG',
+    'OP_DONT_INSERT_EMPTY_FRAGMENTS',
+    'OP_CIPHER_SERVER_PREFERENCE',
+    'OP_TLS_ROLLBACK_BUG',
+    'OP_PKCS1_CHECK_1',
+    'OP_PKCS1_CHECK_2',
+    'OP_NETSCAPE_CA_DN_BUG',
+    'OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG',
+    'OP_NO_COMPRESSION',
+    'OP_NO_QUERY_MTU',
+    'OP_COOKIE_EXCHANGE',
+    'OP_NO_TICKET',
+    'OP_ALL',
+    'VERIFY_PEER',
+    'VERIFY_FAIL_IF_NO_PEER_CERT',
+    'VERIFY_CLIENT_ONCE',
+    'VERIFY_NONE',
+    'SESS_CACHE_OFF',
+    'SESS_CACHE_CLIENT',
+    'SESS_CACHE_SERVER',
+    'SESS_CACHE_BOTH',
+    'SESS_CACHE_NO_AUTO_CLEAR',
+    'SESS_CACHE_NO_INTERNAL_LOOKUP',
+    'SESS_CACHE_NO_INTERNAL_STORE',
+    'SESS_CACHE_NO_INTERNAL',
+    'SSL_ST_CONNECT',
+    'SSL_ST_ACCEPT',
+    'SSL_ST_MASK',
+    'SSL_CB_LOOP',
+    'SSL_CB_EXIT',
+    'SSL_CB_READ',
+    'SSL_CB_WRITE',
+    'SSL_CB_ALERT',
+    'SSL_CB_READ_ALERT',
+    'SSL_CB_WRITE_ALERT',
+    'SSL_CB_ACCEPT_LOOP',
+    'SSL_CB_ACCEPT_EXIT',
+    'SSL_CB_CONNECT_LOOP',
+    'SSL_CB_CONNECT_EXIT',
+    'SSL_CB_HANDSHAKE_START',
+    'SSL_CB_HANDSHAKE_DONE',
+    'Error',
+    'WantReadError',
+    'WantWriteError',
+    'WantX509LookupError',
+    'ZeroReturnError',
+    'SysCallError',
+    'SSLeay_version',
+    'Session',
+    'Context',
+    'Connection'
+]
+
+try:
+    _buffer = buffer
+except NameError:
+    class _buffer(object):
+        pass
+
+OPENSSL_VERSION_NUMBER = _lib.OPENSSL_VERSION_NUMBER
+SSLEAY_VERSION = _lib.SSLEAY_VERSION
+SSLEAY_CFLAGS = _lib.SSLEAY_CFLAGS
+SSLEAY_PLATFORM = _lib.SSLEAY_PLATFORM
+SSLEAY_DIR = _lib.SSLEAY_DIR
+SSLEAY_BUILT_ON = _lib.SSLEAY_BUILT_ON
+
+SENT_SHUTDOWN = _lib.SSL_SENT_SHUTDOWN
+RECEIVED_SHUTDOWN = _lib.SSL_RECEIVED_SHUTDOWN
+
+SSLv2_METHOD = 1
+SSLv3_METHOD = 2
+SSLv23_METHOD = 3
+TLSv1_METHOD = 4
+TLSv1_1_METHOD = 5
+TLSv1_2_METHOD = 6
+
+OP_NO_SSLv2 = _lib.SSL_OP_NO_SSLv2
+OP_NO_SSLv3 = _lib.SSL_OP_NO_SSLv3
+OP_NO_TLSv1 = _lib.SSL_OP_NO_TLSv1
+OP_NO_TLSv1_1 = _lib.SSL_OP_NO_TLSv1_1
+OP_NO_TLSv1_2 = _lib.SSL_OP_NO_TLSv1_2
+
+MODE_RELEASE_BUFFERS = _lib.SSL_MODE_RELEASE_BUFFERS
+
+OP_SINGLE_DH_USE = _lib.SSL_OP_SINGLE_DH_USE
+OP_SINGLE_ECDH_USE = _lib.SSL_OP_SINGLE_ECDH_USE
+OP_EPHEMERAL_RSA = _lib.SSL_OP_EPHEMERAL_RSA
+OP_MICROSOFT_SESS_ID_BUG = _lib.SSL_OP_MICROSOFT_SESS_ID_BUG
+OP_NETSCAPE_CHALLENGE_BUG = _lib.SSL_OP_NETSCAPE_CHALLENGE_BUG
+OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG = (
+    _lib.SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG
+)
+OP_SSLREF2_REUSE_CERT_TYPE_BUG = _lib.SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG
+OP_MICROSOFT_BIG_SSLV3_BUFFER = _lib.SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER
+OP_MSIE_SSLV2_RSA_PADDING = _lib.SSL_OP_MSIE_SSLV2_RSA_PADDING
+OP_SSLEAY_080_CLIENT_DH_BUG = _lib.SSL_OP_SSLEAY_080_CLIENT_DH_BUG
+OP_TLS_D5_BUG = _lib.SSL_OP_TLS_D5_BUG
+OP_TLS_BLOCK_PADDING_BUG = _lib.SSL_OP_TLS_BLOCK_PADDING_BUG
+OP_DONT_INSERT_EMPTY_FRAGMENTS = _lib.SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS
+OP_CIPHER_SERVER_PREFERENCE = _lib.SSL_OP_CIPHER_SERVER_PREFERENCE
+OP_TLS_ROLLBACK_BUG = _lib.SSL_OP_TLS_ROLLBACK_BUG
+OP_PKCS1_CHECK_1 = _lib.SSL_OP_PKCS1_CHECK_1
+OP_PKCS1_CHECK_2 = _lib.SSL_OP_PKCS1_CHECK_2
+OP_NETSCAPE_CA_DN_BUG = _lib.SSL_OP_NETSCAPE_CA_DN_BUG
+OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG = (
+    _lib.SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG
+)
+OP_NO_COMPRESSION = _lib.SSL_OP_NO_COMPRESSION
+
+OP_NO_QUERY_MTU = _lib.SSL_OP_NO_QUERY_MTU
+OP_COOKIE_EXCHANGE = _lib.SSL_OP_COOKIE_EXCHANGE
+OP_NO_TICKET = _lib.SSL_OP_NO_TICKET
+
+OP_ALL = _lib.SSL_OP_ALL
+
+VERIFY_PEER = _lib.SSL_VERIFY_PEER
+VERIFY_FAIL_IF_NO_PEER_CERT = _lib.SSL_VERIFY_FAIL_IF_NO_PEER_CERT
+VERIFY_CLIENT_ONCE = _lib.SSL_VERIFY_CLIENT_ONCE
+VERIFY_NONE = _lib.SSL_VERIFY_NONE
+
+SESS_CACHE_OFF = _lib.SSL_SESS_CACHE_OFF
+SESS_CACHE_CLIENT = _lib.SSL_SESS_CACHE_CLIENT
+SESS_CACHE_SERVER = _lib.SSL_SESS_CACHE_SERVER
+SESS_CACHE_BOTH = _lib.SSL_SESS_CACHE_BOTH
+SESS_CACHE_NO_AUTO_CLEAR = _lib.SSL_SESS_CACHE_NO_AUTO_CLEAR
+SESS_CACHE_NO_INTERNAL_LOOKUP = _lib.SSL_SESS_CACHE_NO_INTERNAL_LOOKUP
+SESS_CACHE_NO_INTERNAL_STORE = _lib.SSL_SESS_CACHE_NO_INTERNAL_STORE
+SESS_CACHE_NO_INTERNAL = _lib.SSL_SESS_CACHE_NO_INTERNAL
+
+SSL_ST_CONNECT = _lib.SSL_ST_CONNECT
+SSL_ST_ACCEPT = _lib.SSL_ST_ACCEPT
+SSL_ST_MASK = _lib.SSL_ST_MASK
+if _lib.Cryptography_HAS_SSL_ST:
+    SSL_ST_INIT = _lib.SSL_ST_INIT
+    SSL_ST_BEFORE = _lib.SSL_ST_BEFORE
+    SSL_ST_OK = _lib.SSL_ST_OK
+    SSL_ST_RENEGOTIATE = _lib.SSL_ST_RENEGOTIATE
+    __all__.extend([
+        'SSL_ST_INIT',
+        'SSL_ST_BEFORE',
+        'SSL_ST_OK',
+        'SSL_ST_RENEGOTIATE',
+    ])
+
+SSL_CB_LOOP = _lib.SSL_CB_LOOP
+SSL_CB_EXIT = _lib.SSL_CB_EXIT
+SSL_CB_READ = _lib.SSL_CB_READ
+SSL_CB_WRITE = _lib.SSL_CB_WRITE
+SSL_CB_ALERT = _lib.SSL_CB_ALERT
+SSL_CB_READ_ALERT = _lib.SSL_CB_READ_ALERT
+SSL_CB_WRITE_ALERT = _lib.SSL_CB_WRITE_ALERT
+SSL_CB_ACCEPT_LOOP = _lib.SSL_CB_ACCEPT_LOOP
+SSL_CB_ACCEPT_EXIT = _lib.SSL_CB_ACCEPT_EXIT
+SSL_CB_CONNECT_LOOP = _lib.SSL_CB_CONNECT_LOOP
+SSL_CB_CONNECT_EXIT = _lib.SSL_CB_CONNECT_EXIT
+SSL_CB_HANDSHAKE_START = _lib.SSL_CB_HANDSHAKE_START
+SSL_CB_HANDSHAKE_DONE = _lib.SSL_CB_HANDSHAKE_DONE
+
+# Taken from https://golang.org/src/crypto/x509/root_linux.go
+_CERTIFICATE_FILE_LOCATIONS = [
+    "/etc/ssl/certs/ca-certificates.crt",  # Debian/Ubuntu/Gentoo etc.
+    "/etc/pki/tls/certs/ca-bundle.crt",  # Fedora/RHEL 6
+    "/etc/ssl/ca-bundle.pem",  # OpenSUSE
+    "/etc/pki/tls/cacert.pem",  # OpenELEC
+    "/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem",  # CentOS/RHEL 7
+]
+
+_CERTIFICATE_PATH_LOCATIONS = [
+    "/etc/ssl/certs",  # SLES10/SLES11
+]
+
+# These values are compared to output from cffi's ffi.string so they must be
+# byte strings.
+_CRYPTOGRAPHY_MANYLINUX1_CA_DIR = b"/opt/pyca/cryptography/openssl/certs"
+_CRYPTOGRAPHY_MANYLINUX1_CA_FILE = b"/opt/pyca/cryptography/openssl/cert.pem"
+
+
+class Error(Exception):
+    """
+    An error occurred in an `OpenSSL.SSL` API.
+    """
+
+
+_raise_current_error = partial(_exception_from_error_queue, Error)
+_openssl_assert = _make_assert(Error)
+
+
+class WantReadError(Error):
+    pass
+
+
+class WantWriteError(Error):
+    pass
+
+
+class WantX509LookupError(Error):
+    pass
+
+
+class ZeroReturnError(Error):
+    pass
+
+
+class SysCallError(Error):
+    pass
+
+
+class _CallbackExceptionHelper(object):
+    """
+    A base class for wrapper classes that allow for intelligent exception
+    handling in OpenSSL callbacks.
+
+    :ivar list _problems: Any exceptions that occurred while executing in a
+        context where they could not be raised in the normal way.  Typically
+        this is because OpenSSL has called into some Python code and requires a
+        return value.  The exceptions are saved to be raised later when it is
+        possible to do so.
+    """
+
+    def __init__(self):
+        self._problems = []
+
+    def raise_if_problem(self):
+        """
+        Raise an exception from the OpenSSL error queue or that was previously
+        captured whe running a callback.
+        """
+        if self._problems:
+            try:
+                _raise_current_error()
+            except Error:
+                pass
+            raise self._problems.pop(0)
+
+
+class _VerifyHelper(_CallbackExceptionHelper):
+    """
+    Wrap a callback such that it can be used as a certificate verification
+    callback.
+    """
+
+    def __init__(self, callback):
+        _CallbackExceptionHelper.__init__(self)
+
+        @wraps(callback)
+        def wrapper(ok, store_ctx):
+            x509 = _lib.X509_STORE_CTX_get_current_cert(store_ctx)
+            _lib.X509_up_ref(x509)
+            cert = X509._from_raw_x509_ptr(x509)
+            error_number = _lib.X509_STORE_CTX_get_error(store_ctx)
+            error_depth = _lib.X509_STORE_CTX_get_error_depth(store_ctx)
+
+            index = _lib.SSL_get_ex_data_X509_STORE_CTX_idx()
+            ssl = _lib.X509_STORE_CTX_get_ex_data(store_ctx, index)
+            connection = Connection._reverse_mapping[ssl]
+
+            try:
+                result = callback(
+                    connection, cert, error_number, error_depth, ok
+                )
+            except Exception as e:
+                self._problems.append(e)
+                return 0
+            else:
+                if result:
+                    _lib.X509_STORE_CTX_set_error(store_ctx, _lib.X509_V_OK)
+                    return 1
+                else:
+                    return 0
+
+        self.callback = _ffi.callback(
+            "int (*)(int, X509_STORE_CTX *)", wrapper)
+
+
+class _NpnAdvertiseHelper(_CallbackExceptionHelper):
+    """
+    Wrap a callback such that it can be used as an NPN advertisement callback.
+    """
+
+    def __init__(self, callback):
+        _CallbackExceptionHelper.__init__(self)
+
+        @wraps(callback)
+        def wrapper(ssl, out, outlen, arg):
+            try:
+                conn = Connection._reverse_mapping[ssl]
+                protos = callback(conn)
+
+                # Join the protocols into a Python bytestring, length-prefixing
+                # each element.
+                protostr = b''.join(
+                    chain.from_iterable((int2byte(len(p)), p) for p in protos)
+                )
+
+                # Save our callback arguments on the connection object. This is
+                # done to make sure that they don't get freed before OpenSSL
+                # uses them. Then, return them appropriately in the output
+                # parameters.
+                conn._npn_advertise_callback_args = [
+                    _ffi.new("unsigned int *", len(protostr)),
+                    _ffi.new("unsigned char[]", protostr),
+                ]
+                outlen[0] = conn._npn_advertise_callback_args[0][0]
+                out[0] = conn._npn_advertise_callback_args[1]
+                return 0
+            except Exception as e:
+                self._problems.append(e)
+                return 2  # SSL_TLSEXT_ERR_ALERT_FATAL
+
+        self.callback = _ffi.callback(
+            "int (*)(SSL *, const unsigned char **, unsigned int *, void *)",
+            wrapper
+        )
+
+
+class _NpnSelectHelper(_CallbackExceptionHelper):
+    """
+    Wrap a callback such that it can be used as an NPN selection callback.
+    """
+
+    def __init__(self, callback):
+        _CallbackExceptionHelper.__init__(self)
+
+        @wraps(callback)
+        def wrapper(ssl, out, outlen, in_, inlen, arg):
+            try:
+                conn = Connection._reverse_mapping[ssl]
+
+                # The string passed to us is actually made up of multiple
+                # length-prefixed bytestrings. We need to split that into a
+                # list.
+                instr = _ffi.buffer(in_, inlen)[:]
+                protolist = []
+                while instr:
+                    length = indexbytes(instr, 0)
+                    proto = instr[1:length + 1]
+                    protolist.append(proto)
+                    instr = instr[length + 1:]
+
+                # Call the callback
+                outstr = callback(conn, protolist)
+
+                # Save our callback arguments on the connection object. This is
+                # done to make sure that they don't get freed before OpenSSL
+                # uses them. Then, return them appropriately in the output
+                # parameters.
+                conn._npn_select_callback_args = [
+                    _ffi.new("unsigned char *", len(outstr)),
+                    _ffi.new("unsigned char[]", outstr),
+                ]
+                outlen[0] = conn._npn_select_callback_args[0][0]
+                out[0] = conn._npn_select_callback_args[1]
+                return 0
+            except Exception as e:
+                self._problems.append(e)
+                return 2  # SSL_TLSEXT_ERR_ALERT_FATAL
+
+        self.callback = _ffi.callback(
+            ("int (*)(SSL *, unsigned char **, unsigned char *, "
+                "const unsigned char *, unsigned int, void *)"),
+            wrapper
+        )
+
+
+class _ALPNSelectHelper(_CallbackExceptionHelper):
+    """
+    Wrap a callback such that it can be used as an ALPN selection callback.
+    """
+
+    def __init__(self, callback):
+        _CallbackExceptionHelper.__init__(self)
+
+        @wraps(callback)
+        def wrapper(ssl, out, outlen, in_, inlen, arg):
+            try:
+                conn = Connection._reverse_mapping[ssl]
+
+                # The string passed to us is made up of multiple
+                # length-prefixed bytestrings. We need to split that into a
+                # list.
+                instr = _ffi.buffer(in_, inlen)[:]
+                protolist = []
+                while instr:
+                    encoded_len = indexbytes(instr, 0)
+                    proto = instr[1:encoded_len + 1]
+                    protolist.append(proto)
+                    instr = instr[encoded_len + 1:]
+
+                # Call the callback
+                outstr = callback(conn, protolist)
+
+                if not isinstance(outstr, _binary_type):
+                    raise TypeError("ALPN callback must return a bytestring.")
+
+                # Save our callback arguments on the connection object to make
+                # sure that they don't get freed before OpenSSL can use them.
+                # Then, return them in the appropriate output parameters.
+                conn._alpn_select_callback_args = [
+                    _ffi.new("unsigned char *", len(outstr)),
+                    _ffi.new("unsigned char[]", outstr),
+                ]
+                outlen[0] = conn._alpn_select_callback_args[0][0]
+                out[0] = conn._alpn_select_callback_args[1]
+                return 0
+            except Exception as e:
+                self._problems.append(e)
+                return 2  # SSL_TLSEXT_ERR_ALERT_FATAL
+
+        self.callback = _ffi.callback(
+            ("int (*)(SSL *, unsigned char **, unsigned char *, "
+                "const unsigned char *, unsigned int, void *)"),
+            wrapper
+        )
+
+
+class _OCSPServerCallbackHelper(_CallbackExceptionHelper):
+    """
+    Wrap a callback such that it can be used as an OCSP callback for the server
+    side.
+
+    Annoyingly, OpenSSL defines one OCSP callback but uses it in two different
+    ways. For servers, that callback is expected to retrieve some OCSP data and
+    hand it to OpenSSL, and may return only SSL_TLSEXT_ERR_OK,
+    SSL_TLSEXT_ERR_FATAL, and SSL_TLSEXT_ERR_NOACK. For clients, that callback
+    is expected to check the OCSP data, and returns a negative value on error,
+    0 if the response is not acceptable, or positive if it is. These are
+    mutually exclusive return code behaviours, and they mean that we need two
+    helpers so that we always return an appropriate error code if the user's
+    code throws an exception.
+
+    Given that we have to have two helpers anyway, these helpers are a bit more
+    helpery than most: specifically, they hide a few more of the OpenSSL
+    functions so that the user has an easier time writing these callbacks.
+
+    This helper implements the server side.
+    """
+
+    def __init__(self, callback):
+        _CallbackExceptionHelper.__init__(self)
+
+        @wraps(callback)
+        def wrapper(ssl, cdata):
+            try:
+                conn = Connection._reverse_mapping[ssl]
+
+                # Extract the data if any was provided.
+                if cdata != _ffi.NULL:
+                    data = _ffi.from_handle(cdata)
+                else:
+                    data = None
+
+                # Call the callback.
+                ocsp_data = callback(conn, data)
+
+                if not isinstance(ocsp_data, _binary_type):
+                    raise TypeError("OCSP callback must return a bytestring.")
+
+                # If the OCSP data was provided, we will pass it to OpenSSL.
+                # However, we have an early exit here: if no OCSP data was
+                # provided we will just exit out and tell OpenSSL that there
+                # is nothing to do.
+                if not ocsp_data:
+                    return 3  # SSL_TLSEXT_ERR_NOACK
+
+                # OpenSSL takes ownership of this data and expects it to have
+                # been allocated by OPENSSL_malloc.
+                ocsp_data_length = len(ocsp_data)
+                data_ptr = _lib.OPENSSL_malloc(ocsp_data_length)
+                _ffi.buffer(data_ptr, ocsp_data_length)[:] = ocsp_data
+
+                _lib.SSL_set_tlsext_status_ocsp_resp(
+                    ssl, data_ptr, ocsp_data_length
+                )
+
+                return 0
+            except Exception as e:
+                self._problems.append(e)
+                return 2  # SSL_TLSEXT_ERR_ALERT_FATAL
+
+        self.callback = _ffi.callback("int (*)(SSL *, void *)", wrapper)
+
+
+class _OCSPClientCallbackHelper(_CallbackExceptionHelper):
+    """
+    Wrap a callback such that it can be used as an OCSP callback for the client
+    side.
+
+    Annoyingly, OpenSSL defines one OCSP callback but uses it in two different
+    ways. For servers, that callback is expected to retrieve some OCSP data and
+    hand it to OpenSSL, and may return only SSL_TLSEXT_ERR_OK,
+    SSL_TLSEXT_ERR_FATAL, and SSL_TLSEXT_ERR_NOACK. For clients, that callback
+    is expected to check the OCSP data, and returns a negative value on error,
+    0 if the response is not acceptable, or positive if it is. These are
+    mutually exclusive return code behaviours, and they mean that we need two
+    helpers so that we always return an appropriate error code if the user's
+    code throws an exception.
+
+    Given that we have to have two helpers anyway, these helpers are a bit more
+    helpery than most: specifically, they hide a few more of the OpenSSL
+    functions so that the user has an easier time writing these callbacks.
+
+    This helper implements the client side.
+    """
+
+    def __init__(self, callback):
+        _CallbackExceptionHelper.__init__(self)
+
+        @wraps(callback)
+        def wrapper(ssl, cdata):
+            try:
+                conn = Connection._reverse_mapping[ssl]
+
+                # Extract the data if any was provided.
+                if cdata != _ffi.NULL:
+                    data = _ffi.from_handle(cdata)
+                else:
+                    data = None
+
+                # Get the OCSP data.
+                ocsp_ptr = _ffi.new("unsigned char **")
+                ocsp_len = _lib.SSL_get_tlsext_status_ocsp_resp(ssl, ocsp_ptr)
+                if ocsp_len < 0:
+                    # No OCSP data.
+                    ocsp_data = b''
+                else:
+                    # Copy the OCSP data, then pass it to the callback.
+                    ocsp_data = _ffi.buffer(ocsp_ptr[0], ocsp_len)[:]
+
+                valid = callback(conn, ocsp_data, data)
+
+                # Return 1 on success or 0 on error.
+                return int(bool(valid))
+
+            except Exception as e:
+                self._problems.append(e)
+                # Return negative value if an exception is hit.
+                return -1
+
+        self.callback = _ffi.callback("int (*)(SSL *, void *)", wrapper)
+
+
+def _asFileDescriptor(obj):
+    fd = None
+    if not isinstance(obj, integer_types):
+        meth = getattr(obj, "fileno", None)
+        if meth is not None:
+            obj = meth()
+
+    if isinstance(obj, integer_types):
+        fd = obj
+
+    if not isinstance(fd, integer_types):
+        raise TypeError("argument must be an int, or have a fileno() method.")
+    elif fd < 0:
+        raise ValueError(
+            "file descriptor cannot be a negative integer (%i)" % (fd,))
+
+    return fd
+
+
+def SSLeay_version(type):
+    """
+    Return a string describing the version of OpenSSL in use.
+
+    :param type: One of the :const:`SSLEAY_` constants defined in this module.
+    """
+    return _ffi.string(_lib.SSLeay_version(type))
+
+
+def _make_requires(flag, error):
+    """
+    Builds a decorator that ensures that functions that rely on OpenSSL
+    functions that are not present in this build raise NotImplementedError,
+    rather than AttributeError coming out of cryptography.
+
+    :param flag: A cryptography flag that guards the functions, e.g.
+        ``Cryptography_HAS_NEXTPROTONEG``.
+    :param error: The string to be used in the exception if the flag is false.
+    """
+    def _requires_decorator(func):
+        if not flag:
+            @wraps(func)
+            def explode(*args, **kwargs):
+                raise NotImplementedError(error)
+            return explode
+        else:
+            return func
+
+    return _requires_decorator
+
+
+_requires_npn = _make_requires(
+    _lib.Cryptography_HAS_NEXTPROTONEG, "NPN not available"
+)
+
+
+_requires_alpn = _make_requires(
+    _lib.Cryptography_HAS_ALPN, "ALPN not available"
+)
+
+
+_requires_sni = _make_requires(
+    _lib.Cryptography_HAS_TLSEXT_HOSTNAME, "SNI not available"
+)
+
+
+class Session(object):
+    """
+    A class representing an SSL session.  A session defines certain connection
+    parameters which may be re-used to speed up the setup of subsequent
+    connections.
+
+    .. versionadded:: 0.14
+    """
+    pass
+
+
+class Context(object):
+    """
+    :class:`OpenSSL.SSL.Context` instances define the parameters for setting
+    up new SSL connections.
+
+    :param method: One of SSLv2_METHOD, SSLv3_METHOD, SSLv23_METHOD, or
+        TLSv1_METHOD.
+    """
+    _methods = {
+        SSLv2_METHOD: "SSLv2_method",
+        SSLv3_METHOD: "SSLv3_method",
+        SSLv23_METHOD: "SSLv23_method",
+        TLSv1_METHOD: "TLSv1_method",
+        TLSv1_1_METHOD: "TLSv1_1_method",
+        TLSv1_2_METHOD: "TLSv1_2_method",
+    }
+    _methods = dict(
+        (identifier, getattr(_lib, name))
+        for (identifier, name) in _methods.items()
+        if getattr(_lib, name, None) is not None)
+
+    def __init__(self, method):
+        if not isinstance(method, integer_types):
+            raise TypeError("method must be an integer")
+
+        try:
+            method_func = self._methods[method]
+        except KeyError:
+            raise ValueError("No such protocol")
+
+        method_obj = method_func()
+        _openssl_assert(method_obj != _ffi.NULL)
+
+        context = _lib.SSL_CTX_new(method_obj)
+        _openssl_assert(context != _ffi.NULL)
+        context = _ffi.gc(context, _lib.SSL_CTX_free)
+
+        # If SSL_CTX_set_ecdh_auto is available then set it so the ECDH curve
+        # will be auto-selected. This function was added in 1.0.2 and made a
+        # noop in 1.1.0+ (where it is set automatically).
+        try:
+            res = _lib.SSL_CTX_set_ecdh_auto(context, 1)
+            _openssl_assert(res == 1)
+        except AttributeError:
+            pass
+
+        self._context = context
+        self._passphrase_helper = None
+        self._passphrase_callback = None
+        self._passphrase_userdata = None
+        self._verify_helper = None
+        self._verify_callback = None
+        self._info_callback = None
+        self._tlsext_servername_callback = None
+        self._app_data = None
+        self._npn_advertise_helper = None
+        self._npn_advertise_callback = None
+        self._npn_select_helper = None
+        self._npn_select_callback = None
+        self._alpn_select_helper = None
+        self._alpn_select_callback = None
+        self._ocsp_helper = None
+        self._ocsp_callback = None
+        self._ocsp_data = None
+
+        self.set_mode(_lib.SSL_MODE_ENABLE_PARTIAL_WRITE)
+
+    def load_verify_locations(self, cafile, capath=None):
+        """
+        Let SSL know where we can find trusted certificates for the certificate
+        chain.  Note that the certificates have to be in PEM format.
+
+        If capath is passed, it must be a directory prepared using the
+        ``c_rehash`` tool included with OpenSSL.  Either, but not both, of
+        *pemfile* or *capath* may be :data:`None`.
+
+        :param cafile: In which file we can find the certificates (``bytes`` or
+            ``unicode``).
+        :param capath: In which directory we can find the certificates
+            (``bytes`` or ``unicode``).
+
+        :return: None
+        """
+        if cafile is None:
+            cafile = _ffi.NULL
+        else:
+            cafile = _path_string(cafile)
+
+        if capath is None:
+            capath = _ffi.NULL
+        else:
+            capath = _path_string(capath)
+
+        load_result = _lib.SSL_CTX_load_verify_locations(
+            self._context, cafile, capath
+        )
+        if not load_result:
+            _raise_current_error()
+
+    def _wrap_callback(self, callback):
+        @wraps(callback)
+        def wrapper(size, verify, userdata):
+            return callback(size, verify, self._passphrase_userdata)
+        return _PassphraseHelper(
+            FILETYPE_PEM, wrapper, more_args=True, truncate=True)
+
+    def set_passwd_cb(self, callback, userdata=None):
+        """
+        Set the passphrase callback.  This function will be called
+        when a private key with a passphrase is loaded.
+
+        :param callback: The Python callback to use.  This must accept three
+            positional arguments.  First, an integer giving the maximum length
+            of the passphrase it may return.  If the returned passphrase is
+            longer than this, it will be truncated.  Second, a boolean value
+            which will be true if the user should be prompted for the
+            passphrase twice and the callback should verify that the two values
+            supplied are equal. Third, the value given as the *userdata*
+            parameter to :meth:`set_passwd_cb`.  The *callback* must return
+            a byte string. If an error occurs, *callback* should return a false
+            value (e.g. an empty string).
+        :param userdata: (optional) A Python object which will be given as
+                         argument to the callback
+        :return: None
+        """
+        if not callable(callback):
+            raise TypeError("callback must be callable")
+
+        self._passphrase_helper = self._wrap_callback(callback)
+        self._passphrase_callback = self._passphrase_helper.callback
+        _lib.SSL_CTX_set_default_passwd_cb(
+            self._context, self._passphrase_callback)
+        self._passphrase_userdata = userdata
+
+    def set_default_verify_paths(self):
+        """
+        Specify that the platform provided CA certificates are to be used for
+        verification purposes. This method has some caveats related to the
+        binary wheels that cryptography (pyOpenSSL's primary dependency) ships:
+
+        *   macOS will only load certificates using this method if the user has
+            the ``openssl@1.1`` `Homebrew <https://brew.sh>`_ formula installed
+            in the default location.
+        *   Windows will not work.
+        *   manylinux1 cryptography wheels will work on most common Linux
+            distributions in pyOpenSSL 17.1.0 and above.  pyOpenSSL detects the
+            manylinux1 wheel and attempts to load roots via a fallback path.
+
+        :return: None
+        """
+        # SSL_CTX_set_default_verify_paths will attempt to load certs from
+        # both a cafile and capath that are set at compile time. However,
+        # it will first check environment variables and, if present, load
+        # those paths instead
+        set_result = _lib.SSL_CTX_set_default_verify_paths(self._context)
+        _openssl_assert(set_result == 1)
+        # After attempting to set default_verify_paths we need to know whether
+        # to go down the fallback path.
+        # First we'll check to see if any env vars have been set. If so,
+        # we won't try to do anything else because the user has set the path
+        # themselves.
+        dir_env_var = _ffi.string(
+            _lib.X509_get_default_cert_dir_env()
+        ).decode("ascii")
+        file_env_var = _ffi.string(
+            _lib.X509_get_default_cert_file_env()
+        ).decode("ascii")
+        if not self._check_env_vars_set(dir_env_var, file_env_var):
+            default_dir = _ffi.string(_lib.X509_get_default_cert_dir())
+            default_file = _ffi.string(_lib.X509_get_default_cert_file())
+            # Now we check to see if the default_dir and default_file are set
+            # to the exact values we use in our manylinux1 builds. If they are
+            # then we know to load the fallbacks
+            if (
+                default_dir == _CRYPTOGRAPHY_MANYLINUX1_CA_DIR and
+                default_file == _CRYPTOGRAPHY_MANYLINUX1_CA_FILE
+            ):
+                # This is manylinux1, let's load our fallback paths
+                self._fallback_default_verify_paths(
+                    _CERTIFICATE_FILE_LOCATIONS,
+                    _CERTIFICATE_PATH_LOCATIONS
+                )
+
+    def _check_env_vars_set(self, dir_env_var, file_env_var):
+        """
+        Check to see if the default cert dir/file environment vars are present.
+
+        :return: bool
+        """
+        return (
+            os.environ.get(file_env_var) is not None or
+            os.environ.get(dir_env_var) is not None
+        )
+
+    def _fallback_default_verify_paths(self, file_path, dir_path):
+        """
+        Default verify paths are based on the compiled version of OpenSSL.
+        However, when pyca/cryptography is compiled as a manylinux1 wheel
+        that compiled location can potentially be wrong. So, like Go, we
+        will try a predefined set of paths and attempt to load roots
+        from there.
+
+        :return: None
+        """
+        for cafile in file_path:
+            if os.path.isfile(cafile):
+                self.load_verify_locations(cafile)
+                break
+
+        for capath in dir_path:
+            if os.path.isdir(capath):
+                self.load_verify_locations(None, capath)
+                break
+
+    def use_certificate_chain_file(self, certfile):
+        """
+        Load a certificate chain from a file.
+
+        :param certfile: The name of the certificate chain file (``bytes`` or
+            ``unicode``).  Must be PEM encoded.
+
+        :return: None
+        """
+        certfile = _path_string(certfile)
+
+        result = _lib.SSL_CTX_use_certificate_chain_file(
+            self._context, certfile
+        )
+        if not result:
+            _raise_current_error()
+
+    def use_certificate_file(self, certfile, filetype=FILETYPE_PEM):
+        """
+        Load a certificate from a file
+
+        :param certfile: The name of the certificate file (``bytes`` or
+            ``unicode``).
+        :param filetype: (optional) The encoding of the file, which is either
+            :const:`FILETYPE_PEM` or :const:`FILETYPE_ASN1`.  The default is
+            :const:`FILETYPE_PEM`.
+
+        :return: None
+        """
+        certfile = _path_string(certfile)
+        if not isinstance(filetype, integer_types):
+            raise TypeError("filetype must be an integer")
+
+        use_result = _lib.SSL_CTX_use_certificate_file(
+            self._context, certfile, filetype
+        )
+        if not use_result:
+            _raise_current_error()
+
+    def use_certificate(self, cert):
+        """
+        Load a certificate from a X509 object
+
+        :param cert: The X509 object
+        :return: None
+        """
+        if not isinstance(cert, X509):
+            raise TypeError("cert must be an X509 instance")
+
+        use_result = _lib.SSL_CTX_use_certificate(self._context, cert._x509)
+        if not use_result:
+            _raise_current_error()
+
+    def add_extra_chain_cert(self, certobj):
+        """
+        Add certificate to chain
+
+        :param certobj: The X509 certificate object to add to the chain
+        :return: None
+        """
+        if not isinstance(certobj, X509):
+            raise TypeError("certobj must be an X509 instance")
+
+        copy = _lib.X509_dup(certobj._x509)
+        add_result = _lib.SSL_CTX_add_extra_chain_cert(self._context, copy)
+        if not add_result:
+            # TODO: This is untested.
+            _lib.X509_free(copy)
+            _raise_current_error()
+
+    def _raise_passphrase_exception(self):
+        if self._passphrase_helper is not None:
+            self._passphrase_helper.raise_if_problem(Error)
+
+        _raise_current_error()
+
+    def use_privatekey_file(self, keyfile, filetype=_UNSPECIFIED):
+        """
+        Load a private key from a file
+
+        :param keyfile: The name of the key file (``bytes`` or ``unicode``)
+        :param filetype: (optional) The encoding of the file, which is either
+            :const:`FILETYPE_PEM` or :const:`FILETYPE_ASN1`.  The default is
+            :const:`FILETYPE_PEM`.
+
+        :return: None
+        """
+        keyfile = _path_string(keyfile)
+
+        if filetype is _UNSPECIFIED:
+            filetype = FILETYPE_PEM
+        elif not isinstance(filetype, integer_types):
+            raise TypeError("filetype must be an integer")
+
+        use_result = _lib.SSL_CTX_use_PrivateKey_file(
+            self._context, keyfile, filetype)
+        if not use_result:
+            self._raise_passphrase_exception()
+
+    def use_privatekey(self, pkey):
+        """
+        Load a private key from a PKey object
+
+        :param pkey: The PKey object
+        :return: None
+        """
+        if not isinstance(pkey, PKey):
+            raise TypeError("pkey must be a PKey instance")
+
+        use_result = _lib.SSL_CTX_use_PrivateKey(self._context, pkey._pkey)
+        if not use_result:
+            self._raise_passphrase_exception()
+
+    def check_privatekey(self):
+        """
+        Check if the private key (loaded with :meth:`use_privatekey`) matches
+        the certificate (loaded with :meth:`use_certificate`)
+
+        :return: :data:`None` (raises :exc:`Error` if something's wrong)
+        """
+        if not _lib.SSL_CTX_check_private_key(self._context):
+            _raise_current_error()
+
+    def load_client_ca(self, cafile):
+        """
+        Load the trusted certificates that will be sent to the client.  Does
+        not actually imply any of the certificates are trusted; that must be
+        configured separately.
+
+        :param bytes cafile: The path to a certificates file in PEM format.
+        :return: None
+        """
+        ca_list = _lib.SSL_load_client_CA_file(
+            _text_to_bytes_and_warn("cafile", cafile)
+        )
+        _openssl_assert(ca_list != _ffi.NULL)
+        _lib.SSL_CTX_set_client_CA_list(self._context, ca_list)
+
+    def set_session_id(self, buf):
+        """
+        Set the session id to *buf* within which a session can be reused for
+        this Context object.  This is needed when doing session resumption,
+        because there is no way for a stored session to know which Context
+        object it is associated with.
+
+        :param bytes buf: The session id.
+
+        :returns: None
+        """
+        buf = _text_to_bytes_and_warn("buf", buf)
+        _openssl_assert(
+            _lib.SSL_CTX_set_session_id_context(
+                self._context,
+                buf,
+                len(buf),
+            ) == 1
+        )
+
+    def set_session_cache_mode(self, mode):
+        """
+        Set the behavior of the session cache used by all connections using
+        this Context.  The previously set mode is returned.  See
+        :const:`SESS_CACHE_*` for details about particular modes.
+
+        :param mode: One or more of the SESS_CACHE_* flags (combine using
+            bitwise or)
+        :returns: The previously set caching mode.
+
+        .. versionadded:: 0.14
+        """
+        if not isinstance(mode, integer_types):
+            raise TypeError("mode must be an integer")
+
+        return _lib.SSL_CTX_set_session_cache_mode(self._context, mode)
+
+    def get_session_cache_mode(self):
+        """
+        Get the current session cache mode.
+
+        :returns: The currently used cache mode.
+
+        .. versionadded:: 0.14
+        """
+        return _lib.SSL_CTX_get_session_cache_mode(self._context)
+
+    def set_verify(self, mode, callback):
+        """
+        et the verification flags for this Context object to *mode* and specify
+        that *callback* should be used for verification callbacks.
+
+        :param mode: The verify mode, this should be one of
+            :const:`VERIFY_NONE` and :const:`VERIFY_PEER`. If
+            :const:`VERIFY_PEER` is used, *mode* can be OR:ed with
+            :const:`VERIFY_FAIL_IF_NO_PEER_CERT` and
+            :const:`VERIFY_CLIENT_ONCE` to further control the behaviour.
+        :param callback: The Python callback to use.  This should take five
+            arguments: A Connection object, an X509 object, and three integer
+            variables, which are in turn potential error number, error depth
+            and return code. *callback* should return True if verification
+            passes and False otherwise.
+        :return: None
+
+        See SSL_CTX_set_verify(3SSL) for further details.
+        """
+        if not isinstance(mode, integer_types):
+            raise TypeError("mode must be an integer")
+
+        if not callable(callback):
+            raise TypeError("callback must be callable")
+
+        self._verify_helper = _VerifyHelper(callback)
+        self._verify_callback = self._verify_helper.callback
+        _lib.SSL_CTX_set_verify(self._context, mode, self._verify_callback)
+
+    def set_verify_depth(self, depth):
+        """
+        Set the maximum depth for the certificate chain verification that shall
+        be allowed for this Context object.
+
+        :param depth: An integer specifying the verify depth
+        :return: None
+        """
+        if not isinstance(depth, integer_types):
+            raise TypeError("depth must be an integer")
+
+        _lib.SSL_CTX_set_verify_depth(self._context, depth)
+
+    def get_verify_mode(self):
+        """
+        Retrieve the Context object's verify mode, as set by
+        :meth:`set_verify`.
+
+        :return: The verify mode
+        """
+        return _lib.SSL_CTX_get_verify_mode(self._context)
+
+    def get_verify_depth(self):
+        """
+        Retrieve the Context object's verify depth, as set by
+        :meth:`set_verify_depth`.
+
+        :return: The verify depth
+        """
+        return _lib.SSL_CTX_get_verify_depth(self._context)
+
+    def load_tmp_dh(self, dhfile):
+        """
+        Load parameters for Ephemeral Diffie-Hellman
+
+        :param dhfile: The file to load EDH parameters from (``bytes`` or
+            ``unicode``).
+
+        :return: None
+        """
+        dhfile = _path_string(dhfile)
+
+        bio = _lib.BIO_new_file(dhfile, b"r")
+        if bio == _ffi.NULL:
+            _raise_current_error()
+        bio = _ffi.gc(bio, _lib.BIO_free)
+
+        dh = _lib.PEM_read_bio_DHparams(bio, _ffi.NULL, _ffi.NULL, _ffi.NULL)
+        dh = _ffi.gc(dh, _lib.DH_free)
+        _lib.SSL_CTX_set_tmp_dh(self._context, dh)
+
+    def set_tmp_ecdh(self, curve):
+        """
+        Select a curve to use for ECDHE key exchange.
+
+        :param curve: A curve object to use as returned by either
+            :meth:`OpenSSL.crypto.get_elliptic_curve` or
+            :meth:`OpenSSL.crypto.get_elliptic_curves`.
+
+        :return: None
+        """
+        _lib.SSL_CTX_set_tmp_ecdh(self._context, curve._to_EC_KEY())
+
+    def set_cipher_list(self, cipher_list):
+        """
+        Set the list of ciphers to be used in this context.
+
+        See the OpenSSL manual for more information (e.g.
+        :manpage:`ciphers(1)`).
+
+        :param bytes cipher_list: An OpenSSL cipher string.
+        :return: None
+        """
+        cipher_list = _text_to_bytes_and_warn("cipher_list", cipher_list)
+
+        if not isinstance(cipher_list, bytes):
+            raise TypeError("cipher_list must be a byte string.")
+
+        _openssl_assert(
+            _lib.SSL_CTX_set_cipher_list(self._context, cipher_list) == 1
+        )
+        # In OpenSSL 1.1.1 setting the cipher list will always return TLS 1.3
+        # ciphers even if you pass an invalid cipher. Applications (like
+        # Twisted) have tests that depend on an error being raised if an
+        # invalid cipher string is passed, but without the following check
+        # for the TLS 1.3 specific cipher suites it would never error.
+        tmpconn = Connection(self, None)
+        _openssl_assert(
+            tmpconn.get_cipher_list() != [
+                'TLS_AES_256_GCM_SHA384',
+                'TLS_CHACHA20_POLY1305_SHA256',
+                'TLS_AES_128_GCM_SHA256'
+            ]
+        )
+
+    def set_client_ca_list(self, certificate_authorities):
+        """
+        Set the list of preferred client certificate signers for this server
+        context.
+
+        This list of certificate authorities will be sent to the client when
+        the server requests a client certificate.
+
+        :param certificate_authorities: a sequence of X509Names.
+        :return: None
+
+        .. versionadded:: 0.10
+        """
+        name_stack = _lib.sk_X509_NAME_new_null()
+        _openssl_assert(name_stack != _ffi.NULL)
+
+        try:
+            for ca_name in certificate_authorities:
+                if not isinstance(ca_name, X509Name):
+                    raise TypeError(
+                        "client CAs must be X509Name objects, not %s "
+                        "objects" % (
+                            type(ca_name).__name__,
+                        )
+                    )
+                copy = _lib.X509_NAME_dup(ca_name._name)
+                _openssl_assert(copy != _ffi.NULL)
+                push_result = _lib.sk_X509_NAME_push(name_stack, copy)
+                if not push_result:
+                    _lib.X509_NAME_free(copy)
+                    _raise_current_error()
+        except Exception:
+            _lib.sk_X509_NAME_free(name_stack)
+            raise
+
+        _lib.SSL_CTX_set_client_CA_list(self._context, name_stack)
+
+    def add_client_ca(self, certificate_authority):
+        """
+        Add the CA certificate to the list of preferred signers for this
+        context.
+
+        The list of certificate authorities will be sent to the client when the
+        server requests a client certificate.
+
+        :param certificate_authority: certificate authority's X509 certificate.
+        :return: None
+
+        .. versionadded:: 0.10
+        """
+        if not isinstance(certificate_authority, X509):
+            raise TypeError("certificate_authority must be an X509 instance")
+
+        add_result = _lib.SSL_CTX_add_client_CA(
+            self._context, certificate_authority._x509)
+        _openssl_assert(add_result == 1)
+
+    def set_timeout(self, timeout):
+        """
+        Set the timeout for newly created sessions for this Context object to
+        *timeout*.  The default value is 300 seconds. See the OpenSSL manual
+        for more information (e.g. :manpage:`SSL_CTX_set_timeout(3)`).
+
+        :param timeout: The timeout in (whole) seconds
+        :return: The previous session timeout
+        """
+        if not isinstance(timeout, integer_types):
+            raise TypeError("timeout must be an integer")
+
+        return _lib.SSL_CTX_set_timeout(self._context, timeout)
+
+    def get_timeout(self):
+        """
+        Retrieve session timeout, as set by :meth:`set_timeout`. The default
+        is 300 seconds.
+
+        :return: The session timeout
+        """
+        return _lib.SSL_CTX_get_timeout(self._context)
+
+    def set_info_callback(self, callback):
+        """
+        Set the information callback to *callback*. This function will be
+        called from time to time during SSL handshakes.
+
+        :param callback: The Python callback to use.  This should take three
+            arguments: a Connection object and two integers.  The first integer
+            specifies where in the SSL handshake the function was called, and
+            the other the return code from a (possibly failed) internal
+            function call.
+        :return: None
+        """
+        @wraps(callback)
+        def wrapper(ssl, where, return_code):
+            callback(Connection._reverse_mapping[ssl], where, return_code)
+        self._info_callback = _ffi.callback(
+            "void (*)(const SSL *, int, int)", wrapper)
+        _lib.SSL_CTX_set_info_callback(self._context, self._info_callback)
+
+    def get_app_data(self):
+        """
+        Get the application data (supplied via :meth:`set_app_data()`)
+
+        :return: The application data
+        """
+        return self._app_data
+
+    def set_app_data(self, data):
+        """
+        Set the application data (will be returned from get_app_data())
+
+        :param data: Any Python object
+        :return: None
+        """
+        self._app_data = data
+
+    def get_cert_store(self):
+        """
+        Get the certificate store for the context.  This can be used to add
+        "trusted" certificates without using the
+        :meth:`load_verify_locations` method.
+
+        :return: A X509Store object or None if it does not have one.
+        """
+        store = _lib.SSL_CTX_get_cert_store(self._context)
+        if store == _ffi.NULL:
+            # TODO: This is untested.
+            return None
+
+        pystore = X509Store.__new__(X509Store)
+        pystore._store = store
+        return pystore
+
+    def set_options(self, options):
+        """
+        Add options. Options set before are not cleared!
+        This method should be used with the :const:`OP_*` constants.
+
+        :param options: The options to add.
+        :return: The new option bitmask.
+        """
+        if not isinstance(options, integer_types):
+            raise TypeError("options must be an integer")
+
+        return _lib.SSL_CTX_set_options(self._context, options)
+
+    def set_mode(self, mode):
+        """
+        Add modes via bitmask. Modes set before are not cleared!  This method
+        should be used with the :const:`MODE_*` constants.
+
+        :param mode: The mode to add.
+        :return: The new mode bitmask.
+        """
+        if not isinstance(mode, integer_types):
+            raise TypeError("mode must be an integer")
+
+        return _lib.SSL_CTX_set_mode(self._context, mode)
+
+    @_requires_sni
+    def set_tlsext_servername_callback(self, callback):
+        """
+        Specify a callback function to be called when clients specify a server
+        name.
+
+        :param callback: The callback function.  It will be invoked with one
+            argument, the Connection instance.
+
+        .. versionadded:: 0.13
+        """
+        @wraps(callback)
+        def wrapper(ssl, alert, arg):
+            callback(Connection._reverse_mapping[ssl])
+            return 0
+
+        self._tlsext_servername_callback = _ffi.callback(
+            "int (*)(SSL *, int *, void *)", wrapper)
+        _lib.SSL_CTX_set_tlsext_servername_callback(
+            self._context, self._tlsext_servername_callback)
+
+    def set_tlsext_use_srtp(self, profiles):
+        """
+        Enable support for negotiating SRTP keying material.
+
+        :param bytes profiles: A colon delimited list of protection profile
+            names, like ``b'SRTP_AES128_CM_SHA1_80:SRTP_AES128_CM_SHA1_32'``.
+        :return: None
+        """
+        if not isinstance(profiles, bytes):
+            raise TypeError("profiles must be a byte string.")
+
+        _openssl_assert(
+            _lib.SSL_CTX_set_tlsext_use_srtp(self._context, profiles) == 0
+        )
+
+    @_requires_npn
+    def set_npn_advertise_callback(self, callback):
+        """
+        Specify a callback function that will be called when offering `Next
+        Protocol Negotiation
+        <https://technotes.googlecode.com/git/nextprotoneg.html>`_ as a server.
+
+        :param callback: The callback function.  It will be invoked with one
+            argument, the :class:`Connection` instance.  It should return a
+            list of bytestrings representing the advertised protocols, like
+            ``[b'http/1.1', b'spdy/2']``.
+
+        .. versionadded:: 0.15
+        """
+        self._npn_advertise_helper = _NpnAdvertiseHelper(callback)
+        self._npn_advertise_callback = self._npn_advertise_helper.callback
+        _lib.SSL_CTX_set_next_protos_advertised_cb(
+            self._context, self._npn_advertise_callback, _ffi.NULL)
+
+    @_requires_npn
+    def set_npn_select_callback(self, callback):
+        """
+        Specify a callback function that will be called when a server offers
+        Next Protocol Negotiation options.
+
+        :param callback: The callback function.  It will be invoked with two
+            arguments: the Connection, and a list of offered protocols as
+            bytestrings, e.g. ``[b'http/1.1', b'spdy/2']``.  It should return
+            one of those bytestrings, the chosen protocol.
+
+        .. versionadded:: 0.15
+        """
+        self._npn_select_helper = _NpnSelectHelper(callback)
+        self._npn_select_callback = self._npn_select_helper.callback
+        _lib.SSL_CTX_set_next_proto_select_cb(
+            self._context, self._npn_select_callback, _ffi.NULL)
+
+    @_requires_alpn
+    def set_alpn_protos(self, protos):
+        """
+        Specify the protocols that the client is prepared to speak after the
+        TLS connection has been negotiated using Application Layer Protocol
+        Negotiation.
+
+        :param protos: A list of the protocols to be offered to the server.
+            This list should be a Python list of bytestrings representing the
+            protocols to offer, e.g. ``[b'http/1.1', b'spdy/2']``.
+        """
+        # Take the list of protocols and join them together, prefixing them
+        # with their lengths.
+        protostr = b''.join(
+            chain.from_iterable((int2byte(len(p)), p) for p in protos)
+        )
+
+        # Build a C string from the list. We don't need to save this off
+        # because OpenSSL immediately copies the data out.
+        input_str = _ffi.new("unsigned char[]", protostr)
+        _lib.SSL_CTX_set_alpn_protos(self._context, input_str, len(protostr))
+
+    @_requires_alpn
+    def set_alpn_select_callback(self, callback):
+        """
+        Specify a callback function that will be called on the server when a
+        client offers protocols using ALPN.
+
+        :param callback: The callback function.  It will be invoked with two
+            arguments: the Connection, and a list of offered protocols as
+            bytestrings, e.g ``[b'http/1.1', b'spdy/2']``.  It should return
+            one of those bytestrings, the chosen protocol.
+        """
+        self._alpn_select_helper = _ALPNSelectHelper(callback)
+        self._alpn_select_callback = self._alpn_select_helper.callback
+        _lib.SSL_CTX_set_alpn_select_cb(
+            self._context, self._alpn_select_callback, _ffi.NULL)
+
+    def _set_ocsp_callback(self, helper, data):
+        """
+        This internal helper does the common work for
+        ``set_ocsp_server_callback`` and ``set_ocsp_client_callback``, which is
+        almost all of it.
+        """
+        self._ocsp_helper = helper
+        self._ocsp_callback = helper.callback
+        if data is None:
+            self._ocsp_data = _ffi.NULL
+        else:
+            self._ocsp_data = _ffi.new_handle(data)
+
+        rc = _lib.SSL_CTX_set_tlsext_status_cb(
+            self._context, self._ocsp_callback
+        )
+        _openssl_assert(rc == 1)
+        rc = _lib.SSL_CTX_set_tlsext_status_arg(self._context, self._ocsp_data)
+        _openssl_assert(rc == 1)
+
+    def set_ocsp_server_callback(self, callback, data=None):
+        """
+        Set a callback to provide OCSP data to be stapled to the TLS handshake
+        on the server side.
+
+        :param callback: The callback function. It will be invoked with two
+            arguments: the Connection, and the optional arbitrary data you have
+            provided. The callback must return a bytestring that contains the
+            OCSP data to staple to the handshake. If no OCSP data is available
+            for this connection, return the empty bytestring.
+        :param data: Some opaque data that will be passed into the callback
+            function when called. This can be used to avoid needing to do
+            complex data lookups or to keep track of what context is being
+            used. This parameter is optional.
+        """
+        helper = _OCSPServerCallbackHelper(callback)
+        self._set_ocsp_callback(helper, data)
+
+    def set_ocsp_client_callback(self, callback, data=None):
+        """
+        Set a callback to validate OCSP data stapled to the TLS handshake on
+        the client side.
+
+        :param callback: The callback function. It will be invoked with three
+            arguments: the Connection, a bytestring containing the stapled OCSP
+            assertion, and the optional arbitrary data you have provided. The
+            callback must return a boolean that indicates the result of
+            validating the OCSP data: ``True`` if the OCSP data is valid and
+            the certificate can be trusted, or ``False`` if either the OCSP
+            data is invalid or the certificate has been revoked.
+        :param data: Some opaque data that will be passed into the callback
+            function when called. This can be used to avoid needing to do
+            complex data lookups or to keep track of what context is being
+            used. This parameter is optional.
+        """
+        helper = _OCSPClientCallbackHelper(callback)
+        self._set_ocsp_callback(helper, data)
+
+
+ContextType = deprecated(
+    Context, __name__,
+    "ContextType has been deprecated, use Context instead", DeprecationWarning
+)
+
+
+class Connection(object):
+    """
+    """
+    _reverse_mapping = WeakValueDictionary()
+
+    def __init__(self, context, socket=None):
+        """
+        Create a new Connection object, using the given OpenSSL.SSL.Context
+        instance and socket.
+
+        :param context: An SSL Context to use for this connection
+        :param socket: The socket to use for transport layer
+        """
+        if not isinstance(context, Context):
+            raise TypeError("context must be a Context instance")
+
+        ssl = _lib.SSL_new(context._context)
+        self._ssl = _ffi.gc(ssl, _lib.SSL_free)
+        # We set SSL_MODE_AUTO_RETRY to handle situations where OpenSSL returns
+        # an SSL_ERROR_WANT_READ when processing a non-application data packet
+        # even though there is still data on the underlying transport.
+        # See https://github.com/openssl/openssl/issues/6234 for more details.
+        _lib.SSL_set_mode(self._ssl, _lib.SSL_MODE_AUTO_RETRY)
+        self._context = context
+        self._app_data = None
+
+        # References to strings used for Next Protocol Negotiation. OpenSSL's
+        # header files suggest that these might get copied at some point, but
+        # doesn't specify when, so we store them here to make sure they don't
+        # get freed before OpenSSL uses them.
+        self._npn_advertise_callback_args = None
+        self._npn_select_callback_args = None
+
+        # References to strings used for Application Layer Protocol
+        # Negotiation. These strings get copied at some point but it's well
+        # after the callback returns, so we have to hang them somewhere to
+        # avoid them getting freed.
+        self._alpn_select_callback_args = None
+
+        self._reverse_mapping[self._ssl] = self
+
+        if socket is None:
+            self._socket = None
+            # Don't set up any gc for these, SSL_free will take care of them.
+            self._into_ssl = _lib.BIO_new(_lib.BIO_s_mem())
+            _openssl_assert(self._into_ssl != _ffi.NULL)
+
+            self._from_ssl = _lib.BIO_new(_lib.BIO_s_mem())
+            _openssl_assert(self._from_ssl != _ffi.NULL)
+
+            _lib.SSL_set_bio(self._ssl, self._into_ssl, self._from_ssl)
+        else:
+            self._into_ssl = None
+            self._from_ssl = None
+            self._socket = socket
+            set_result = _lib.SSL_set_fd(
+                self._ssl, _asFileDescriptor(self._socket))
+            _openssl_assert(set_result == 1)
+
+    def __getattr__(self, name):
+        """
+        Look up attributes on the wrapped socket object if they are not found
+        on the Connection object.
+        """
+        if self._socket is None:
+            raise AttributeError("'%s' object has no attribute '%s'" % (
+                self.__class__.__name__, name
+            ))
+        else:
+            return getattr(self._socket, name)
+
+    def _raise_ssl_error(self, ssl, result):
+        if self._context._verify_helper is not None:
+            self._context._verify_helper.raise_if_problem()
+        if self._context._npn_advertise_helper is not None:
+            self._context._npn_advertise_helper.raise_if_problem()
+        if self._context._npn_select_helper is not None:
+            self._context._npn_select_helper.raise_if_problem()
+        if self._context._alpn_select_helper is not None:
+            self._context._alpn_select_helper.raise_if_problem()
+        if self._context._ocsp_helper is not None:
+            self._context._ocsp_helper.raise_if_problem()
+
+        error = _lib.SSL_get_error(ssl, result)
+        if error == _lib.SSL_ERROR_WANT_READ:
+            raise WantReadError()
+        elif error == _lib.SSL_ERROR_WANT_WRITE:
+            raise WantWriteError()
+        elif error == _lib.SSL_ERROR_ZERO_RETURN:
+            raise ZeroReturnError()
+        elif error == _lib.SSL_ERROR_WANT_X509_LOOKUP:
+            # TODO: This is untested.
+            raise WantX509LookupError()
+        elif error == _lib.SSL_ERROR_SYSCALL:
+            if _lib.ERR_peek_error() == 0:
+                if result < 0:
+                    if platform == "win32":
+                        errno = _ffi.getwinerror()[0]
+                    else:
+                        errno = _ffi.errno
+
+                    if errno != 0:
+                        raise SysCallError(errno, errorcode.get(errno))
+                raise SysCallError(-1, "Unexpected EOF")
+            else:
+                # TODO: This is untested.
+                _raise_current_error()
+        elif error == _lib.SSL_ERROR_NONE:
+            pass
+        else:
+            _raise_current_error()
+
+    def get_context(self):
+        """
+        Retrieve the :class:`Context` object associated with this
+        :class:`Connection`.
+        """
+        return self._context
+
+    def set_context(self, context):
+        """
+        Switch this connection to a new session context.
+
+        :param context: A :class:`Context` instance giving the new session
+            context to use.
+        """
+        if not isinstance(context, Context):
+            raise TypeError("context must be a Context instance")
+
+        _lib.SSL_set_SSL_CTX(self._ssl, context._context)
+        self._context = context
+
+    @_requires_sni
+    def get_servername(self):
+        """
+        Retrieve the servername extension value if provided in the client hello
+        message, or None if there wasn't one.
+
+        :return: A byte string giving the server name or :data:`None`.
+
+        .. versionadded:: 0.13
+        """
+        name = _lib.SSL_get_servername(
+            self._ssl, _lib.TLSEXT_NAMETYPE_host_name
+        )
+        if name == _ffi.NULL:
+            return None
+
+        return _ffi.string(name)
+
+    @_requires_sni
+    def set_tlsext_host_name(self, name):
+        """
+        Set the value of the servername extension to send in the client hello.
+
+        :param name: A byte string giving the name.
+
+        .. versionadded:: 0.13
+        """
+        if not isinstance(name, bytes):
+            raise TypeError("name must be a byte string")
+        elif b"\0" in name:
+            raise TypeError("name must not contain NUL byte")
+
+        # XXX I guess this can fail sometimes?
+        _lib.SSL_set_tlsext_host_name(self._ssl, name)
+
+    def pending(self):
+        """
+        Get the number of bytes that can be safely read from the SSL buffer
+        (**not** the underlying transport buffer).
+
+        :return: The number of bytes available in the receive buffer.
+        """
+        return _lib.SSL_pending(self._ssl)
+
+    def send(self, buf, flags=0):
+        """
+        Send data on the connection. NOTE: If you get one of the WantRead,
+        WantWrite or WantX509Lookup exceptions on this, you have to call the
+        method again with the SAME buffer.
+
+        :param buf: The string, buffer or memoryview to send
+        :param flags: (optional) Included for compatibility with the socket
+                      API, the value is ignored
+        :return: The number of bytes written
+        """
+        # Backward compatibility
+        buf = _text_to_bytes_and_warn("buf", buf)
+
+        if isinstance(buf, memoryview):
+            buf = buf.tobytes()
+        if isinstance(buf, _buffer):
+            buf = str(buf)
+        if not isinstance(buf, bytes):
+            raise TypeError("data must be a memoryview, buffer or byte string")
+        if len(buf) > 2147483647:
+            raise ValueError("Cannot send more than 2**31-1 bytes at once.")
+
+        result = _lib.SSL_write(self._ssl, buf, len(buf))
+        self._raise_ssl_error(self._ssl, result)
+        return result
+    write = send
+
+    def sendall(self, buf, flags=0):
+        """
+        Send "all" data on the connection. This calls send() repeatedly until
+        all data is sent. If an error occurs, it's impossible to tell how much
+        data has been sent.
+
+        :param buf: The string, buffer or memoryview to send
+        :param flags: (optional) Included for compatibility with the socket
+                      API, the value is ignored
+        :return: The number of bytes written
+        """
+        buf = _text_to_bytes_and_warn("buf", buf)
+
+        if isinstance(buf, memoryview):
+            buf = buf.tobytes()
+        if isinstance(buf, _buffer):
+            buf = str(buf)
+        if not isinstance(buf, bytes):
+            raise TypeError("buf must be a memoryview, buffer or byte string")
+
+        left_to_send = len(buf)
+        total_sent = 0
+        data = _ffi.new("char[]", buf)
+
+        while left_to_send:
+            # SSL_write's num arg is an int,
+            # so we cannot send more than 2**31-1 bytes at once.
+            result = _lib.SSL_write(
+                self._ssl,
+                data + total_sent,
+                min(left_to_send, 2147483647)
+            )
+            self._raise_ssl_error(self._ssl, result)
+            total_sent += result
+            left_to_send -= result
+
+    def recv(self, bufsiz, flags=None):
+        """
+        Receive data on the connection.
+
+        :param bufsiz: The maximum number of bytes to read
+        :param flags: (optional) The only supported flag is ``MSG_PEEK``,
+            all other flags are ignored.
+        :return: The string read from the Connection
+        """
+        buf = _no_zero_allocator("char[]", bufsiz)
+        if flags is not None and flags & socket.MSG_PEEK:
+            result = _lib.SSL_peek(self._ssl, buf, bufsiz)
+        else:
+            result = _lib.SSL_read(self._ssl, buf, bufsiz)
+        self._raise_ssl_error(self._ssl, result)
+        return _ffi.buffer(buf, result)[:]
+    read = recv
+
+    def recv_into(self, buffer, nbytes=None, flags=None):
+        """
+        Receive data on the connection and copy it directly into the provided
+        buffer, rather than creating a new string.
+
+        :param buffer: The buffer to copy into.
+        :param nbytes: (optional) The maximum number of bytes to read into the
+            buffer. If not present, defaults to the size of the buffer. If
+            larger than the size of the buffer, is reduced to the size of the
+            buffer.
+        :param flags: (optional) The only supported flag is ``MSG_PEEK``,
+            all other flags are ignored.
+        :return: The number of bytes read into the buffer.
+        """
+        if nbytes is None:
+            nbytes = len(buffer)
+        else:
+            nbytes = min(nbytes, len(buffer))
+
+        # We need to create a temporary buffer. This is annoying, it would be
+        # better if we could pass memoryviews straight into the SSL_read call,
+        # but right now we can't. Revisit this if CFFI gets that ability.
+        buf = _no_zero_allocator("char[]", nbytes)
+        if flags is not None and flags & socket.MSG_PEEK:
+            result = _lib.SSL_peek(self._ssl, buf, nbytes)
+        else:
+            result = _lib.SSL_read(self._ssl, buf, nbytes)
+        self._raise_ssl_error(self._ssl, result)
+
+        # This strange line is all to avoid a memory copy. The buffer protocol
+        # should allow us to assign a CFFI buffer to the LHS of this line, but
+        # on CPython 3.3+ that segfaults. As a workaround, we can temporarily
+        # wrap it in a memoryview.
+        buffer[:result] = memoryview(_ffi.buffer(buf, result))
+
+        return result
+
+    def _handle_bio_errors(self, bio, result):
+        if _lib.BIO_should_retry(bio):
+            if _lib.BIO_should_read(bio):
+                raise WantReadError()
+            elif _lib.BIO_should_write(bio):
+                # TODO: This is untested.
+                raise WantWriteError()
+            elif _lib.BIO_should_io_special(bio):
+                # TODO: This is untested.  I think io_special means the socket
+                # BIO has a not-yet connected socket.
+                raise ValueError("BIO_should_io_special")
+            else:
+                # TODO: This is untested.
+                raise ValueError("unknown bio failure")
+        else:
+            # TODO: This is untested.
+            _raise_current_error()
+
+    def bio_read(self, bufsiz):
+        """
+        If the Connection was created with a memory BIO, this method can be
+        used to read bytes from the write end of that memory BIO.  Many
+        Connection methods will add bytes which must be read in this manner or
+        the buffer will eventually fill up and the Connection will be able to
+        take no further actions.
+
+        :param bufsiz: The maximum number of bytes to read
+        :return: The string read.
+        """
+        if self._from_ssl is None:
+            raise TypeError("Connection sock was not None")
+
+        if not isinstance(bufsiz, integer_types):
+            raise TypeError("bufsiz must be an integer")
+
+        buf = _no_zero_allocator("char[]", bufsiz)
+        result = _lib.BIO_read(self._from_ssl, buf, bufsiz)
+        if result <= 0:
+            self._handle_bio_errors(self._from_ssl, result)
+
+        return _ffi.buffer(buf, result)[:]
+
+    def bio_write(self, buf):
+        """
+        If the Connection was created with a memory BIO, this method can be
+        used to add bytes to the read end of that memory BIO.  The Connection
+        can then read the bytes (for example, in response to a call to
+        :meth:`recv`).
+
+        :param buf: The string to put into the memory BIO.
+        :return: The number of bytes written
+        """
+        buf = _text_to_bytes_and_warn("buf", buf)
+
+        if self._into_ssl is None:
+            raise TypeError("Connection sock was not None")
+
+        result = _lib.BIO_write(self._into_ssl, buf, len(buf))
+        if result <= 0:
+            self._handle_bio_errors(self._into_ssl, result)
+        return result
+
+    def renegotiate(self):
+        """
+        Renegotiate the session.
+
+        :return: True if the renegotiation can be started, False otherwise
+        :rtype: bool
+        """
+        if not self.renegotiate_pending():
+            _openssl_assert(_lib.SSL_renegotiate(self._ssl) == 1)
+            return True
+        return False
+
+    def do_handshake(self):
+        """
+        Perform an SSL handshake (usually called after :meth:`renegotiate` or
+        one of :meth:`set_accept_state` or :meth:`set_accept_state`). This can
+        raise the same exceptions as :meth:`send` and :meth:`recv`.
+
+        :return: None.
+        """
+        result = _lib.SSL_do_handshake(self._ssl)
+        self._raise_ssl_error(self._ssl, result)
+
+    def renegotiate_pending(self):
+        """
+        Check if there's a renegotiation in progress, it will return False once
+        a renegotiation is finished.
+
+        :return: Whether there's a renegotiation in progress
+        :rtype: bool
+        """
+        return _lib.SSL_renegotiate_pending(self._ssl) == 1
+
+    def total_renegotiations(self):
+        """
+        Find out the total number of renegotiations.
+
+        :return: The number of renegotiations.
+        :rtype: int
+        """
+        return _lib.SSL_total_renegotiations(self._ssl)
+
+    def connect(self, addr):
+        """
+        Call the :meth:`connect` method of the underlying socket and set up SSL
+        on the socket, using the :class:`Context` object supplied to this
+        :class:`Connection` object at creation.
+
+        :param addr: A remote address
+        :return: What the socket's connect method returns
+        """
+        _lib.SSL_set_connect_state(self._ssl)
+        return self._socket.connect(addr)
+
+    def connect_ex(self, addr):
+        """
+        Call the :meth:`connect_ex` method of the underlying socket and set up
+        SSL on the socket, using the Context object supplied to this Connection
+        object at creation. Note that if the :meth:`connect_ex` method of the
+        socket doesn't return 0, SSL won't be initialized.
+
+        :param addr: A remove address
+        :return: What the socket's connect_ex method returns
+        """
+        connect_ex = self._socket.connect_ex
+        self.set_connect_state()
+        return connect_ex(addr)
+
+    def accept(self):
+        """
+        Call the :meth:`accept` method of the underlying socket and set up SSL
+        on the returned socket, using the Context object supplied to this
+        :class:`Connection` object at creation.
+
+        :return: A *(conn, addr)* pair where *conn* is the new
+            :class:`Connection` object created, and *address* is as returned by
+            the socket's :meth:`accept`.
+        """
+        client, addr = self._socket.accept()
+        conn = Connection(self._context, client)
+        conn.set_accept_state()
+        return (conn, addr)
+
+    def bio_shutdown(self):
+        """
+        If the Connection was created with a memory BIO, this method can be
+        used to indicate that *end of file* has been reached on the read end of
+        that memory BIO.
+
+        :return: None
+        """
+        if self._from_ssl is None:
+            raise TypeError("Connection sock was not None")
+
+        _lib.BIO_set_mem_eof_return(self._into_ssl, 0)
+
+    def shutdown(self):
+        """
+        Send the shutdown message to the Connection.
+
+        :return: True if the shutdown completed successfully (i.e. both sides
+                 have sent closure alerts), False otherwise (in which case you
+                 call :meth:`recv` or :meth:`send` when the connection becomes
+                 readable/writeable).
+        """
+        result = _lib.SSL_shutdown(self._ssl)
+        if result < 0:
+            self._raise_ssl_error(self._ssl, result)
+        elif result > 0:
+            return True
+        else:
+            return False
+
+    def get_cipher_list(self):
+        """
+        Retrieve the list of ciphers used by the Connection object.
+
+        :return: A list of native cipher strings.
+        """
+        ciphers = []
+        for i in count():
+            result = _lib.SSL_get_cipher_list(self._ssl, i)
+            if result == _ffi.NULL:
+                break
+            ciphers.append(_native(_ffi.string(result)))
+        return ciphers
+
+    def get_client_ca_list(self):
+        """
+        Get CAs whose certificates are suggested for client authentication.
+
+        :return: If this is a server connection, the list of certificate
+            authorities that will be sent or has been sent to the client, as
+            controlled by this :class:`Connection`'s :class:`Context`.
+
+            If this is a client connection, the list will be empty until the
+            connection with the server is established.
+
+        .. versionadded:: 0.10
+        """
+        ca_names = _lib.SSL_get_client_CA_list(self._ssl)
+        if ca_names == _ffi.NULL:
+            # TODO: This is untested.
+            return []
+
+        result = []
+        for i in range(_lib.sk_X509_NAME_num(ca_names)):
+            name = _lib.sk_X509_NAME_value(ca_names, i)
+            copy = _lib.X509_NAME_dup(name)
+            _openssl_assert(copy != _ffi.NULL)
+
+            pyname = X509Name.__new__(X509Name)
+            pyname._name = _ffi.gc(copy, _lib.X509_NAME_free)
+            result.append(pyname)
+        return result
+
+    def makefile(self, *args, **kwargs):
+        """
+        The makefile() method is not implemented, since there is no dup
+        semantics for SSL connections
+
+        :raise: NotImplementedError
+        """
+        raise NotImplementedError(
+            "Cannot make file object of OpenSSL.SSL.Connection")
+
+    def get_app_data(self):
+        """
+        Retrieve application data as set by :meth:`set_app_data`.
+
+        :return: The application data
+        """
+        return self._app_data
+
+    def set_app_data(self, data):
+        """
+        Set application data
+
+        :param data: The application data
+        :return: None
+        """
+        self._app_data = data
+
+    def get_shutdown(self):
+        """
+        Get the shutdown state of the Connection.
+
+        :return: The shutdown state, a bitvector of SENT_SHUTDOWN,
+            RECEIVED_SHUTDOWN.
+        """
+        return _lib.SSL_get_shutdown(self._ssl)
+
+    def set_shutdown(self, state):
+        """
+        Set the shutdown state of the Connection.
+
+        :param state: bitvector of SENT_SHUTDOWN, RECEIVED_SHUTDOWN.
+        :return: None
+        """
+        if not isinstance(state, integer_types):
+            raise TypeError("state must be an integer")
+
+        _lib.SSL_set_shutdown(self._ssl, state)
+
+    def get_state_string(self):
+        """
+        Retrieve a verbose string detailing the state of the Connection.
+
+        :return: A string representing the state
+        :rtype: bytes
+        """
+        return _ffi.string(_lib.SSL_state_string_long(self._ssl))
+
+    def server_random(self):
+        """
+        Retrieve the random value used with the server hello message.
+
+        :return: A string representing the state
+        """
+        session = _lib.SSL_get_session(self._ssl)
+        if session == _ffi.NULL:
+            return None
+        length = _lib.SSL_get_server_random(self._ssl, _ffi.NULL, 0)
+        assert length > 0
+        outp = _no_zero_allocator("unsigned char[]", length)
+        _lib.SSL_get_server_random(self._ssl, outp, length)
+        return _ffi.buffer(outp, length)[:]
+
+    def client_random(self):
+        """
+        Retrieve the random value used with the client hello message.
+
+        :return: A string representing the state
+        """
+        session = _lib.SSL_get_session(self._ssl)
+        if session == _ffi.NULL:
+            return None
+
+        length = _lib.SSL_get_client_random(self._ssl, _ffi.NULL, 0)
+        assert length > 0
+        outp = _no_zero_allocator("unsigned char[]", length)
+        _lib.SSL_get_client_random(self._ssl, outp, length)
+        return _ffi.buffer(outp, length)[:]
+
+    def master_key(self):
+        """
+        Retrieve the value of the master key for this session.
+
+        :return: A string representing the state
+        """
+        session = _lib.SSL_get_session(self._ssl)
+        if session == _ffi.NULL:
+            return None
+
+        length = _lib.SSL_SESSION_get_master_key(session, _ffi.NULL, 0)
+        assert length > 0
+        outp = _no_zero_allocator("unsigned char[]", length)
+        _lib.SSL_SESSION_get_master_key(session, outp, length)
+        return _ffi.buffer(outp, length)[:]
+
+    def export_keying_material(self, label, olen, context=None):
+        """
+        Obtain keying material for application use.
+
+        :param: label - a disambiguating label string as described in RFC 5705
+        :param: olen - the length of the exported key material in bytes
+        :param: context - a per-association context value
+        :return: the exported key material bytes or None
+        """
+        outp = _no_zero_allocator("unsigned char[]", olen)
+        context_buf = _ffi.NULL
+        context_len = 0
+        use_context = 0
+        if context is not None:
+            context_buf = context
+            context_len = len(context)
+            use_context = 1
+        success = _lib.SSL_export_keying_material(self._ssl, outp, olen,
+                                                  label, len(label),
+                                                  context_buf, context_len,
+                                                  use_context)
+        _openssl_assert(success == 1)
+        return _ffi.buffer(outp, olen)[:]
+
+    def sock_shutdown(self, *args, **kwargs):
+        """
+        Call the :meth:`shutdown` method of the underlying socket.
+        See :manpage:`shutdown(2)`.
+
+        :return: What the socket's shutdown() method returns
+        """
+        return self._socket.shutdown(*args, **kwargs)
+
+    def get_certificate(self):
+        """
+        Retrieve the local certificate (if any)
+
+        :return: The local certificate
+        """
+        cert = _lib.SSL_get_certificate(self._ssl)
+        if cert != _ffi.NULL:
+            _lib.X509_up_ref(cert)
+            return X509._from_raw_x509_ptr(cert)
+        return None
+
+    def get_peer_certificate(self):
+        """
+        Retrieve the other side's certificate (if any)
+
+        :return: The peer's certificate
+        """
+        cert = _lib.SSL_get_peer_certificate(self._ssl)
+        if cert != _ffi.NULL:
+            return X509._from_raw_x509_ptr(cert)
+        return None
+
+    def get_peer_cert_chain(self):
+        """
+        Retrieve the other side's certificate (if any)
+
+        :return: A list of X509 instances giving the peer's certificate chain,
+                 or None if it does not have one.
+        """
+        cert_stack = _lib.SSL_get_peer_cert_chain(self._ssl)
+        if cert_stack == _ffi.NULL:
+            return None
+
+        result = []
+        for i in range(_lib.sk_X509_num(cert_stack)):
+            # TODO could incref instead of dup here
+            cert = _lib.X509_dup(_lib.sk_X509_value(cert_stack, i))
+            pycert = X509._from_raw_x509_ptr(cert)
+            result.append(pycert)
+        return result
+
+    def want_read(self):
+        """
+        Checks if more data has to be read from the transport layer to complete
+        an operation.
+
+        :return: True iff more data has to be read
+        """
+        return _lib.SSL_want_read(self._ssl)
+
+    def want_write(self):
+        """
+        Checks if there is data to write to the transport layer to complete an
+        operation.
+
+        :return: True iff there is data to write
+        """
+        return _lib.SSL_want_write(self._ssl)
+
+    def set_accept_state(self):
+        """
+        Set the connection to work in server mode. The handshake will be
+        handled automatically by read/write.
+
+        :return: None
+        """
+        _lib.SSL_set_accept_state(self._ssl)
+
+    def set_connect_state(self):
+        """
+        Set the connection to work in client mode. The handshake will be
+        handled automatically by read/write.
+
+        :return: None
+        """
+        _lib.SSL_set_connect_state(self._ssl)
+
+    def get_session(self):
+        """
+        Returns the Session currently used.
+
+        :return: An instance of :class:`OpenSSL.SSL.Session` or
+            :obj:`None` if no session exists.
+
+        .. versionadded:: 0.14
+        """
+        session = _lib.SSL_get1_session(self._ssl)
+        if session == _ffi.NULL:
+            return None
+
+        pysession = Session.__new__(Session)
+        pysession._session = _ffi.gc(session, _lib.SSL_SESSION_free)
+        return pysession
+
+    def set_session(self, session):
+        """
+        Set the session to be used when the TLS/SSL connection is established.
+
+        :param session: A Session instance representing the session to use.
+        :returns: None
+
+        .. versionadded:: 0.14
+        """
+        if not isinstance(session, Session):
+            raise TypeError("session must be a Session instance")
+
+        result = _lib.SSL_set_session(self._ssl, session._session)
+        if not result:
+            _raise_current_error()
+
+    def _get_finished_message(self, function):
+        """
+        Helper to implement :meth:`get_finished` and
+        :meth:`get_peer_finished`.
+
+        :param function: Either :data:`SSL_get_finished`: or
+            :data:`SSL_get_peer_finished`.
+
+        :return: :data:`None` if the desired message has not yet been
+            received, otherwise the contents of the message.
+        :rtype: :class:`bytes` or :class:`NoneType`
+        """
+        # The OpenSSL documentation says nothing about what might happen if the
+        # count argument given is zero.  Specifically, it doesn't say whether
+        # the output buffer may be NULL in that case or not.  Inspection of the
+        # implementation reveals that it calls memcpy() unconditionally.
+        # Section 7.1.4, paragraph 1 of the C standard suggests that
+        # memcpy(NULL, source, 0) is not guaranteed to produce defined (let
+        # alone desirable) behavior (though it probably does on just about
+        # every implementation...)
+        #
+        # Allocate a tiny buffer to pass in (instead of just passing NULL as
+        # one might expect) for the initial call so as to be safe against this
+        # potentially undefined behavior.
+        empty = _ffi.new("char[]", 0)
+        size = function(self._ssl, empty, 0)
+        if size == 0:
+            # No Finished message so far.
+            return None
+
+        buf = _no_zero_allocator("char[]", size)
+        function(self._ssl, buf, size)
+        return _ffi.buffer(buf, size)[:]
+
+    def get_finished(self):
+        """
+        Obtain the latest TLS Finished message that we sent.
+
+        :return: The contents of the message or :obj:`None` if the TLS
+            handshake has not yet completed.
+        :rtype: :class:`bytes` or :class:`NoneType`
+
+        .. versionadded:: 0.15
+        """
+        return self._get_finished_message(_lib.SSL_get_finished)
+
+    def get_peer_finished(self):
+        """
+        Obtain the latest TLS Finished message that we received from the peer.
+
+        :return: The contents of the message or :obj:`None` if the TLS
+            handshake has not yet completed.
+        :rtype: :class:`bytes` or :class:`NoneType`
+
+        .. versionadded:: 0.15
+        """
+        return self._get_finished_message(_lib.SSL_get_peer_finished)
+
+    def get_cipher_name(self):
+        """
+        Obtain the name of the currently used cipher.
+
+        :returns: The name of the currently used cipher or :obj:`None`
+            if no connection has been established.
+        :rtype: :class:`unicode` or :class:`NoneType`
+
+        .. versionadded:: 0.15
+        """
+        cipher = _lib.SSL_get_current_cipher(self._ssl)
+        if cipher == _ffi.NULL:
+            return None
+        else:
+            name = _ffi.string(_lib.SSL_CIPHER_get_name(cipher))
+            return name.decode("utf-8")
+
+    def get_cipher_bits(self):
+        """
+        Obtain the number of secret bits of the currently used cipher.
+
+        :returns: The number of secret bits of the currently used cipher
+            or :obj:`None` if no connection has been established.
+        :rtype: :class:`int` or :class:`NoneType`
+
+        .. versionadded:: 0.15
+        """
+        cipher = _lib.SSL_get_current_cipher(self._ssl)
+        if cipher == _ffi.NULL:
+            return None
+        else:
+            return _lib.SSL_CIPHER_get_bits(cipher, _ffi.NULL)
+
+    def get_cipher_version(self):
+        """
+        Obtain the protocol version of the currently used cipher.
+
+        :returns: The protocol name of the currently used cipher
+            or :obj:`None` if no connection has been established.
+        :rtype: :class:`unicode` or :class:`NoneType`
+
+        .. versionadded:: 0.15
+        """
+        cipher = _lib.SSL_get_current_cipher(self._ssl)
+        if cipher == _ffi.NULL:
+            return None
+        else:
+            version = _ffi.string(_lib.SSL_CIPHER_get_version(cipher))
+            return version.decode("utf-8")
+
+    def get_protocol_version_name(self):
+        """
+        Retrieve the protocol version of the current connection.
+
+        :returns: The TLS version of the current connection, for example
+            the value for TLS 1.2 would be ``TLSv1.2``or ``Unknown``
+            for connections that were not successfully established.
+        :rtype: :class:`unicode`
+        """
+        version = _ffi.string(_lib.SSL_get_version(self._ssl))
+        return version.decode("utf-8")
+
+    def get_protocol_version(self):
+        """
+        Retrieve the SSL or TLS protocol version of the current connection.
+
+        :returns: The TLS version of the current connection.  For example,
+            it will return ``0x769`` for connections made over TLS version 1.
+        :rtype: :class:`int`
+        """
+        version = _lib.SSL_version(self._ssl)
+        return version
+
+    @_requires_npn
+    def get_next_proto_negotiated(self):
+        """
+        Get the protocol that was negotiated by NPN.
+
+        :returns: A bytestring of the protocol name.  If no protocol has been
+            negotiated yet, returns an empty string.
+
+        .. versionadded:: 0.15
+        """
+        data = _ffi.new("unsigned char **")
+        data_len = _ffi.new("unsigned int *")
+
+        _lib.SSL_get0_next_proto_negotiated(self._ssl, data, data_len)
+
+        return _ffi.buffer(data[0], data_len[0])[:]
+
+    @_requires_alpn
+    def set_alpn_protos(self, protos):
+        """
+        Specify the client's ALPN protocol list.
+
+        These protocols are offered to the server during protocol negotiation.
+
+        :param protos: A list of the protocols to be offered to the server.
+            This list should be a Python list of bytestrings representing the
+            protocols to offer, e.g. ``[b'http/1.1', b'spdy/2']``.
+        """
+        # Take the list of protocols and join them together, prefixing them
+        # with their lengths.
+        protostr = b''.join(
+            chain.from_iterable((int2byte(len(p)), p) for p in protos)
+        )
+
+        # Build a C string from the list. We don't need to save this off
+        # because OpenSSL immediately copies the data out.
+        input_str = _ffi.new("unsigned char[]", protostr)
+        _lib.SSL_set_alpn_protos(self._ssl, input_str, len(protostr))
+
+    @_requires_alpn
+    def get_alpn_proto_negotiated(self):
+        """
+        Get the protocol that was negotiated by ALPN.
+
+        :returns: A bytestring of the protocol name.  If no protocol has been
+            negotiated yet, returns an empty string.
+        """
+        data = _ffi.new("unsigned char **")
+        data_len = _ffi.new("unsigned int *")
+
+        _lib.SSL_get0_alpn_selected(self._ssl, data, data_len)
+
+        if not data_len:
+            return b''
+
+        return _ffi.buffer(data[0], data_len[0])[:]
+
+    def request_ocsp(self):
+        """
+        Called to request that the server sends stapled OCSP data, if
+        available. If this is not called on the client side then the server
+        will not send OCSP data. Should be used in conjunction with
+        :meth:`Context.set_ocsp_client_callback`.
+        """
+        rc = _lib.SSL_set_tlsext_status_type(
+            self._ssl, _lib.TLSEXT_STATUSTYPE_ocsp
+        )
+        _openssl_assert(rc == 1)
+
+
+ConnectionType = deprecated(
+    Connection, __name__,
+    "ConnectionType has been deprecated, use Connection instead",
+    DeprecationWarning
+)
+
+# This is similar to the initialization calls at the end of OpenSSL/crypto.py
+# but is exercised mostly by the Context initializer.
+_lib.SSL_library_init()
diff --git a/src/OpenSSL/__init__.py b/src/OpenSSL/__init__.py
new file mode 100644
index 0000000..810d00d
--- /dev/null
+++ b/src/OpenSSL/__init__.py
@@ -0,0 +1,20 @@
+# Copyright (C) AB Strakt
+# See LICENSE for details.
+
+"""
+pyOpenSSL - A simple wrapper around the OpenSSL library
+"""
+
+from OpenSSL import crypto, SSL
+from OpenSSL.version import (
+    __author__, __copyright__, __email__, __license__, __summary__, __title__,
+    __uri__, __version__,
+)
+
+
+__all__ = [
+    "SSL", "crypto",
+
+    "__author__", "__copyright__", "__email__", "__license__", "__summary__",
+    "__title__", "__uri__", "__version__",
+]
diff --git a/src/OpenSSL/_util.py b/src/OpenSSL/_util.py
new file mode 100644
index 0000000..cf8b888
--- /dev/null
+++ b/src/OpenSSL/_util.py
@@ -0,0 +1,147 @@
+import sys
+import warnings
+
+from six import PY3, binary_type, text_type
+
+from cryptography.hazmat.bindings.openssl.binding import Binding
+
+
+binding = Binding()
+binding.init_static_locks()
+ffi = binding.ffi
+lib = binding.lib
+
+
+# This is a special CFFI allocator that does not bother to zero its memory
+# after allocation. This has vastly better performance on large allocations and
+# so should be used whenever we don't need the memory zeroed out.
+no_zero_allocator = ffi.new_allocator(should_clear_after_alloc=False)
+
+
+def text(charp):
+    """
+    Get a native string type representing of the given CFFI ``char*`` object.
+
+    :param charp: A C-style string represented using CFFI.
+
+    :return: :class:`str`
+    """
+    if not charp:
+        return ""
+    return native(ffi.string(charp))
+
+
+def exception_from_error_queue(exception_type):
+    """
+    Convert an OpenSSL library failure into a Python exception.
+
+    When a call to the native OpenSSL library fails, this is usually signalled
+    by the return value, and an error code is stored in an error queue
+    associated with the current thread. The err library provides functions to
+    obtain these error codes and textual error messages.
+    """
+    errors = []
+
+    while True:
+        error = lib.ERR_get_error()
+        if error == 0:
+            break
+        errors.append((
+            text(lib.ERR_lib_error_string(error)),
+            text(lib.ERR_func_error_string(error)),
+            text(lib.ERR_reason_error_string(error))))
+
+    raise exception_type(errors)
+
+
+def make_assert(error):
+    """
+    Create an assert function that uses :func:`exception_from_error_queue` to
+    raise an exception wrapped by *error*.
+    """
+    def openssl_assert(ok):
+        """
+        If *ok* is not True, retrieve the error from OpenSSL and raise it.
+        """
+        if ok is not True:
+            exception_from_error_queue(error)
+
+    return openssl_assert
+
+
+def native(s):
+    """
+    Convert :py:class:`bytes` or :py:class:`unicode` to the native
+    :py:class:`str` type, using UTF-8 encoding if conversion is necessary.
+
+    :raise UnicodeError: The input string is not UTF-8 decodeable.
+
+    :raise TypeError: The input is neither :py:class:`bytes` nor
+        :py:class:`unicode`.
+    """
+    if not isinstance(s, (binary_type, text_type)):
+        raise TypeError("%r is neither bytes nor unicode" % s)
+    if PY3:
+        if isinstance(s, binary_type):
+            return s.decode("utf-8")
+    else:
+        if isinstance(s, text_type):
+            return s.encode("utf-8")
+    return s
+
+
+def path_string(s):
+    """
+    Convert a Python string to a :py:class:`bytes` string identifying the same
+    path and which can be passed into an OpenSSL API accepting a filename.
+
+    :param s: An instance of :py:class:`bytes` or :py:class:`unicode`.
+
+    :return: An instance of :py:class:`bytes`.
+    """
+    if isinstance(s, binary_type):
+        return s
+    elif isinstance(s, text_type):
+        return s.encode(sys.getfilesystemencoding())
+    else:
+        raise TypeError("Path must be represented as bytes or unicode string")
+
+
+if PY3:
+    def byte_string(s):
+        return s.encode("charmap")
+else:
+    def byte_string(s):
+        return s
+
+
+# A marker object to observe whether some optional arguments are passed any
+# value or not.
+UNSPECIFIED = object()
+
+_TEXT_WARNING = (
+    text_type.__name__ + " for {0} is no longer accepted, use bytes"
+)
+
+
+def text_to_bytes_and_warn(label, obj):
+    """
+    If ``obj`` is text, emit a warning that it should be bytes instead and try
+    to convert it to bytes automatically.
+
+    :param str label: The name of the parameter from which ``obj`` was taken
+        (so a developer can easily find the source of the problem and correct
+        it).
+
+    :return: If ``obj`` is the text string type, a ``bytes`` object giving the
+        UTF-8 encoding of that text is returned.  Otherwise, ``obj`` itself is
+        returned.
+    """
+    if isinstance(obj, text_type):
+        warnings.warn(
+            _TEXT_WARNING.format(label),
+            category=DeprecationWarning,
+            stacklevel=3
+        )
+        return obj.encode('utf-8')
+    return obj
diff --git a/src/OpenSSL/crypto.py b/src/OpenSSL/crypto.py
new file mode 100644
index 0000000..12e92df
--- /dev/null
+++ b/src/OpenSSL/crypto.py
@@ -0,0 +1,3135 @@
+import datetime
+
+from base64 import b16encode
+from functools import partial
+from operator import __eq__, __ne__, __lt__, __le__, __gt__, __ge__
+
+from six import (
+    integer_types as _integer_types,
+    text_type as _text_type,
+    PY3 as _PY3)
+
+from cryptography import x509
+from cryptography.hazmat.primitives.asymmetric import dsa, rsa
+from cryptography.utils import deprecated
+
+from OpenSSL._util import (
+    ffi as _ffi,
+    lib as _lib,
+    exception_from_error_queue as _exception_from_error_queue,
+    byte_string as _byte_string,
+    native as _native,
+    UNSPECIFIED as _UNSPECIFIED,
+    text_to_bytes_and_warn as _text_to_bytes_and_warn,
+    make_assert as _make_assert,
+)
+
+__all__ = [
+    'FILETYPE_PEM',
+    'FILETYPE_ASN1',
+    'FILETYPE_TEXT',
+    'TYPE_RSA',
+    'TYPE_DSA',
+    'Error',
+    'PKey',
+    'get_elliptic_curves',
+    'get_elliptic_curve',
+    'X509Name',
+    'X509Extension',
+    'X509Req',
+    'X509',
+    'X509StoreFlags',
+    'X509Store',
+    'X509StoreContextError',
+    'X509StoreContext',
+    'load_certificate',
+    'dump_certificate',
+    'dump_publickey',
+    'dump_privatekey',
+    'Revoked',
+    'CRL',
+    'PKCS7',
+    'PKCS12',
+    'NetscapeSPKI',
+    'load_publickey',
+    'load_privatekey',
+    'dump_certificate_request',
+    'load_certificate_request',
+    'sign',
+    'verify',
+    'dump_crl',
+    'load_crl',
+    'load_pkcs7_data',
+    'load_pkcs12'
+]
+
+FILETYPE_PEM = _lib.SSL_FILETYPE_PEM
+FILETYPE_ASN1 = _lib.SSL_FILETYPE_ASN1
+
+# TODO This was an API mistake.  OpenSSL has no such constant.
+FILETYPE_TEXT = 2 ** 16 - 1
+
+TYPE_RSA = _lib.EVP_PKEY_RSA
+TYPE_DSA = _lib.EVP_PKEY_DSA
+TYPE_DH = _lib.EVP_PKEY_DH
+TYPE_EC = _lib.EVP_PKEY_EC
+
+
+class Error(Exception):
+    """
+    An error occurred in an `OpenSSL.crypto` API.
+    """
+
+
+_raise_current_error = partial(_exception_from_error_queue, Error)
+_openssl_assert = _make_assert(Error)
+
+
+def _get_backend():
+    """
+    Importing the backend from cryptography has the side effect of activating
+    the osrandom engine. This mutates the global state of OpenSSL in the
+    process and causes issues for various programs that use subinterpreters or
+    embed Python. By putting the import in this function we can avoid
+    triggering this side effect unless _get_backend is called.
+    """
+    from cryptography.hazmat.backends.openssl.backend import backend
+    return backend
+
+
+def _untested_error(where):
+    """
+    An OpenSSL API failed somehow.  Additionally, the failure which was
+    encountered isn't one that's exercised by the test suite so future behavior
+    of pyOpenSSL is now somewhat less predictable.
+    """
+    raise RuntimeError("Unknown %s failure" % (where,))
+
+
+def _new_mem_buf(buffer=None):
+    """
+    Allocate a new OpenSSL memory BIO.
+
+    Arrange for the garbage collector to clean it up automatically.
+
+    :param buffer: None or some bytes to use to put into the BIO so that they
+        can be read out.
+    """
+    if buffer is None:
+        bio = _lib.BIO_new(_lib.BIO_s_mem())
+        free = _lib.BIO_free
+    else:
+        data = _ffi.new("char[]", buffer)
+        bio = _lib.BIO_new_mem_buf(data, len(buffer))
+
+        # Keep the memory alive as long as the bio is alive!
+        def free(bio, ref=data):
+            return _lib.BIO_free(bio)
+
+    _openssl_assert(bio != _ffi.NULL)
+
+    bio = _ffi.gc(bio, free)
+    return bio
+
+
+def _bio_to_string(bio):
+    """
+    Copy the contents of an OpenSSL BIO object into a Python byte string.
+    """
+    result_buffer = _ffi.new('char**')
+    buffer_length = _lib.BIO_get_mem_data(bio, result_buffer)
+    return _ffi.buffer(result_buffer[0], buffer_length)[:]
+
+
+def _set_asn1_time(boundary, when):
+    """
+    The the time value of an ASN1 time object.
+
+    @param boundary: An ASN1_TIME pointer (or an object safely
+        castable to that type) which will have its value set.
+    @param when: A string representation of the desired time value.
+
+    @raise TypeError: If C{when} is not a L{bytes} string.
+    @raise ValueError: If C{when} does not represent a time in the required
+        format.
+    @raise RuntimeError: If the time value cannot be set for some other
+        (unspecified) reason.
+    """
+    if not isinstance(when, bytes):
+        raise TypeError("when must be a byte string")
+
+    set_result = _lib.ASN1_TIME_set_string(boundary, when)
+    if set_result == 0:
+        raise ValueError("Invalid string")
+
+
+def _get_asn1_time(timestamp):
+    """
+    Retrieve the time value of an ASN1 time object.
+
+    @param timestamp: An ASN1_GENERALIZEDTIME* (or an object safely castable to
+        that type) from which the time value will be retrieved.
+
+    @return: The time value from C{timestamp} as a L{bytes} string in a certain
+        format.  Or C{None} if the object contains no time value.
+    """
+    string_timestamp = _ffi.cast('ASN1_STRING*', timestamp)
+    if _lib.ASN1_STRING_length(string_timestamp) == 0:
+        return None
+    elif (
+        _lib.ASN1_STRING_type(string_timestamp) == _lib.V_ASN1_GENERALIZEDTIME
+    ):
+        return _ffi.string(_lib.ASN1_STRING_data(string_timestamp))
+    else:
+        generalized_timestamp = _ffi.new("ASN1_GENERALIZEDTIME**")
+        _lib.ASN1_TIME_to_generalizedtime(timestamp, generalized_timestamp)
+        if generalized_timestamp[0] == _ffi.NULL:
+            # This may happen:
+            #   - if timestamp was not an ASN1_TIME
+            #   - if allocating memory for the ASN1_GENERALIZEDTIME failed
+            #   - if a copy of the time data from timestamp cannot be made for
+            #     the newly allocated ASN1_GENERALIZEDTIME
+            #
+            # These are difficult to test.  cffi enforces the ASN1_TIME type.
+            # Memory allocation failures are a pain to trigger
+            # deterministically.
+            _untested_error("ASN1_TIME_to_generalizedtime")
+        else:
+            string_timestamp = _ffi.cast(
+                "ASN1_STRING*", generalized_timestamp[0])
+            string_data = _lib.ASN1_STRING_data(string_timestamp)
+            string_result = _ffi.string(string_data)
+            _lib.ASN1_GENERALIZEDTIME_free(generalized_timestamp[0])
+            return string_result
+
+
+class _X509NameInvalidator(object):
+    def __init__(self):
+        self._names = []
+
+    def add(self, name):
+        self._names.append(name)
+
+    def clear(self):
+        for name in self._names:
+            # Breaks the object, but also prevents UAF!
+            del name._name
+
+
+class PKey(object):
+    """
+    A class representing an DSA or RSA public key or key pair.
+    """
+    _only_public = False
+    _initialized = True
+
+    def __init__(self):
+        pkey = _lib.EVP_PKEY_new()
+        self._pkey = _ffi.gc(pkey, _lib.EVP_PKEY_free)
+        self._initialized = False
+
+    def to_cryptography_key(self):
+        """
+        Export as a ``cryptography`` key.
+
+        :rtype: One of ``cryptography``'s `key interfaces`_.
+
+        .. _key interfaces: https://cryptography.io/en/latest/hazmat/\
+            primitives/asymmetric/rsa/#key-interfaces
+
+        .. versionadded:: 16.1.0
+        """
+        backend = _get_backend()
+        if self._only_public:
+            return backend._evp_pkey_to_public_key(self._pkey)
+        else:
+            return backend._evp_pkey_to_private_key(self._pkey)
+
+    @classmethod
+    def from_cryptography_key(cls, crypto_key):
+        """
+        Construct based on a ``cryptography`` *crypto_key*.
+
+        :param crypto_key: A ``cryptography`` key.
+        :type crypto_key: One of ``cryptography``'s `key interfaces`_.
+
+        :rtype: PKey
+
+        .. versionadded:: 16.1.0
+        """
+        pkey = cls()
+        if not isinstance(crypto_key, (rsa.RSAPublicKey, rsa.RSAPrivateKey,
+                                       dsa.DSAPublicKey, dsa.DSAPrivateKey)):
+            raise TypeError("Unsupported key type")
+
+        pkey._pkey = crypto_key._evp_pkey
+        if isinstance(crypto_key, (rsa.RSAPublicKey, dsa.DSAPublicKey)):
+            pkey._only_public = True
+        pkey._initialized = True
+        return pkey
+
+    def generate_key(self, type, bits):
+        """
+        Generate a key pair of the given type, with the given number of bits.
+
+        This generates a key "into" the this object.
+
+        :param type: The key type.
+        :type type: :py:data:`TYPE_RSA` or :py:data:`TYPE_DSA`
+        :param bits: The number of bits.
+        :type bits: :py:data:`int` ``>= 0``
+        :raises TypeError: If :py:data:`type` or :py:data:`bits` isn't
+            of the appropriate type.
+        :raises ValueError: If the number of bits isn't an integer of
+            the appropriate size.
+        :return: ``None``
+        """
+        if not isinstance(type, int):
+            raise TypeError("type must be an integer")
+
+        if not isinstance(bits, int):
+            raise TypeError("bits must be an integer")
+
+        if type == TYPE_RSA:
+            if bits <= 0:
+                raise ValueError("Invalid number of bits")
+
+            # TODO Check error return
+            exponent = _lib.BN_new()
+            exponent = _ffi.gc(exponent, _lib.BN_free)
+            _lib.BN_set_word(exponent, _lib.RSA_F4)
+
+            rsa = _lib.RSA_new()
+
+            result = _lib.RSA_generate_key_ex(rsa, bits, exponent, _ffi.NULL)
+            _openssl_assert(result == 1)
+
+            result = _lib.EVP_PKEY_assign_RSA(self._pkey, rsa)
+            _openssl_assert(result == 1)
+
+        elif type == TYPE_DSA:
+            dsa = _lib.DSA_new()
+            _openssl_assert(dsa != _ffi.NULL)
+
+            dsa = _ffi.gc(dsa, _lib.DSA_free)
+            res = _lib.DSA_generate_parameters_ex(
+                dsa, bits, _ffi.NULL, 0, _ffi.NULL, _ffi.NULL, _ffi.NULL
+            )
+            _openssl_assert(res == 1)
+
+            _openssl_assert(_lib.DSA_generate_key(dsa) == 1)
+            _openssl_assert(_lib.EVP_PKEY_set1_DSA(self._pkey, dsa) == 1)
+        else:
+            raise Error("No such key type")
+
+        self._initialized = True
+
+    def check(self):
+        """
+        Check the consistency of an RSA private key.
+
+        This is the Python equivalent of OpenSSL's ``RSA_check_key``.
+
+        :return: ``True`` if key is consistent.
+
+        :raise OpenSSL.crypto.Error: if the key is inconsistent.
+
+        :raise TypeError: if the key is of a type which cannot be checked.
+            Only RSA keys can currently be checked.
+        """
+        if self._only_public:
+            raise TypeError("public key only")
+
+        if _lib.EVP_PKEY_type(self.type()) != _lib.EVP_PKEY_RSA:
+            raise TypeError("key type unsupported")
+
+        rsa = _lib.EVP_PKEY_get1_RSA(self._pkey)
+        rsa = _ffi.gc(rsa, _lib.RSA_free)
+        result = _lib.RSA_check_key(rsa)
+        if result:
+            return True
+        _raise_current_error()
+
+    def type(self):
+        """
+        Returns the type of the key
+
+        :return: The type of the key.
+        """
+        return _lib.EVP_PKEY_id(self._pkey)
+
+    def bits(self):
+        """
+        Returns the number of bits of the key
+
+        :return: The number of bits of the key.
+        """
+        return _lib.EVP_PKEY_bits(self._pkey)
+
+
+PKeyType = deprecated(
+    PKey, __name__,
+    "PKeyType has been deprecated, use PKey instead",
+    DeprecationWarning
+)
+
+
+class _EllipticCurve(object):
+    """
+    A representation of a supported elliptic curve.
+
+    @cvar _curves: :py:obj:`None` until an attempt is made to load the curves.
+        Thereafter, a :py:type:`set` containing :py:type:`_EllipticCurve`
+        instances each of which represents one curve supported by the system.
+    @type _curves: :py:type:`NoneType` or :py:type:`set`
+    """
+    _curves = None
+
+    if _PY3:
+        # This only necessary on Python 3.  Morever, it is broken on Python 2.
+        def __ne__(self, other):
+            """
+            Implement cooperation with the right-hand side argument of ``!=``.
+
+            Python 3 seems to have dropped this cooperation in this very narrow
+            circumstance.
+            """
+            if isinstance(other, _EllipticCurve):
+                return super(_EllipticCurve, self).__ne__(other)
+            return NotImplemented
+
+    @classmethod
+    def _load_elliptic_curves(cls, lib):
+        """
+        Get the curves supported by OpenSSL.
+
+        :param lib: The OpenSSL library binding object.
+
+        :return: A :py:type:`set` of ``cls`` instances giving the names of the
+            elliptic curves the underlying library supports.
+        """
+        num_curves = lib.EC_get_builtin_curves(_ffi.NULL, 0)
+        builtin_curves = _ffi.new('EC_builtin_curve[]', num_curves)
+        # The return value on this call should be num_curves again.  We
+        # could check it to make sure but if it *isn't* then.. what could
+        # we do? Abort the whole process, I suppose...?  -exarkun
+        lib.EC_get_builtin_curves(builtin_curves, num_curves)
+        return set(
+            cls.from_nid(lib, c.nid)
+            for c in builtin_curves)
+
+    @classmethod
+    def _get_elliptic_curves(cls, lib):
+        """
+        Get, cache, and return the curves supported by OpenSSL.
+
+        :param lib: The OpenSSL library binding object.
+
+        :return: A :py:type:`set` of ``cls`` instances giving the names of the
+            elliptic curves the underlying library supports.
+        """
+        if cls._curves is None:
+            cls._curves = cls._load_elliptic_curves(lib)
+        return cls._curves
+
+    @classmethod
+    def from_nid(cls, lib, nid):
+        """
+        Instantiate a new :py:class:`_EllipticCurve` associated with the given
+        OpenSSL NID.
+
+        :param lib: The OpenSSL library binding object.
+
+        :param nid: The OpenSSL NID the resulting curve object will represent.
+            This must be a curve NID (and not, for example, a hash NID) or
+            subsequent operations will fail in unpredictable ways.
+        :type nid: :py:class:`int`
+
+        :return: The curve object.
+        """
+        return cls(lib, nid, _ffi.string(lib.OBJ_nid2sn(nid)).decode("ascii"))
+
+    def __init__(self, lib, nid, name):
+        """
+        :param _lib: The :py:mod:`cryptography` binding instance used to
+            interface with OpenSSL.
+
+        :param _nid: The OpenSSL NID identifying the curve this object
+            represents.
+        :type _nid: :py:class:`int`
+
+        :param name: The OpenSSL short name identifying the curve this object
+            represents.
+        :type name: :py:class:`unicode`
+        """
+        self._lib = lib
+        self._nid = nid
+        self.name = name
+
+    def __repr__(self):
+        return "<Curve %r>" % (self.name,)
+
+    def _to_EC_KEY(self):
+        """
+        Create a new OpenSSL EC_KEY structure initialized to use this curve.
+
+        The structure is automatically garbage collected when the Python object
+        is garbage collected.
+        """
+        key = self._lib.EC_KEY_new_by_curve_name(self._nid)
+        return _ffi.gc(key, _lib.EC_KEY_free)
+
+
+def get_elliptic_curves():
+    """
+    Return a set of objects representing the elliptic curves supported in the
+    OpenSSL build in use.
+
+    The curve objects have a :py:class:`unicode` ``name`` attribute by which
+    they identify themselves.
+
+    The curve objects are useful as values for the argument accepted by
+    :py:meth:`Context.set_tmp_ecdh` to specify which elliptical curve should be
+    used for ECDHE key exchange.
+    """
+    return _EllipticCurve._get_elliptic_curves(_lib)
+
+
+def get_elliptic_curve(name):
+    """
+    Return a single curve object selected by name.
+
+    See :py:func:`get_elliptic_curves` for information about curve objects.
+
+    :param name: The OpenSSL short name identifying the curve object to
+        retrieve.
+    :type name: :py:class:`unicode`
+
+    If the named curve is not supported then :py:class:`ValueError` is raised.
+    """
+    for curve in get_elliptic_curves():
+        if curve.name == name:
+            return curve
+    raise ValueError("unknown curve name", name)
+
+
+class X509Name(object):
+    """
+    An X.509 Distinguished Name.
+
+    :ivar countryName: The country of the entity.
+    :ivar C: Alias for  :py:attr:`countryName`.
+
+    :ivar stateOrProvinceName: The state or province of the entity.
+    :ivar ST: Alias for :py:attr:`stateOrProvinceName`.
+
+    :ivar localityName: The locality of the entity.
+    :ivar L: Alias for :py:attr:`localityName`.
+
+    :ivar organizationName: The organization name of the entity.
+    :ivar O: Alias for :py:attr:`organizationName`.
+
+    :ivar organizationalUnitName: The organizational unit of the entity.
+    :ivar OU: Alias for :py:attr:`organizationalUnitName`
+
+    :ivar commonName: The common name of the entity.
+    :ivar CN: Alias for :py:attr:`commonName`.
+
+    :ivar emailAddress: The e-mail address of the entity.
+    """
+
+    def __init__(self, name):
+        """
+        Create a new X509Name, copying the given X509Name instance.
+
+        :param name: The name to copy.
+        :type name: :py:class:`X509Name`
+        """
+        name = _lib.X509_NAME_dup(name._name)
+        self._name = _ffi.gc(name, _lib.X509_NAME_free)
+
+    def __setattr__(self, name, value):
+        if name.startswith('_'):
+            return super(X509Name, self).__setattr__(name, value)
+
+        # Note: we really do not want str subclasses here, so we do not use
+        # isinstance.
+        if type(name) is not str:
+            raise TypeError("attribute name must be string, not '%.200s'" % (
+                type(value).__name__,))
+
+        nid = _lib.OBJ_txt2nid(_byte_string(name))
+        if nid == _lib.NID_undef:
+            try:
+                _raise_current_error()
+            except Error:
+                pass
+            raise AttributeError("No such attribute")
+
+        # If there's an old entry for this NID, remove it
+        for i in range(_lib.X509_NAME_entry_count(self._name)):
+            ent = _lib.X509_NAME_get_entry(self._name, i)
+            ent_obj = _lib.X509_NAME_ENTRY_get_object(ent)
+            ent_nid = _lib.OBJ_obj2nid(ent_obj)
+            if nid == ent_nid:
+                ent = _lib.X509_NAME_delete_entry(self._name, i)
+                _lib.X509_NAME_ENTRY_free(ent)
+                break
+
+        if isinstance(value, _text_type):
+            value = value.encode('utf-8')
+
+        add_result = _lib.X509_NAME_add_entry_by_NID(
+            self._name, nid, _lib.MBSTRING_UTF8, value, -1, -1, 0)
+        if not add_result:
+            _raise_current_error()
+
+    def __getattr__(self, name):
+        """
+        Find attribute. An X509Name object has the following attributes:
+        countryName (alias C), stateOrProvince (alias ST), locality (alias L),
+        organization (alias O), organizationalUnit (alias OU), commonName
+        (alias CN) and more...
+        """
+        nid = _lib.OBJ_txt2nid(_byte_string(name))
+        if nid == _lib.NID_undef:
+            # This is a bit weird.  OBJ_txt2nid indicated failure, but it seems
+            # a lower level function, a2d_ASN1_OBJECT, also feels the need to
+            # push something onto the error queue.  If we don't clean that up
+            # now, someone else will bump into it later and be quite confused.
+            # See lp#314814.
+            try:
+                _raise_current_error()
+            except Error:
+                pass
+            return super(X509Name, self).__getattr__(name)
+
+        entry_index = _lib.X509_NAME_get_index_by_NID(self._name, nid, -1)
+        if entry_index == -1:
+            return None
+
+        entry = _lib.X509_NAME_get_entry(self._name, entry_index)
+        data = _lib.X509_NAME_ENTRY_get_data(entry)
+
+        result_buffer = _ffi.new("unsigned char**")
+        data_length = _lib.ASN1_STRING_to_UTF8(result_buffer, data)
+        _openssl_assert(data_length >= 0)
+
+        try:
+            result = _ffi.buffer(
+                result_buffer[0], data_length
+            )[:].decode('utf-8')
+        finally:
+            # XXX untested
+            _lib.OPENSSL_free(result_buffer[0])
+        return result
+
+    def _cmp(op):
+        def f(self, other):
+            if not isinstance(other, X509Name):
+                return NotImplemented
+            result = _lib.X509_NAME_cmp(self._name, other._name)
+            return op(result, 0)
+        return f
+
+    __eq__ = _cmp(__eq__)
+    __ne__ = _cmp(__ne__)
+
+    __lt__ = _cmp(__lt__)
+    __le__ = _cmp(__le__)
+
+    __gt__ = _cmp(__gt__)
+    __ge__ = _cmp(__ge__)
+
+    def __repr__(self):
+        """
+        String representation of an X509Name
+        """
+        result_buffer = _ffi.new("char[]", 512)
+        format_result = _lib.X509_NAME_oneline(
+            self._name, result_buffer, len(result_buffer))
+        _openssl_assert(format_result != _ffi.NULL)
+
+        return "<X509Name object '%s'>" % (
+            _native(_ffi.string(result_buffer)),)
+
+    def hash(self):
+        """
+        Return an integer representation of the first four bytes of the
+        MD5 digest of the DER representation of the name.
+
+        This is the Python equivalent of OpenSSL's ``X509_NAME_hash``.
+
+        :return: The (integer) hash of this name.
+        :rtype: :py:class:`int`
+        """
+        return _lib.X509_NAME_hash(self._name)
+
+    def der(self):
+        """
+        Return the DER encoding of this name.
+
+        :return: The DER encoded form of this name.
+        :rtype: :py:class:`bytes`
+        """
+        result_buffer = _ffi.new('unsigned char**')
+        encode_result = _lib.i2d_X509_NAME(self._name, result_buffer)
+        _openssl_assert(encode_result >= 0)
+
+        string_result = _ffi.buffer(result_buffer[0], encode_result)[:]
+        _lib.OPENSSL_free(result_buffer[0])
+        return string_result
+
+    def get_components(self):
+        """
+        Returns the components of this name, as a sequence of 2-tuples.
+
+        :return: The components of this name.
+        :rtype: :py:class:`list` of ``name, value`` tuples.
+        """
+        result = []
+        for i in range(_lib.X509_NAME_entry_count(self._name)):
+            ent = _lib.X509_NAME_get_entry(self._name, i)
+
+            fname = _lib.X509_NAME_ENTRY_get_object(ent)
+            fval = _lib.X509_NAME_ENTRY_get_data(ent)
+
+            nid = _lib.OBJ_obj2nid(fname)
+            name = _lib.OBJ_nid2sn(nid)
+
+            # ffi.string does not handle strings containing NULL bytes
+            # (which may have been generated by old, broken software)
+            value = _ffi.buffer(_lib.ASN1_STRING_data(fval),
+                                _lib.ASN1_STRING_length(fval))[:]
+            result.append((_ffi.string(name), value))
+
+        return result
+
+
+X509NameType = deprecated(
+    X509Name, __name__,
+    "X509NameType has been deprecated, use X509Name instead",
+    DeprecationWarning
+)
+
+
+class X509Extension(object):
+    """
+    An X.509 v3 certificate extension.
+    """
+
+    def __init__(self, type_name, critical, value, subject=None, issuer=None):
+        """
+        Initializes an X509 extension.
+
+        :param type_name: The name of the type of extension_ to create.
+        :type type_name: :py:data:`bytes`
+
+        :param bool critical: A flag indicating whether this is a critical
+            extension.
+
+        :param value: The value of the extension.
+        :type value: :py:data:`bytes`
+
+        :param subject: Optional X509 certificate to use as subject.
+        :type subject: :py:class:`X509`
+
+        :param issuer: Optional X509 certificate to use as issuer.
+        :type issuer: :py:class:`X509`
+
+        .. _extension: https://www.openssl.org/docs/manmaster/man5/
+            x509v3_config.html#STANDARD-EXTENSIONS
+        """
+        ctx = _ffi.new("X509V3_CTX*")
+
+        # A context is necessary for any extension which uses the r2i
+        # conversion method.  That is, X509V3_EXT_nconf may segfault if passed
+        # a NULL ctx. Start off by initializing most of the fields to NULL.
+        _lib.X509V3_set_ctx(ctx, _ffi.NULL, _ffi.NULL, _ffi.NULL, _ffi.NULL, 0)
+
+        # We have no configuration database - but perhaps we should (some
+        # extensions may require it).
+        _lib.X509V3_set_ctx_nodb(ctx)
+
+        # Initialize the subject and issuer, if appropriate.  ctx is a local,
+        # and as far as I can tell none of the X509V3_* APIs invoked here steal
+        # any references, so no need to mess with reference counts or
+        # duplicates.
+        if issuer is not None:
+            if not isinstance(issuer, X509):
+                raise TypeError("issuer must be an X509 instance")
+            ctx.issuer_cert = issuer._x509
+        if subject is not None:
+            if not isinstance(subject, X509):
+                raise TypeError("subject must be an X509 instance")
+            ctx.subject_cert = subject._x509
+
+        if critical:
+            # There are other OpenSSL APIs which would let us pass in critical
+            # separately, but they're harder to use, and since value is already
+            # a pile of crappy junk smuggling a ton of utterly important
+            # structured data, what's the point of trying to avoid nasty stuff
+            # with strings? (However, X509V3_EXT_i2d in particular seems like
+            # it would be a better API to invoke.  I do not know where to get
+            # the ext_struc it desires for its last parameter, though.)
+            value = b"critical," + value
+
+        extension = _lib.X509V3_EXT_nconf(_ffi.NULL, ctx, type_name, value)
+        if extension == _ffi.NULL:
+            _raise_current_error()
+        self._extension = _ffi.gc(extension, _lib.X509_EXTENSION_free)
+
+    @property
+    def _nid(self):
+        return _lib.OBJ_obj2nid(
+            _lib.X509_EXTENSION_get_object(self._extension)
+        )
+
+    _prefixes = {
+        _lib.GEN_EMAIL: "email",
+        _lib.GEN_DNS: "DNS",
+        _lib.GEN_URI: "URI",
+    }
+
+    def _subjectAltNameString(self):
+        names = _ffi.cast(
+            "GENERAL_NAMES*", _lib.X509V3_EXT_d2i(self._extension)
+        )
+
+        names = _ffi.gc(names, _lib.GENERAL_NAMES_free)
+        parts = []
+        for i in range(_lib.sk_GENERAL_NAME_num(names)):
+            name = _lib.sk_GENERAL_NAME_value(names, i)
+            try:
+                label = self._prefixes[name.type]
+            except KeyError:
+                bio = _new_mem_buf()
+                _lib.GENERAL_NAME_print(bio, name)
+                parts.append(_native(_bio_to_string(bio)))
+            else:
+                value = _native(
+                    _ffi.buffer(name.d.ia5.data, name.d.ia5.length)[:])
+                parts.append(label + ":" + value)
+        return ", ".join(parts)
+
+    def __str__(self):
+        """
+        :return: a nice text representation of the extension
+        """
+        if _lib.NID_subject_alt_name == self._nid:
+            return self._subjectAltNameString()
+
+        bio = _new_mem_buf()
+        print_result = _lib.X509V3_EXT_print(bio, self._extension, 0, 0)
+        _openssl_assert(print_result != 0)
+
+        return _native(_bio_to_string(bio))
+
+    def get_critical(self):
+        """
+        Returns the critical field of this X.509 extension.
+
+        :return: The critical field.
+        """
+        return _lib.X509_EXTENSION_get_critical(self._extension)
+
+    def get_short_name(self):
+        """
+        Returns the short type name of this X.509 extension.
+
+        The result is a byte string such as :py:const:`b"basicConstraints"`.
+
+        :return: The short type name.
+        :rtype: :py:data:`bytes`
+
+        .. versionadded:: 0.12
+        """
+        obj = _lib.X509_EXTENSION_get_object(self._extension)
+        nid = _lib.OBJ_obj2nid(obj)
+        return _ffi.string(_lib.OBJ_nid2sn(nid))
+
+    def get_data(self):
+        """
+        Returns the data of the X509 extension, encoded as ASN.1.
+
+        :return: The ASN.1 encoded data of this X509 extension.
+        :rtype: :py:data:`bytes`
+
+        .. versionadded:: 0.12
+        """
+        octet_result = _lib.X509_EXTENSION_get_data(self._extension)
+        string_result = _ffi.cast('ASN1_STRING*', octet_result)
+        char_result = _lib.ASN1_STRING_data(string_result)
+        result_length = _lib.ASN1_STRING_length(string_result)
+        return _ffi.buffer(char_result, result_length)[:]
+
+
+X509ExtensionType = deprecated(
+    X509Extension, __name__,
+    "X509ExtensionType has been deprecated, use X509Extension instead",
+    DeprecationWarning
+)
+
+
+class X509Req(object):
+    """
+    An X.509 certificate signing requests.
+    """
+
+    def __init__(self):
+        req = _lib.X509_REQ_new()
+        self._req = _ffi.gc(req, _lib.X509_REQ_free)
+        # Default to version 0.
+        self.set_version(0)
+
+    def to_cryptography(self):
+        """
+        Export as a ``cryptography`` certificate signing request.
+
+        :rtype: ``cryptography.x509.CertificateSigningRequest``
+
+        .. versionadded:: 17.1.0
+        """
+        from cryptography.hazmat.backends.openssl.x509 import (
+            _CertificateSigningRequest
+        )
+        backend = _get_backend()
+        return _CertificateSigningRequest(backend, self._req)
+
+    @classmethod
+    def from_cryptography(cls, crypto_req):
+        """
+        Construct based on a ``cryptography`` *crypto_req*.
+
+        :param crypto_req: A ``cryptography`` X.509 certificate signing request
+        :type crypto_req: ``cryptography.x509.CertificateSigningRequest``
+
+        :rtype: X509Req
+
+        .. versionadded:: 17.1.0
+        """
+        if not isinstance(crypto_req, x509.CertificateSigningRequest):
+            raise TypeError("Must be a certificate signing request")
+
+        req = cls()
+        req._req = crypto_req._x509_req
+        return req
+
+    def set_pubkey(self, pkey):
+        """
+        Set the public key of the certificate signing request.
+
+        :param pkey: The public key to use.
+        :type pkey: :py:class:`PKey`
+
+        :return: ``None``
+        """
+        set_result = _lib.X509_REQ_set_pubkey(self._req, pkey._pkey)
+        _openssl_assert(set_result == 1)
+
+    def get_pubkey(self):
+        """
+        Get the public key of the certificate signing request.
+
+        :return: The public key.
+        :rtype: :py:class:`PKey`
+        """
+        pkey = PKey.__new__(PKey)
+        pkey._pkey = _lib.X509_REQ_get_pubkey(self._req)
+        _openssl_assert(pkey._pkey != _ffi.NULL)
+        pkey._pkey = _ffi.gc(pkey._pkey, _lib.EVP_PKEY_free)
+        pkey._only_public = True
+        return pkey
+
+    def set_version(self, version):
+        """
+        Set the version subfield (RFC 2459, section 4.1.2.1) of the certificate
+        request.
+
+        :param int version: The version number.
+        :return: ``None``
+        """
+        set_result = _lib.X509_REQ_set_version(self._req, version)
+        _openssl_assert(set_result == 1)
+
+    def get_version(self):
+        """
+        Get the version subfield (RFC 2459, section 4.1.2.1) of the certificate
+        request.
+
+        :return: The value of the version subfield.
+        :rtype: :py:class:`int`
+        """
+        return _lib.X509_REQ_get_version(self._req)
+
+    def get_subject(self):
+        """
+        Return the subject of this certificate signing request.
+
+        This creates a new :class:`X509Name` that wraps the underlying subject
+        name field on the certificate signing request. Modifying it will modify
+        the underlying signing request, and will have the effect of modifying
+        any other :class:`X509Name` that refers to this subject.
+
+        :return: The subject of this certificate signing request.
+        :rtype: :class:`X509Name`
+        """
+        name = X509Name.__new__(X509Name)
+        name._name = _lib.X509_REQ_get_subject_name(self._req)
+        _openssl_assert(name._name != _ffi.NULL)
+
+        # The name is owned by the X509Req structure.  As long as the X509Name
+        # Python object is alive, keep the X509Req Python object alive.
+        name._owner = self
+
+        return name
+
+    def add_extensions(self, extensions):
+        """
+        Add extensions to the certificate signing request.
+
+        :param extensions: The X.509 extensions to add.
+        :type extensions: iterable of :py:class:`X509Extension`
+        :return: ``None``
+        """
+        stack = _lib.sk_X509_EXTENSION_new_null()
+        _openssl_assert(stack != _ffi.NULL)
+
+        stack = _ffi.gc(stack, _lib.sk_X509_EXTENSION_free)
+
+        for ext in extensions:
+            if not isinstance(ext, X509Extension):
+                raise ValueError("One of the elements is not an X509Extension")
+
+            # TODO push can fail (here and elsewhere)
+            _lib.sk_X509_EXTENSION_push(stack, ext._extension)
+
+        add_result = _lib.X509_REQ_add_extensions(self._req, stack)
+        _openssl_assert(add_result == 1)
+
+    def get_extensions(self):
+        """
+        Get X.509 extensions in the certificate signing request.
+
+        :return: The X.509 extensions in this request.
+        :rtype: :py:class:`list` of :py:class:`X509Extension` objects.
+
+        .. versionadded:: 0.15
+        """
+        exts = []
+        native_exts_obj = _lib.X509_REQ_get_extensions(self._req)
+        for i in range(_lib.sk_X509_EXTENSION_num(native_exts_obj)):
+            ext = X509Extension.__new__(X509Extension)
+            ext._extension = _lib.sk_X509_EXTENSION_value(native_exts_obj, i)
+            exts.append(ext)
+        return exts
+
+    def sign(self, pkey, digest):
+        """
+        Sign the certificate signing request with this key and digest type.
+
+        :param pkey: The key pair to sign with.
+        :type pkey: :py:class:`PKey`
+        :param digest: The name of the message digest to use for the signature,
+            e.g. :py:data:`b"sha256"`.
+        :type digest: :py:class:`bytes`
+        :return: ``None``
+        """
+        if pkey._only_public:
+            raise ValueError("Key has only public part")
+
+        if not pkey._initialized:
+            raise ValueError("Key is uninitialized")
+
+        digest_obj = _lib.EVP_get_digestbyname(_byte_string(digest))
+        if digest_obj == _ffi.NULL:
+            raise ValueError("No such digest method")
+
+        sign_result = _lib.X509_REQ_sign(self._req, pkey._pkey, digest_obj)
+        _openssl_assert(sign_result > 0)
+
+    def verify(self, pkey):
+        """
+        Verifies the signature on this certificate signing request.
+
+        :param PKey key: A public key.
+
+        :return: ``True`` if the signature is correct.
+        :rtype: bool
+
+        :raises OpenSSL.crypto.Error: If the signature is invalid or there is a
+            problem verifying the signature.
+        """
+        if not isinstance(pkey, PKey):
+            raise TypeError("pkey must be a PKey instance")
+
+        result = _lib.X509_REQ_verify(self._req, pkey._pkey)
+        if result <= 0:
+            _raise_current_error()
+
+        return result
+
+
+X509ReqType = deprecated(
+    X509Req, __name__,
+    "X509ReqType has been deprecated, use X509Req instead",
+    DeprecationWarning
+)
+
+
+class X509(object):
+    """
+    An X.509 certificate.
+    """
+    def __init__(self):
+        x509 = _lib.X509_new()
+        _openssl_assert(x509 != _ffi.NULL)
+        self._x509 = _ffi.gc(x509, _lib.X509_free)
+
+        self._issuer_invalidator = _X509NameInvalidator()
+        self._subject_invalidator = _X509NameInvalidator()
+
+    @classmethod
+    def _from_raw_x509_ptr(cls, x509):
+        cert = cls.__new__(cls)
+        cert._x509 = _ffi.gc(x509, _lib.X509_free)
+        cert._issuer_invalidator = _X509NameInvalidator()
+        cert._subject_invalidator = _X509NameInvalidator()
+        return cert
+
+    def to_cryptography(self):
+        """
+        Export as a ``cryptography`` certificate.
+
+        :rtype: ``cryptography.x509.Certificate``
+
+        .. versionadded:: 17.1.0
+        """
+        from cryptography.hazmat.backends.openssl.x509 import _Certificate
+        backend = _get_backend()
+        return _Certificate(backend, self._x509)
+
+    @classmethod
+    def from_cryptography(cls, crypto_cert):
+        """
+        Construct based on a ``cryptography`` *crypto_cert*.
+
+        :param crypto_key: A ``cryptography`` X.509 certificate.
+        :type crypto_key: ``cryptography.x509.Certificate``
+
+        :rtype: X509
+
+        .. versionadded:: 17.1.0
+        """
+        if not isinstance(crypto_cert, x509.Certificate):
+            raise TypeError("Must be a certificate")
+
+        cert = cls()
+        cert._x509 = crypto_cert._x509
+        return cert
+
+    def set_version(self, version):
+        """
+        Set the version number of the certificate. Note that the
+        version value is zero-based, eg. a value of 0 is V1.
+
+        :param version: The version number of the certificate.
+        :type version: :py:class:`int`
+
+        :return: ``None``
+        """
+        if not isinstance(version, int):
+            raise TypeError("version must be an integer")
+
+        _lib.X509_set_version(self._x509, version)
+
+    def get_version(self):
+        """
+        Return the version number of the certificate.
+
+        :return: The version number of the certificate.
+        :rtype: :py:class:`int`
+        """
+        return _lib.X509_get_version(self._x509)
+
+    def get_pubkey(self):
+        """
+        Get the public key of the certificate.
+
+        :return: The public key.
+        :rtype: :py:class:`PKey`
+        """
+        pkey = PKey.__new__(PKey)
+        pkey._pkey = _lib.X509_get_pubkey(self._x509)
+        if pkey._pkey == _ffi.NULL:
+            _raise_current_error()
+        pkey._pkey = _ffi.gc(pkey._pkey, _lib.EVP_PKEY_free)
+        pkey._only_public = True
+        return pkey
+
+    def set_pubkey(self, pkey):
+        """
+        Set the public key of the certificate.
+
+        :param pkey: The public key.
+        :type pkey: :py:class:`PKey`
+
+        :return: :py:data:`None`
+        """
+        if not isinstance(pkey, PKey):
+            raise TypeError("pkey must be a PKey instance")
+
+        set_result = _lib.X509_set_pubkey(self._x509, pkey._pkey)
+        _openssl_assert(set_result == 1)
+
+    def sign(self, pkey, digest):
+        """
+        Sign the certificate with this key and digest type.
+
+        :param pkey: The key to sign with.
+        :type pkey: :py:class:`PKey`
+
+        :param digest: The name of the message digest to use.
+        :type digest: :py:class:`bytes`
+
+        :return: :py:data:`None`
+        """
+        if not isinstance(pkey, PKey):
+            raise TypeError("pkey must be a PKey instance")
+
+        if pkey._only_public:
+            raise ValueError("Key only has public part")
+
+        if not pkey._initialized:
+            raise ValueError("Key is uninitialized")
+
+        evp_md = _lib.EVP_get_digestbyname(_byte_string(digest))
+        if evp_md == _ffi.NULL:
+            raise ValueError("No such digest method")
+
+        sign_result = _lib.X509_sign(self._x509, pkey._pkey, evp_md)
+        _openssl_assert(sign_result > 0)
+
+    def get_signature_algorithm(self):
+        """
+        Return the signature algorithm used in the certificate.
+
+        :return: The name of the algorithm.
+        :rtype: :py:class:`bytes`
+
+        :raises ValueError: If the signature algorithm is undefined.
+
+        .. versionadded:: 0.13
+        """
+        algor = _lib.X509_get0_tbs_sigalg(self._x509)
+        nid = _lib.OBJ_obj2nid(algor.algorithm)
+        if nid == _lib.NID_undef:
+            raise ValueError("Undefined signature algorithm")
+        return _ffi.string(_lib.OBJ_nid2ln(nid))
+
+    def digest(self, digest_name):
+        """
+        Return the digest of the X509 object.
+
+        :param digest_name: The name of the digest algorithm to use.
+        :type digest_name: :py:class:`bytes`
+
+        :return: The digest of the object, formatted as
+            :py:const:`b":"`-delimited hex pairs.
+        :rtype: :py:class:`bytes`
+        """
+        digest = _lib.EVP_get_digestbyname(_byte_string(digest_name))
+        if digest == _ffi.NULL:
+            raise ValueError("No such digest method")
+
+        result_buffer = _ffi.new("unsigned char[]", _lib.EVP_MAX_MD_SIZE)
+        result_length = _ffi.new("unsigned int[]", 1)
+        result_length[0] = len(result_buffer)
+
+        digest_result = _lib.X509_digest(
+            self._x509, digest, result_buffer, result_length)
+        _openssl_assert(digest_result == 1)
+
+        return b":".join([
+            b16encode(ch).upper() for ch
+            in _ffi.buffer(result_buffer, result_length[0])])
+
+    def subject_name_hash(self):
+        """
+        Return the hash of the X509 subject.
+
+        :return: The hash of the subject.
+        :rtype: :py:class:`bytes`
+        """
+        return _lib.X509_subject_name_hash(self._x509)
+
+    def set_serial_number(self, serial):
+        """
+        Set the serial number of the certificate.
+
+        :param serial: The new serial number.
+        :type serial: :py:class:`int`
+
+        :return: :py:data`None`
+        """
+        if not isinstance(serial, _integer_types):
+            raise TypeError("serial must be an integer")
+
+        hex_serial = hex(serial)[2:]
+        if not isinstance(hex_serial, bytes):
+            hex_serial = hex_serial.encode('ascii')
+
+        bignum_serial = _ffi.new("BIGNUM**")
+
+        # BN_hex2bn stores the result in &bignum.  Unless it doesn't feel like
+        # it.  If bignum is still NULL after this call, then the return value
+        # is actually the result.  I hope.  -exarkun
+        small_serial = _lib.BN_hex2bn(bignum_serial, hex_serial)
+
+        if bignum_serial[0] == _ffi.NULL:
+            set_result = _lib.ASN1_INTEGER_set(
+                _lib.X509_get_serialNumber(self._x509), small_serial)
+            if set_result:
+                # TODO Not tested
+                _raise_current_error()
+        else:
+            asn1_serial = _lib.BN_to_ASN1_INTEGER(bignum_serial[0], _ffi.NULL)
+            _lib.BN_free(bignum_serial[0])
+            if asn1_serial == _ffi.NULL:
+                # TODO Not tested
+                _raise_current_error()
+            asn1_serial = _ffi.gc(asn1_serial, _lib.ASN1_INTEGER_free)
+            set_result = _lib.X509_set_serialNumber(self._x509, asn1_serial)
+            _openssl_assert(set_result == 1)
+
+    def get_serial_number(self):
+        """
+        Return the serial number of this certificate.
+
+        :return: The serial number.
+        :rtype: int
+        """
+        asn1_serial = _lib.X509_get_serialNumber(self._x509)
+        bignum_serial = _lib.ASN1_INTEGER_to_BN(asn1_serial, _ffi.NULL)
+        try:
+            hex_serial = _lib.BN_bn2hex(bignum_serial)
+            try:
+                hexstring_serial = _ffi.string(hex_serial)
+                serial = int(hexstring_serial, 16)
+                return serial
+            finally:
+                _lib.OPENSSL_free(hex_serial)
+        finally:
+            _lib.BN_free(bignum_serial)
+
+    def gmtime_adj_notAfter(self, amount):
+        """
+        Adjust the time stamp on which the certificate stops being valid.
+
+        :param int amount: The number of seconds by which to adjust the
+            timestamp.
+        :return: ``None``
+        """
+        if not isinstance(amount, int):
+            raise TypeError("amount must be an integer")
+
+        notAfter = _lib.X509_get_notAfter(self._x509)
+        _lib.X509_gmtime_adj(notAfter, amount)
+
+    def gmtime_adj_notBefore(self, amount):
+        """
+        Adjust the timestamp on which the certificate starts being valid.
+
+        :param amount: The number of seconds by which to adjust the timestamp.
+        :return: ``None``
+        """
+        if not isinstance(amount, int):
+            raise TypeError("amount must be an integer")
+
+        notBefore = _lib.X509_get_notBefore(self._x509)
+        _lib.X509_gmtime_adj(notBefore, amount)
+
+    def has_expired(self):
+        """
+        Check whether the certificate has expired.
+
+        :return: ``True`` if the certificate has expired, ``False`` otherwise.
+        :rtype: bool
+        """
+        time_string = _native(self.get_notAfter())
+        not_after = datetime.datetime.strptime(time_string, "%Y%m%d%H%M%SZ")
+
+        return not_after < datetime.datetime.utcnow()
+
+    def _get_boundary_time(self, which):
+        return _get_asn1_time(which(self._x509))
+
+    def get_notBefore(self):
+        """
+        Get the timestamp at which the certificate starts being valid.
+
+        The timestamp is formatted as an ASN.1 TIME::
+
+            YYYYMMDDhhmmssZ
+
+        :return: A timestamp string, or ``None`` if there is none.
+        :rtype: bytes or NoneType
+        """
+        return self._get_boundary_time(_lib.X509_get_notBefore)
+
+    def _set_boundary_time(self, which, when):
+        return _set_asn1_time(which(self._x509), when)
+
+    def set_notBefore(self, when):
+        """
+        Set the timestamp at which the certificate starts being valid.
+
+        The timestamp is formatted as an ASN.1 TIME::
+
+            YYYYMMDDhhmmssZ
+
+        :param bytes when: A timestamp string.
+        :return: ``None``
+        """
+        return self._set_boundary_time(_lib.X509_get_notBefore, when)
+
+    def get_notAfter(self):
+        """
+        Get the timestamp at which the certificate stops being valid.
+
+        The timestamp is formatted as an ASN.1 TIME::
+
+            YYYYMMDDhhmmssZ
+
+        :return: A timestamp string, or ``None`` if there is none.
+        :rtype: bytes or NoneType
+        """
+        return self._get_boundary_time(_lib.X509_get_notAfter)
+
+    def set_notAfter(self, when):
+        """
+        Set the timestamp at which the certificate stops being valid.
+
+        The timestamp is formatted as an ASN.1 TIME::
+
+            YYYYMMDDhhmmssZ
+
+        :param bytes when: A timestamp string.
+        :return: ``None``
+        """
+        return self._set_boundary_time(_lib.X509_get_notAfter, when)
+
+    def _get_name(self, which):
+        name = X509Name.__new__(X509Name)
+        name._name = which(self._x509)
+        _openssl_assert(name._name != _ffi.NULL)
+
+        # The name is owned by the X509 structure.  As long as the X509Name
+        # Python object is alive, keep the X509 Python object alive.
+        name._owner = self
+
+        return name
+
+    def _set_name(self, which, name):
+        if not isinstance(name, X509Name):
+            raise TypeError("name must be an X509Name")
+        set_result = which(self._x509, name._name)
+        _openssl_assert(set_result == 1)
+
+    def get_issuer(self):
+        """
+        Return the issuer of this certificate.
+
+        This creates a new :class:`X509Name` that wraps the underlying issuer
+        name field on the certificate. Modifying it will modify the underlying
+        certificate, and will have the effect of modifying any other
+        :class:`X509Name` that refers to this issuer.
+
+        :return: The issuer of this certificate.
+        :rtype: :class:`X509Name`
+        """
+        name = self._get_name(_lib.X509_get_issuer_name)
+        self._issuer_invalidator.add(name)
+        return name
+
+    def set_issuer(self, issuer):
+        """
+        Set the issuer of this certificate.
+
+        :param issuer: The issuer.
+        :type issuer: :py:class:`X509Name`
+
+        :return: ``None``
+        """
+        self._set_name(_lib.X509_set_issuer_name, issuer)
+        self._issuer_invalidator.clear()
+
+    def get_subject(self):
+        """
+        Return the subject of this certificate.
+
+        This creates a new :class:`X509Name` that wraps the underlying subject
+        name field on the certificate. Modifying it will modify the underlying
+        certificate, and will have the effect of modifying any other
+        :class:`X509Name` that refers to this subject.
+
+        :return: The subject of this certificate.
+        :rtype: :class:`X509Name`
+        """
+        name = self._get_name(_lib.X509_get_subject_name)
+        self._subject_invalidator.add(name)
+        return name
+
+    def set_subject(self, subject):
+        """
+        Set the subject of this certificate.
+
+        :param subject: The subject.
+        :type subject: :py:class:`X509Name`
+
+        :return: ``None``
+        """
+        self._set_name(_lib.X509_set_subject_name, subject)
+        self._subject_invalidator.clear()
+
+    def get_extension_count(self):
+        """
+        Get the number of extensions on this certificate.
+
+        :return: The number of extensions.
+        :rtype: :py:class:`int`
+
+        .. versionadded:: 0.12
+        """
+        return _lib.X509_get_ext_count(self._x509)
+
+    def add_extensions(self, extensions):
+        """
+        Add extensions to the certificate.
+
+        :param extensions: The extensions to add.
+        :type extensions: An iterable of :py:class:`X509Extension` objects.
+        :return: ``None``
+        """
+        for ext in extensions:
+            if not isinstance(ext, X509Extension):
+                raise ValueError("One of the elements is not an X509Extension")
+
+            add_result = _lib.X509_add_ext(self._x509, ext._extension, -1)
+            if not add_result:
+                _raise_current_error()
+
+    def get_extension(self, index):
+        """
+        Get a specific extension of the certificate by index.
+
+        Extensions on a certificate are kept in order. The index
+        parameter selects which extension will be returned.
+
+        :param int index: The index of the extension to retrieve.
+        :return: The extension at the specified index.
+        :rtype: :py:class:`X509Extension`
+        :raises IndexError: If the extension index was out of bounds.
+
+        .. versionadded:: 0.12
+        """
+        ext = X509Extension.__new__(X509Extension)
+        ext._extension = _lib.X509_get_ext(self._x509, index)
+        if ext._extension == _ffi.NULL:
+            raise IndexError("extension index out of bounds")
+
+        extension = _lib.X509_EXTENSION_dup(ext._extension)
+        ext._extension = _ffi.gc(extension, _lib.X509_EXTENSION_free)
+        return ext
+
+
+X509Type = deprecated(
+    X509, __name__,
+    "X509Type has been deprecated, use X509 instead",
+    DeprecationWarning
+)
+
+
+class X509StoreFlags(object):
+    """
+    Flags for X509 verification, used to change the behavior of
+    :class:`X509Store`.
+
+    See `OpenSSL Verification Flags`_ for details.
+
+    .. _OpenSSL Verification Flags:
+        https://www.openssl.org/docs/manmaster/man3/X509_VERIFY_PARAM_set_flags.html
+    """
+    CRL_CHECK = _lib.X509_V_FLAG_CRL_CHECK
+    CRL_CHECK_ALL = _lib.X509_V_FLAG_CRL_CHECK_ALL
+    IGNORE_CRITICAL = _lib.X509_V_FLAG_IGNORE_CRITICAL
+    X509_STRICT = _lib.X509_V_FLAG_X509_STRICT
+    ALLOW_PROXY_CERTS = _lib.X509_V_FLAG_ALLOW_PROXY_CERTS
+    POLICY_CHECK = _lib.X509_V_FLAG_POLICY_CHECK
+    EXPLICIT_POLICY = _lib.X509_V_FLAG_EXPLICIT_POLICY
+    INHIBIT_MAP = _lib.X509_V_FLAG_INHIBIT_MAP
+    NOTIFY_POLICY = _lib.X509_V_FLAG_NOTIFY_POLICY
+    CHECK_SS_SIGNATURE = _lib.X509_V_FLAG_CHECK_SS_SIGNATURE
+    CB_ISSUER_CHECK = _lib.X509_V_FLAG_CB_ISSUER_CHECK
+
+
+class X509Store(object):
+    """
+    An X.509 store.
+
+    An X.509 store is used to describe a context in which to verify a
+    certificate. A description of a context may include a set of certificates
+    to trust, a set of certificate revocation lists, verification flags and
+    more.
+
+    An X.509 store, being only a description, cannot be used by itself to
+    verify a certificate. To carry out the actual verification process, see
+    :class:`X509StoreContext`.
+    """
+
+    def __init__(self):
+        store = _lib.X509_STORE_new()
+        self._store = _ffi.gc(store, _lib.X509_STORE_free)
+
+    def add_cert(self, cert):
+        """
+        Adds a trusted certificate to this store.
+
+        Adding a certificate with this method adds this certificate as a
+        *trusted* certificate.
+
+        :param X509 cert: The certificate to add to this store.
+
+        :raises TypeError: If the certificate is not an :class:`X509`.
+
+        :raises OpenSSL.crypto.Error: If OpenSSL was unhappy with your
+            certificate.
+
+        :return: ``None`` if the certificate was added successfully.
+        """
+        if not isinstance(cert, X509):
+            raise TypeError()
+
+        # As of OpenSSL 1.1.0i adding the same cert to the store more than
+        # once doesn't cause an error. Accordingly, this code now silences
+        # the error for OpenSSL < 1.1.0i as well.
+        if _lib.X509_STORE_add_cert(self._store, cert._x509) == 0:
+            code = _lib.ERR_peek_error()
+            err_reason = _lib.ERR_GET_REASON(code)
+            _openssl_assert(
+                err_reason == _lib.X509_R_CERT_ALREADY_IN_HASH_TABLE
+            )
+            _lib.ERR_clear_error()
+
+    def add_crl(self, crl):
+        """
+        Add a certificate revocation list to this store.
+
+        The certificate revocation lists added to a store will only be used if
+        the associated flags are configured to check certificate revocation
+        lists.
+
+        .. versionadded:: 16.1.0
+
+        :param CRL crl: The certificate revocation list to add to this store.
+        :return: ``None`` if the certificate revocation list was added
+            successfully.
+        """
+        _openssl_assert(_lib.X509_STORE_add_crl(self._store, crl._crl) != 0)
+
+    def set_flags(self, flags):
+        """
+        Set verification flags to this store.
+
+        Verification flags can be combined by oring them together.
+
+        .. note::
+
+          Setting a verification flag sometimes requires clients to add
+          additional information to the store, otherwise a suitable error will
+          be raised.
+
+          For example, in setting flags to enable CRL checking a
+          suitable CRL must be added to the store otherwise an error will be
+          raised.
+
+        .. versionadded:: 16.1.0
+
+        :param int flags: The verification flags to set on this store.
+            See :class:`X509StoreFlags` for available constants.
+        :return: ``None`` if the verification flags were successfully set.
+        """
+        _openssl_assert(_lib.X509_STORE_set_flags(self._store, flags) != 0)
+
+    def set_time(self, vfy_time):
+        """
+        Set the time against which the certificates are verified.
+
+        Normally the current time is used.
+
+        .. note::
+
+          For example, you can determine if a certificate was valid at a given
+          time.
+
+        .. versionadded:: 17.0.0
+
+        :param datetime vfy_time: The verification time to set on this store.
+        :return: ``None`` if the verification time was successfully set.
+        """
+        param = _lib.X509_VERIFY_PARAM_new()
+        param = _ffi.gc(param, _lib.X509_VERIFY_PARAM_free)
+
+        _lib.X509_VERIFY_PARAM_set_time(param, int(vfy_time.strftime('%s')))
+        _openssl_assert(_lib.X509_STORE_set1_param(self._store, param) != 0)
+
+
+X509StoreType = deprecated(
+    X509Store, __name__,
+    "X509StoreType has been deprecated, use X509Store instead",
+    DeprecationWarning
+)
+
+
+class X509StoreContextError(Exception):
+    """
+    An exception raised when an error occurred while verifying a certificate
+    using `OpenSSL.X509StoreContext.verify_certificate`.
+
+    :ivar certificate: The certificate which caused verificate failure.
+    :type certificate: :class:`X509`
+    """
+
+    def __init__(self, message, certificate):
+        super(X509StoreContextError, self).__init__(message)
+        self.certificate = certificate
+
+
+class X509StoreContext(object):
+    """
+    An X.509 store context.
+
+    An X.509 store context is used to carry out the actual verification process
+    of a certificate in a described context. For describing such a context, see
+    :class:`X509Store`.
+
+    :ivar _store_ctx: The underlying X509_STORE_CTX structure used by this
+        instance.  It is dynamically allocated and automatically garbage
+        collected.
+    :ivar _store: See the ``store`` ``__init__`` parameter.
+    :ivar _cert: See the ``certificate`` ``__init__`` parameter.
+    :param X509Store store: The certificates which will be trusted for the
+        purposes of any verifications.
+    :param X509 certificate: The certificate to be verified.
+    """
+
+    def __init__(self, store, certificate):
+        store_ctx = _lib.X509_STORE_CTX_new()
+        self._store_ctx = _ffi.gc(store_ctx, _lib.X509_STORE_CTX_free)
+        self._store = store
+        self._cert = certificate
+        # Make the store context available for use after instantiating this
+        # class by initializing it now. Per testing, subsequent calls to
+        # :meth:`_init` have no adverse affect.
+        self._init()
+
+    def _init(self):
+        """
+        Set up the store context for a subsequent verification operation.
+
+        Calling this method more than once without first calling
+        :meth:`_cleanup` will leak memory.
+        """
+        ret = _lib.X509_STORE_CTX_init(
+            self._store_ctx, self._store._store, self._cert._x509, _ffi.NULL
+        )
+        if ret <= 0:
+            _raise_current_error()
+
+    def _cleanup(self):
+        """
+        Internally cleans up the store context.
+
+        The store context can then be reused with a new call to :meth:`_init`.
+        """
+        _lib.X509_STORE_CTX_cleanup(self._store_ctx)
+
+    def _exception_from_context(self):
+        """
+        Convert an OpenSSL native context error failure into a Python
+        exception.
+
+        When a call to native OpenSSL X509_verify_cert fails, additional
+        information about the failure can be obtained from the store context.
+        """
+        errors = [
+            _lib.X509_STORE_CTX_get_error(self._store_ctx),
+            _lib.X509_STORE_CTX_get_error_depth(self._store_ctx),
+            _native(_ffi.string(_lib.X509_verify_cert_error_string(
+                _lib.X509_STORE_CTX_get_error(self._store_ctx)))),
+        ]
+        # A context error should always be associated with a certificate, so we
+        # expect this call to never return :class:`None`.
+        _x509 = _lib.X509_STORE_CTX_get_current_cert(self._store_ctx)
+        _cert = _lib.X509_dup(_x509)
+        pycert = X509._from_raw_x509_ptr(_cert)
+        return X509StoreContextError(errors, pycert)
+
+    def set_store(self, store):
+        """
+        Set the context's X.509 store.
+
+        .. versionadded:: 0.15
+
+        :param X509Store store: The store description which will be used for
+            the purposes of any *future* verifications.
+        """
+        self._store = store
+
+    def verify_certificate(self):
+        """
+        Verify a certificate in a context.
+
+        .. versionadded:: 0.15
+
+        :raises X509StoreContextError: If an error occurred when validating a
+          certificate in the context. Sets ``certificate`` attribute to
+          indicate which certificate caused the error.
+        """
+        # Always re-initialize the store context in case
+        # :meth:`verify_certificate` is called multiple times.
+        #
+        # :meth:`_init` is called in :meth:`__init__` so _cleanup is called
+        # before _init to ensure memory is not leaked.
+        self._cleanup()
+        self._init()
+        ret = _lib.X509_verify_cert(self._store_ctx)
+        self._cleanup()
+        if ret <= 0:
+            raise self._exception_from_context()
+
+
+def load_certificate(type, buffer):
+    """
+    Load a certificate (X509) from the string *buffer* encoded with the
+    type *type*.
+
+    :param type: The file type (one of FILETYPE_PEM, FILETYPE_ASN1)
+
+    :param bytes buffer: The buffer the certificate is stored in
+
+    :return: The X509 object
+    """
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    if type == FILETYPE_PEM:
+        x509 = _lib.PEM_read_bio_X509(bio, _ffi.NULL, _ffi.NULL, _ffi.NULL)
+    elif type == FILETYPE_ASN1:
+        x509 = _lib.d2i_X509_bio(bio, _ffi.NULL)
+    else:
+        raise ValueError(
+            "type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    if x509 == _ffi.NULL:
+        _raise_current_error()
+
+    return X509._from_raw_x509_ptr(x509)
+
+
+def dump_certificate(type, cert):
+    """
+    Dump the certificate *cert* into a buffer string encoded with the type
+    *type*.
+
+    :param type: The file type (one of FILETYPE_PEM, FILETYPE_ASN1, or
+        FILETYPE_TEXT)
+    :param cert: The certificate to dump
+    :return: The buffer with the dumped certificate in
+    """
+    bio = _new_mem_buf()
+
+    if type == FILETYPE_PEM:
+        result_code = _lib.PEM_write_bio_X509(bio, cert._x509)
+    elif type == FILETYPE_ASN1:
+        result_code = _lib.i2d_X509_bio(bio, cert._x509)
+    elif type == FILETYPE_TEXT:
+        result_code = _lib.X509_print_ex(bio, cert._x509, 0, 0)
+    else:
+        raise ValueError(
+            "type argument must be FILETYPE_PEM, FILETYPE_ASN1, or "
+            "FILETYPE_TEXT")
+
+    assert result_code == 1
+    return _bio_to_string(bio)
+
+
+def dump_publickey(type, pkey):
+    """
+    Dump a public key to a buffer.
+
+    :param type: The file type (one of :data:`FILETYPE_PEM` or
+        :data:`FILETYPE_ASN1`).
+    :param PKey pkey: The public key to dump
+    :return: The buffer with the dumped key in it.
+    :rtype: bytes
+    """
+    bio = _new_mem_buf()
+    if type == FILETYPE_PEM:
+        write_bio = _lib.PEM_write_bio_PUBKEY
+    elif type == FILETYPE_ASN1:
+        write_bio = _lib.i2d_PUBKEY_bio
+    else:
+        raise ValueError("type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    result_code = write_bio(bio, pkey._pkey)
+    if result_code != 1:  # pragma: no cover
+        _raise_current_error()
+
+    return _bio_to_string(bio)
+
+
+def dump_privatekey(type, pkey, cipher=None, passphrase=None):
+    """
+    Dump the private key *pkey* into a buffer string encoded with the type
+    *type*.  Optionally (if *type* is :const:`FILETYPE_PEM`) encrypting it
+    using *cipher* and *passphrase*.
+
+    :param type: The file type (one of :const:`FILETYPE_PEM`,
+        :const:`FILETYPE_ASN1`, or :const:`FILETYPE_TEXT`)
+    :param PKey pkey: The PKey to dump
+    :param cipher: (optional) if encrypted PEM format, the cipher to use
+    :param passphrase: (optional) if encrypted PEM format, this can be either
+        the passphrase to use, or a callback for providing the passphrase.
+
+    :return: The buffer with the dumped key in
+    :rtype: bytes
+    """
+    bio = _new_mem_buf()
+
+    if not isinstance(pkey, PKey):
+        raise TypeError("pkey must be a PKey")
+
+    if cipher is not None:
+        if passphrase is None:
+            raise TypeError(
+                "if a value is given for cipher "
+                "one must also be given for passphrase")
+        cipher_obj = _lib.EVP_get_cipherbyname(_byte_string(cipher))
+        if cipher_obj == _ffi.NULL:
+            raise ValueError("Invalid cipher name")
+    else:
+        cipher_obj = _ffi.NULL
+
+    helper = _PassphraseHelper(type, passphrase)
+    if type == FILETYPE_PEM:
+        result_code = _lib.PEM_write_bio_PrivateKey(
+            bio, pkey._pkey, cipher_obj, _ffi.NULL, 0,
+            helper.callback, helper.callback_args)
+        helper.raise_if_problem()
+    elif type == FILETYPE_ASN1:
+        result_code = _lib.i2d_PrivateKey_bio(bio, pkey._pkey)
+    elif type == FILETYPE_TEXT:
+        if _lib.EVP_PKEY_id(pkey._pkey) != _lib.EVP_PKEY_RSA:
+            raise TypeError("Only RSA keys are supported for FILETYPE_TEXT")
+
+        rsa = _ffi.gc(
+            _lib.EVP_PKEY_get1_RSA(pkey._pkey),
+            _lib.RSA_free
+        )
+        result_code = _lib.RSA_print(bio, rsa, 0)
+    else:
+        raise ValueError(
+            "type argument must be FILETYPE_PEM, FILETYPE_ASN1, or "
+            "FILETYPE_TEXT")
+
+    _openssl_assert(result_code != 0)
+
+    return _bio_to_string(bio)
+
+
+class Revoked(object):
+    """
+    A certificate revocation.
+    """
+    # https://www.openssl.org/docs/manmaster/man5/x509v3_config.html#CRL-distribution-points
+    # which differs from crl_reasons of crypto/x509v3/v3_enum.c that matches
+    # OCSP_crl_reason_str.  We use the latter, just like the command line
+    # program.
+    _crl_reasons = [
+        b"unspecified",
+        b"keyCompromise",
+        b"CACompromise",
+        b"affiliationChanged",
+        b"superseded",
+        b"cessationOfOperation",
+        b"certificateHold",
+        # b"removeFromCRL",
+    ]
+
+    def __init__(self):
+        revoked = _lib.X509_REVOKED_new()
+        self._revoked = _ffi.gc(revoked, _lib.X509_REVOKED_free)
+
+    def set_serial(self, hex_str):
+        """
+        Set the serial number.
+
+        The serial number is formatted as a hexadecimal number encoded in
+        ASCII.
+
+        :param bytes hex_str: The new serial number.
+
+        :return: ``None``
+        """
+        bignum_serial = _ffi.gc(_lib.BN_new(), _lib.BN_free)
+        bignum_ptr = _ffi.new("BIGNUM**")
+        bignum_ptr[0] = bignum_serial
+        bn_result = _lib.BN_hex2bn(bignum_ptr, hex_str)
+        if not bn_result:
+            raise ValueError("bad hex string")
+
+        asn1_serial = _ffi.gc(
+            _lib.BN_to_ASN1_INTEGER(bignum_serial, _ffi.NULL),
+            _lib.ASN1_INTEGER_free)
+        _lib.X509_REVOKED_set_serialNumber(self._revoked, asn1_serial)
+
+    def get_serial(self):
+        """
+        Get the serial number.
+
+        The serial number is formatted as a hexadecimal number encoded in
+        ASCII.
+
+        :return: The serial number.
+        :rtype: bytes
+        """
+        bio = _new_mem_buf()
+
+        asn1_int = _lib.X509_REVOKED_get0_serialNumber(self._revoked)
+        _openssl_assert(asn1_int != _ffi.NULL)
+        result = _lib.i2a_ASN1_INTEGER(bio, asn1_int)
+        _openssl_assert(result >= 0)
+        return _bio_to_string(bio)
+
+    def _delete_reason(self):
+        for i in range(_lib.X509_REVOKED_get_ext_count(self._revoked)):
+            ext = _lib.X509_REVOKED_get_ext(self._revoked, i)
+            obj = _lib.X509_EXTENSION_get_object(ext)
+            if _lib.OBJ_obj2nid(obj) == _lib.NID_crl_reason:
+                _lib.X509_EXTENSION_free(ext)
+                _lib.X509_REVOKED_delete_ext(self._revoked, i)
+                break
+
+    def set_reason(self, reason):
+        """
+        Set the reason of this revocation.
+
+        If :data:`reason` is ``None``, delete the reason instead.
+
+        :param reason: The reason string.
+        :type reason: :class:`bytes` or :class:`NoneType`
+
+        :return: ``None``
+
+        .. seealso::
+
+            :meth:`all_reasons`, which gives you a list of all supported
+            reasons which you might pass to this method.
+        """
+        if reason is None:
+            self._delete_reason()
+        elif not isinstance(reason, bytes):
+            raise TypeError("reason must be None or a byte string")
+        else:
+            reason = reason.lower().replace(b' ', b'')
+            reason_code = [r.lower() for r in self._crl_reasons].index(reason)
+
+            new_reason_ext = _lib.ASN1_ENUMERATED_new()
+            _openssl_assert(new_reason_ext != _ffi.NULL)
+            new_reason_ext = _ffi.gc(new_reason_ext, _lib.ASN1_ENUMERATED_free)
+
+            set_result = _lib.ASN1_ENUMERATED_set(new_reason_ext, reason_code)
+            _openssl_assert(set_result != _ffi.NULL)
+
+            self._delete_reason()
+            add_result = _lib.X509_REVOKED_add1_ext_i2d(
+                self._revoked, _lib.NID_crl_reason, new_reason_ext, 0, 0)
+            _openssl_assert(add_result == 1)
+
+    def get_reason(self):
+        """
+        Get the reason of this revocation.
+
+        :return: The reason, or ``None`` if there is none.
+        :rtype: bytes or NoneType
+
+        .. seealso::
+
+            :meth:`all_reasons`, which gives you a list of all supported
+            reasons this method might return.
+        """
+        for i in range(_lib.X509_REVOKED_get_ext_count(self._revoked)):
+            ext = _lib.X509_REVOKED_get_ext(self._revoked, i)
+            obj = _lib.X509_EXTENSION_get_object(ext)
+            if _lib.OBJ_obj2nid(obj) == _lib.NID_crl_reason:
+                bio = _new_mem_buf()
+
+                print_result = _lib.X509V3_EXT_print(bio, ext, 0, 0)
+                if not print_result:
+                    print_result = _lib.M_ASN1_OCTET_STRING_print(
+                        bio, _lib.X509_EXTENSION_get_data(ext)
+                    )
+                    _openssl_assert(print_result != 0)
+
+                return _bio_to_string(bio)
+
+    def all_reasons(self):
+        """
+        Return a list of all the supported reason strings.
+
+        This list is a copy; modifying it does not change the supported reason
+        strings.
+
+        :return: A list of reason strings.
+        :rtype: :class:`list` of :class:`bytes`
+        """
+        return self._crl_reasons[:]
+
+    def set_rev_date(self, when):
+        """
+        Set the revocation timestamp.
+
+        :param bytes when: The timestamp of the revocation,
+            as ASN.1 TIME.
+        :return: ``None``
+        """
+        dt = _lib.X509_REVOKED_get0_revocationDate(self._revoked)
+        return _set_asn1_time(dt, when)
+
+    def get_rev_date(self):
+        """
+        Get the revocation timestamp.
+
+        :return: The timestamp of the revocation, as ASN.1 TIME.
+        :rtype: bytes
+        """
+        dt = _lib.X509_REVOKED_get0_revocationDate(self._revoked)
+        return _get_asn1_time(dt)
+
+
+class CRL(object):
+    """
+    A certificate revocation list.
+    """
+
+    def __init__(self):
+        crl = _lib.X509_CRL_new()
+        self._crl = _ffi.gc(crl, _lib.X509_CRL_free)
+
+    def to_cryptography(self):
+        """
+        Export as a ``cryptography`` CRL.
+
+        :rtype: ``cryptography.x509.CertificateRevocationList``
+
+        .. versionadded:: 17.1.0
+        """
+        from cryptography.hazmat.backends.openssl.x509 import (
+            _CertificateRevocationList
+        )
+        backend = _get_backend()
+        return _CertificateRevocationList(backend, self._crl)
+
+    @classmethod
+    def from_cryptography(cls, crypto_crl):
+        """
+        Construct based on a ``cryptography`` *crypto_crl*.
+
+        :param crypto_crl: A ``cryptography`` certificate revocation list
+        :type crypto_crl: ``cryptography.x509.CertificateRevocationList``
+
+        :rtype: CRL
+
+        .. versionadded:: 17.1.0
+        """
+        if not isinstance(crypto_crl, x509.CertificateRevocationList):
+            raise TypeError("Must be a certificate revocation list")
+
+        crl = cls()
+        crl._crl = crypto_crl._x509_crl
+        return crl
+
+    def get_revoked(self):
+        """
+        Return the revocations in this certificate revocation list.
+
+        These revocations will be provided by value, not by reference.
+        That means it's okay to mutate them: it won't affect this CRL.
+
+        :return: The revocations in this CRL.
+        :rtype: :class:`tuple` of :class:`Revocation`
+        """
+        results = []
+        revoked_stack = _lib.X509_CRL_get_REVOKED(self._crl)
+        for i in range(_lib.sk_X509_REVOKED_num(revoked_stack)):
+            revoked = _lib.sk_X509_REVOKED_value(revoked_stack, i)
+            revoked_copy = _lib.Cryptography_X509_REVOKED_dup(revoked)
+            pyrev = Revoked.__new__(Revoked)
+            pyrev._revoked = _ffi.gc(revoked_copy, _lib.X509_REVOKED_free)
+            results.append(pyrev)
+        if results:
+            return tuple(results)
+
+    def add_revoked(self, revoked):
+        """
+        Add a revoked (by value not reference) to the CRL structure
+
+        This revocation will be added by value, not by reference. That
+        means it's okay to mutate it after adding: it won't affect
+        this CRL.
+
+        :param Revoked revoked: The new revocation.
+        :return: ``None``
+        """
+        copy = _lib.Cryptography_X509_REVOKED_dup(revoked._revoked)
+        _openssl_assert(copy != _ffi.NULL)
+
+        add_result = _lib.X509_CRL_add0_revoked(self._crl, copy)
+        _openssl_assert(add_result != 0)
+
+    def get_issuer(self):
+        """
+        Get the CRL's issuer.
+
+        .. versionadded:: 16.1.0
+
+        :rtype: X509Name
+        """
+        _issuer = _lib.X509_NAME_dup(_lib.X509_CRL_get_issuer(self._crl))
+        _openssl_assert(_issuer != _ffi.NULL)
+        _issuer = _ffi.gc(_issuer, _lib.X509_NAME_free)
+        issuer = X509Name.__new__(X509Name)
+        issuer._name = _issuer
+        return issuer
+
+    def set_version(self, version):
+        """
+        Set the CRL version.
+
+        .. versionadded:: 16.1.0
+
+        :param int version: The version of the CRL.
+        :return: ``None``
+        """
+        _openssl_assert(_lib.X509_CRL_set_version(self._crl, version) != 0)
+
+    def _set_boundary_time(self, which, when):
+        return _set_asn1_time(which(self._crl), when)
+
+    def set_lastUpdate(self, when):
+        """
+        Set when the CRL was last updated.
+
+        The timestamp is formatted as an ASN.1 TIME::
+
+            YYYYMMDDhhmmssZ
+
+        .. versionadded:: 16.1.0
+
+        :param bytes when: A timestamp string.
+        :return: ``None``
+        """
+        return self._set_boundary_time(_lib.X509_CRL_get_lastUpdate, when)
+
+    def set_nextUpdate(self, when):
+        """
+        Set when the CRL will next be udpated.
+
+        The timestamp is formatted as an ASN.1 TIME::
+
+            YYYYMMDDhhmmssZ
+
+        .. versionadded:: 16.1.0
+
+        :param bytes when: A timestamp string.
+        :return: ``None``
+        """
+        return self._set_boundary_time(_lib.X509_CRL_get_nextUpdate, when)
+
+    def sign(self, issuer_cert, issuer_key, digest):
+        """
+        Sign the CRL.
+
+        Signing a CRL enables clients to associate the CRL itself with an
+        issuer. Before a CRL is meaningful to other OpenSSL functions, it must
+        be signed by an issuer.
+
+        This method implicitly sets the issuer's name based on the issuer
+        certificate and private key used to sign the CRL.
+
+        .. versionadded:: 16.1.0
+
+        :param X509 issuer_cert: The issuer's certificate.
+        :param PKey issuer_key: The issuer's private key.
+        :param bytes digest: The digest method to sign the CRL with.
+        """
+        digest_obj = _lib.EVP_get_digestbyname(digest)
+        _openssl_assert(digest_obj != _ffi.NULL)
+        _lib.X509_CRL_set_issuer_name(
+            self._crl, _lib.X509_get_subject_name(issuer_cert._x509))
+        _lib.X509_CRL_sort(self._crl)
+        result = _lib.X509_CRL_sign(self._crl, issuer_key._pkey, digest_obj)
+        _openssl_assert(result != 0)
+
+    def export(self, cert, key, type=FILETYPE_PEM, days=100,
+               digest=_UNSPECIFIED):
+        """
+        Export the CRL as a string.
+
+        :param X509 cert: The certificate used to sign the CRL.
+        :param PKey key: The key used to sign the CRL.
+        :param int type: The export format, either :data:`FILETYPE_PEM`,
+            :data:`FILETYPE_ASN1`, or :data:`FILETYPE_TEXT`.
+        :param int days: The number of days until the next update of this CRL.
+        :param bytes digest: The name of the message digest to use (eg
+            ``b"sha2566"``).
+        :rtype: bytes
+        """
+
+        if not isinstance(cert, X509):
+            raise TypeError("cert must be an X509 instance")
+        if not isinstance(key, PKey):
+            raise TypeError("key must be a PKey instance")
+        if not isinstance(type, int):
+            raise TypeError("type must be an integer")
+
+        if digest is _UNSPECIFIED:
+            raise TypeError("digest must be provided")
+
+        digest_obj = _lib.EVP_get_digestbyname(digest)
+        if digest_obj == _ffi.NULL:
+            raise ValueError("No such digest method")
+
+        bio = _lib.BIO_new(_lib.BIO_s_mem())
+        _openssl_assert(bio != _ffi.NULL)
+
+        # A scratch time object to give different values to different CRL
+        # fields
+        sometime = _lib.ASN1_TIME_new()
+        _openssl_assert(sometime != _ffi.NULL)
+
+        _lib.X509_gmtime_adj(sometime, 0)
+        _lib.X509_CRL_set_lastUpdate(self._crl, sometime)
+
+        _lib.X509_gmtime_adj(sometime, days * 24 * 60 * 60)
+        _lib.X509_CRL_set_nextUpdate(self._crl, sometime)
+
+        _lib.X509_CRL_set_issuer_name(
+            self._crl, _lib.X509_get_subject_name(cert._x509)
+        )
+
+        sign_result = _lib.X509_CRL_sign(self._crl, key._pkey, digest_obj)
+        if not sign_result:
+            _raise_current_error()
+
+        return dump_crl(type, self)
+
+
+CRLType = deprecated(
+    CRL, __name__,
+    "CRLType has been deprecated, use CRL instead",
+    DeprecationWarning
+)
+
+
+class PKCS7(object):
+    def type_is_signed(self):
+        """
+        Check if this NID_pkcs7_signed object
+
+        :return: True if the PKCS7 is of type signed
+        """
+        return bool(_lib.PKCS7_type_is_signed(self._pkcs7))
+
+    def type_is_enveloped(self):
+        """
+        Check if this NID_pkcs7_enveloped object
+
+        :returns: True if the PKCS7 is of type enveloped
+        """
+        return bool(_lib.PKCS7_type_is_enveloped(self._pkcs7))
+
+    def type_is_signedAndEnveloped(self):
+        """
+        Check if this NID_pkcs7_signedAndEnveloped object
+
+        :returns: True if the PKCS7 is of type signedAndEnveloped
+        """
+        return bool(_lib.PKCS7_type_is_signedAndEnveloped(self._pkcs7))
+
+    def type_is_data(self):
+        """
+        Check if this NID_pkcs7_data object
+
+        :return: True if the PKCS7 is of type data
+        """
+        return bool(_lib.PKCS7_type_is_data(self._pkcs7))
+
+    def get_type_name(self):
+        """
+        Returns the type name of the PKCS7 structure
+
+        :return: A string with the typename
+        """
+        nid = _lib.OBJ_obj2nid(self._pkcs7.type)
+        string_type = _lib.OBJ_nid2sn(nid)
+        return _ffi.string(string_type)
+
+
+PKCS7Type = deprecated(
+    PKCS7, __name__,
+    "PKCS7Type has been deprecated, use PKCS7 instead",
+    DeprecationWarning
+)
+
+
+class PKCS12(object):
+    """
+    A PKCS #12 archive.
+    """
+
+    def __init__(self):
+        self._pkey = None
+        self._cert = None
+        self._cacerts = None
+        self._friendlyname = None
+
+    def get_certificate(self):
+        """
+        Get the certificate in the PKCS #12 structure.
+
+        :return: The certificate, or :py:const:`None` if there is none.
+        :rtype: :py:class:`X509` or :py:const:`None`
+        """
+        return self._cert
+
+    def set_certificate(self, cert):
+        """
+        Set the certificate in the PKCS #12 structure.
+
+        :param cert: The new certificate, or :py:const:`None` to unset it.
+        :type cert: :py:class:`X509` or :py:const:`None`
+
+        :return: ``None``
+        """
+        if not isinstance(cert, X509):
+            raise TypeError("cert must be an X509 instance")
+        self._cert = cert
+
+    def get_privatekey(self):
+        """
+        Get the private key in the PKCS #12 structure.
+
+        :return: The private key, or :py:const:`None` if there is none.
+        :rtype: :py:class:`PKey`
+        """
+        return self._pkey
+
+    def set_privatekey(self, pkey):
+        """
+        Set the certificate portion of the PKCS #12 structure.
+
+        :param pkey: The new private key, or :py:const:`None` to unset it.
+        :type pkey: :py:class:`PKey` or :py:const:`None`
+
+        :return: ``None``
+        """
+        if not isinstance(pkey, PKey):
+            raise TypeError("pkey must be a PKey instance")
+        self._pkey = pkey
+
+    def get_ca_certificates(self):
+        """
+        Get the CA certificates in the PKCS #12 structure.
+
+        :return: A tuple with the CA certificates in the chain, or
+            :py:const:`None` if there are none.
+        :rtype: :py:class:`tuple` of :py:class:`X509` or :py:const:`None`
+        """
+        if self._cacerts is not None:
+            return tuple(self._cacerts)
+
+    def set_ca_certificates(self, cacerts):
+        """
+        Replace or set the CA certificates within the PKCS12 object.
+
+        :param cacerts: The new CA certificates, or :py:const:`None` to unset
+            them.
+        :type cacerts: An iterable of :py:class:`X509` or :py:const:`None`
+
+        :return: ``None``
+        """
+        if cacerts is None:
+            self._cacerts = None
+        else:
+            cacerts = list(cacerts)
+            for cert in cacerts:
+                if not isinstance(cert, X509):
+                    raise TypeError(
+                        "iterable must only contain X509 instances"
+                    )
+            self._cacerts = cacerts
+
+    def set_friendlyname(self, name):
+        """
+        Set the friendly name in the PKCS #12 structure.
+
+        :param name: The new friendly name, or :py:const:`None` to unset.
+        :type name: :py:class:`bytes` or :py:const:`None`
+
+        :return: ``None``
+        """
+        if name is None:
+            self._friendlyname = None
+        elif not isinstance(name, bytes):
+            raise TypeError(
+                "name must be a byte string or None (not %r)" % (name,)
+            )
+        self._friendlyname = name
+
+    def get_friendlyname(self):
+        """
+        Get the friendly name in the PKCS# 12 structure.
+
+        :returns: The friendly name,  or :py:const:`None` if there is none.
+        :rtype: :py:class:`bytes` or :py:const:`None`
+        """
+        return self._friendlyname
+
+    def export(self, passphrase=None, iter=2048, maciter=1):
+        """
+        Dump a PKCS12 object as a string.
+
+        For more information, see the :c:func:`PKCS12_create` man page.
+
+        :param passphrase: The passphrase used to encrypt the structure. Unlike
+            some other passphrase arguments, this *must* be a string, not a
+            callback.
+        :type passphrase: :py:data:`bytes`
+
+        :param iter: Number of times to repeat the encryption step.
+        :type iter: :py:data:`int`
+
+        :param maciter: Number of times to repeat the MAC step.
+        :type maciter: :py:data:`int`
+
+        :return: The string representation of the PKCS #12 structure.
+        :rtype:
+        """
+        passphrase = _text_to_bytes_and_warn("passphrase", passphrase)
+
+        if self._cacerts is None:
+            cacerts = _ffi.NULL
+        else:
+            cacerts = _lib.sk_X509_new_null()
+            cacerts = _ffi.gc(cacerts, _lib.sk_X509_free)
+            for cert in self._cacerts:
+                _lib.sk_X509_push(cacerts, cert._x509)
+
+        if passphrase is None:
+            passphrase = _ffi.NULL
+
+        friendlyname = self._friendlyname
+        if friendlyname is None:
+            friendlyname = _ffi.NULL
+
+        if self._pkey is None:
+            pkey = _ffi.NULL
+        else:
+            pkey = self._pkey._pkey
+
+        if self._cert is None:
+            cert = _ffi.NULL
+        else:
+            cert = self._cert._x509
+
+        pkcs12 = _lib.PKCS12_create(
+            passphrase, friendlyname, pkey, cert, cacerts,
+            _lib.NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
+            _lib.NID_pbe_WithSHA1And3_Key_TripleDES_CBC,
+            iter, maciter, 0)
+        if pkcs12 == _ffi.NULL:
+            _raise_current_error()
+        pkcs12 = _ffi.gc(pkcs12, _lib.PKCS12_free)
+
+        bio = _new_mem_buf()
+        _lib.i2d_PKCS12_bio(bio, pkcs12)
+        return _bio_to_string(bio)
+
+
+PKCS12Type = deprecated(
+    PKCS12, __name__,
+    "PKCS12Type has been deprecated, use PKCS12 instead",
+    DeprecationWarning
+)
+
+
+class NetscapeSPKI(object):
+    """
+    A Netscape SPKI object.
+    """
+
+    def __init__(self):
+        spki = _lib.NETSCAPE_SPKI_new()
+        self._spki = _ffi.gc(spki, _lib.NETSCAPE_SPKI_free)
+
+    def sign(self, pkey, digest):
+        """
+        Sign the certificate request with this key and digest type.
+
+        :param pkey: The private key to sign with.
+        :type pkey: :py:class:`PKey`
+
+        :param digest: The message digest to use.
+        :type digest: :py:class:`bytes`
+
+        :return: ``None``
+        """
+        if pkey._only_public:
+            raise ValueError("Key has only public part")
+
+        if not pkey._initialized:
+            raise ValueError("Key is uninitialized")
+
+        digest_obj = _lib.EVP_get_digestbyname(_byte_string(digest))
+        if digest_obj == _ffi.NULL:
+            raise ValueError("No such digest method")
+
+        sign_result = _lib.NETSCAPE_SPKI_sign(
+            self._spki, pkey._pkey, digest_obj
+        )
+        _openssl_assert(sign_result > 0)
+
+    def verify(self, key):
+        """
+        Verifies a signature on a certificate request.
+
+        :param PKey key: The public key that signature is supposedly from.
+
+        :return: ``True`` if the signature is correct.
+        :rtype: bool
+
+        :raises OpenSSL.crypto.Error: If the signature is invalid, or there was
+            a problem verifying the signature.
+        """
+        answer = _lib.NETSCAPE_SPKI_verify(self._spki, key._pkey)
+        if answer <= 0:
+            _raise_current_error()
+        return True
+
+    def b64_encode(self):
+        """
+        Generate a base64 encoded representation of this SPKI object.
+
+        :return: The base64 encoded string.
+        :rtype: :py:class:`bytes`
+        """
+        encoded = _lib.NETSCAPE_SPKI_b64_encode(self._spki)
+        result = _ffi.string(encoded)
+        _lib.OPENSSL_free(encoded)
+        return result
+
+    def get_pubkey(self):
+        """
+        Get the public key of this certificate.
+
+        :return: The public key.
+        :rtype: :py:class:`PKey`
+        """
+        pkey = PKey.__new__(PKey)
+        pkey._pkey = _lib.NETSCAPE_SPKI_get_pubkey(self._spki)
+        _openssl_assert(pkey._pkey != _ffi.NULL)
+        pkey._pkey = _ffi.gc(pkey._pkey, _lib.EVP_PKEY_free)
+        pkey._only_public = True
+        return pkey
+
+    def set_pubkey(self, pkey):
+        """
+        Set the public key of the certificate
+
+        :param pkey: The public key
+        :return: ``None``
+        """
+        set_result = _lib.NETSCAPE_SPKI_set_pubkey(self._spki, pkey._pkey)
+        _openssl_assert(set_result == 1)
+
+
+NetscapeSPKIType = deprecated(
+    NetscapeSPKI, __name__,
+    "NetscapeSPKIType has been deprecated, use NetscapeSPKI instead",
+    DeprecationWarning
+)
+
+
+class _PassphraseHelper(object):
+    def __init__(self, type, passphrase, more_args=False, truncate=False):
+        if type != FILETYPE_PEM and passphrase is not None:
+            raise ValueError(
+                "only FILETYPE_PEM key format supports encryption"
+            )
+        self._passphrase = passphrase
+        self._more_args = more_args
+        self._truncate = truncate
+        self._problems = []
+
+    @property
+    def callback(self):
+        if self._passphrase is None:
+            return _ffi.NULL
+        elif isinstance(self._passphrase, bytes):
+            return _ffi.NULL
+        elif callable(self._passphrase):
+            return _ffi.callback("pem_password_cb", self._read_passphrase)
+        else:
+            raise TypeError(
+                "Last argument must be a byte string or a callable."
+            )
+
+    @property
+    def callback_args(self):
+        if self._passphrase is None:
+            return _ffi.NULL
+        elif isinstance(self._passphrase, bytes):
+            return self._passphrase
+        elif callable(self._passphrase):
+            return _ffi.NULL
+        else:
+            raise TypeError(
+                "Last argument must be a byte string or a callable."
+            )
+
+    def raise_if_problem(self, exceptionType=Error):
+        if self._problems:
+
+            # Flush the OpenSSL error queue
+            try:
+                _exception_from_error_queue(exceptionType)
+            except exceptionType:
+                pass
+
+            raise self._problems.pop(0)
+
+    def _read_passphrase(self, buf, size, rwflag, userdata):
+        try:
+            if self._more_args:
+                result = self._passphrase(size, rwflag, userdata)
+            else:
+                result = self._passphrase(rwflag)
+            if not isinstance(result, bytes):
+                raise ValueError("String expected")
+            if len(result) > size:
+                if self._truncate:
+                    result = result[:size]
+                else:
+                    raise ValueError(
+                        "passphrase returned by callback is too long"
+                    )
+            for i in range(len(result)):
+                buf[i] = result[i:i + 1]
+            return len(result)
+        except Exception as e:
+            self._problems.append(e)
+            return 0
+
+
+def load_publickey(type, buffer):
+    """
+    Load a public key from a buffer.
+
+    :param type: The file type (one of :data:`FILETYPE_PEM`,
+        :data:`FILETYPE_ASN1`).
+    :param buffer: The buffer the key is stored in.
+    :type buffer: A Python string object, either unicode or bytestring.
+    :return: The PKey object.
+    :rtype: :class:`PKey`
+    """
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    if type == FILETYPE_PEM:
+        evp_pkey = _lib.PEM_read_bio_PUBKEY(
+            bio, _ffi.NULL, _ffi.NULL, _ffi.NULL)
+    elif type == FILETYPE_ASN1:
+        evp_pkey = _lib.d2i_PUBKEY_bio(bio, _ffi.NULL)
+    else:
+        raise ValueError("type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    if evp_pkey == _ffi.NULL:
+        _raise_current_error()
+
+    pkey = PKey.__new__(PKey)
+    pkey._pkey = _ffi.gc(evp_pkey, _lib.EVP_PKEY_free)
+    pkey._only_public = True
+    return pkey
+
+
+def load_privatekey(type, buffer, passphrase=None):
+    """
+    Load a private key (PKey) from the string *buffer* encoded with the type
+    *type*.
+
+    :param type: The file type (one of FILETYPE_PEM, FILETYPE_ASN1)
+    :param buffer: The buffer the key is stored in
+    :param passphrase: (optional) if encrypted PEM format, this can be
+                       either the passphrase to use, or a callback for
+                       providing the passphrase.
+
+    :return: The PKey object
+    """
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    helper = _PassphraseHelper(type, passphrase)
+    if type == FILETYPE_PEM:
+        evp_pkey = _lib.PEM_read_bio_PrivateKey(
+            bio, _ffi.NULL, helper.callback, helper.callback_args)
+        helper.raise_if_problem()
+    elif type == FILETYPE_ASN1:
+        evp_pkey = _lib.d2i_PrivateKey_bio(bio, _ffi.NULL)
+    else:
+        raise ValueError("type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    if evp_pkey == _ffi.NULL:
+        _raise_current_error()
+
+    pkey = PKey.__new__(PKey)
+    pkey._pkey = _ffi.gc(evp_pkey, _lib.EVP_PKEY_free)
+    return pkey
+
+
+def dump_certificate_request(type, req):
+    """
+    Dump the certificate request *req* into a buffer string encoded with the
+    type *type*.
+
+    :param type: The file type (one of FILETYPE_PEM, FILETYPE_ASN1)
+    :param req: The certificate request to dump
+    :return: The buffer with the dumped certificate request in
+    """
+    bio = _new_mem_buf()
+
+    if type == FILETYPE_PEM:
+        result_code = _lib.PEM_write_bio_X509_REQ(bio, req._req)
+    elif type == FILETYPE_ASN1:
+        result_code = _lib.i2d_X509_REQ_bio(bio, req._req)
+    elif type == FILETYPE_TEXT:
+        result_code = _lib.X509_REQ_print_ex(bio, req._req, 0, 0)
+    else:
+        raise ValueError(
+            "type argument must be FILETYPE_PEM, FILETYPE_ASN1, or "
+            "FILETYPE_TEXT"
+        )
+
+    _openssl_assert(result_code != 0)
+
+    return _bio_to_string(bio)
+
+
+def load_certificate_request(type, buffer):
+    """
+    Load a certificate request (X509Req) from the string *buffer* encoded with
+    the type *type*.
+
+    :param type: The file type (one of FILETYPE_PEM, FILETYPE_ASN1)
+    :param buffer: The buffer the certificate request is stored in
+    :return: The X509Req object
+    """
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    if type == FILETYPE_PEM:
+        req = _lib.PEM_read_bio_X509_REQ(bio, _ffi.NULL, _ffi.NULL, _ffi.NULL)
+    elif type == FILETYPE_ASN1:
+        req = _lib.d2i_X509_REQ_bio(bio, _ffi.NULL)
+    else:
+        raise ValueError("type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    _openssl_assert(req != _ffi.NULL)
+
+    x509req = X509Req.__new__(X509Req)
+    x509req._req = _ffi.gc(req, _lib.X509_REQ_free)
+    return x509req
+
+
+def sign(pkey, data, digest):
+    """
+    Sign a data string using the given key and message digest.
+
+    :param pkey: PKey to sign with
+    :param data: data to be signed
+    :param digest: message digest to use
+    :return: signature
+
+    .. versionadded:: 0.11
+    """
+    data = _text_to_bytes_and_warn("data", data)
+
+    digest_obj = _lib.EVP_get_digestbyname(_byte_string(digest))
+    if digest_obj == _ffi.NULL:
+        raise ValueError("No such digest method")
+
+    md_ctx = _lib.Cryptography_EVP_MD_CTX_new()
+    md_ctx = _ffi.gc(md_ctx, _lib.Cryptography_EVP_MD_CTX_free)
+
+    _lib.EVP_SignInit(md_ctx, digest_obj)
+    _lib.EVP_SignUpdate(md_ctx, data, len(data))
+
+    length = _lib.EVP_PKEY_size(pkey._pkey)
+    _openssl_assert(length > 0)
+    signature_buffer = _ffi.new("unsigned char[]", length)
+    signature_length = _ffi.new("unsigned int *")
+    final_result = _lib.EVP_SignFinal(
+        md_ctx, signature_buffer, signature_length, pkey._pkey)
+    _openssl_assert(final_result == 1)
+
+    return _ffi.buffer(signature_buffer, signature_length[0])[:]
+
+
+def verify(cert, signature, data, digest):
+    """
+    Verify the signature for a data string.
+
+    :param cert: signing certificate (X509 object) corresponding to the
+        private key which generated the signature.
+    :param signature: signature returned by sign function
+    :param data: data to be verified
+    :param digest: message digest to use
+    :return: ``None`` if the signature is correct, raise exception otherwise.
+
+    .. versionadded:: 0.11
+    """
+    data = _text_to_bytes_and_warn("data", data)
+
+    digest_obj = _lib.EVP_get_digestbyname(_byte_string(digest))
+    if digest_obj == _ffi.NULL:
+        raise ValueError("No such digest method")
+
+    pkey = _lib.X509_get_pubkey(cert._x509)
+    _openssl_assert(pkey != _ffi.NULL)
+    pkey = _ffi.gc(pkey, _lib.EVP_PKEY_free)
+
+    md_ctx = _lib.Cryptography_EVP_MD_CTX_new()
+    md_ctx = _ffi.gc(md_ctx, _lib.Cryptography_EVP_MD_CTX_free)
+
+    _lib.EVP_VerifyInit(md_ctx, digest_obj)
+    _lib.EVP_VerifyUpdate(md_ctx, data, len(data))
+    verify_result = _lib.EVP_VerifyFinal(
+        md_ctx, signature, len(signature), pkey
+    )
+
+    if verify_result != 1:
+        _raise_current_error()
+
+
+def dump_crl(type, crl):
+    """
+    Dump a certificate revocation list to a buffer.
+
+    :param type: The file type (one of ``FILETYPE_PEM``, ``FILETYPE_ASN1``, or
+        ``FILETYPE_TEXT``).
+    :param CRL crl: The CRL to dump.
+
+    :return: The buffer with the CRL.
+    :rtype: bytes
+    """
+    bio = _new_mem_buf()
+
+    if type == FILETYPE_PEM:
+        ret = _lib.PEM_write_bio_X509_CRL(bio, crl._crl)
+    elif type == FILETYPE_ASN1:
+        ret = _lib.i2d_X509_CRL_bio(bio, crl._crl)
+    elif type == FILETYPE_TEXT:
+        ret = _lib.X509_CRL_print(bio, crl._crl)
+    else:
+        raise ValueError(
+            "type argument must be FILETYPE_PEM, FILETYPE_ASN1, or "
+            "FILETYPE_TEXT")
+
+    assert ret == 1
+    return _bio_to_string(bio)
+
+
+def load_crl(type, buffer):
+    """
+    Load Certificate Revocation List (CRL) data from a string *buffer*.
+    *buffer* encoded with the type *type*.
+
+    :param type: The file type (one of FILETYPE_PEM, FILETYPE_ASN1)
+    :param buffer: The buffer the CRL is stored in
+
+    :return: The PKey object
+    """
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    if type == FILETYPE_PEM:
+        crl = _lib.PEM_read_bio_X509_CRL(bio, _ffi.NULL, _ffi.NULL, _ffi.NULL)
+    elif type == FILETYPE_ASN1:
+        crl = _lib.d2i_X509_CRL_bio(bio, _ffi.NULL)
+    else:
+        raise ValueError("type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    if crl == _ffi.NULL:
+        _raise_current_error()
+
+    result = CRL.__new__(CRL)
+    result._crl = _ffi.gc(crl, _lib.X509_CRL_free)
+    return result
+
+
+def load_pkcs7_data(type, buffer):
+    """
+    Load pkcs7 data from the string *buffer* encoded with the type
+    *type*.
+
+    :param type: The file type (one of FILETYPE_PEM or FILETYPE_ASN1)
+    :param buffer: The buffer with the pkcs7 data.
+    :return: The PKCS7 object
+    """
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    if type == FILETYPE_PEM:
+        pkcs7 = _lib.PEM_read_bio_PKCS7(bio, _ffi.NULL, _ffi.NULL, _ffi.NULL)
+    elif type == FILETYPE_ASN1:
+        pkcs7 = _lib.d2i_PKCS7_bio(bio, _ffi.NULL)
+    else:
+        raise ValueError("type argument must be FILETYPE_PEM or FILETYPE_ASN1")
+
+    if pkcs7 == _ffi.NULL:
+        _raise_current_error()
+
+    pypkcs7 = PKCS7.__new__(PKCS7)
+    pypkcs7._pkcs7 = _ffi.gc(pkcs7, _lib.PKCS7_free)
+    return pypkcs7
+
+
+def load_pkcs12(buffer, passphrase=None):
+    """
+    Load pkcs12 data from the string *buffer*. If the pkcs12 structure is
+    encrypted, a *passphrase* must be included.  The MAC is always
+    checked and thus required.
+
+    See also the man page for the C function :py:func:`PKCS12_parse`.
+
+    :param buffer: The buffer the certificate is stored in
+    :param passphrase: (Optional) The password to decrypt the PKCS12 lump
+    :returns: The PKCS12 object
+    """
+    passphrase = _text_to_bytes_and_warn("passphrase", passphrase)
+
+    if isinstance(buffer, _text_type):
+        buffer = buffer.encode("ascii")
+
+    bio = _new_mem_buf(buffer)
+
+    # Use null passphrase if passphrase is None or empty string. With PKCS#12
+    # password based encryption no password and a zero length password are two
+    # different things, but OpenSSL implementation will try both to figure out
+    # which one works.
+    if not passphrase:
+        passphrase = _ffi.NULL
+
+    p12 = _lib.d2i_PKCS12_bio(bio, _ffi.NULL)
+    if p12 == _ffi.NULL:
+        _raise_current_error()
+    p12 = _ffi.gc(p12, _lib.PKCS12_free)
+
+    pkey = _ffi.new("EVP_PKEY**")
+    cert = _ffi.new("X509**")
+    cacerts = _ffi.new("Cryptography_STACK_OF_X509**")
+
+    parse_result = _lib.PKCS12_parse(p12, passphrase, pkey, cert, cacerts)
+    if not parse_result:
+        _raise_current_error()
+
+    cacerts = _ffi.gc(cacerts[0], _lib.sk_X509_free)
+
+    # openssl 1.0.0 sometimes leaves an X509_check_private_key error in the
+    # queue for no particular reason.  This error isn't interesting to anyone
+    # outside this function.  It's not even interesting to us.  Get rid of it.
+    try:
+        _raise_current_error()
+    except Error:
+        pass
+
+    if pkey[0] == _ffi.NULL:
+        pykey = None
+    else:
+        pykey = PKey.__new__(PKey)
+        pykey._pkey = _ffi.gc(pkey[0], _lib.EVP_PKEY_free)
+
+    if cert[0] == _ffi.NULL:
+        pycert = None
+        friendlyname = None
+    else:
+        pycert = X509._from_raw_x509_ptr(cert[0])
+
+        friendlyname_length = _ffi.new("int*")
+        friendlyname_buffer = _lib.X509_alias_get0(
+            cert[0], friendlyname_length
+        )
+        friendlyname = _ffi.buffer(
+            friendlyname_buffer, friendlyname_length[0]
+        )[:]
+        if friendlyname_buffer == _ffi.NULL:
+            friendlyname = None
+
+    pycacerts = []
+    for i in range(_lib.sk_X509_num(cacerts)):
+        x509 = _lib.sk_X509_value(cacerts, i)
+        pycacert = X509._from_raw_x509_ptr(x509)
+        pycacerts.append(pycacert)
+    if not pycacerts:
+        pycacerts = None
+
+    pkcs12 = PKCS12.__new__(PKCS12)
+    pkcs12._pkey = pykey
+    pkcs12._cert = pycert
+    pkcs12._cacerts = pycacerts
+    pkcs12._friendlyname = friendlyname
+    return pkcs12
+
+
+# There are no direct unit tests for this initialization.  It is tested
+# indirectly since it is necessary for functions like dump_privatekey when
+# using encryption.
+#
+# Thus OpenSSL.test.test_crypto.FunctionTests.test_dump_privatekey_passphrase
+# and some other similar tests may fail without this (though they may not if
+# the Python runtime has already done some initialization of the underlying
+# OpenSSL library (and is linked against the same one that cryptography is
+# using)).
+_lib.OpenSSL_add_all_algorithms()
+
+# This is similar but exercised mainly by exception_from_error_queue.  It calls
+# both ERR_load_crypto_strings() and ERR_load_SSL_strings().
+_lib.SSL_load_error_strings()
+
+
+# Set the default string mask to match OpenSSL upstream (since 2005) and
+# RFC5280 recommendations.
+_lib.ASN1_STRING_set_default_mask_asc(b'utf8only')
diff --git a/src/OpenSSL/debug.py b/src/OpenSSL/debug.py
new file mode 100644
index 0000000..0d37bf5
--- /dev/null
+++ b/src/OpenSSL/debug.py
@@ -0,0 +1,42 @@
+from __future__ import print_function
+
+import ssl
+import sys
+
+import OpenSSL.SSL
+import cffi
+import cryptography
+
+from . import version
+
+
+_env_info = u"""\
+pyOpenSSL: {pyopenssl}
+cryptography: {cryptography}
+cffi: {cffi}
+cryptography's compiled against OpenSSL: {crypto_openssl_compile}
+cryptography's linked OpenSSL: {crypto_openssl_link}
+Pythons's OpenSSL: {python_openssl}
+Python executable: {python}
+Python version: {python_version}
+Platform: {platform}
+sys.path: {sys_path}""".format(
+    pyopenssl=version.__version__,
+    crypto_openssl_compile=OpenSSL._util.ffi.string(
+        OpenSSL._util.lib.OPENSSL_VERSION_TEXT,
+    ).decode("ascii"),
+    crypto_openssl_link=OpenSSL.SSL.SSLeay_version(
+        OpenSSL.SSL.SSLEAY_VERSION
+    ).decode("ascii"),
+    python_openssl=getattr(ssl, "OPENSSL_VERSION", "n/a"),
+    cryptography=cryptography.__version__,
+    cffi=cffi.__version__,
+    python=sys.executable,
+    python_version=sys.version,
+    platform=sys.platform,
+    sys_path=sys.path,
+)
+
+
+if __name__ == "__main__":
+    print(_env_info)
diff --git a/src/OpenSSL/rand.py b/src/OpenSSL/rand.py
new file mode 100644
index 0000000..d2c1767
--- /dev/null
+++ b/src/OpenSSL/rand.py
@@ -0,0 +1,40 @@
+"""
+PRNG management routines, thin wrappers.
+"""
+
+from OpenSSL._util import lib as _lib
+
+
+def add(buffer, entropy):
+    """
+    Mix bytes from *string* into the PRNG state.
+
+    The *entropy* argument is (the lower bound of) an estimate of how much
+    randomness is contained in *string*, measured in bytes.
+
+    For more information, see e.g. :rfc:`1750`.
+
+    This function is only relevant if you are forking Python processes and
+    need to reseed the CSPRNG after fork.
+
+    :param buffer: Buffer with random data.
+    :param entropy: The entropy (in bytes) measurement of the buffer.
+
+    :return: :obj:`None`
+    """
+    if not isinstance(buffer, bytes):
+        raise TypeError("buffer must be a byte string")
+
+    if not isinstance(entropy, int):
+        raise TypeError("entropy must be an integer")
+
+    _lib.RAND_add(buffer, len(buffer), entropy)
+
+
+def status():
+    """
+    Check whether the PRNG has been seeded with enough data.
+
+    :return: 1 if the PRNG is seeded enough, 0 otherwise.
+    """
+    return _lib.RAND_status()
diff --git a/src/OpenSSL/tsafe.py b/src/OpenSSL/tsafe.py
new file mode 100644
index 0000000..f1c6f67
--- /dev/null
+++ b/src/OpenSSL/tsafe.py
@@ -0,0 +1,31 @@
+import warnings
+from threading import RLock as _RLock
+
+from OpenSSL import SSL as _ssl
+
+
+warnings.warn(
+    "OpenSSL.tsafe is deprecated and will be removed",
+    DeprecationWarning, stacklevel=3
+)
+
+
+class Connection:
+    def __init__(self, *args):
+        self._ssl_conn = _ssl.Connection(*args)
+        self._lock = _RLock()
+
+    for f in ('get_context', 'pending', 'send', 'write', 'recv', 'read',
+              'renegotiate', 'bind', 'listen', 'connect', 'accept',
+              'setblocking', 'fileno', 'shutdown', 'close', 'get_cipher_list',
+              'getpeername', 'getsockname', 'getsockopt', 'setsockopt',
+              'makefile', 'get_app_data', 'set_app_data', 'state_string',
+              'sock_shutdown', 'get_peer_certificate', 'get_peer_cert_chain',
+              'want_read', 'want_write', 'set_connect_state',
+              'set_accept_state', 'connect_ex', 'sendall'):
+        exec("""def %s(self, *args):
+            self._lock.acquire()
+            try:
+                return self._ssl_conn.%s(*args)
+            finally:
+                self._lock.release()\n""" % (f, f))
diff --git a/src/OpenSSL/version.py b/src/OpenSSL/version.py
new file mode 100644
index 0000000..40f31c3
--- /dev/null
+++ b/src/OpenSSL/version.py
@@ -0,0 +1,22 @@
+# Copyright (C) AB Strakt
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+pyOpenSSL - A simple wrapper around the OpenSSL library
+"""
+
+__all__ = [
+    "__author__", "__copyright__", "__email__", "__license__", "__summary__",
+    "__title__", "__uri__", "__version__",
+]
+
+__version__ = "19.0.0"
+
+__title__ = "pyOpenSSL"
+__uri__ = "https://pyopenssl.org/"
+__summary__ = "Python wrapper module around the OpenSSL library"
+__author__ = "The pyOpenSSL developers"
+__email__ = "cryptography-dev@python.org"
+__license__ = "Apache License, Version 2.0"
+__copyright__ = "Copyright 2001-2017 {0}".format(__author__)
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..9b08060
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,6 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+Package containing unit tests for :py:mod:`OpenSSL`.
+"""
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..366624e
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,26 @@
+# Copyright (c) The pyOpenSSL developers
+# See LICENSE for details.
+
+from tempfile import mktemp
+
+import pytest
+
+
+def pytest_report_header(config):
+    import OpenSSL.SSL
+    import cryptography
+
+    return "OpenSSL: {openssl}\ncryptography: {cryptography}".format(
+        openssl=OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION),
+        cryptography=cryptography.__version__
+    )
+
+
+@pytest.fixture
+def tmpfile(tmpdir):
+    """
+    Return UTF-8-encoded bytes of a path to a tmp file.
+
+    The file will be cleaned up after the test run.
+    """
+    return mktemp(dir=tmpdir.dirname).encode("utf-8")
diff --git a/tests/memdbg.py b/tests/memdbg.py
new file mode 100644
index 0000000..6e608a7
--- /dev/null
+++ b/tests/memdbg.py
@@ -0,0 +1,87 @@
+import sys
+
+import traceback
+
+from cffi import api as _api
+
+
+sys.modules['ssl'] = None
+sys.modules['_hashlib'] = None
+
+
+_ffi = _api.FFI()
+_ffi.cdef(
+    """
+    void *malloc(size_t size);
+    void free(void *ptr);
+    void *realloc(void *ptr, size_t size);
+
+    int  CRYPTO_set_mem_functions(void *(*m)(size_t),void *(*r)(void *,size_t), void (*f)(void *));
+
+    int backtrace(void **buffer, int size);
+    char **backtrace_symbols(void *const *buffer, int size);
+    void backtrace_symbols_fd(void *const *buffer, int size, int fd);
+    """)  # noqa
+_api = _ffi.verify(
+    """
+    #include <openssl/crypto.h>
+    #include <stdlib.h>
+    #include <execinfo.h>
+    """, libraries=["crypto"])
+C = _ffi.dlopen(None)
+
+verbose = False
+
+
+def log(s):
+    if verbose:
+        print(s)
+
+
+def _backtrace():
+    buf = _ffi.new("void*[]", 64)
+    result = _api.backtrace(buf, len(buf))
+    strings = _api.backtrace_symbols(buf, result)
+    stack = [_ffi.string(strings[i]) for i in range(result)]
+    C.free(strings)
+    return stack
+
+
+@_ffi.callback("void*(*)(size_t)")
+def malloc(n):
+    memory = C.malloc(n)
+    python_stack = traceback.extract_stack(limit=3)
+    c_stack = _backtrace()
+    heap[memory] = [(n, python_stack, c_stack)]
+    log("malloc(%d) -> %s" % (n, memory))
+    return memory
+
+
+@_ffi.callback("void*(*)(void*, size_t)")
+def realloc(p, n):
+    memory = C.realloc(p, n)
+    old = heap.pop(p)
+
+    python_stack = traceback.extract_stack(limit=3)
+    c_stack = _backtrace()
+
+    old.append((n, python_stack, c_stack))
+    heap[memory] = old
+    log("realloc(0x%x, %d) -> %s" % (int(_ffi.cast("int", p)), n, memory))
+    return memory
+
+
+@_ffi.callback("void(*)(void*)")
+def free(p):
+    if p != _ffi.NULL:
+        C.free(p)
+        del heap[p]
+        log("free(0x%x)" % (int(_ffi.cast("int", p)),))
+
+
+if _api.CRYPTO_set_mem_functions(malloc, realloc, free):
+    log('Enabled memory debugging')
+    heap = {}
+else:
+    log('Failed to enable memory debugging')
+    heap = None
diff --git a/tests/test_crypto.py b/tests/test_crypto.py
new file mode 100644
index 0000000..c938021
--- /dev/null
+++ b/tests/test_crypto.py
@@ -0,0 +1,3844 @@
+# Copyright (c) Jean-Paul Calderone
+# See LICENSE file for details.
+
+"""
+Unit tests for :py:mod:`OpenSSL.crypto`.
+"""
+
+from warnings import simplefilter
+
+import base64
+from subprocess import PIPE, Popen
+from datetime import datetime, timedelta
+
+import pytest
+
+from six import binary_type
+
+from cryptography import x509
+from cryptography.hazmat.backends.openssl.backend import backend
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import rsa
+
+import flaky
+
+from OpenSSL.crypto import TYPE_RSA, TYPE_DSA, Error, PKey, PKeyType
+from OpenSSL.crypto import X509, X509Type, X509Name, X509NameType
+from OpenSSL.crypto import (
+    X509Store,
+    X509StoreFlags,
+    X509StoreType,
+    X509StoreContext,
+    X509StoreContextError
+)
+from OpenSSL.crypto import X509Req, X509ReqType
+from OpenSSL.crypto import X509Extension, X509ExtensionType
+from OpenSSL.crypto import load_certificate, load_privatekey
+from OpenSSL.crypto import load_publickey, dump_publickey
+from OpenSSL.crypto import FILETYPE_PEM, FILETYPE_ASN1, FILETYPE_TEXT
+from OpenSSL.crypto import dump_certificate, load_certificate_request
+from OpenSSL.crypto import dump_certificate_request, dump_privatekey
+from OpenSSL.crypto import PKCS7, PKCS7Type, load_pkcs7_data
+from OpenSSL.crypto import PKCS12, PKCS12Type, load_pkcs12
+from OpenSSL.crypto import CRL, Revoked, dump_crl, load_crl
+from OpenSSL.crypto import NetscapeSPKI, NetscapeSPKIType
+from OpenSSL.crypto import (
+    sign, verify, get_elliptic_curve, get_elliptic_curves)
+
+from .util import EqualityTestsMixin, is_consistent_type, WARNING_TYPE_EXPECTED
+
+
+def normalize_privatekey_pem(pem):
+    return dump_privatekey(FILETYPE_PEM, load_privatekey(FILETYPE_PEM, pem))
+
+
+GOOD_CIPHER = "blowfish"
+BAD_CIPHER = "zippers"
+
+GOOD_DIGEST = "SHA1"
+BAD_DIGEST = "monkeys"
+
+old_root_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+
+root_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+
+root_key_pem = b"""-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+"""
+
+intermediate_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+
+intermediate_key_pem = b"""-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+"""
+
+server_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+
+server_key_pem = normalize_privatekey_pem(b"""-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+""")
+
+intermediate_server_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+
+intermediate_server_key_pem = b"""-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+"""
+
+client_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+
+client_key_pem = normalize_privatekey_pem(b"""-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+""")
+
+cleartextCertificatePEM = b"""-----BEGIN CERTIFICATE-----
+MIIC6TCCAlKgAwIBAgIIPQzE4MbeufQwDQYJKoZIhvcNAQEFBQAwWDELMAkGA1UE
+BhMCVVMxCzAJBgNVBAgTAklMMRAwDgYDVQQHEwdDaGljYWdvMRAwDgYDVQQKEwdU
+ZXN0aW5nMRgwFgYDVQQDEw9UZXN0aW5nIFJvb3QgQ0EwHhcNMTcwNjExMjIzMjU5
+WhcNMzcwNjA2MjIzMjU5WjBYMQswCQYDVQQGEwJVUzELMAkGA1UECBMCSUwxEDAO
+BgNVBAcTB0NoaWNhZ28xEDAOBgNVBAoTB1Rlc3RpbmcxGDAWBgNVBAMTD1Rlc3Rp
+bmcgUm9vdCBDQTCBnzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEA+ZpC6Yu6ukTn
+bu5IQd0vWmpwNGZbO773xjpgfNP8nspYRqbIwI1np9FbUkJHvzZRDxrTt/LbFewr
+LhZ0prHIbwJxq3CZe+m9FDjh1IA0yKEcQukA1N3JWnoMLKwQPrCRAW6seUXV2yER
+onDxv/KkOGZtUijoKLXG8ImqK9ssWdsCAwEAAaOBuzCBuDAdBgNVHQ4EFgQUg1V3
+LV4h8UkMCSTnVAkSjch+BK4wgYgGA1UdIwSBgDB+gBSDVXctXiHxSQwJJOdUCRKN
+yH4ErqFcpFowWDELMAkGA1UEBhMCVVMxCzAJBgNVBAgTAklMMRAwDgYDVQQHEwdD
+aGljYWdvMRAwDgYDVQQKEwdUZXN0aW5nMRgwFgYDVQQDEw9UZXN0aW5nIFJvb3Qg
+Q0GCCD0MxODG3rn0MAwGA1UdEwQFMAMBAf8wDQYJKoZIhvcNAQEFBQADgYEANFYQ
+R+T70VcZ+SnvURnwviFgCXeedBzCr21meo+DNHbkp2gudB9W8Xrned/wtUBVymy9
+gjB5jINfU7Lci0H57Evsw96UJJVfhXdUMHpqt1RGCoEd9FWnrDyrSy0NysnBT2bH
+lEqxh3aFEUx9IOQ4sgnx1/NOFXBpkRtivl6O0Ec=
+-----END CERTIFICATE-----
+"""
+
+cleartextPrivateKeyPEM = normalize_privatekey_pem(b"""\
+-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----
+""")
+
+cleartextCertificateRequestPEM = b"""-----BEGIN CERTIFICATE REQUEST-----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+-----END CERTIFICATE REQUEST-----
+"""
+
+encryptedPrivateKeyPEM = b"""-----BEGIN RSA PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: DES-EDE3-CBC,9573604A18579E9E
+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+-----END RSA PRIVATE KEY-----
+"""
+
+encryptedPrivateKeyPEMPassphrase = b"foobar"
+
+
+cleartextPublicKeyPEM = b"""-----BEGIN PUBLIC KEY-----
+MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAxszlc+b71LvlLS0ypt/l
+gT/JzSVJtnEqw9WUNGeiChywX2mmQLHEt7KP0JikqUFZOtPclNY823Q4pErMTSWC
+90qlUxI47vNJbXGRfmO2q6Zfw6SE+E9iUb74xezbOJLjBuUIkQzEKEFV+8taiRV+
+ceg1v01yCT2+OjhQW3cxG42zxyRFmqesbQAUWgS3uhPrUQqYQUEiTmVhh4FBUKZ5
+XIneGUpX1S7mXRxTLH6YzRoGFqRoc9A0BBNcoXHTWnxV215k4TeHMFYE5RG0KYAS
+8Xk5iKICEXwnZreIt3jyygqoOKsKZMK/Zl2VhMGhJR6HXRpQCyASzEG7bgtROLhL
+ywIDAQAB
+-----END PUBLIC KEY-----
+"""
+
+# Some PKCS#7 stuff.  Generated with the openssl command line:
+#
+#    openssl crl2pkcs7 -inform pem -outform pem -certfile s.pem -nocrl
+#
+# with a certificate and key (but the key should be irrelevant) in s.pem
+pkcs7Data = b"""\
+-----BEGIN PKCS7-----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+-----END PKCS7-----
+"""
+
+pkcs7DataASN1 = base64.b64decode(b"""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+""")
+
+crlData = b"""\
+-----BEGIN X509 CRL-----
+MIIBWzCBxTANBgkqhkiG9w0BAQQFADBYMQswCQYDVQQGEwJVUzELMAkGA1UECBMC
+SUwxEDAOBgNVBAcTB0NoaWNhZ28xEDAOBgNVBAoTB1Rlc3RpbmcxGDAWBgNVBAMT
+D1Rlc3RpbmcgUm9vdCBDQRcNMDkwNzI2MDQzNDU2WhcNMTIwOTI3MDI0MTUyWjA8
+MBUCAgOrGA8yMDA5MDcyNTIzMzQ1NlowIwICAQAYDzIwMDkwNzI1MjMzNDU2WjAM
+MAoGA1UdFQQDCgEEMA0GCSqGSIb3DQEBBAUAA4GBAEBt7xTs2htdD3d4ErrcGAw1
+4dKcVnIWTutoI7xxen26Wwvh8VCsT7i/UeP+rBl9rC/kfjWjzQk3/zleaarGTpBT
+0yp4HXRFFoRhhSE/hP+eteaPXRgrsNRLHe9ZDd69wmh7J1wMDb0m81RG7kqcbsid
+vrzEeLDRiiPl92dyyWmu
+-----END X509 CRL-----
+"""
+
+crlDataUnsupportedExtension = b"""\
+-----BEGIN X509 CRL-----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+-----END X509 CRL-----
+"""
+
+
+# A broken RSA private key which can be used to test the error path through
+# PKey.check.
+inconsistentPrivateKeyPEM = b"""-----BEGIN RSA PRIVATE KEY-----
+MIIBPAIBAAJBAKy+e3dulvXzV7zoTZWc5TzgApr8DmeQHTYC8ydfzH7EECe4R1Xh
+5kwIzOuuFfn178FBiS84gngaNcrFi0Z5fAkCAwEaAQJBAIqm/bz4NA1H++Vx5Ewx
+OcKp3w19QSaZAwlGRtsUxrP7436QjnREM3Bm8ygU11BjkPVmtrKm6AayQfCHqJoT
+zIECIQDW0BoMoL0HOYM/mrTLhaykYAVqgIeJsPjvkEhTFXWBuQIhAM3deFAvWNu4
+nklUQ37XsCT2c9tmNt1LAT+slG2JOTTRAiAuXDtC/m3NYVwyHfFm+zKHRzHkClk2
+HjubeEgjpj32AQIhAJqMGTaZVOwevTXvvHwNeH+vRWsAYU/gbx+OQB+7VOcBAiEA
+oolb6NMg/R3enNPvS1O4UU1H8wpaF77L4yiSWlE0p4w=
+-----END RSA PRIVATE KEY-----
+"""
+
+# certificate with NULL bytes in subjectAltName and common name
+
+nulbyteSubjectAltNamePEM = b"""-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----"""
+
+large_key_pem = b"""-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----"""
+
+ec_private_key_pem = b"""-----BEGIN PRIVATE KEY-----
+MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQgYirTZSx+5O8Y6tlG
+cka6W6btJiocdrdolfcukSoTEk+hRANCAAQkvPNu7Pa1GcsWU4v7ptNfqCJVq8Cx
+zo0MUVPQgwJ3aJtNM1QMOQUayCrRwfklg+D/rFSUwEUqtZh7fJDiFqz3
+-----END PRIVATE KEY-----
+"""
+
+ec_root_key_pem = b"""-----BEGIN EC PRIVATE KEY-----
+MIGlAgEBBDEAz/HOBFPYLB0jLWeTpJn4Yc4m/C4mdWymVHBjOmnwiPHKT326iYN/
+ZhmSs+RM94RsoAcGBSuBBAAioWQDYgAEwE5vDdla/nLpWAPAQ0yFGqwLuw4BcN2r
+U+sKab5EAEHzLeceRa8ffncYdCXNoVsBcdob1y66CFZMEWLetPTmGapyWkBAs6/L
+8kUlkU9OsE+7IVo4QQJkgV5gM+Dim1XE
+-----END EC PRIVATE KEY-----
+"""
+
+ec_root_cert_pem = b"""-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----"""
+
+
+@pytest.fixture
+def x509_data():
+    """
+    Create a new private key and start a certificate request (for a test
+    to finish in one way or another).
+    """
+    # Basic setup stuff to generate a certificate
+    pkey = PKey()
+    pkey.generate_key(TYPE_RSA, 512)
+    req = X509Req()
+    req.set_pubkey(pkey)
+    # Authority good you have.
+    req.get_subject().commonName = "Yoda root CA"
+    x509 = X509()
+    subject = x509.get_subject()
+    subject.commonName = req.get_subject().commonName
+    x509.set_issuer(subject)
+    x509.set_pubkey(pkey)
+    now = datetime.now()
+    expire = datetime.now() + timedelta(days=100)
+    x509.set_notBefore(now.strftime("%Y%m%d%H%M%SZ").encode())
+    x509.set_notAfter(expire.strftime("%Y%m%d%H%M%SZ").encode())
+    yield pkey, x509
+
+
+class TestX509Ext(object):
+    """
+    Tests for `OpenSSL.crypto.X509Extension`.
+    """
+
+    def test_str(self):
+        """
+        The string representation of `X509Extension` instances as
+        returned by `str` includes stuff.
+        """
+        # This isn't necessarily the best string representation.  Perhaps it
+        # will be changed/improved in the future.
+        assert (
+            str(X509Extension(b'basicConstraints', True, b'CA:false')) ==
+            'CA:FALSE'
+        )
+
+    def test_type(self):
+        """
+        `X509Extension` and `X509ExtensionType` refer to the same type object
+        and can be used to create instances of that type.
+        """
+        assert X509Extension is X509ExtensionType
+        assert is_consistent_type(
+            X509Extension,
+            'X509Extension', b'basicConstraints', True, b'CA:true')
+
+    def test_construction(self):
+        """
+        `X509Extension` accepts an extension type name, a critical flag,
+        and an extension value and returns an `X509ExtensionType` instance.
+        """
+        basic = X509Extension(b'basicConstraints', True, b'CA:true')
+        assert isinstance(basic, X509ExtensionType)
+
+        comment = X509Extension(b'nsComment', False, b'pyOpenSSL unit test')
+        assert isinstance(comment, X509ExtensionType)
+
+    @pytest.mark.parametrize('type_name, critical, value', [
+        (b'thisIsMadeUp', False, b'hi'),
+        (b'basicConstraints', False, b'blah blah'),
+
+        # Exercise a weird one (an extension which uses the r2i method).  This
+        # exercises the codepath that requires a non-NULL ctx to be passed to
+        # X509V3_EXT_nconf.  It can't work now because we provide no
+        # configuration database.  It might be made to work in the future.
+        (b'proxyCertInfo', True,
+         b'language:id-ppl-anyLanguage,pathlen:1,policy:text:AB')
+    ])
+    def test_invalid_extension(self, type_name, critical, value):
+        """
+        `X509Extension` raises something if it is passed a bad
+        extension name or value.
+        """
+        with pytest.raises(Error):
+            X509Extension(type_name, critical, value)
+
+    @pytest.mark.parametrize('critical_flag', [True, False])
+    def test_get_critical(self, critical_flag):
+        """
+        `X509ExtensionType.get_critical` returns the value of the
+        extension's critical flag.
+        """
+        ext = X509Extension(b'basicConstraints', critical_flag, b'CA:true')
+        assert ext.get_critical() == critical_flag
+
+    @pytest.mark.parametrize('short_name, value', [
+        (b'basicConstraints', b'CA:true'),
+        (b'nsComment', b'foo bar'),
+    ])
+    def test_get_short_name(self, short_name, value):
+        """
+        `X509ExtensionType.get_short_name` returns a string giving the
+        short type name of the extension.
+        """
+        ext = X509Extension(short_name, True, value)
+        assert ext.get_short_name() == short_name
+
+    def test_get_data(self):
+        """
+        `X509Extension.get_data` returns a string giving the data of
+        the extension.
+        """
+        ext = X509Extension(b'basicConstraints', True, b'CA:true')
+        # Expect to get back the DER encoded form of CA:true.
+        assert ext.get_data() == b'0\x03\x01\x01\xff'
+
+    def test_unused_subject(self, x509_data):
+        """
+        The `subject` parameter to `X509Extension` may be provided for an
+        extension which does not use it and is ignored in this case.
+        """
+        pkey, x509 = x509_data
+        ext1 = X509Extension(
+            b'basicConstraints', False, b'CA:TRUE', subject=x509)
+        x509.add_extensions([ext1])
+        x509.sign(pkey, 'sha1')
+        # This is a little lame.  Can we think of a better way?
+        text = dump_certificate(FILETYPE_TEXT, x509)
+        assert b'X509v3 Basic Constraints:' in text
+        assert b'CA:TRUE' in text
+
+    def test_subject(self, x509_data):
+        """
+        If an extension requires a subject, the `subject` parameter to
+        `X509Extension` provides its value.
+        """
+        pkey, x509 = x509_data
+        ext3 = X509Extension(
+            b'subjectKeyIdentifier', False, b'hash', subject=x509)
+        x509.add_extensions([ext3])
+        x509.sign(pkey, 'sha1')
+        text = dump_certificate(FILETYPE_TEXT, x509)
+        assert b'X509v3 Subject Key Identifier:' in text
+
+    def test_missing_subject(self):
+        """
+        If an extension requires a subject and the `subject` parameter
+        is given no value, something happens.
+        """
+        with pytest.raises(Error):
+            X509Extension(b'subjectKeyIdentifier', False, b'hash')
+
+    @pytest.mark.parametrize('bad_obj', [
+        True,
+        object(),
+        "hello",
+        [],
+    ])
+    def test_invalid_subject(self, bad_obj):
+        """
+        If the `subject` parameter is given a value which is not an
+        `X509` instance, `TypeError` is raised.
+        """
+        with pytest.raises(TypeError):
+            X509Extension(
+                'basicConstraints', False, 'CA:TRUE', subject=bad_obj)
+
+    def test_unused_issuer(self, x509_data):
+        """
+        The `issuer` parameter to `X509Extension` may be provided for an
+        extension which does not use it and is ignored in this case.
+        """
+        pkey, x509 = x509_data
+        ext1 = X509Extension(
+            b'basicConstraints', False, b'CA:TRUE', issuer=x509)
+        x509.add_extensions([ext1])
+        x509.sign(pkey, 'sha1')
+        text = dump_certificate(FILETYPE_TEXT, x509)
+        assert b'X509v3 Basic Constraints:' in text
+        assert b'CA:TRUE' in text
+
+    def test_issuer(self, x509_data):
+        """
+        If an extension requires an issuer, the `issuer` parameter to
+        `X509Extension` provides its value.
+        """
+        pkey, x509 = x509_data
+        ext2 = X509Extension(
+            b'authorityKeyIdentifier', False, b'issuer:always',
+            issuer=x509)
+        x509.add_extensions([ext2])
+        x509.sign(pkey, 'sha1')
+        text = dump_certificate(FILETYPE_TEXT, x509)
+        assert b'X509v3 Authority Key Identifier:' in text
+        assert b'DirName:/CN=Yoda root CA' in text
+
+    def test_missing_issuer(self):
+        """
+        If an extension requires an issue and the `issuer` parameter is
+        given no value, something happens.
+        """
+        with pytest.raises(Error):
+            X509Extension(
+                b'authorityKeyIdentifier',
+                False, b'keyid:always,issuer:always')
+
+    @pytest.mark.parametrize('bad_obj', [
+        True,
+        object(),
+        "hello",
+        [],
+    ])
+    def test_invalid_issuer(self, bad_obj):
+        """
+        If the `issuer` parameter is given a value which is not an
+        `X509` instance, `TypeError` is raised.
+        """
+        with pytest.raises(TypeError):
+            X509Extension(
+                'basicConstraints', False, 'keyid:always,issuer:always',
+                issuer=bad_obj)
+
+
+class TestPKey(object):
+    """
+    Tests for `OpenSSL.crypto.PKey`.
+    """
+
+    def test_convert_from_cryptography_private_key(self):
+        """
+        PKey.from_cryptography_key creates a proper private PKey.
+        """
+        key = serialization.load_pem_private_key(
+            intermediate_key_pem, None, backend
+        )
+        pkey = PKey.from_cryptography_key(key)
+
+        assert isinstance(pkey, PKey)
+        assert pkey.bits() == key.key_size
+        assert pkey._only_public is False
+        assert pkey._initialized is True
+
+    def test_convert_from_cryptography_public_key(self):
+        """
+        PKey.from_cryptography_key creates a proper public PKey.
+        """
+        key = serialization.load_pem_public_key(cleartextPublicKeyPEM, backend)
+        pkey = PKey.from_cryptography_key(key)
+
+        assert isinstance(pkey, PKey)
+        assert pkey.bits() == key.key_size
+        assert pkey._only_public is True
+        assert pkey._initialized is True
+
+    def test_convert_from_cryptography_unsupported_type(self):
+        """
+        PKey.from_cryptography_key raises TypeError with an unsupported type.
+        """
+        key = serialization.load_pem_private_key(
+            ec_private_key_pem, None, backend
+        )
+        with pytest.raises(TypeError):
+            PKey.from_cryptography_key(key)
+
+    def test_convert_public_pkey_to_cryptography_key(self):
+        """
+        PKey.to_cryptography_key creates a proper cryptography public key.
+        """
+        pkey = load_publickey(FILETYPE_PEM, cleartextPublicKeyPEM)
+        key = pkey.to_cryptography_key()
+
+        assert isinstance(key, rsa.RSAPublicKey)
+        assert pkey.bits() == key.key_size
+
+    def test_convert_private_pkey_to_cryptography_key(self):
+        """
+        PKey.to_cryptography_key creates a proper cryptography private key.
+        """
+        pkey = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        key = pkey.to_cryptography_key()
+
+        assert isinstance(key, rsa.RSAPrivateKey)
+        assert pkey.bits() == key.key_size
+
+    def test_type(self):
+        """
+        `PKey` and `PKeyType` refer to the same type object and can be used to
+        create instances of that type.
+        """
+        assert PKey is PKeyType
+        assert is_consistent_type(PKey, 'PKey')
+
+    def test_construction(self):
+        """
+        `PKey` takes no arguments and returns a new `PKey` instance.
+        """
+        key = PKey()
+        assert isinstance(key, PKey)
+
+    def test_pregeneration(self):
+        """
+        `PKey.bits` and `PKey.type` return `0` before the key is generated.
+        `PKey.check` raises `TypeError` before the key is generated.
+        """
+        key = PKey()
+        assert key.type() == 0
+        assert key.bits() == 0
+        with pytest.raises(TypeError):
+            key.check()
+
+    def test_failed_generation(self):
+        """
+        `PKey.generate_key` takes two arguments, the first giving the key type
+        as one of `TYPE_RSA` or `TYPE_DSA` and the second giving the number of
+        bits to generate.  If an invalid type is specified or generation fails,
+        `Error` is raised.  If an invalid number of bits is specified,
+        `ValueError` or `Error` is raised.
+        """
+        key = PKey()
+        with pytest.raises(TypeError):
+            key.generate_key("foo", "bar")
+        with pytest.raises(Error):
+            key.generate_key(-1, 0)
+
+        with pytest.raises(ValueError):
+            key.generate_key(TYPE_RSA, -1)
+        with pytest.raises(ValueError):
+            key.generate_key(TYPE_RSA, 0)
+
+        with pytest.raises(TypeError):
+            key.generate_key(TYPE_RSA, object())
+
+        # XXX RSA generation for small values of bits is fairly buggy in a wide
+        # range of OpenSSL versions.  I need to figure out what the safe lower
+        # bound for a reasonable number of OpenSSL versions is and explicitly
+        # check for that in the wrapper.  The failure behavior is typically an
+        # infinite loop inside OpenSSL.
+
+        # with pytest.raises(Error):
+        #     key.generate_key(TYPE_RSA, 2)
+
+        # XXX DSA generation seems happy with any number of bits.  The DSS
+        # says bits must be between 512 and 1024 inclusive.  OpenSSL's DSA
+        # generator doesn't seem to care about the upper limit at all.  For
+        # the lower limit, it uses 512 if anything smaller is specified.
+        # So, it doesn't seem possible to make generate_key fail for
+        # TYPE_DSA with a bits argument which is at least an int.
+
+        # with pytest.raises(Error):
+        #     key.generate_key(TYPE_DSA, -7)
+
+    def test_rsa_generation(self):
+        """
+        `PKey.generate_key` generates an RSA key when passed `TYPE_RSA` as a
+        type and a reasonable number of bits.
+        """
+        bits = 512
+        key = PKey()
+        key.generate_key(TYPE_RSA, bits)
+        assert key.type() == TYPE_RSA
+        assert key.bits() == bits
+        assert key.check()
+
+    def test_dsa_generation(self):
+        """
+        `PKey.generate_key` generates a DSA key when passed `TYPE_DSA` as a
+        type and a reasonable number of bits.
+        """
+        # 512 is a magic number.  The DSS (Digital Signature Standard)
+        # allows a minimum of 512 bits for DSA.  DSA_generate_parameters
+        # will silently promote any value below 512 to 512.
+        bits = 512
+        key = PKey()
+        key.generate_key(TYPE_DSA, bits)
+        assert key.type() == TYPE_DSA
+        assert key.bits() == bits
+        with pytest.raises(TypeError):
+            key.check()
+
+    def test_regeneration(self):
+        """
+        `PKey.generate_key` can be called multiple times on the same key to
+        generate new keys.
+        """
+        key = PKey()
+        for type, bits in [(TYPE_RSA, 512), (TYPE_DSA, 576)]:
+            key.generate_key(type, bits)
+            assert key.type() == type
+            assert key.bits() == bits
+
+    def test_inconsistent_key(self):
+        """
+        `PKey.check` returns `Error` if the key is not consistent.
+        """
+        key = load_privatekey(FILETYPE_PEM, inconsistentPrivateKeyPEM)
+        with pytest.raises(Error):
+            key.check()
+
+    def test_check_public_key(self):
+        """
+        `PKey.check` raises `TypeError` if only the public part of the key
+        is available.
+        """
+        # A trick to get a public-only key
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        cert = X509()
+        cert.set_pubkey(key)
+        pub = cert.get_pubkey()
+        with pytest.raises(TypeError):
+            pub.check()
+
+
+def x509_name(**attrs):
+    """
+    Return a new X509Name with the given attributes.
+    """
+    # XXX There's no other way to get a new X509Name yet.
+    name = X509().get_subject()
+    attrs = list(attrs.items())
+
+    # Make the order stable - order matters!
+    def key(attr):
+        return attr[1]
+    attrs.sort(key=key)
+    for k, v in attrs:
+        setattr(name, k, v)
+    return name
+
+
+class TestX509Name(object):
+    """
+    Unit tests for `OpenSSL.crypto.X509Name`.
+    """
+
+    def test_type(self):
+        """
+        The type of X509Name objects is `X509NameType`.
+        """
+        assert X509Name is X509NameType
+        assert X509NameType.__name__ == 'X509Name'
+        assert isinstance(X509NameType, type)
+
+        name = x509_name()
+        assert isinstance(name, X509NameType)
+
+    def test_only_string_attributes(self):
+        """
+        Attempting to set a non-`str` attribute name on an `X509Name` instance
+        causes `TypeError` to be raised.
+        """
+        name = x509_name()
+        # Beyond these cases, you may also think that unicode should be
+        # rejected.  Sorry, you're wrong.  unicode is automatically converted
+        # to str outside of the control of X509Name, so there's no way to
+        # reject it.
+
+        # Also, this used to test str subclasses, but that test is less
+        # relevant now that the implementation is in Python instead of C.  Also
+        # PyPy automatically converts str subclasses to str when they are
+        # passed to setattr, so we can't test it on PyPy.  Apparently CPython
+        # does this sometimes as well.
+        with pytest.raises(TypeError):
+            setattr(name, None, "hello")
+        with pytest.raises(TypeError):
+            setattr(name, 30, "hello")
+
+    def test_set_invalid_attribute(self):
+        """
+        Attempting to set any attribute name on an `X509Name` instance for
+        which no corresponding NID is defined causes `AttributeError` to be
+        raised.
+        """
+        name = x509_name()
+        with pytest.raises(AttributeError):
+            setattr(name, "no such thing", None)
+
+    def test_attributes(self):
+        """
+        `X509Name` instances have attributes for each standard (?)
+        X509Name field.
+        """
+        name = x509_name()
+        name.commonName = "foo"
+        assert name.commonName == "foo"
+        assert name.CN == "foo"
+
+        name.CN = "baz"
+        assert name.commonName == "baz"
+        assert name.CN == "baz"
+
+        name.commonName = "bar"
+        assert name.commonName == "bar"
+        assert name.CN == "bar"
+
+        name.CN = "quux"
+        assert name.commonName == "quux"
+        assert name.CN == "quux"
+
+        assert name.OU is None
+
+        with pytest.raises(AttributeError):
+            name.foobar
+
+    def test_copy(self):
+        """
+        `X509Name` creates a new `X509Name` instance with all the same
+        attributes as an existing `X509Name` instance when called with one.
+        """
+        name = x509_name(commonName="foo", emailAddress="bar@example.com")
+
+        copy = X509Name(name)
+        assert copy.commonName == "foo"
+        assert copy.emailAddress == "bar@example.com"
+
+        # Mutate the copy and ensure the original is unmodified.
+        copy.commonName = "baz"
+        assert name.commonName == "foo"
+
+        # Mutate the original and ensure the copy is unmodified.
+        name.emailAddress = "quux@example.com"
+        assert copy.emailAddress == "bar@example.com"
+
+    def test_repr(self):
+        """
+        `repr` passed an `X509Name` instance should return a string containing
+        a description of the type and the NIDs which have been set on it.
+        """
+        name = x509_name(commonName="foo", emailAddress="bar")
+        assert repr(name) == "<X509Name object '/emailAddress=bar/CN=foo'>"
+
+    def test_comparison(self):
+        """
+        `X509Name` instances should compare based on their NIDs.
+        """
+        def _equality(a, b, assert_true, assert_false):
+            assert_true(a == b)
+            assert_false(a != b)
+            assert_true(b == a)
+            assert_false(b != a)
+
+        def assert_true(x):
+            assert x
+
+        def assert_false(x):
+            assert not x
+
+        def assert_equal(a, b):
+            _equality(a, b, assert_true, assert_false)
+
+        # Instances compare equal to themselves.
+        name = x509_name()
+        assert_equal(name, name)
+
+        # Empty instances should compare equal to each other.
+        assert_equal(x509_name(), x509_name())
+
+        # Instances with equal NIDs should compare equal to each other.
+        assert_equal(x509_name(commonName="foo"),
+                     x509_name(commonName="foo"))
+
+        # Instance with equal NIDs set using different aliases should compare
+        # equal to each other.
+        assert_equal(x509_name(commonName="foo"),
+                     x509_name(CN="foo"))
+
+        # Instances with more than one NID with the same values should compare
+        # equal to each other.
+        assert_equal(x509_name(CN="foo", organizationalUnitName="bar"),
+                     x509_name(commonName="foo", OU="bar"))
+
+        def assert_not_equal(a, b):
+            _equality(a, b, assert_false, assert_true)
+
+        # Instances with different values for the same NID should not compare
+        # equal to each other.
+        assert_not_equal(x509_name(CN="foo"),
+                         x509_name(CN="bar"))
+
+        # Instances with different NIDs should not compare equal to each other.
+        assert_not_equal(x509_name(CN="foo"),
+                         x509_name(OU="foo"))
+
+        assert_not_equal(x509_name(), object())
+
+        def _inequality(a, b, assert_true, assert_false):
+            assert_true(a < b)
+            assert_true(a <= b)
+            assert_true(b > a)
+            assert_true(b >= a)
+            assert_false(a > b)
+            assert_false(a >= b)
+            assert_false(b < a)
+            assert_false(b <= a)
+
+        def assert_less_than(a, b):
+            _inequality(a, b, assert_true, assert_false)
+
+        # An X509Name with a NID with a value which sorts less than the value
+        # of the same NID on another X509Name compares less than the other
+        # X509Name.
+        assert_less_than(x509_name(CN="abc"),
+                         x509_name(CN="def"))
+
+        def assert_greater_than(a, b):
+            _inequality(a, b, assert_false, assert_true)
+
+        # An X509Name with a NID with a value which sorts greater than the
+        # value of the same NID on another X509Name compares greater than the
+        # other X509Name.
+        assert_greater_than(x509_name(CN="def"),
+                            x509_name(CN="abc"))
+
+    def test_hash(self):
+        """
+        `X509Name.hash` returns an integer hash based on the value of the name.
+        """
+        a = x509_name(CN="foo")
+        b = x509_name(CN="foo")
+        assert a.hash() == b.hash()
+        a.CN = "bar"
+        assert a.hash() != b.hash()
+
+    def test_der(self):
+        """
+        `X509Name.der` returns the DER encoded form of the name.
+        """
+        a = x509_name(CN="foo", C="US")
+        assert (a.der() ==
+                b'0\x1b1\x0b0\t\x06\x03U\x04\x06\x13\x02US'
+                b'1\x0c0\n\x06\x03U\x04\x03\x0c\x03foo')
+
+    def test_get_components(self):
+        """
+        `X509Name.get_components` returns a `list` of two-tuples of `str`
+        giving the NIDs and associated values which make up the name.
+        """
+        a = x509_name()
+        assert a.get_components() == []
+        a.CN = "foo"
+        assert a.get_components() == [(b"CN", b"foo")]
+        a.organizationalUnitName = "bar"
+        assert a.get_components() == [(b"CN", b"foo"), (b"OU", b"bar")]
+
+    def test_load_nul_byte_attribute(self):
+        """
+        An `X509Name` from an `X509` instance loaded from a file can have a
+        NUL byte in the value of one of its attributes.
+        """
+        cert = load_certificate(FILETYPE_PEM, nulbyteSubjectAltNamePEM)
+        subject = cert.get_subject()
+        assert "null.python.org\x00example.org" == subject.commonName
+
+    def test_load_nul_byte_components(self):
+        """
+        An `X509Name` from an `X509` instance loaded from a file can have a
+        NUL byte in the value of its components
+        """
+        cert = load_certificate(FILETYPE_PEM, nulbyteSubjectAltNamePEM)
+        subject = cert.get_subject()
+        components = subject.get_components()
+        ccn = [value for name, value in components if name == b'CN']
+        assert ccn[0] == b'null.python.org\x00example.org'
+
+    def test_set_attribute_failure(self):
+        """
+        If the value of an attribute cannot be set for some reason then
+        `Error` is raised.
+        """
+        name = x509_name()
+        # This value is too long
+        with pytest.raises(Error):
+            setattr(name, "O", b"x" * 512)
+
+
+class _PKeyInteractionTestsMixin:
+    """
+    Tests which involve another thing and a PKey.
+    """
+
+    def signable(self):
+        """
+        Return something with a `set_pubkey`, `set_pubkey`, and `sign` method.
+        """
+        raise NotImplementedError()
+
+    def test_sign_with_ungenerated(self):
+        """
+        `X509Req.sign` raises `ValueError` when passed a `PKey` with no parts.
+        """
+        request = self.signable()
+        key = PKey()
+        with pytest.raises(ValueError):
+            request.sign(key, GOOD_DIGEST)
+
+    def test_sign_with_public_key(self):
+        """
+        `X509Req.sign` raises `ValueError` when passed a `PKey` with no private
+        part as the signing key.
+        """
+        request = self.signable()
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        request.set_pubkey(key)
+        pub = request.get_pubkey()
+        with pytest.raises(ValueError):
+            request.sign(pub, GOOD_DIGEST)
+
+    def test_sign_with_unknown_digest(self):
+        """
+        `X509Req.sign` raises `ValueError` when passed a digest name which is
+        not known.
+        """
+        request = self.signable()
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        with pytest.raises(ValueError):
+            request.sign(key, BAD_DIGEST)
+
+    def test_sign(self):
+        """
+        `X509Req.sign` succeeds when passed a private key object and a
+        valid digest function. `X509Req.verify` can be used to check
+        the signature.
+        """
+        request = self.signable()
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        request.set_pubkey(key)
+        request.sign(key, GOOD_DIGEST)
+        # If the type has a verify method, cover that too.
+        if getattr(request, 'verify', None) is not None:
+            pub = request.get_pubkey()
+            assert request.verify(pub)
+            # Make another key that won't verify.
+            key = PKey()
+            key.generate_key(TYPE_RSA, 512)
+            with pytest.raises(Error):
+                request.verify(key)
+
+
+class TestX509Req(_PKeyInteractionTestsMixin):
+    """
+    Tests for `OpenSSL.crypto.X509Req`.
+    """
+
+    def signable(self):
+        """
+        Create and return a new `X509Req`.
+        """
+        return X509Req()
+
+    def test_type(self):
+        """
+        `X509Req` and `X509ReqType` refer to the same type object and can be
+        used to create instances of that type.
+        """
+        assert X509Req is X509ReqType
+        assert is_consistent_type(X509Req, 'X509Req')
+
+    def test_construction(self):
+        """
+        `X509Req` takes no arguments and returns an `X509ReqType` instance.
+        """
+        request = X509Req()
+        assert isinstance(request, X509ReqType)
+
+    def test_version(self):
+        """
+        `X509Req.set_version` sets the X.509 version of the certificate
+        request. `X509Req.get_version` returns the X.509 version of the
+        certificate request. The initial value of the version is 0.
+        """
+        request = X509Req()
+        assert request.get_version() == 0
+        request.set_version(1)
+        assert request.get_version() == 1
+        request.set_version(3)
+        assert request.get_version() == 3
+
+    def test_version_wrong_args(self):
+        """
+        `X509Req.set_version` raises `TypeError` if called with a non-`int`
+        argument.
+        """
+        request = X509Req()
+        with pytest.raises(TypeError):
+            request.set_version("foo")
+
+    def test_get_subject(self):
+        """
+        `X509Req.get_subject` returns an `X509Name` for the subject of the
+        request and which is valid even after the request object is
+        otherwise dead.
+        """
+        request = X509Req()
+        subject = request.get_subject()
+        assert isinstance(subject, X509NameType)
+        subject.commonName = "foo"
+        assert request.get_subject().commonName == "foo"
+        del request
+        subject.commonName = "bar"
+        assert subject.commonName == "bar"
+
+    def test_add_extensions(self):
+        """
+        `X509Req.add_extensions` accepts a `list` of `X509Extension` instances
+        and adds them to the X509 request.
+        """
+        request = X509Req()
+        request.add_extensions([
+            X509Extension(b'basicConstraints', True, b'CA:false')])
+        exts = request.get_extensions()
+        assert len(exts) == 1
+        assert exts[0].get_short_name() == b'basicConstraints'
+        assert exts[0].get_critical() == 1
+        assert exts[0].get_data() == b'0\x00'
+
+    def test_get_extensions(self):
+        """
+        `X509Req.get_extensions` returns a `list` of extensions added to this
+        X509 request.
+        """
+        request = X509Req()
+        exts = request.get_extensions()
+        assert exts == []
+        request.add_extensions([
+            X509Extension(b'basicConstraints', True, b'CA:true'),
+            X509Extension(b'keyUsage', False, b'digitalSignature')])
+        exts = request.get_extensions()
+        assert len(exts) == 2
+        assert exts[0].get_short_name() == b'basicConstraints'
+        assert exts[0].get_critical() == 1
+        assert exts[0].get_data() == b'0\x03\x01\x01\xff'
+        assert exts[1].get_short_name() == b'keyUsage'
+        assert exts[1].get_critical() == 0
+        assert exts[1].get_data() == b'\x03\x02\x07\x80'
+
+    def test_add_extensions_wrong_args(self):
+        """
+        `X509Req.add_extensions` raises `TypeError` if called with a
+        non-`list`.  Or it raises `ValueError` if called with a `list`
+        containing objects other than `X509Extension` instances.
+        """
+        request = X509Req()
+        with pytest.raises(TypeError):
+            request.add_extensions(object())
+        with pytest.raises(ValueError):
+            request.add_extensions([object()])
+
+    def test_verify_wrong_args(self):
+        """
+        `X509Req.verify` raises `TypeError` if passed anything other than a
+        `PKey` instance as its single argument.
+        """
+        request = X509Req()
+        with pytest.raises(TypeError):
+            request.verify(object())
+
+    def test_verify_uninitialized_key(self):
+        """
+        `X509Req.verify` raises `OpenSSL.crypto.Error` if called with a
+        `OpenSSL.crypto.PKey` which contains no key data.
+        """
+        request = X509Req()
+        pkey = PKey()
+        with pytest.raises(Error):
+            request.verify(pkey)
+
+    def test_verify_wrong_key(self):
+        """
+        `X509Req.verify` raises `OpenSSL.crypto.Error` if called with a
+        `OpenSSL.crypto.PKey` which does not represent the public part of the
+        key which signed the request.
+        """
+        request = X509Req()
+        pkey = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        request.sign(pkey, GOOD_DIGEST)
+        another_pkey = load_privatekey(FILETYPE_PEM, client_key_pem)
+        with pytest.raises(Error):
+            request.verify(another_pkey)
+
+    def test_verify_success(self):
+        """
+        `X509Req.verify` returns `True` if called with a `OpenSSL.crypto.PKey`
+        which represents the public part of the key which signed the request.
+        """
+        request = X509Req()
+        pkey = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        request.sign(pkey, GOOD_DIGEST)
+        assert request.verify(pkey)
+
+    def test_convert_from_cryptography(self):
+        crypto_req = x509.load_pem_x509_csr(
+            cleartextCertificateRequestPEM, backend
+        )
+        req = X509Req.from_cryptography(crypto_req)
+        assert isinstance(req, X509Req)
+
+    def test_convert_from_cryptography_unsupported_type(self):
+        with pytest.raises(TypeError):
+            X509Req.from_cryptography(object())
+
+    def test_convert_to_cryptography_key(self):
+        req = load_certificate_request(
+            FILETYPE_PEM, cleartextCertificateRequestPEM
+        )
+        crypto_req = req.to_cryptography()
+        assert isinstance(crypto_req, x509.CertificateSigningRequest)
+
+
+class TestX509(_PKeyInteractionTestsMixin):
+    """
+    Tests for `OpenSSL.crypto.X509`.
+    """
+    pemData = cleartextCertificatePEM + cleartextPrivateKeyPEM
+
+    extpem = """
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+    """
+
+    def signable(self):
+        """
+        Create and return a new `X509`.
+        """
+        return X509()
+
+    def test_type(self):
+        """
+        `X509` and `X509Type` refer to the same type object and can be used to
+        create instances of that type.
+        """
+        assert X509 is X509Type
+        assert is_consistent_type(X509, 'X509')
+
+    def test_construction(self):
+        """
+        `X509` takes no arguments and returns an instance of `X509Type`.
+        """
+        certificate = X509()
+        assert isinstance(certificate, X509Type)
+        assert type(X509Type).__name__ == 'type'
+        assert type(certificate).__name__ == 'X509'
+        assert type(certificate) == X509Type
+        assert type(certificate) == X509
+
+    def test_set_version_wrong_args(self):
+        """
+        `X509.set_version` raises `TypeError` if invoked with an argument
+        not of type `int`.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.set_version(None)
+
+    def test_version(self):
+        """
+        `X509.set_version` sets the certificate version number.
+        `X509.get_version` retrieves it.
+        """
+        cert = X509()
+        cert.set_version(1234)
+        assert cert.get_version() == 1234
+
+    def test_serial_number(self):
+        """
+        The serial number of an `X509` can be retrieved and
+        modified with `X509.get_serial_number` and
+        `X509.set_serial_number`.
+        """
+        certificate = X509()
+        with pytest.raises(TypeError):
+            certificate.set_serial_number("1")
+        assert certificate.get_serial_number() == 0
+        certificate.set_serial_number(1)
+        assert certificate.get_serial_number() == 1
+        certificate.set_serial_number(2 ** 32 + 1)
+        assert certificate.get_serial_number() == 2 ** 32 + 1
+        certificate.set_serial_number(2 ** 64 + 1)
+        assert certificate.get_serial_number() == 2 ** 64 + 1
+        certificate.set_serial_number(2 ** 128 + 1)
+        assert certificate.get_serial_number() == 2 ** 128 + 1
+
+    def _setBoundTest(self, which):
+        """
+        `X509.set_notBefore` takes a string in the format of an
+        ASN1 GENERALIZEDTIME and sets the beginning of the certificate's
+        validity period to it.
+        """
+        certificate = X509()
+        set = getattr(certificate, 'set_not' + which)
+        get = getattr(certificate, 'get_not' + which)
+
+        # Starts with no value.
+        assert get() is None
+
+        # GMT (Or is it UTC?) -exarkun
+        when = b"20040203040506Z"
+        set(when)
+        assert get() == when
+
+        # A plus two hours and thirty minutes offset
+        when = b"20040203040506+0530"
+        set(when)
+        assert get() == when
+
+        # A minus one hour fifteen minutes offset
+        when = b"20040203040506-0115"
+        set(when)
+        assert get() == when
+
+        # An invalid string results in a ValueError
+        with pytest.raises(ValueError):
+            set(b"foo bar")
+
+        # The wrong number of arguments results in a TypeError.
+        with pytest.raises(TypeError):
+            set()
+        with pytest.raises(TypeError):
+            set(b"20040203040506Z", b"20040203040506Z")
+        with pytest.raises(TypeError):
+            get(b"foo bar")
+
+    # XXX ASN1_TIME (not GENERALIZEDTIME)
+
+    def test_set_notBefore(self):
+        """
+        `X509.set_notBefore` takes a string in the format of an
+        ASN1 GENERALIZEDTIME and sets the beginning of the certificate's
+        validity period to it.
+        """
+        self._setBoundTest("Before")
+
+    def test_set_notAfter(self):
+        """
+        `X509.set_notAfter` takes a string in the format of an ASN1
+        GENERALIZEDTIME and sets the end of the certificate's validity period
+        to it.
+        """
+        self._setBoundTest("After")
+
+    def test_get_notBefore(self):
+        """
+        `X509.get_notBefore` returns a string in the format of an
+        ASN1 GENERALIZEDTIME even for certificates which store it as UTCTIME
+        internally.
+        """
+        cert = load_certificate(FILETYPE_PEM, old_root_cert_pem)
+        assert cert.get_notBefore() == b"20090325123658Z"
+
+    def test_get_notAfter(self):
+        """
+        `X509.get_notAfter` returns a string in the format of an
+        ASN1 GENERALIZEDTIME even for certificates which store it as UTCTIME
+        internally.
+        """
+        cert = load_certificate(FILETYPE_PEM, old_root_cert_pem)
+        assert cert.get_notAfter() == b"20170611123658Z"
+
+    def test_gmtime_adj_notBefore_wrong_args(self):
+        """
+        `X509.gmtime_adj_notBefore` raises `TypeError` if called with a
+        non-`int` argument.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.gmtime_adj_notBefore(None)
+
+    @flaky.flaky
+    def test_gmtime_adj_notBefore(self):
+        """
+        `X509.gmtime_adj_notBefore` changes the not-before timestamp to be the
+        current time plus the number of seconds passed in.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        not_before_min = (
+            datetime.utcnow().replace(microsecond=0) + timedelta(seconds=100)
+        )
+        cert.gmtime_adj_notBefore(100)
+        not_before = datetime.strptime(
+            cert.get_notBefore().decode(), "%Y%m%d%H%M%SZ"
+        )
+        not_before_max = datetime.utcnow() + timedelta(seconds=100)
+        assert not_before_min <= not_before <= not_before_max
+
+    def test_gmtime_adj_notAfter_wrong_args(self):
+        """
+        `X509.gmtime_adj_notAfter` raises `TypeError` if called with a
+        non-`int` argument.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.gmtime_adj_notAfter(None)
+
+    @flaky.flaky
+    def test_gmtime_adj_notAfter(self):
+        """
+        `X509.gmtime_adj_notAfter` changes the not-after timestamp
+        to be the current time plus the number of seconds passed in.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        not_after_min = (
+            datetime.utcnow().replace(microsecond=0) + timedelta(seconds=100)
+        )
+        cert.gmtime_adj_notAfter(100)
+        not_after = datetime.strptime(
+            cert.get_notAfter().decode(), "%Y%m%d%H%M%SZ"
+        )
+        not_after_max = datetime.utcnow() + timedelta(seconds=100)
+        assert not_after_min <= not_after <= not_after_max
+
+    def test_has_expired(self):
+        """
+        `X509.has_expired` returns `True` if the certificate's not-after time
+        is in the past.
+        """
+        cert = X509()
+        cert.gmtime_adj_notAfter(-1)
+        assert cert.has_expired()
+
+    def test_has_not_expired(self):
+        """
+        `X509.has_expired` returns `False` if the certificate's not-after time
+        is in the future.
+        """
+        cert = X509()
+        cert.gmtime_adj_notAfter(2)
+        assert not cert.has_expired()
+
+    def test_root_has_not_expired(self):
+        """
+        `X509.has_expired` returns `False` if the certificate's not-after time
+        is in the future.
+        """
+        cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        assert not cert.has_expired()
+
+    def test_digest(self):
+        """
+        `X509.digest` returns a string giving ":"-separated hex-encoded
+        words of the digest of the certificate.
+        """
+        cert = load_certificate(FILETYPE_PEM, old_root_cert_pem)
+        assert (
+            # This is MD5 instead of GOOD_DIGEST because the digest algorithm
+            # actually matters to the assertion (ie, another arbitrary, good
+            # digest will not product the same digest).
+            # Digest verified with the command:
+            # openssl x509 -in root_cert.pem -noout -fingerprint -md5
+            cert.digest("MD5") ==
+            b"19:B3:05:26:2B:F8:F2:FF:0B:8F:21:07:A8:28:B8:75")
+
+    def _extcert(self, pkey, extensions):
+        cert = X509()
+        cert.set_pubkey(pkey)
+        cert.get_subject().commonName = "Unit Tests"
+        cert.get_issuer().commonName = "Unit Tests"
+        when = datetime.now().strftime("%Y%m%d%H%M%SZ").encode("ascii")
+        cert.set_notBefore(when)
+        cert.set_notAfter(when)
+
+        cert.add_extensions(extensions)
+        cert.sign(pkey, 'sha1')
+        return load_certificate(
+            FILETYPE_PEM, dump_certificate(FILETYPE_PEM, cert))
+
+    def test_extension_count(self):
+        """
+        `X509.get_extension_count` returns the number of extensions
+        that are present in the certificate.
+        """
+        pkey = load_privatekey(FILETYPE_PEM, client_key_pem)
+        ca = X509Extension(b'basicConstraints', True, b'CA:FALSE')
+        key = X509Extension(b'keyUsage', True, b'digitalSignature')
+        subjectAltName = X509Extension(
+            b'subjectAltName', True, b'DNS:example.com')
+
+        # Try a certificate with no extensions at all.
+        c = self._extcert(pkey, [])
+        assert c.get_extension_count() == 0
+
+        # And a certificate with one
+        c = self._extcert(pkey, [ca])
+        assert c.get_extension_count() == 1
+
+        # And a certificate with several
+        c = self._extcert(pkey, [ca, key, subjectAltName])
+        assert c.get_extension_count() == 3
+
+    def test_get_extension(self):
+        """
+        `X509.get_extension` takes an integer and returns an
+        `X509Extension` corresponding to the extension at that index.
+        """
+        pkey = load_privatekey(FILETYPE_PEM, client_key_pem)
+        ca = X509Extension(b'basicConstraints', True, b'CA:FALSE')
+        key = X509Extension(b'keyUsage', True, b'digitalSignature')
+        subjectAltName = X509Extension(
+            b'subjectAltName', False, b'DNS:example.com')
+
+        cert = self._extcert(pkey, [ca, key, subjectAltName])
+
+        ext = cert.get_extension(0)
+        assert isinstance(ext, X509Extension)
+        assert ext.get_critical()
+        assert ext.get_short_name() == b'basicConstraints'
+
+        ext = cert.get_extension(1)
+        assert isinstance(ext, X509Extension)
+        assert ext.get_critical()
+        assert ext.get_short_name() == b'keyUsage'
+
+        ext = cert.get_extension(2)
+        assert isinstance(ext, X509Extension)
+        assert not ext.get_critical()
+        assert ext.get_short_name() == b'subjectAltName'
+
+        with pytest.raises(IndexError):
+            cert.get_extension(-1)
+        with pytest.raises(IndexError):
+            cert.get_extension(4)
+        with pytest.raises(TypeError):
+            cert.get_extension("hello")
+
+    def test_nullbyte_subjectAltName(self):
+        """
+        The fields of a `subjectAltName` extension on an X509 may contain NUL
+        bytes and this value is reflected in the string representation of the
+        extension object.
+        """
+        cert = load_certificate(FILETYPE_PEM, nulbyteSubjectAltNamePEM)
+
+        ext = cert.get_extension(3)
+        assert ext.get_short_name() == b'subjectAltName'
+        assert (
+            b"DNS:altnull.python.org\x00example.com, "
+            b"email:null@python.org\x00user@example.org, "
+            b"URI:http://null.python.org\x00http://example.org, "
+            b"IP Address:192.0.2.1, IP Address:2001:DB8:0:0:0:0:0:1\n" ==
+            str(ext).encode("ascii"))
+
+    def test_invalid_digest_algorithm(self):
+        """
+        `X509.digest` raises `ValueError` if called with an unrecognized hash
+        algorithm.
+        """
+        cert = X509()
+        with pytest.raises(ValueError):
+            cert.digest(BAD_DIGEST)
+
+    def test_get_subject(self):
+        """
+        `X509.get_subject` returns an `X509Name` instance.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        subj = cert.get_subject()
+        assert isinstance(subj, X509Name)
+        assert (
+            subj.get_components() ==
+            [(b'C', b'US'), (b'ST', b'IL'), (b'L', b'Chicago'),
+             (b'O', b'Testing'), (b'CN', b'Testing Root CA')])
+
+    def test_set_subject_wrong_args(self):
+        """
+        `X509.set_subject` raises a `TypeError` if called with an argument not
+        of type `X509Name`.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.set_subject(None)
+
+    def test_set_subject(self):
+        """
+        `X509.set_subject` changes the subject of the certificate to the one
+        passed in.
+        """
+        cert = X509()
+        name = cert.get_subject()
+        name.C = 'AU'
+        name.OU = 'Unit Tests'
+        cert.set_subject(name)
+        assert (
+            cert.get_subject().get_components() ==
+            [(b'C', b'AU'), (b'OU', b'Unit Tests')])
+
+    def test_get_issuer(self):
+        """
+        `X509.get_issuer` returns an `X509Name` instance.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        subj = cert.get_issuer()
+        assert isinstance(subj, X509Name)
+        comp = subj.get_components()
+        assert (
+            comp ==
+            [(b'C', b'US'), (b'ST', b'IL'), (b'L', b'Chicago'),
+             (b'O', b'Testing'), (b'CN', b'Testing Root CA')])
+
+    def test_set_issuer_wrong_args(self):
+        """
+        `X509.set_issuer` raises a `TypeError` if called with an argument not
+        of type `X509Name`.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.set_issuer(None)
+
+    def test_set_issuer(self):
+        """
+        `X509.set_issuer` changes the issuer of the certificate to the
+        one passed in.
+        """
+        cert = X509()
+        name = cert.get_issuer()
+        name.C = 'AU'
+        name.OU = 'Unit Tests'
+        cert.set_issuer(name)
+        assert (
+            cert.get_issuer().get_components() ==
+            [(b'C', b'AU'), (b'OU', b'Unit Tests')])
+
+    def test_get_pubkey_uninitialized(self):
+        """
+        When called on a certificate with no public key, `X509.get_pubkey`
+        raises `OpenSSL.crypto.Error`.
+        """
+        cert = X509()
+        with pytest.raises(Error):
+            cert.get_pubkey()
+
+    def test_set_pubkey_wrong_type(self):
+        """
+        `X509.set_pubkey` raises `TypeError` when given an object of the
+        wrong type.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.set_pubkey(object())
+
+    def test_subject_name_hash(self):
+        """
+        `X509.subject_name_hash` returns the hash of the certificate's
+        subject name.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        assert cert.subject_name_hash() in [
+            3350047874,  # OpenSSL 0.9.8, MD5
+            3278919224,  # OpenSSL 1.0.0, SHA1
+        ]
+
+    def test_get_signature_algorithm(self):
+        """
+        `X509.get_signature_algorithm` returns a string which means
+        the algorithm used to sign the certificate.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        assert b"sha1WithRSAEncryption" == cert.get_signature_algorithm()
+
+    def test_get_undefined_signature_algorithm(self):
+        """
+        `X509.get_signature_algorithm` raises `ValueError` if the signature
+        algorithm is undefined or unknown.
+        """
+        # This certificate has been modified to indicate a bogus OID in the
+        # signature algorithm field so that OpenSSL does not recognize it.
+        certPEM = b"""\
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+"""
+        cert = load_certificate(FILETYPE_PEM, certPEM)
+        with pytest.raises(ValueError):
+            cert.get_signature_algorithm()
+
+    def test_sign_bad_pubkey_type(self):
+        """
+        `X509.sign` raises `TypeError` when called with the wrong type.
+        """
+        cert = X509()
+        with pytest.raises(TypeError):
+            cert.sign(object(), b"sha256")
+
+    def test_convert_from_cryptography(self):
+        crypto_cert = x509.load_pem_x509_certificate(
+            intermediate_cert_pem, backend
+        )
+        cert = X509.from_cryptography(crypto_cert)
+
+        assert isinstance(cert, X509)
+        assert cert.get_version() == crypto_cert.version.value
+
+    def test_convert_from_cryptography_unsupported_type(self):
+        with pytest.raises(TypeError):
+            X509.from_cryptography(object())
+
+    def test_convert_to_cryptography_key(self):
+        cert = load_certificate(FILETYPE_PEM, intermediate_cert_pem)
+        crypto_cert = cert.to_cryptography()
+
+        assert isinstance(crypto_cert, x509.Certificate)
+        assert crypto_cert.version.value == cert.get_version()
+
+
+class TestX509Store(object):
+    """
+    Test for `OpenSSL.crypto.X509Store`.
+    """
+
+    def test_type(self):
+        """
+        `X509Store` is a type object.
+        """
+        assert X509Store is X509StoreType
+        assert is_consistent_type(X509Store, 'X509Store')
+
+    def test_add_cert(self):
+        """
+        `X509Store.add_cert` adds a `X509` instance to the certificate store.
+        """
+        cert = load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        store = X509Store()
+        store.add_cert(cert)
+
+    @pytest.mark.parametrize('cert', [None, 1.0, 'cert', object()])
+    def test_add_cert_wrong_args(self, cert):
+        """
+        `X509Store.add_cert` raises `TypeError` if passed a non-X509 object
+        as its first argument.
+        """
+        store = X509Store()
+        with pytest.raises(TypeError):
+            store.add_cert(cert)
+
+    def test_add_cert_accepts_duplicate(self):
+        """
+        `X509Store.add_cert` doesn't raise `OpenSSL.crypto.Error` if an attempt
+        is made to add the same certificate to the store more than once.
+        """
+        cert = load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        store = X509Store()
+        store.add_cert(cert)
+        store.add_cert(cert)
+
+
+class TestPKCS12(object):
+    """
+    Test for `OpenSSL.crypto.PKCS12` and `OpenSSL.crypto.load_pkcs12`.
+    """
+    pemData = cleartextCertificatePEM + cleartextPrivateKeyPEM
+
+    def test_type(self):
+        """
+        `PKCS12Type` is a type object.
+        """
+        assert PKCS12 is PKCS12Type
+        assert is_consistent_type(PKCS12, 'PKCS12')
+
+    def test_empty_construction(self):
+        """
+        `PKCS12` returns a new instance of `PKCS12` with no certificate,
+        private key, CA certificates, or friendly name.
+        """
+        p12 = PKCS12()
+        assert None is p12.get_certificate()
+        assert None is p12.get_privatekey()
+        assert None is p12.get_ca_certificates()
+        assert None is p12.get_friendlyname()
+
+    def test_type_errors(self):
+        """
+        The `PKCS12` setter functions (`set_certificate`, `set_privatekey`,
+        `set_ca_certificates`, and `set_friendlyname`) raise `TypeError`
+        when passed objects of types other than those expected.
+        """
+        p12 = PKCS12()
+        for bad_arg in [3, PKey(), X509]:
+            with pytest.raises(TypeError):
+                p12.set_certificate(bad_arg)
+        for bad_arg in [3, 'legbone', X509()]:
+            with pytest.raises(TypeError):
+                p12.set_privatekey(bad_arg)
+        for bad_arg in [3, X509(), (3, 4), (PKey(),)]:
+            with pytest.raises(TypeError):
+                p12.set_ca_certificates(bad_arg)
+        for bad_arg in [6, ('foo', 'bar')]:
+            with pytest.raises(TypeError):
+                p12.set_friendlyname(bad_arg)
+
+    def test_key_only(self):
+        """
+        A `PKCS12` with only a private key can be exported using
+        `PKCS12.export` and loaded again using `load_pkcs12`.
+        """
+        passwd = b"blah"
+        p12 = PKCS12()
+        pkey = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        p12.set_privatekey(pkey)
+        assert None is p12.get_certificate()
+        assert pkey == p12.get_privatekey()
+        try:
+            dumped_p12 = p12.export(passphrase=passwd, iter=2, maciter=3)
+        except Error:
+            # Some versions of OpenSSL will throw an exception
+            # for this nearly useless PKCS12 we tried to generate:
+            # [('PKCS12 routines', 'PKCS12_create', 'invalid null argument')]
+            return
+        p12 = load_pkcs12(dumped_p12, passwd)
+        assert None is p12.get_ca_certificates()
+        assert None is p12.get_certificate()
+
+        # OpenSSL fails to bring the key back to us.  So sad.  Perhaps in the
+        # future this will be improved.
+        assert isinstance(p12.get_privatekey(), (PKey, type(None)))
+
+    def test_cert_only(self):
+        """
+        A `PKCS12` with only a certificate can be exported using
+        `PKCS12.export` and loaded again using `load_pkcs12`.
+        """
+        passwd = b"blah"
+        p12 = PKCS12()
+        cert = load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        p12.set_certificate(cert)
+        assert cert == p12.get_certificate()
+        assert None is p12.get_privatekey()
+        try:
+            dumped_p12 = p12.export(passphrase=passwd, iter=2, maciter=3)
+        except Error:
+            # Some versions of OpenSSL will throw an exception
+            # for this nearly useless PKCS12 we tried to generate:
+            # [('PKCS12 routines', 'PKCS12_create', 'invalid null argument')]
+            return
+        p12 = load_pkcs12(dumped_p12, passwd)
+        assert None is p12.get_privatekey()
+
+        # OpenSSL fails to bring the cert back to us.  Groany mcgroan.
+        assert isinstance(p12.get_certificate(), (X509, type(None)))
+
+        # Oh ho.  It puts the certificate into the ca certificates list, in
+        # fact.  Totally bogus, I would think.  Nevertheless, let's exploit
+        # that to check to see if it reconstructed the certificate we expected
+        # it to.  At some point, hopefully this will change so that
+        # p12.get_certificate() is actually what returns the loaded
+        # certificate.
+        assert (
+            cleartextCertificatePEM ==
+            dump_certificate(FILETYPE_PEM, p12.get_ca_certificates()[0]))
+
+    def gen_pkcs12(self, cert_pem=None, key_pem=None, ca_pem=None,
+                   friendly_name=None):
+        """
+        Generate a PKCS12 object with components from PEM.  Verify that the set
+        functions return None.
+        """
+        p12 = PKCS12()
+        if cert_pem:
+            ret = p12.set_certificate(load_certificate(FILETYPE_PEM, cert_pem))
+            assert ret is None
+        if key_pem:
+            ret = p12.set_privatekey(load_privatekey(FILETYPE_PEM, key_pem))
+            assert ret is None
+        if ca_pem:
+            ret = p12.set_ca_certificates(
+                (load_certificate(FILETYPE_PEM, ca_pem),)
+            )
+            assert ret is None
+        if friendly_name:
+            ret = p12.set_friendlyname(friendly_name)
+            assert ret is None
+        return p12
+
+    def check_recovery(self, p12_str, key=None, cert=None, ca=None, passwd=b"",
+                       extra=()):
+        """
+        Use openssl program to confirm three components are recoverable from a
+        PKCS12 string.
+        """
+        if key:
+            recovered_key = _runopenssl(
+                p12_str, b"pkcs12", b"-nocerts", b"-nodes", b"-passin",
+                b"pass:" + passwd, *extra)
+            assert recovered_key[-len(key):] == key
+        if cert:
+            recovered_cert = _runopenssl(
+                p12_str, b"pkcs12", b"-clcerts", b"-nodes", b"-passin",
+                b"pass:" + passwd, b"-nokeys", *extra)
+            assert recovered_cert[-len(cert):] == cert
+        if ca:
+            recovered_cert = _runopenssl(
+                p12_str, b"pkcs12", b"-cacerts", b"-nodes", b"-passin",
+                b"pass:" + passwd, b"-nokeys", *extra)
+            assert recovered_cert[-len(ca):] == ca
+
+    def verify_pkcs12_container(self, p12):
+        """
+        Verify that the PKCS#12 container contains the correct client
+        certificate and private key.
+
+        :param p12: The PKCS12 instance to verify.
+        :type p12: `PKCS12`
+        """
+        cert_pem = dump_certificate(FILETYPE_PEM, p12.get_certificate())
+        key_pem = dump_privatekey(FILETYPE_PEM, p12.get_privatekey())
+        assert (
+            (client_cert_pem, client_key_pem, None) ==
+            (cert_pem, key_pem, p12.get_ca_certificates()))
+
+    def test_load_pkcs12(self):
+        """
+        A PKCS12 string generated using the openssl command line can be loaded
+        with `load_pkcs12` and its components extracted and examined.
+        """
+        passwd = b"whatever"
+        pem = client_key_pem + client_cert_pem
+        p12_str = _runopenssl(
+            pem,
+            b"pkcs12",
+            b"-export",
+            b"-clcerts",
+            b"-passout",
+            b"pass:" + passwd
+        )
+        p12 = load_pkcs12(p12_str, passphrase=passwd)
+        self.verify_pkcs12_container(p12)
+
+    def test_load_pkcs12_text_passphrase(self):
+        """
+        A PKCS12 string generated using the openssl command line can be loaded
+        with `load_pkcs12` and its components extracted and examined.
+        Using text as passphrase instead of bytes. DeprecationWarning expected.
+        """
+        pem = client_key_pem + client_cert_pem
+        passwd = b"whatever"
+        p12_str = _runopenssl(pem, b"pkcs12", b"-export", b"-clcerts",
+                              b"-passout", b"pass:" + passwd)
+        with pytest.warns(DeprecationWarning) as w:
+            simplefilter("always")
+            p12 = load_pkcs12(p12_str, passphrase=b"whatever".decode("ascii"))
+            assert (
+                "{0} for passphrase is no longer accepted, use bytes".format(
+                    WARNING_TYPE_EXPECTED
+                ) == str(w[-1].message))
+
+        self.verify_pkcs12_container(p12)
+
+    def test_load_pkcs12_no_passphrase(self):
+        """
+        A PKCS12 string generated using openssl command line can be loaded with
+        `load_pkcs12` without a passphrase and its components extracted
+        and examined.
+        """
+        pem = client_key_pem + client_cert_pem
+        p12_str = _runopenssl(
+            pem, b"pkcs12", b"-export", b"-clcerts", b"-passout", b"pass:")
+        p12 = load_pkcs12(p12_str)
+        self.verify_pkcs12_container(p12)
+
+    def _dump_and_load(self, dump_passphrase, load_passphrase):
+        """
+        A helper method to dump and load a PKCS12 object.
+        """
+        p12 = self.gen_pkcs12(client_cert_pem, client_key_pem)
+        dumped_p12 = p12.export(passphrase=dump_passphrase, iter=2, maciter=3)
+        return load_pkcs12(dumped_p12, passphrase=load_passphrase)
+
+    def test_load_pkcs12_null_passphrase_load_empty(self):
+        """
+        A PKCS12 string can be dumped with a null passphrase, loaded with an
+        empty passphrase with `load_pkcs12`, and its components
+        extracted and examined.
+        """
+        self.verify_pkcs12_container(
+            self._dump_and_load(dump_passphrase=None, load_passphrase=b''))
+
+    def test_load_pkcs12_null_passphrase_load_null(self):
+        """
+        A PKCS12 string can be dumped with a null passphrase, loaded with a
+        null passphrase with `load_pkcs12`, and its components
+        extracted and examined.
+        """
+        self.verify_pkcs12_container(
+            self._dump_and_load(dump_passphrase=None, load_passphrase=None))
+
+    def test_load_pkcs12_empty_passphrase_load_empty(self):
+        """
+        A PKCS12 string can be dumped with an empty passphrase, loaded with an
+        empty passphrase with `load_pkcs12`, and its components
+        extracted and examined.
+        """
+        self.verify_pkcs12_container(
+            self._dump_and_load(dump_passphrase=b'', load_passphrase=b''))
+
+    def test_load_pkcs12_empty_passphrase_load_null(self):
+        """
+        A PKCS12 string can be dumped with an empty passphrase, loaded with a
+        null passphrase with `load_pkcs12`, and its components
+        extracted and examined.
+        """
+        self.verify_pkcs12_container(
+            self._dump_and_load(dump_passphrase=b'', load_passphrase=None))
+
+    def test_load_pkcs12_garbage(self):
+        """
+        `load_pkcs12` raises `OpenSSL.crypto.Error` when passed
+        a string which is not a PKCS12 dump.
+        """
+        passwd = 'whatever'
+        with pytest.raises(Error) as err:
+            load_pkcs12(b'fruit loops', passwd)
+        assert err.value.args[0][0][0] == 'asn1 encoding routines'
+        assert len(err.value.args[0][0]) == 3
+
+    def test_replace(self):
+        """
+        `PKCS12.set_certificate` replaces the certificate in a PKCS12
+        cluster. `PKCS12.set_privatekey` replaces the private key.
+        `PKCS12.set_ca_certificates` replaces the CA certificates.
+        """
+        p12 = self.gen_pkcs12(client_cert_pem, client_key_pem, root_cert_pem)
+        p12.set_certificate(load_certificate(FILETYPE_PEM, server_cert_pem))
+        p12.set_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+        root_cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        client_cert = load_certificate(FILETYPE_PEM, client_cert_pem)
+        p12.set_ca_certificates([root_cert])  # not a tuple
+        assert 1 == len(p12.get_ca_certificates())
+        assert root_cert == p12.get_ca_certificates()[0]
+        p12.set_ca_certificates([client_cert, root_cert])
+        assert 2 == len(p12.get_ca_certificates())
+        assert client_cert == p12.get_ca_certificates()[0]
+        assert root_cert == p12.get_ca_certificates()[1]
+
+    def test_friendly_name(self):
+        """
+        The *friendlyName* of a PKCS12 can be set and retrieved via
+        `PKCS12.get_friendlyname` and `PKCS12_set_friendlyname`, and a
+        `PKCS12` with a friendly name set can be dumped with `PKCS12.export`.
+        """
+        passwd = b'Dogmeat[]{}!@#$%^&*()~`?/.,<>-_+=";:'
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
+        for friendly_name in [b'Serverlicious', None, b'###']:
+            p12.set_friendlyname(friendly_name)
+            assert p12.get_friendlyname() == friendly_name
+            dumped_p12 = p12.export(passphrase=passwd, iter=2, maciter=3)
+            reloaded_p12 = load_pkcs12(dumped_p12, passwd)
+            assert p12.get_friendlyname() == reloaded_p12.get_friendlyname()
+            # We would use the openssl program to confirm the friendly
+            # name, but it is not possible.  The pkcs12 command
+            # does not store the friendly name in the cert's
+            # alias, which we could then extract.
+            self.check_recovery(
+                dumped_p12, key=server_key_pem, cert=server_cert_pem,
+                ca=root_cert_pem, passwd=passwd)
+
+    def test_various_empty_passphrases(self):
+        """
+        Test that missing, None, and '' passphrases are identical for PKCS12
+        export.
+        """
+        p12 = self.gen_pkcs12(client_cert_pem, client_key_pem, root_cert_pem)
+        passwd = b""
+        dumped_p12_empty = p12.export(iter=2, maciter=0, passphrase=passwd)
+        dumped_p12_none = p12.export(iter=3, maciter=2, passphrase=None)
+        dumped_p12_nopw = p12.export(iter=9, maciter=4)
+        for dumped_p12 in [dumped_p12_empty, dumped_p12_none, dumped_p12_nopw]:
+            self.check_recovery(
+                dumped_p12, key=client_key_pem, cert=client_cert_pem,
+                ca=root_cert_pem, passwd=passwd)
+
+    def test_removing_ca_cert(self):
+        """
+        Passing `None` to `PKCS12.set_ca_certificates` removes all CA
+        certificates.
+        """
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
+        p12.set_ca_certificates(None)
+        assert None is p12.get_ca_certificates()
+
+    def test_export_without_mac(self):
+        """
+        Exporting a PKCS12 with a `maciter` of `-1` excludes the MAC entirely.
+        """
+        passwd = b"Lake Michigan"
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
+        dumped_p12 = p12.export(maciter=-1, passphrase=passwd, iter=2)
+        self.check_recovery(
+            dumped_p12, key=server_key_pem, cert=server_cert_pem,
+            passwd=passwd, extra=(b"-nomacver",))
+
+    def test_load_without_mac(self):
+        """
+        Loading a PKCS12 without a MAC does something other than crash.
+        """
+        passwd = b"Lake Michigan"
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
+        dumped_p12 = p12.export(maciter=-1, passphrase=passwd, iter=2)
+        try:
+            recovered_p12 = load_pkcs12(dumped_p12, passwd)
+            # The person who generated this PCKS12 should be flogged,
+            # or better yet we should have a means to determine
+            # whether a PCKS12 had a MAC that was verified.
+            # Anyway, libopenssl chooses to allow it, so the
+            # pyopenssl binding does as well.
+            assert isinstance(recovered_p12, PKCS12)
+        except Error:
+            # Failing here with an exception is preferred as some openssl
+            # versions do.
+            pass
+
+    def test_zero_len_list_for_ca(self):
+        """
+        A PKCS12 with an empty CA certificates list can be exported.
+        """
+        passwd = b'Hobie 18'
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem)
+        p12.set_ca_certificates([])
+        assert () == p12.get_ca_certificates()
+        dumped_p12 = p12.export(passphrase=passwd, iter=3)
+        self.check_recovery(
+            dumped_p12, key=server_key_pem, cert=server_cert_pem,
+            passwd=passwd)
+
+    def test_export_without_args(self):
+        """
+        All the arguments to `PKCS12.export` are optional.
+        """
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
+        dumped_p12 = p12.export()  # no args
+        self.check_recovery(
+            dumped_p12, key=server_key_pem, cert=server_cert_pem, passwd=b"")
+
+    def test_export_without_bytes(self):
+        """
+        Test `PKCS12.export` with text not bytes as passphrase
+        """
+        p12 = self.gen_pkcs12(server_cert_pem, server_key_pem, root_cert_pem)
+
+        with pytest.warns(DeprecationWarning) as w:
+            simplefilter("always")
+            dumped_p12 = p12.export(passphrase=b"randomtext".decode("ascii"))
+            assert (
+                "{0} for passphrase is no longer accepted, use bytes".format(
+                    WARNING_TYPE_EXPECTED
+                ) == str(w[-1].message))
+        self.check_recovery(
+            dumped_p12,
+            key=server_key_pem,
+            cert=server_cert_pem,
+            passwd=b"randomtext"
+        )
+
+    def test_key_cert_mismatch(self):
+        """
+        `PKCS12.export` raises an exception when a key and certificate
+        mismatch.
+        """
+        p12 = self.gen_pkcs12(server_cert_pem, client_key_pem, root_cert_pem)
+        with pytest.raises(Error):
+            p12.export()
+
+
+def _runopenssl(pem, *args):
+    """
+    Run the command line openssl tool with the given arguments and write
+    the given PEM to its stdin.  Not safe for quotes.
+    """
+    proc = Popen([b"openssl"] + list(args), stdin=PIPE, stdout=PIPE)
+    proc.stdin.write(pem)
+    proc.stdin.close()
+    output = proc.stdout.read()
+    proc.stdout.close()
+    proc.wait()
+    return output
+
+
+class TestLoadPublicKey(object):
+    """
+    Tests for :func:`load_publickey`.
+    """
+    def test_loading_works(self):
+        """
+        load_publickey loads public keys and sets correct attributes.
+        """
+        key = load_publickey(FILETYPE_PEM, cleartextPublicKeyPEM)
+
+        assert True is key._only_public
+        assert 2048 == key.bits()
+        assert TYPE_RSA == key.type()
+
+    def test_invalid_type(self):
+        """
+        load_publickey doesn't support FILETYPE_TEXT.
+        """
+        with pytest.raises(ValueError):
+            load_publickey(FILETYPE_TEXT, cleartextPublicKeyPEM)
+
+    def test_invalid_key_format(self):
+        """
+        load_publickey explodes on incorrect keys.
+        """
+        with pytest.raises(Error):
+            load_publickey(FILETYPE_ASN1, cleartextPublicKeyPEM)
+
+    def test_tolerates_unicode_strings(self):
+        """
+        load_publickey works with text strings, not just bytes.
+        """
+        serialized = cleartextPublicKeyPEM.decode('ascii')
+        key = load_publickey(FILETYPE_PEM, serialized)
+        dumped_pem = dump_publickey(FILETYPE_PEM, key)
+
+        assert dumped_pem == cleartextPublicKeyPEM
+
+
+class TestFunction(object):
+    """
+    Tests for free-functions in the `OpenSSL.crypto` module.
+    """
+
+    def test_load_privatekey_invalid_format(self):
+        """
+        `load_privatekey` raises `ValueError` if passed an unknown filetype.
+        """
+        with pytest.raises(ValueError):
+            load_privatekey(100, root_key_pem)
+
+    def test_load_privatekey_invalid_passphrase_type(self):
+        """
+        `load_privatekey` raises `TypeError` if passed a passphrase that is
+        neither a `str` nor a callable.
+        """
+        with pytest.raises(TypeError):
+            load_privatekey(
+                FILETYPE_PEM, encryptedPrivateKeyPEMPassphrase, object())
+
+    def test_load_privatekey_wrongPassphrase(self):
+        """
+        `load_privatekey` raises `OpenSSL.crypto.Error` when it is passed an
+        encrypted PEM and an incorrect passphrase.
+        """
+        with pytest.raises(Error) as err:
+            load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, b"quack")
+        assert err.value.args[0] != []
+
+    def test_load_privatekey_passphraseWrongType(self):
+        """
+        `load_privatekey` raises `ValueError` when it is passeda passphrase
+        with a private key encoded in a format, that doesn't support
+        encryption.
+        """
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        blob = dump_privatekey(FILETYPE_ASN1, key)
+        with pytest.raises(ValueError):
+            load_privatekey(FILETYPE_ASN1, blob, "secret")
+
+    def test_load_privatekey_passphrase(self):
+        """
+        `load_privatekey` can create a `PKey` object from an encrypted PEM
+        string if given the passphrase.
+        """
+        key = load_privatekey(
+            FILETYPE_PEM, encryptedPrivateKeyPEM,
+            encryptedPrivateKeyPEMPassphrase)
+        assert isinstance(key, PKeyType)
+
+    def test_load_privatekey_passphrase_exception(self):
+        """
+        If the passphrase callback raises an exception, that exception is
+        raised by `load_privatekey`.
+        """
+        def cb(ignored):
+            raise ArithmeticError
+
+        with pytest.raises(ArithmeticError):
+            load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, cb)
+
+    def test_load_privatekey_wrongPassphraseCallback(self):
+        """
+        `load_privatekey` raises `OpenSSL.crypto.Error` when it
+        is passed an encrypted PEM and a passphrase callback which returns an
+        incorrect passphrase.
+        """
+        called = []
+
+        def cb(*a):
+            called.append(None)
+            return b"quack"
+        with pytest.raises(Error) as err:
+            load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, cb)
+        assert called
+        assert err.value.args[0] != []
+
+    def test_load_privatekey_passphraseCallback(self):
+        """
+        `load_privatekey` can create a `PKey` object from an encrypted PEM
+        string if given a passphrase callback which returns the correct
+        password.
+        """
+        called = []
+
+        def cb(writing):
+            called.append(writing)
+            return encryptedPrivateKeyPEMPassphrase
+        key = load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, cb)
+        assert isinstance(key, PKeyType)
+        assert called == [False]
+
+    def test_load_privatekey_passphrase_wrong_return_type(self):
+        """
+        `load_privatekey` raises `ValueError` if the passphrase callback
+        returns something other than a byte string.
+        """
+        with pytest.raises(ValueError):
+            load_privatekey(
+                FILETYPE_PEM, encryptedPrivateKeyPEM, lambda *args: 3)
+
+    def test_dump_privatekey_wrong_args(self):
+        """
+        `dump_privatekey` raises `TypeError` if called with a `cipher`
+        argument but no `passphrase` argument.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        with pytest.raises(TypeError):
+            dump_privatekey(FILETYPE_PEM, key, cipher=GOOD_CIPHER)
+
+    def test_dump_privatekey_not_rsa_key(self):
+        """
+        `dump_privatekey` raises `TypeError` if called with a key that is
+        not RSA.
+        """
+        key = PKey()
+        key.generate_key(TYPE_DSA, 512)
+        with pytest.raises(TypeError):
+            dump_privatekey(FILETYPE_TEXT, key)
+
+    def test_dump_privatekey_invalid_pkey(self):
+        with pytest.raises(TypeError):
+            dump_privatekey(FILETYPE_TEXT, object())
+
+    def test_dump_privatekey_unknown_cipher(self):
+        """
+        `dump_privatekey` raises `ValueError` if called with an unrecognized
+        cipher name.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        with pytest.raises(ValueError):
+            dump_privatekey(FILETYPE_PEM, key, BAD_CIPHER, "passphrase")
+
+    def test_dump_privatekey_invalid_passphrase_type(self):
+        """
+        `dump_privatekey` raises `TypeError` if called with a passphrase which
+        is neither a `str` nor a callable.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        with pytest.raises(TypeError):
+            dump_privatekey(FILETYPE_PEM, key, GOOD_CIPHER, object())
+
+    def test_dump_privatekey_invalid_filetype(self):
+        """
+        `dump_privatekey` raises `ValueError` if called with an unrecognized
+        filetype.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        with pytest.raises(ValueError):
+            dump_privatekey(100, key)
+
+    def test_load_privatekey_passphrase_callback_length(self):
+        """
+        `crypto.load_privatekey` should raise an error when the passphrase
+        provided by the callback is too long, not silently truncate it.
+        """
+        def cb(ignored):
+            return "a" * 1025
+
+        with pytest.raises(ValueError):
+            load_privatekey(FILETYPE_PEM, encryptedPrivateKeyPEM, cb)
+
+    def test_dump_privatekey_passphrase(self):
+        """
+        `dump_privatekey` writes an encrypted PEM when given a passphrase.
+        """
+        passphrase = b"foo"
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        pem = dump_privatekey(FILETYPE_PEM, key, GOOD_CIPHER, passphrase)
+        assert isinstance(pem, binary_type)
+        loadedKey = load_privatekey(FILETYPE_PEM, pem, passphrase)
+        assert isinstance(loadedKey, PKeyType)
+        assert loadedKey.type() == key.type()
+        assert loadedKey.bits() == key.bits()
+
+    def test_dump_privatekey_passphrase_wrong_type(self):
+        """
+        `dump_privatekey` raises `ValueError` when it is passed a passphrase
+        with a private key encoded in a format, that doesn't support
+        encryption.
+        """
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        with pytest.raises(ValueError):
+            dump_privatekey(FILETYPE_ASN1, key, GOOD_CIPHER, "secret")
+
+    def test_dump_certificate(self):
+        """
+        `dump_certificate` writes PEM, DER, and text.
+        """
+        pemData = cleartextCertificatePEM + cleartextPrivateKeyPEM
+        cert = load_certificate(FILETYPE_PEM, pemData)
+        dumped_pem = dump_certificate(FILETYPE_PEM, cert)
+        assert dumped_pem == cleartextCertificatePEM
+        dumped_der = dump_certificate(FILETYPE_ASN1, cert)
+        good_der = _runopenssl(dumped_pem, b"x509", b"-outform", b"DER")
+        assert dumped_der == good_der
+        cert2 = load_certificate(FILETYPE_ASN1, dumped_der)
+        dumped_pem2 = dump_certificate(FILETYPE_PEM, cert2)
+        assert dumped_pem2 == cleartextCertificatePEM
+        dumped_text = dump_certificate(FILETYPE_TEXT, cert)
+        good_text = _runopenssl(
+            dumped_pem, b"x509", b"-noout", b"-text", b"-nameopt", b"")
+        assert dumped_text == good_text
+
+    def test_dump_certificate_bad_type(self):
+        """
+        `dump_certificate` raises a `ValueError` if it's called with
+        a bad type.
+        """
+        cert = load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        with pytest.raises(ValueError):
+            dump_certificate(object(), cert)
+
+    def test_dump_privatekey_pem(self):
+        """
+        `dump_privatekey` writes a PEM
+        """
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        assert key.check()
+        dumped_pem = dump_privatekey(FILETYPE_PEM, key)
+        assert dumped_pem == cleartextPrivateKeyPEM
+
+    def test_dump_privatekey_asn1(self):
+        """
+        `dump_privatekey` writes a DER
+        """
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        dumped_pem = dump_privatekey(FILETYPE_PEM, key)
+
+        dumped_der = dump_privatekey(FILETYPE_ASN1, key)
+        # XXX This OpenSSL call writes "writing RSA key" to standard out.  Sad.
+        good_der = _runopenssl(dumped_pem, b"rsa", b"-outform", b"DER")
+        assert dumped_der == good_der
+        key2 = load_privatekey(FILETYPE_ASN1, dumped_der)
+        dumped_pem2 = dump_privatekey(FILETYPE_PEM, key2)
+        assert dumped_pem2 == cleartextPrivateKeyPEM
+
+    def test_dump_privatekey_text(self):
+        """
+        `dump_privatekey` writes a text
+        """
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        dumped_pem = dump_privatekey(FILETYPE_PEM, key)
+
+        dumped_text = dump_privatekey(FILETYPE_TEXT, key)
+        good_text = _runopenssl(dumped_pem, b"rsa", b"-noout", b"-text")
+        assert dumped_text == good_text
+
+    def test_dump_publickey_pem(self):
+        """
+        dump_publickey writes a PEM.
+        """
+        key = load_publickey(FILETYPE_PEM, cleartextPublicKeyPEM)
+        dumped_pem = dump_publickey(FILETYPE_PEM, key)
+        assert dumped_pem == cleartextPublicKeyPEM
+
+    def test_dump_publickey_asn1(self):
+        """
+        dump_publickey writes a DER.
+        """
+        key = load_publickey(FILETYPE_PEM, cleartextPublicKeyPEM)
+        dumped_der = dump_publickey(FILETYPE_ASN1, key)
+        key2 = load_publickey(FILETYPE_ASN1, dumped_der)
+        dumped_pem2 = dump_publickey(FILETYPE_PEM, key2)
+        assert dumped_pem2 == cleartextPublicKeyPEM
+
+    def test_dump_publickey_invalid_type(self):
+        """
+        dump_publickey doesn't support FILETYPE_TEXT.
+        """
+        key = load_publickey(FILETYPE_PEM, cleartextPublicKeyPEM)
+
+        with pytest.raises(ValueError):
+            dump_publickey(FILETYPE_TEXT, key)
+
+    def test_dump_certificate_request(self):
+        """
+        `dump_certificate_request` writes a PEM, DER, and text.
+        """
+        req = load_certificate_request(
+            FILETYPE_PEM, cleartextCertificateRequestPEM)
+        dumped_pem = dump_certificate_request(FILETYPE_PEM, req)
+        assert dumped_pem == cleartextCertificateRequestPEM
+        dumped_der = dump_certificate_request(FILETYPE_ASN1, req)
+        good_der = _runopenssl(dumped_pem, b"req", b"-outform", b"DER")
+        assert dumped_der == good_der
+        req2 = load_certificate_request(FILETYPE_ASN1, dumped_der)
+        dumped_pem2 = dump_certificate_request(FILETYPE_PEM, req2)
+        assert dumped_pem2 == cleartextCertificateRequestPEM
+        dumped_text = dump_certificate_request(FILETYPE_TEXT, req)
+        good_text = _runopenssl(
+            dumped_pem, b"req", b"-noout", b"-text", b"-nameopt", b"")
+        assert dumped_text == good_text
+        with pytest.raises(ValueError):
+            dump_certificate_request(100, req)
+
+    def test_dump_privatekey_passphrase_callback(self):
+        """
+        `dump_privatekey` writes an encrypted PEM when given a callback
+        which returns the correct passphrase.
+        """
+        passphrase = b"foo"
+        called = []
+
+        def cb(writing):
+            called.append(writing)
+            return passphrase
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        pem = dump_privatekey(FILETYPE_PEM, key, GOOD_CIPHER, cb)
+        assert isinstance(pem, binary_type)
+        assert called == [True]
+        loadedKey = load_privatekey(FILETYPE_PEM, pem, passphrase)
+        assert isinstance(loadedKey, PKeyType)
+        assert loadedKey.type() == key.type()
+        assert loadedKey.bits() == key.bits()
+
+    def test_dump_privatekey_passphrase_exception(self):
+        """
+        `dump_privatekey` should not overwrite the exception raised
+        by the passphrase callback.
+        """
+        def cb(ignored):
+            raise ArithmeticError
+
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        with pytest.raises(ArithmeticError):
+            dump_privatekey(FILETYPE_PEM, key, GOOD_CIPHER, cb)
+
+    def test_dump_privatekey_passphraseCallbackLength(self):
+        """
+        `crypto.dump_privatekey` should raise an error when the passphrase
+        provided by the callback is too long, not silently truncate it.
+        """
+        def cb(ignored):
+            return "a" * 1025
+
+        key = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+        with pytest.raises(ValueError):
+            dump_privatekey(FILETYPE_PEM, key, GOOD_CIPHER, cb)
+
+    def test_load_pkcs7_data_pem(self):
+        """
+        `load_pkcs7_data` accepts a PKCS#7 string and returns an instance of
+        `PKCS`.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        assert isinstance(pkcs7, PKCS7)
+
+    def test_load_pkcs7_data_asn1(self):
+        """
+        `load_pkcs7_data` accepts a bytes containing ASN1 data representing
+        PKCS#7 and returns an instance of `PKCS7`.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_ASN1, pkcs7DataASN1)
+        assert isinstance(pkcs7, PKCS7)
+
+    def test_load_pkcs7_data_invalid(self):
+        """
+        If the data passed to `load_pkcs7_data` is invalid, `Error` is raised.
+        """
+        with pytest.raises(Error):
+            load_pkcs7_data(FILETYPE_PEM, b"foo")
+
+    def test_load_pkcs7_type_invalid(self):
+        """
+        If the type passed to `load_pkcs7_data`, `ValueError` is raised.
+        """
+        with pytest.raises(ValueError):
+            load_pkcs7_data(object(), b"foo")
+
+
+class TestLoadCertificate(object):
+    """
+    Tests for `load_certificate_request`.
+    """
+
+    def test_bad_file_type(self):
+        """
+        If the file type passed to `load_certificate_request` is neither
+        `FILETYPE_PEM` nor `FILETYPE_ASN1` then `ValueError` is raised.
+        """
+        with pytest.raises(ValueError):
+            load_certificate_request(object(), b"")
+        with pytest.raises(ValueError):
+            load_certificate(object(), b"")
+
+    def test_bad_certificate(self):
+        """
+        If the bytes passed to `load_certificate` are not a valid certificate,
+        an exception is raised.
+        """
+        with pytest.raises(Error):
+            load_certificate(FILETYPE_ASN1, b"lol")
+
+
+class TestPKCS7(object):
+    """
+    Tests for `PKCS7`.
+    """
+
+    def test_type(self):
+        """
+        `PKCS7` is a type object.
+        """
+        assert isinstance(PKCS7, type)
+        assert PKCS7Type.__name__ == 'PKCS7'
+        assert PKCS7 is PKCS7Type
+
+    def test_type_is_signed(self):
+        """
+        `PKCS7.type_is_signed` returns `True` if the PKCS7 object is of
+        the type *signed*.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        assert pkcs7.type_is_signed()
+
+    def test_type_is_enveloped(self):
+        """
+        `PKCS7.type_is_enveloped` returns `False` if the PKCS7 object is not
+        of the type *enveloped*.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        assert not pkcs7.type_is_enveloped()
+
+    def test_type_is_signed_and_enveloped(self):
+        """
+        `PKCS7.type_is_signedAndEnveloped` returns `False`
+        if the PKCS7 object is not of the type *signed and enveloped*.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        assert not pkcs7.type_is_signedAndEnveloped()
+
+    def test_type_is_data(self):
+        """
+        `PKCS7.type_is_data` returns `False` if the PKCS7 object is not of
+        the type data.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        assert not pkcs7.type_is_data()
+
+    def test_get_type_name(self):
+        """
+        `PKCS7.get_type_name` returns a `str` giving the
+        type name.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        assert pkcs7.get_type_name() == b'pkcs7-signedData'
+
+    def test_attribute(self):
+        """
+        If an attribute other than one of the methods tested here is accessed
+        on an instance of `PKCS7`, `AttributeError` is raised.
+        """
+        pkcs7 = load_pkcs7_data(FILETYPE_PEM, pkcs7Data)
+        with pytest.raises(AttributeError):
+            pkcs7.foo
+
+
+class TestNetscapeSPKI(_PKeyInteractionTestsMixin):
+    """
+    Tests for `OpenSSL.crypto.NetscapeSPKI`.
+    """
+
+    def signable(self):
+        """
+        Return a new `NetscapeSPKI` for use with signing tests.
+        """
+        return NetscapeSPKI()
+
+    def test_type(self):
+        """
+        `NetscapeSPKI` and `NetscapeSPKIType` refer to the same type object
+        and can be used to create instances of that type.
+        """
+        assert NetscapeSPKI is NetscapeSPKIType
+        assert is_consistent_type(NetscapeSPKI, 'NetscapeSPKI')
+
+    def test_construction(self):
+        """
+        `NetscapeSPKI` returns an instance of `NetscapeSPKIType`.
+        """
+        nspki = NetscapeSPKI()
+        assert isinstance(nspki, NetscapeSPKIType)
+
+    def test_invalid_attribute(self):
+        """
+        Accessing a non-existent attribute of a `NetscapeSPKI` instance
+        causes an `AttributeError` to be raised.
+        """
+        nspki = NetscapeSPKI()
+        with pytest.raises(AttributeError):
+            nspki.foo
+
+    def test_b64_encode(self):
+        """
+        `NetscapeSPKI.b64_encode` encodes the certificate to a base64 blob.
+        """
+        nspki = NetscapeSPKI()
+        blob = nspki.b64_encode()
+        assert isinstance(blob, binary_type)
+
+
+class TestRevoked(object):
+    """
+    Tests for `OpenSSL.crypto.Revoked`.
+    """
+    def test_ignores_unsupported_revoked_cert_extension_get_reason(self):
+        """
+        The get_reason method on the Revoked class checks to see if the
+        extension is NID_crl_reason and should skip it otherwise. This test
+        loads a CRL with extensions it should ignore.
+        """
+        crl = load_crl(FILETYPE_PEM, crlDataUnsupportedExtension)
+        revoked = crl.get_revoked()
+        reason = revoked[1].get_reason()
+        assert reason == b'Unspecified'
+
+    def test_ignores_unsupported_revoked_cert_extension_set_new_reason(self):
+        crl = load_crl(FILETYPE_PEM, crlDataUnsupportedExtension)
+        revoked = crl.get_revoked()
+        revoked[1].set_reason(None)
+        reason = revoked[1].get_reason()
+        assert reason is None
+
+    def test_construction(self):
+        """
+        Confirm we can create `OpenSSL.crypto.Revoked`.  Check that it is
+        empty.
+        """
+        revoked = Revoked()
+        assert isinstance(revoked, Revoked)
+        assert type(revoked) == Revoked
+        assert revoked.get_serial() == b'00'
+        assert revoked.get_rev_date() is None
+        assert revoked.get_reason() is None
+
+    def test_serial(self):
+        """
+        Confirm we can set and get serial numbers from
+        `OpenSSL.crypto.Revoked`.  Confirm errors are handled with grace.
+        """
+        revoked = Revoked()
+        ret = revoked.set_serial(b'10b')
+        assert ret is None
+        ser = revoked.get_serial()
+        assert ser == b'010B'
+
+        revoked.set_serial(b'31ppp')  # a type error would be nice
+        ser = revoked.get_serial()
+        assert ser == b'31'
+
+        with pytest.raises(ValueError):
+            revoked.set_serial(b'pqrst')
+        with pytest.raises(TypeError):
+            revoked.set_serial(100)
+
+    def test_date(self):
+        """
+        Confirm we can set and get revocation dates from
+        `OpenSSL.crypto.Revoked`.  Confirm errors are handled with grace.
+        """
+        revoked = Revoked()
+        date = revoked.get_rev_date()
+        assert date is None
+
+        now = datetime.now().strftime("%Y%m%d%H%M%SZ").encode("ascii")
+        ret = revoked.set_rev_date(now)
+        assert ret is None
+        date = revoked.get_rev_date()
+        assert date == now
+
+    def test_reason(self):
+        """
+        Confirm we can set and get revocation reasons from
+        `OpenSSL.crypto.Revoked`.  The "get" need to work as "set".
+        Likewise, each reason of all_reasons() must work.
+        """
+        revoked = Revoked()
+        for r in revoked.all_reasons():
+            for x in range(2):
+                ret = revoked.set_reason(r)
+                assert ret is None
+                reason = revoked.get_reason()
+                assert (
+                    reason.lower().replace(b' ', b'') ==
+                    r.lower().replace(b' ', b''))
+                r = reason  # again with the resp of get
+
+        revoked.set_reason(None)
+        assert revoked.get_reason() is None
+
+    @pytest.mark.parametrize('reason', [object(), 1.0, u'foo'])
+    def test_set_reason_wrong_args(self, reason):
+        """
+        `Revoked.set_reason` raises `TypeError` if called with an argument
+        which is neither `None` nor a byte string.
+        """
+        revoked = Revoked()
+        with pytest.raises(TypeError):
+            revoked.set_reason(reason)
+
+    def test_set_reason_invalid_reason(self):
+        """
+        Calling `OpenSSL.crypto.Revoked.set_reason` with an argument which
+        isn't a valid reason results in `ValueError` being raised.
+        """
+        revoked = Revoked()
+        with pytest.raises(ValueError):
+            revoked.set_reason(b'blue')
+
+
+class TestCRL(object):
+    """
+    Tests for `OpenSSL.crypto.CRL`.
+    """
+    cert = load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+    pkey = load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM)
+
+    root_cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+    root_key = load_privatekey(FILETYPE_PEM, root_key_pem)
+    intermediate_cert = load_certificate(FILETYPE_PEM, intermediate_cert_pem)
+    intermediate_key = load_privatekey(FILETYPE_PEM, intermediate_key_pem)
+    intermediate_server_cert = load_certificate(
+        FILETYPE_PEM, intermediate_server_cert_pem)
+    intermediate_server_key = load_privatekey(
+        FILETYPE_PEM, intermediate_server_key_pem)
+
+    def test_construction(self):
+        """
+        Confirm we can create `OpenSSL.crypto.CRL`.  Check
+        that it is empty
+        """
+        crl = CRL()
+        assert isinstance(crl, CRL)
+        assert crl.get_revoked() is None
+
+    def _get_crl(self):
+        """
+        Get a new ``CRL`` with a revocation.
+        """
+        crl = CRL()
+        revoked = Revoked()
+        now = datetime.now().strftime("%Y%m%d%H%M%SZ").encode("ascii")
+        revoked.set_rev_date(now)
+        revoked.set_serial(b'3ab')
+        revoked.set_reason(b'sUpErSeDEd')
+        crl.add_revoked(revoked)
+        return crl
+
+    def test_export_pem(self):
+        """
+        If not passed a format, ``CRL.export`` returns a "PEM" format string
+        representing a serial number, a revoked reason, and certificate issuer
+        information.
+        """
+        # PEM format
+        dumped_crl = self._get_crl().export(
+            self.cert, self.pkey, days=20, digest=b"sha256"
+        )
+        crl = x509.load_pem_x509_crl(dumped_crl, backend)
+        revoked = crl.get_revoked_certificate_by_serial_number(0x03AB)
+        assert revoked is not None
+        assert crl.issuer == x509.Name([
+            x509.NameAttribute(x509.NameOID.COUNTRY_NAME, u"US"),
+            x509.NameAttribute(x509.NameOID.STATE_OR_PROVINCE_NAME, u"IL"),
+            x509.NameAttribute(x509.NameOID.LOCALITY_NAME, u"Chicago"),
+            x509.NameAttribute(x509.NameOID.ORGANIZATION_NAME, u"Testing"),
+            x509.NameAttribute(x509.NameOID.COMMON_NAME, u"Testing Root CA"),
+        ])
+
+    def test_export_der(self):
+        """
+        If passed ``FILETYPE_ASN1`` for the format, ``CRL.export`` returns a
+        "DER" format string representing a serial number, a revoked reason, and
+        certificate issuer information.
+        """
+        crl = self._get_crl()
+
+        # DER format
+        dumped_crl = self._get_crl().export(
+            self.cert, self.pkey, FILETYPE_ASN1, digest=b"md5"
+        )
+        crl = x509.load_der_x509_crl(dumped_crl, backend)
+        revoked = crl.get_revoked_certificate_by_serial_number(0x03AB)
+        assert revoked is not None
+        assert crl.issuer == x509.Name([
+            x509.NameAttribute(x509.NameOID.COUNTRY_NAME, u"US"),
+            x509.NameAttribute(x509.NameOID.STATE_OR_PROVINCE_NAME, u"IL"),
+            x509.NameAttribute(x509.NameOID.LOCALITY_NAME, u"Chicago"),
+            x509.NameAttribute(x509.NameOID.ORGANIZATION_NAME, u"Testing"),
+            x509.NameAttribute(x509.NameOID.COMMON_NAME, u"Testing Root CA"),
+        ])
+
+    # Flaky because we compare the output of running commands which sometimes
+    # varies by 1 second
+    @flaky.flaky
+    def test_export_text(self):
+        """
+        If passed ``FILETYPE_TEXT`` for the format, ``CRL.export`` returns a
+        text format string like the one produced by the openssl command line
+        tool.
+        """
+        crl = self._get_crl()
+
+        dumped_crl = crl.export(
+            self.cert, self.pkey, FILETYPE_ASN1, digest=b"md5"
+        )
+        text = _runopenssl(
+            dumped_crl, b"crl", b"-noout", b"-text", b"-inform", b"DER",
+            b"-nameopt", b""
+        )
+
+        # text format
+        dumped_text = crl.export(
+            self.cert, self.pkey, type=FILETYPE_TEXT, digest=b"md5"
+        )
+        assert text == dumped_text
+
+    def test_export_custom_digest(self):
+        """
+        If passed the name of a digest function, ``CRL.export`` uses a
+        signature algorithm based on that digest function.
+        """
+        crl = self._get_crl()
+        dumped_crl = crl.export(self.cert, self.pkey, digest=b"sha1")
+        text = _runopenssl(dumped_crl, b"crl", b"-noout", b"-text")
+        text.index(b'Signature Algorithm: sha1')
+
+    def test_export_md5_digest(self):
+        """
+        If passed md5 as the digest function, ``CRL.export`` uses md5 and does
+        not emit a deprecation warning.
+        """
+        crl = self._get_crl()
+        with pytest.warns(None) as catcher:
+            simplefilter("always")
+        assert 0 == len(catcher)
+        dumped_crl = crl.export(self.cert, self.pkey, digest=b"md5")
+        text = _runopenssl(dumped_crl, b"crl", b"-noout", b"-text")
+        text.index(b'Signature Algorithm: md5')
+
+    def test_export_default_digest(self):
+        """
+        If not passed the name of a digest function, ``CRL.export`` raises a
+        ``TypeError``.
+        """
+        crl = self._get_crl()
+        with pytest.raises(TypeError):
+            crl.export(self.cert, self.pkey)
+
+    def test_export_invalid(self):
+        """
+        If `CRL.export` is used with an uninitialized `X509` instance,
+        `OpenSSL.crypto.Error` is raised.
+        """
+        crl = CRL()
+        with pytest.raises(Error):
+            crl.export(X509(), PKey(), digest=b"sha256")
+
+    def test_add_revoked_keyword(self):
+        """
+        `OpenSSL.CRL.add_revoked` accepts its single argument as the
+        ``revoked`` keyword argument.
+        """
+        crl = CRL()
+        revoked = Revoked()
+        revoked.set_serial(b"01")
+        revoked.set_rev_date(b"20160310020145Z")
+        crl.add_revoked(revoked=revoked)
+        assert isinstance(crl.get_revoked()[0], Revoked)
+
+    def test_export_wrong_args(self):
+        """
+        Calling `OpenSSL.CRL.export` with arguments other than the certificate,
+        private key, integer file type, and integer number of days it
+        expects, results in a `TypeError` being raised.
+        """
+        crl = CRL()
+        with pytest.raises(TypeError):
+            crl.export(None, self.pkey, FILETYPE_PEM, 10)
+        with pytest.raises(TypeError):
+            crl.export(self.cert, None, FILETYPE_PEM, 10)
+        with pytest.raises(TypeError):
+            crl.export(self.cert, self.pkey, None, 10)
+        with pytest.raises(TypeError):
+            crl.export(self.cert, FILETYPE_PEM, None)
+
+    def test_export_unknown_filetype(self):
+        """
+        Calling `OpenSSL.CRL.export` with a file type other than
+        `FILETYPE_PEM`, `FILETYPE_ASN1`, or
+        `FILETYPE_TEXT` results in a `ValueError` being raised.
+        """
+        crl = CRL()
+        with pytest.raises(ValueError):
+            crl.export(self.cert, self.pkey, 100, 10, digest=b"sha256")
+
+    def test_export_unknown_digest(self):
+        """
+        Calling `OpenSSL.CRL.export` with an unsupported digest results
+        in a `ValueError` being raised.
+        """
+        crl = CRL()
+        with pytest.raises(ValueError):
+            crl.export(
+                self.cert, self.pkey, FILETYPE_PEM, 10, b"strange-digest")
+
+    def test_get_revoked(self):
+        """
+        Use python to create a simple CRL with two revocations. Get back the
+        `Revoked` using `OpenSSL.CRL.get_revoked` and verify them.
+        """
+        crl = CRL()
+
+        revoked = Revoked()
+        now = datetime.now().strftime("%Y%m%d%H%M%SZ").encode("ascii")
+        revoked.set_rev_date(now)
+        revoked.set_serial(b'3ab')
+        crl.add_revoked(revoked)
+        revoked.set_serial(b'100')
+        revoked.set_reason(b'sUpErSeDEd')
+        crl.add_revoked(revoked)
+
+        revs = crl.get_revoked()
+        assert len(revs) == 2
+        assert type(revs[0]) == Revoked
+        assert type(revs[1]) == Revoked
+        assert revs[0].get_serial() == b'03AB'
+        assert revs[1].get_serial() == b'0100'
+        assert revs[0].get_rev_date() == now
+        assert revs[1].get_rev_date() == now
+
+    def test_load_crl(self):
+        """
+        Load a known CRL and inspect its revocations.  Both EM and DER formats
+        are loaded.
+        """
+        crl = load_crl(FILETYPE_PEM, crlData)
+        revs = crl.get_revoked()
+        assert len(revs) == 2
+        assert revs[0].get_serial() == b'03AB'
+        assert revs[0].get_reason() is None
+        assert revs[1].get_serial() == b'0100'
+        assert revs[1].get_reason() == b'Superseded'
+
+        der = _runopenssl(crlData, b"crl", b"-outform", b"DER")
+        crl = load_crl(FILETYPE_ASN1, der)
+        revs = crl.get_revoked()
+        assert len(revs) == 2
+        assert revs[0].get_serial() == b'03AB'
+        assert revs[0].get_reason() is None
+        assert revs[1].get_serial() == b'0100'
+        assert revs[1].get_reason() == b'Superseded'
+
+    def test_load_crl_bad_filetype(self):
+        """
+        Calling `OpenSSL.crypto.load_crl` with an unknown file type raises a
+        `ValueError`.
+        """
+        with pytest.raises(ValueError):
+            load_crl(100, crlData)
+
+    def test_load_crl_bad_data(self):
+        """
+        Calling `OpenSSL.crypto.load_crl` with file data which can't be loaded
+        raises a `OpenSSL.crypto.Error`.
+        """
+        with pytest.raises(Error):
+            load_crl(FILETYPE_PEM, b"hello, world")
+
+    def test_get_issuer(self):
+        """
+        Load a known CRL and assert its issuer's common name is what we expect
+        from the encoded crlData string.
+        """
+        crl = load_crl(FILETYPE_PEM, crlData)
+        assert isinstance(crl.get_issuer(), X509Name)
+        assert crl.get_issuer().CN == 'Testing Root CA'
+
+    def test_dump_crl(self):
+        """
+        The dumped CRL matches the original input.
+        """
+        crl = load_crl(FILETYPE_PEM, crlData)
+        buf = dump_crl(FILETYPE_PEM, crl)
+        assert buf == crlData
+
+    def _make_test_crl(self, issuer_cert, issuer_key, certs=()):
+        """
+        Create a CRL.
+
+        :param list[X509] certs: A list of certificates to revoke.
+        :rtype: CRL
+        """
+        crl = CRL()
+        for cert in certs:
+            revoked = Revoked()
+            # FIXME: This string splicing is an unfortunate implementation
+            # detail that has been reported in
+            # https://github.com/pyca/pyopenssl/issues/258
+            serial = hex(cert.get_serial_number())[2:].encode('utf-8')
+            revoked.set_serial(serial)
+            revoked.set_reason(b'unspecified')
+            revoked.set_rev_date(b'20140601000000Z')
+            crl.add_revoked(revoked)
+        crl.set_version(1)
+        crl.set_lastUpdate(b'20140601000000Z')
+        crl.set_nextUpdate(b'20180601000000Z')
+        crl.sign(issuer_cert, issuer_key, digest=b'sha512')
+        return crl
+
+    def test_verify_with_revoked(self):
+        """
+        `verify_certificate` raises error when an intermediate certificate is
+        revoked.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store.add_cert(self.intermediate_cert)
+        root_crl = self._make_test_crl(
+            self.root_cert, self.root_key, certs=[self.intermediate_cert])
+        intermediate_crl = self._make_test_crl(
+            self.intermediate_cert, self.intermediate_key, certs=[])
+        store.add_crl(root_crl)
+        store.add_crl(intermediate_crl)
+        store.set_flags(
+            X509StoreFlags.CRL_CHECK | X509StoreFlags.CRL_CHECK_ALL)
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+        with pytest.raises(X509StoreContextError) as err:
+            store_ctx.verify_certificate()
+        assert err.value.args[0][2] == 'certificate revoked'
+
+    def test_verify_with_missing_crl(self):
+        """
+        `verify_certificate` raises error when an intermediate certificate's
+        CRL is missing.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store.add_cert(self.intermediate_cert)
+        root_crl = self._make_test_crl(
+            self.root_cert, self.root_key, certs=[self.intermediate_cert])
+        store.add_crl(root_crl)
+        store.set_flags(
+            X509StoreFlags.CRL_CHECK | X509StoreFlags.CRL_CHECK_ALL)
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+        with pytest.raises(X509StoreContextError) as err:
+            store_ctx.verify_certificate()
+        assert err.value.args[0][2] == 'unable to get certificate CRL'
+        assert err.value.certificate.get_subject().CN == 'intermediate-service'
+
+    def test_convert_from_cryptography(self):
+        crypto_crl = x509.load_pem_x509_crl(crlData, backend)
+        crl = CRL.from_cryptography(crypto_crl)
+        assert isinstance(crl, CRL)
+
+    def test_convert_from_cryptography_unsupported_type(self):
+        with pytest.raises(TypeError):
+            CRL.from_cryptography(object())
+
+    def test_convert_to_cryptography_key(self):
+        crl = load_crl(FILETYPE_PEM, crlData)
+        crypto_crl = crl.to_cryptography()
+        assert isinstance(crypto_crl, x509.CertificateRevocationList)
+
+
+class TestX509StoreContext(object):
+    """
+    Tests for `OpenSSL.crypto.X509StoreContext`.
+    """
+    root_cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+    intermediate_cert = load_certificate(FILETYPE_PEM, intermediate_cert_pem)
+    intermediate_server_cert = load_certificate(
+        FILETYPE_PEM, intermediate_server_cert_pem)
+
+    def test_valid(self):
+        """
+        `verify_certificate` returns ``None`` when called with a certificate
+        and valid chain.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store.add_cert(self.intermediate_cert)
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+        assert store_ctx.verify_certificate() is None
+
+    def test_reuse(self):
+        """
+        `verify_certificate` can be called multiple times with the same
+        ``X509StoreContext`` instance to produce the same result.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store.add_cert(self.intermediate_cert)
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+        assert store_ctx.verify_certificate() is None
+        assert store_ctx.verify_certificate() is None
+
+    def test_trusted_self_signed(self):
+        """
+        `verify_certificate` returns ``None`` when called with a self-signed
+        certificate and itself in the chain.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store_ctx = X509StoreContext(store, self.root_cert)
+        assert store_ctx.verify_certificate() is None
+
+    def test_untrusted_self_signed(self):
+        """
+        `verify_certificate` raises error when a self-signed certificate is
+        verified without itself in the chain.
+        """
+        store = X509Store()
+        store_ctx = X509StoreContext(store, self.root_cert)
+        with pytest.raises(X509StoreContextError) as exc:
+            store_ctx.verify_certificate()
+
+        assert exc.value.args[0][2] == 'self signed certificate'
+        assert exc.value.certificate.get_subject().CN == 'Testing Root CA'
+
+    def test_invalid_chain_no_root(self):
+        """
+        `verify_certificate` raises error when a root certificate is missing
+        from the chain.
+        """
+        store = X509Store()
+        store.add_cert(self.intermediate_cert)
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+
+        with pytest.raises(X509StoreContextError) as exc:
+            store_ctx.verify_certificate()
+
+        assert exc.value.args[0][2] == 'unable to get issuer certificate'
+        assert exc.value.certificate.get_subject().CN == 'intermediate'
+
+    def test_invalid_chain_no_intermediate(self):
+        """
+        `verify_certificate` raises error when an intermediate certificate is
+        missing from the chain.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+
+        with pytest.raises(X509StoreContextError) as exc:
+            store_ctx.verify_certificate()
+
+        assert exc.value.args[0][2] == 'unable to get local issuer certificate'
+        assert exc.value.certificate.get_subject().CN == 'intermediate-service'
+
+    def test_modification_pre_verify(self):
+        """
+        `verify_certificate` can use a store context modified after
+        instantiation.
+        """
+        store_bad = X509Store()
+        store_bad.add_cert(self.intermediate_cert)
+        store_good = X509Store()
+        store_good.add_cert(self.root_cert)
+        store_good.add_cert(self.intermediate_cert)
+        store_ctx = X509StoreContext(store_bad, self.intermediate_server_cert)
+
+        with pytest.raises(X509StoreContextError) as exc:
+            store_ctx.verify_certificate()
+
+        assert exc.value.args[0][2] == 'unable to get issuer certificate'
+        assert exc.value.certificate.get_subject().CN == 'intermediate'
+
+        store_ctx.set_store(store_good)
+        assert store_ctx.verify_certificate() is None
+
+    def test_verify_with_time(self):
+        """
+        `verify_certificate` raises error when the verification time is
+        set at notAfter.
+        """
+        store = X509Store()
+        store.add_cert(self.root_cert)
+        store.add_cert(self.intermediate_cert)
+
+        expire_time = self.intermediate_server_cert.get_notAfter()
+        expire_datetime = datetime.strptime(
+            expire_time.decode('utf-8'), '%Y%m%d%H%M%SZ'
+        )
+        store.set_time(expire_datetime)
+
+        store_ctx = X509StoreContext(store, self.intermediate_server_cert)
+        with pytest.raises(X509StoreContextError) as exc:
+            store_ctx.verify_certificate()
+
+        assert exc.value.args[0][2] == 'certificate has expired'
+
+
+class TestSignVerify(object):
+    """
+    Tests for `OpenSSL.crypto.sign` and `OpenSSL.crypto.verify`.
+    """
+
+    def test_sign_verify(self):
+        """
+        `sign` generates a cryptographic signature which `verify` can check.
+        """
+        content = (
+            b"It was a bright cold day in April, and the clocks were striking "
+            b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
+            b"effort to escape the vile wind, slipped quickly through the "
+            b"glass doors of Victory Mansions, though not quickly enough to "
+            b"prevent a swirl of gritty dust from entering along with him.")
+
+        # sign the content with this private key
+        priv_key = load_privatekey(FILETYPE_PEM, root_key_pem)
+        # verify the content with this cert
+        good_cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        # certificate unrelated to priv_key, used to trigger an error
+        bad_cert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        for digest in ['md5', 'sha1']:
+            sig = sign(priv_key, content, digest)
+
+            # Verify the signature of content, will throw an exception if
+            # error.
+            verify(good_cert, sig, content, digest)
+
+            # This should fail because the certificate doesn't match the
+            # private key that was used to sign the content.
+            with pytest.raises(Error):
+                verify(bad_cert, sig, content, digest)
+
+            # This should fail because we've "tainted" the content after
+            # signing it.
+            with pytest.raises(Error):
+                verify(good_cert, sig, content + b"tainted", digest)
+
+        # test that unknown digest types fail
+        with pytest.raises(ValueError):
+            sign(priv_key, content, "strange-digest")
+        with pytest.raises(ValueError):
+            verify(good_cert, sig, content, "strange-digest")
+
+    def test_sign_verify_with_text(self):
+        """
+        `sign` generates a cryptographic signature which
+        `verify` can check. Deprecation warnings raised because using
+        text instead of bytes as content
+        """
+        content = (
+            b"It was a bright cold day in April, and the clocks were striking "
+            b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
+            b"effort to escape the vile wind, slipped quickly through the "
+            b"glass doors of Victory Mansions, though not quickly enough to "
+            b"prevent a swirl of gritty dust from entering along with him."
+        ).decode("ascii")
+
+        priv_key = load_privatekey(FILETYPE_PEM, root_key_pem)
+        cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        for digest in ['md5', 'sha1']:
+            with pytest.warns(DeprecationWarning) as w:
+                simplefilter("always")
+                sig = sign(priv_key, content, digest)
+            assert (
+                "{0} for data is no longer accepted, use bytes".format(
+                    WARNING_TYPE_EXPECTED
+                ) == str(w[-1].message))
+
+            with pytest.warns(DeprecationWarning) as w:
+                simplefilter("always")
+                verify(cert, sig, content, digest)
+            assert (
+                "{0} for data is no longer accepted, use bytes".format(
+                    WARNING_TYPE_EXPECTED
+                ) == str(w[-1].message))
+
+    def test_sign_verify_ecdsa(self):
+        """
+        `sign` generates a cryptographic signature which `verify` can check.
+        ECDSA Signatures in the X9.62 format may have variable length,
+        different from the length of the private key.
+        """
+        content = (
+            b"It was a bright cold day in April, and the clocks were striking "
+            b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
+            b"effort to escape the vile wind, slipped quickly through the "
+            b"glass doors of Victory Mansions, though not quickly enough to "
+            b"prevent a swirl of gritty dust from entering along with him."
+        ).decode("ascii")
+        priv_key = load_privatekey(FILETYPE_PEM, ec_root_key_pem)
+        cert = load_certificate(FILETYPE_PEM, ec_root_cert_pem)
+        sig = sign(priv_key, content, "sha1")
+        verify(cert, sig, content, "sha1")
+
+    def test_sign_nulls(self):
+        """
+        `sign` produces a signature for a string with embedded nulls.
+        """
+        content = b"Watch out!  \0  Did you see it?"
+        priv_key = load_privatekey(FILETYPE_PEM, root_key_pem)
+        good_cert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        sig = sign(priv_key, content, "sha1")
+        verify(good_cert, sig, content, "sha1")
+
+    def test_sign_with_large_key(self):
+        """
+        `sign` produces a signature for a string when using a long key.
+        """
+        content = (
+            b"It was a bright cold day in April, and the clocks were striking "
+            b"thirteen. Winston Smith, his chin nuzzled into his breast in an "
+            b"effort to escape the vile wind, slipped quickly through the "
+            b"glass doors of Victory Mansions, though not quickly enough to "
+            b"prevent a swirl of gritty dust from entering along with him.")
+
+        priv_key = load_privatekey(FILETYPE_PEM, large_key_pem)
+        sign(priv_key, content, "sha1")
+
+
+class TestEllipticCurve(object):
+    """
+    Tests for `_EllipticCurve`, `get_elliptic_curve`, and
+    `get_elliptic_curves`.
+    """
+
+    def test_set(self):
+        """
+        `get_elliptic_curves` returns a `set`.
+        """
+        assert isinstance(get_elliptic_curves(), set)
+
+    def test_a_curve(self):
+        """
+        `get_elliptic_curve` can be used to retrieve a particular supported
+        curve.
+        """
+        curves = get_elliptic_curves()
+        curve = next(iter(curves))
+        assert curve.name == get_elliptic_curve(curve.name).name
+
+    def test_not_a_curve(self):
+        """
+        `get_elliptic_curve` raises `ValueError` if called with a name which
+        does not identify a supported curve.
+        """
+        with pytest.raises(ValueError):
+            get_elliptic_curve(u"this curve was just invented")
+
+    def test_repr(self):
+        """
+        The string representation of a curve object includes simply states the
+        object is a curve and what its name is.
+        """
+        curves = get_elliptic_curves()
+        curve = next(iter(curves))
+        assert "<Curve %r>" % (curve.name,) == repr(curve)
+
+    def test_to_EC_KEY(self):
+        """
+        The curve object can export a version of itself as an EC_KEY* via the
+        private `_EllipticCurve._to_EC_KEY`.
+        """
+        curves = get_elliptic_curves()
+        curve = next(iter(curves))
+        # It's not easy to assert anything about this object.  However, see
+        # leakcheck/crypto.py for a test that demonstrates it at least does
+        # not leak memory.
+        curve._to_EC_KEY()
+
+
+class EllipticCurveFactory(object):
+    """
+    A helper to get the names of two curves.
+    """
+
+    def __init__(self):
+        curves = iter(get_elliptic_curves())
+        self.curve_name = next(curves).name
+        self.another_curve_name = next(curves).name
+
+
+class TestEllipticCurveEquality(EqualityTestsMixin):
+    """
+    Tests `_EllipticCurve`'s implementation of ``==`` and ``!=``.
+    """
+    curve_factory = EllipticCurveFactory()
+
+    if curve_factory.curve_name is None:
+        skip = "There are no curves available there can be no curve objects."
+
+    def anInstance(self):
+        """
+        Get the curve object for an arbitrary curve supported by the system.
+        """
+        return get_elliptic_curve(self.curve_factory.curve_name)
+
+    def anotherInstance(self):
+        """
+        Get the curve object for an arbitrary curve supported by the system -
+        but not the one returned by C{anInstance}.
+        """
+        return get_elliptic_curve(self.curve_factory.another_curve_name)
+
+
+class TestEllipticCurveHash(object):
+    """
+    Tests for `_EllipticCurve`'s implementation of hashing (thus use as
+    an item in a `dict` or `set`).
+    """
+    curve_factory = EllipticCurveFactory()
+
+    if curve_factory.curve_name is None:
+        skip = "There are no curves available there can be no curve objects."
+
+    def test_contains(self):
+        """
+        The ``in`` operator reports that a `set` containing a curve does
+        contain that curve.
+        """
+        curve = get_elliptic_curve(self.curve_factory.curve_name)
+        curves = set([curve])
+        assert curve in curves
+
+    def test_does_not_contain(self):
+        """
+        The ``in`` operator reports that a `set` not containing a curve
+        does not contain that curve.
+        """
+        curve = get_elliptic_curve(self.curve_factory.curve_name)
+        curves = set([
+            get_elliptic_curve(self.curve_factory.another_curve_name)
+        ])
+        assert curve not in curves
diff --git a/tests/test_debug.py b/tests/test_debug.py
new file mode 100644
index 0000000..2d62a3a
--- /dev/null
+++ b/tests/test_debug.py
@@ -0,0 +1,10 @@
+from OpenSSL.debug import _env_info
+from OpenSSL import version
+
+
+def test_debug_info():
+    """
+    Debug info contains correct data.
+    """
+    # Just check a sample we control.
+    assert version.__version__ in _env_info
diff --git a/tests/test_rand.py b/tests/test_rand.py
new file mode 100644
index 0000000..e04a24c
--- /dev/null
+++ b/tests/test_rand.py
@@ -0,0 +1,38 @@
+# Copyright (c) Frederick Dean
+# See LICENSE for details.
+
+"""
+Unit tests for `OpenSSL.rand`.
+"""
+
+import pytest
+
+from OpenSSL import rand
+
+
+class TestRand(object):
+
+    @pytest.mark.parametrize('args', [
+        (b"foo", None),
+        (None, 3),
+    ])
+    def test_add_wrong_args(self, args):
+        """
+        `OpenSSL.rand.add` raises `TypeError` if called with arguments not of
+        type `str` and `int`.
+        """
+        with pytest.raises(TypeError):
+            rand.add(*args)
+
+    def test_add(self):
+        """
+        `OpenSSL.rand.add` adds entropy to the PRNG.
+        """
+        rand.add(b'hamburger', 3)
+
+    def test_status(self):
+        """
+        `OpenSSL.rand.status` returns `1` if the PRNG has sufficient entropy,
+        `0` otherwise.
+        """
+        assert rand.status() == 1
diff --git a/tests/test_ssl.py b/tests/test_ssl.py
new file mode 100644
index 0000000..bddeaa9
--- /dev/null
+++ b/tests/test_ssl.py
@@ -0,0 +1,4059 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+Unit tests for :mod:`OpenSSL.SSL`.
+"""
+
+import datetime
+import sys
+import uuid
+
+from gc import collect, get_referrers
+from errno import ECONNREFUSED, EINPROGRESS, EWOULDBLOCK, EPIPE, ESHUTDOWN
+from sys import platform, getfilesystemencoding
+from socket import MSG_PEEK, SHUT_RDWR, error, socket
+from os import makedirs
+from os.path import join
+from weakref import ref
+from warnings import simplefilter
+
+import pytest
+
+from pretend import raiser
+
+from six import PY3, text_type
+
+from cryptography import x509
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import rsa
+from cryptography.x509.oid import NameOID
+
+
+from OpenSSL.crypto import TYPE_RSA, FILETYPE_PEM
+from OpenSSL.crypto import PKey, X509, X509Extension, X509Store
+from OpenSSL.crypto import dump_privatekey, load_privatekey
+from OpenSSL.crypto import dump_certificate, load_certificate
+from OpenSSL.crypto import get_elliptic_curves
+
+from OpenSSL.SSL import OPENSSL_VERSION_NUMBER, SSLEAY_VERSION, SSLEAY_CFLAGS
+from OpenSSL.SSL import SSLEAY_PLATFORM, SSLEAY_DIR, SSLEAY_BUILT_ON
+from OpenSSL.SSL import SENT_SHUTDOWN, RECEIVED_SHUTDOWN
+from OpenSSL.SSL import (
+    SSLv2_METHOD, SSLv3_METHOD, SSLv23_METHOD, TLSv1_METHOD,
+    TLSv1_1_METHOD, TLSv1_2_METHOD)
+from OpenSSL.SSL import OP_SINGLE_DH_USE, OP_NO_SSLv2, OP_NO_SSLv3
+from OpenSSL.SSL import (
+    VERIFY_PEER, VERIFY_FAIL_IF_NO_PEER_CERT, VERIFY_CLIENT_ONCE, VERIFY_NONE)
+
+from OpenSSL import SSL
+from OpenSSL.SSL import (
+    SESS_CACHE_OFF, SESS_CACHE_CLIENT, SESS_CACHE_SERVER, SESS_CACHE_BOTH,
+    SESS_CACHE_NO_AUTO_CLEAR, SESS_CACHE_NO_INTERNAL_LOOKUP,
+    SESS_CACHE_NO_INTERNAL_STORE, SESS_CACHE_NO_INTERNAL)
+
+from OpenSSL.SSL import (
+    Error, SysCallError, WantReadError, WantWriteError, ZeroReturnError)
+from OpenSSL.SSL import (
+    Context, ContextType, Session, Connection, ConnectionType, SSLeay_version)
+from OpenSSL.SSL import _make_requires
+
+from OpenSSL._util import ffi as _ffi, lib as _lib
+
+from OpenSSL.SSL import (
+    OP_NO_QUERY_MTU, OP_COOKIE_EXCHANGE, OP_NO_TICKET, OP_NO_COMPRESSION,
+    MODE_RELEASE_BUFFERS)
+
+from OpenSSL.SSL import (
+    SSL_ST_CONNECT, SSL_ST_ACCEPT, SSL_ST_MASK,
+    SSL_CB_LOOP, SSL_CB_EXIT, SSL_CB_READ, SSL_CB_WRITE, SSL_CB_ALERT,
+    SSL_CB_READ_ALERT, SSL_CB_WRITE_ALERT, SSL_CB_ACCEPT_LOOP,
+    SSL_CB_ACCEPT_EXIT, SSL_CB_CONNECT_LOOP, SSL_CB_CONNECT_EXIT,
+    SSL_CB_HANDSHAKE_START, SSL_CB_HANDSHAKE_DONE)
+
+try:
+    from OpenSSL.SSL import (
+        SSL_ST_INIT, SSL_ST_BEFORE, SSL_ST_OK, SSL_ST_RENEGOTIATE
+    )
+except ImportError:
+    SSL_ST_INIT = SSL_ST_BEFORE = SSL_ST_OK = SSL_ST_RENEGOTIATE = None
+
+from .util import WARNING_TYPE_EXPECTED, NON_ASCII, is_consistent_type
+from .test_crypto import (
+    cleartextCertificatePEM, cleartextPrivateKeyPEM,
+    client_cert_pem, client_key_pem, server_cert_pem, server_key_pem,
+    root_cert_pem)
+
+
+# openssl dhparam 1024 -out dh-1024.pem (note that 1024 is a small number of
+# bits to use)
+dhparam = """\
+-----BEGIN DH PARAMETERS-----
+MIGHAoGBALdUMvn+C9MM+y5BWZs11mSeH6HHoEq0UVbzVq7UojC1hbsZUuGukQ3a
+Qh2/pwqb18BZFykrWB0zv/OkLa0kx4cuUgNrUVq1EFheBiX6YqryJ7t2sO09NQiO
+V7H54LmltOT/hEh6QWsJqb6BQgH65bswvV/XkYGja8/T0GzvbaVzAgEC
+-----END DH PARAMETERS-----
+"""
+
+
+skip_if_py3 = pytest.mark.skipif(PY3, reason="Python 2 only")
+
+
+def join_bytes_or_unicode(prefix, suffix):
+    """
+    Join two path components of either ``bytes`` or ``unicode``.
+
+    The return type is the same as the type of ``prefix``.
+    """
+    # If the types are the same, nothing special is necessary.
+    if type(prefix) == type(suffix):
+        return join(prefix, suffix)
+
+    # Otherwise, coerce suffix to the type of prefix.
+    if isinstance(prefix, text_type):
+        return join(prefix, suffix.decode(getfilesystemencoding()))
+    else:
+        return join(prefix, suffix.encode(getfilesystemencoding()))
+
+
+def verify_cb(conn, cert, errnum, depth, ok):
+    return ok
+
+
+def socket_pair():
+    """
+    Establish and return a pair of network sockets connected to each other.
+    """
+    # Connect a pair of sockets
+    port = socket()
+    port.bind(('', 0))
+    port.listen(1)
+    client = socket()
+    client.setblocking(False)
+    client.connect_ex(("127.0.0.1", port.getsockname()[1]))
+    client.setblocking(True)
+    server = port.accept()[0]
+
+    # Let's pass some unencrypted data to make sure our socket connection is
+    # fine.  Just one byte, so we don't have to worry about buffers getting
+    # filled up or fragmentation.
+    server.send(b"x")
+    assert client.recv(1024) == b"x"
+    client.send(b"y")
+    assert server.recv(1024) == b"y"
+
+    # Most of our callers want non-blocking sockets, make it easy for them.
+    server.setblocking(False)
+    client.setblocking(False)
+
+    return (server, client)
+
+
+def handshake(client, server):
+    conns = [client, server]
+    while conns:
+        for conn in conns:
+            try:
+                conn.do_handshake()
+            except WantReadError:
+                pass
+            else:
+                conns.remove(conn)
+
+
+def _create_certificate_chain():
+    """
+    Construct and return a chain of certificates.
+
+        1. A new self-signed certificate authority certificate (cacert)
+        2. A new intermediate certificate signed by cacert (icert)
+        3. A new server certificate signed by icert (scert)
+    """
+    caext = X509Extension(b'basicConstraints', False, b'CA:true')
+
+    # Step 1
+    cakey = PKey()
+    cakey.generate_key(TYPE_RSA, 1024)
+    cacert = X509()
+    cacert.get_subject().commonName = "Authority Certificate"
+    cacert.set_issuer(cacert.get_subject())
+    cacert.set_pubkey(cakey)
+    cacert.set_notBefore(b"20000101000000Z")
+    cacert.set_notAfter(b"20200101000000Z")
+    cacert.add_extensions([caext])
+    cacert.set_serial_number(0)
+    cacert.sign(cakey, "sha1")
+
+    # Step 2
+    ikey = PKey()
+    ikey.generate_key(TYPE_RSA, 1024)
+    icert = X509()
+    icert.get_subject().commonName = "Intermediate Certificate"
+    icert.set_issuer(cacert.get_subject())
+    icert.set_pubkey(ikey)
+    icert.set_notBefore(b"20000101000000Z")
+    icert.set_notAfter(b"20200101000000Z")
+    icert.add_extensions([caext])
+    icert.set_serial_number(0)
+    icert.sign(cakey, "sha1")
+
+    # Step 3
+    skey = PKey()
+    skey.generate_key(TYPE_RSA, 1024)
+    scert = X509()
+    scert.get_subject().commonName = "Server Certificate"
+    scert.set_issuer(icert.get_subject())
+    scert.set_pubkey(skey)
+    scert.set_notBefore(b"20000101000000Z")
+    scert.set_notAfter(b"20200101000000Z")
+    scert.add_extensions([
+        X509Extension(b'basicConstraints', True, b'CA:false')])
+    scert.set_serial_number(0)
+    scert.sign(ikey, "sha1")
+
+    return [(cakey, cacert), (ikey, icert), (skey, scert)]
+
+
+def loopback_client_factory(socket, version=SSLv23_METHOD):
+    client = Connection(Context(version), socket)
+    client.set_connect_state()
+    return client
+
+
+def loopback_server_factory(socket, version=SSLv23_METHOD):
+    ctx = Context(version)
+    ctx.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+    ctx.use_certificate(load_certificate(FILETYPE_PEM, server_cert_pem))
+    server = Connection(ctx, socket)
+    server.set_accept_state()
+    return server
+
+
+def loopback(server_factory=None, client_factory=None):
+    """
+    Create a connected socket pair and force two connected SSL sockets
+    to talk to each other via memory BIOs.
+    """
+    if server_factory is None:
+        server_factory = loopback_server_factory
+    if client_factory is None:
+        client_factory = loopback_client_factory
+
+    (server, client) = socket_pair()
+    server = server_factory(server)
+    client = client_factory(client)
+
+    handshake(client, server)
+
+    server.setblocking(True)
+    client.setblocking(True)
+    return server, client
+
+
+def interact_in_memory(client_conn, server_conn):
+    """
+    Try to read application bytes from each of the two `Connection` objects.
+    Copy bytes back and forth between their send/receive buffers for as long
+    as there is anything to copy.  When there is nothing more to copy,
+    return `None`.  If one of them actually manages to deliver some application
+    bytes, return a two-tuple of the connection from which the bytes were read
+    and the bytes themselves.
+    """
+    wrote = True
+    while wrote:
+        # Loop until neither side has anything to say
+        wrote = False
+
+        # Copy stuff from each side's send buffer to the other side's
+        # receive buffer.
+        for (read, write) in [(client_conn, server_conn),
+                              (server_conn, client_conn)]:
+
+            # Give the side a chance to generate some more bytes, or succeed.
+            try:
+                data = read.recv(2 ** 16)
+            except WantReadError:
+                # It didn't succeed, so we'll hope it generated some output.
+                pass
+            else:
+                # It did succeed, so we'll stop now and let the caller deal
+                # with it.
+                return (read, data)
+
+            while True:
+                # Keep copying as long as there's more stuff there.
+                try:
+                    dirty = read.bio_read(4096)
+                except WantReadError:
+                    # Okay, nothing more waiting to be sent.  Stop
+                    # processing this send buffer.
+                    break
+                else:
+                    # Keep track of the fact that someone generated some
+                    # output.
+                    wrote = True
+                    write.bio_write(dirty)
+
+
+def handshake_in_memory(client_conn, server_conn):
+    """
+    Perform the TLS handshake between two `Connection` instances connected to
+    each other via memory BIOs.
+    """
+    client_conn.set_connect_state()
+    server_conn.set_accept_state()
+
+    for conn in [client_conn, server_conn]:
+        try:
+            conn.do_handshake()
+        except WantReadError:
+            pass
+
+    interact_in_memory(client_conn, server_conn)
+
+
+class TestVersion(object):
+    """
+    Tests for version information exposed by `OpenSSL.SSL.SSLeay_version` and
+    `OpenSSL.SSL.OPENSSL_VERSION_NUMBER`.
+    """
+    def test_OPENSSL_VERSION_NUMBER(self):
+        """
+        `OPENSSL_VERSION_NUMBER` is an integer with status in the low byte and
+        the patch, fix, minor, and major versions in the nibbles above that.
+        """
+        assert isinstance(OPENSSL_VERSION_NUMBER, int)
+
+    def test_SSLeay_version(self):
+        """
+        `SSLeay_version` takes a version type indicator and returns one of a
+        number of version strings based on that indicator.
+        """
+        versions = {}
+        for t in [SSLEAY_VERSION, SSLEAY_CFLAGS, SSLEAY_BUILT_ON,
+                  SSLEAY_PLATFORM, SSLEAY_DIR]:
+            version = SSLeay_version(t)
+            versions[version] = t
+            assert isinstance(version, bytes)
+        assert len(versions) == 5
+
+
+@pytest.fixture
+def ca_file(tmpdir):
+    """
+    Create a valid PEM file with CA certificates and return the path.
+    """
+    key = rsa.generate_private_key(
+        public_exponent=65537,
+        key_size=2048,
+        backend=default_backend()
+    )
+    public_key = key.public_key()
+
+    builder = x509.CertificateBuilder()
+    builder = builder.subject_name(x509.Name([
+        x509.NameAttribute(NameOID.COMMON_NAME, u"pyopenssl.org"),
+    ]))
+    builder = builder.issuer_name(x509.Name([
+        x509.NameAttribute(NameOID.COMMON_NAME, u"pyopenssl.org"),
+    ]))
+    one_day = datetime.timedelta(1, 0, 0)
+    builder = builder.not_valid_before(datetime.datetime.today() - one_day)
+    builder = builder.not_valid_after(datetime.datetime.today() + one_day)
+    builder = builder.serial_number(int(uuid.uuid4()))
+    builder = builder.public_key(public_key)
+    builder = builder.add_extension(
+        x509.BasicConstraints(ca=True, path_length=None), critical=True,
+    )
+
+    certificate = builder.sign(
+        private_key=key, algorithm=hashes.SHA256(),
+        backend=default_backend()
+    )
+
+    ca_file = tmpdir.join("test.pem")
+    ca_file.write_binary(
+        certificate.public_bytes(
+            encoding=serialization.Encoding.PEM,
+        )
+    )
+
+    return str(ca_file).encode("ascii")
+
+
+@pytest.fixture
+def context():
+    """
+    A simple TLS 1.0 context.
+    """
+    return Context(TLSv1_METHOD)
+
+
+class TestContext(object):
+    """
+    Unit tests for `OpenSSL.SSL.Context`.
+    """
+    @pytest.mark.parametrize("cipher_string", [
+        b"hello world:AES128-SHA",
+        u"hello world:AES128-SHA",
+    ])
+    def test_set_cipher_list(self, context, cipher_string):
+        """
+        `Context.set_cipher_list` accepts both byte and unicode strings
+        for naming the ciphers which connections created with the context
+        object will be able to choose from.
+        """
+        context.set_cipher_list(cipher_string)
+        conn = Connection(context, None)
+
+        assert "AES128-SHA" in conn.get_cipher_list()
+
+    @pytest.mark.parametrize("cipher_list,error", [
+        (object(), TypeError),
+        ("imaginary-cipher", Error),
+    ])
+    def test_set_cipher_list_wrong_args(self, context, cipher_list, error):
+        """
+        `Context.set_cipher_list` raises `TypeError` when passed a non-string
+        argument and raises `OpenSSL.SSL.Error` when passed an incorrect cipher
+        list string.
+        """
+        with pytest.raises(error):
+            context.set_cipher_list(cipher_list)
+
+    def test_load_client_ca(self, context, ca_file):
+        """
+        `Context.load_client_ca` works as far as we can tell.
+        """
+        context.load_client_ca(ca_file)
+
+    def test_load_client_ca_invalid(self, context, tmpdir):
+        """
+        `Context.load_client_ca` raises an Error if the ca file is invalid.
+        """
+        ca_file = tmpdir.join("test.pem")
+        ca_file.write("")
+
+        with pytest.raises(Error) as e:
+            context.load_client_ca(str(ca_file).encode("ascii"))
+
+        assert "PEM routines" == e.value.args[0][0][0]
+
+    def test_load_client_ca_unicode(self, context, ca_file):
+        """
+        Passing the path as unicode raises a warning but works.
+        """
+        pytest.deprecated_call(
+            context.load_client_ca, ca_file.decode("ascii")
+        )
+
+    def test_set_session_id(self, context):
+        """
+        `Context.set_session_id` works as far as we can tell.
+        """
+        context.set_session_id(b"abc")
+
+    def test_set_session_id_fail(self, context):
+        """
+        `Context.set_session_id` errors are propagated.
+        """
+        with pytest.raises(Error) as e:
+            context.set_session_id(b"abc" * 1000)
+
+        assert [
+            ("SSL routines",
+             "SSL_CTX_set_session_id_context",
+             "ssl session id context too long")
+        ] == e.value.args[0]
+
+    def test_set_session_id_unicode(self, context):
+        """
+        `Context.set_session_id` raises a warning if a unicode string is
+        passed.
+        """
+        pytest.deprecated_call(context.set_session_id, u"abc")
+
+    def test_method(self):
+        """
+        `Context` can be instantiated with one of `SSLv2_METHOD`,
+        `SSLv3_METHOD`, `SSLv23_METHOD`, `TLSv1_METHOD`, `TLSv1_1_METHOD`,
+        or `TLSv1_2_METHOD`.
+        """
+        methods = [SSLv23_METHOD, TLSv1_METHOD]
+        for meth in methods:
+            Context(meth)
+
+        maybe = [SSLv2_METHOD, SSLv3_METHOD, TLSv1_1_METHOD, TLSv1_2_METHOD]
+        for meth in maybe:
+            try:
+                Context(meth)
+            except (Error, ValueError):
+                # Some versions of OpenSSL have SSLv2 / TLSv1.1 / TLSv1.2, some
+                # don't.  Difficult to say in advance.
+                pass
+
+        with pytest.raises(TypeError):
+            Context("")
+        with pytest.raises(ValueError):
+            Context(10)
+
+    @skip_if_py3
+    def test_method_long(self):
+        """
+        On Python 2 `Context` accepts values of type `long` as well as `int`.
+        """
+        Context(long(TLSv1_METHOD))
+
+    def test_type(self):
+        """
+        `Context` and `ContextType` refer to the same type object and can
+        be used to create instances of that type.
+        """
+        assert Context is ContextType
+        assert is_consistent_type(Context, 'Context', TLSv1_METHOD)
+
+    def test_use_privatekey(self):
+        """
+        `Context.use_privatekey` takes an `OpenSSL.crypto.PKey` instance.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_privatekey(key)
+        with pytest.raises(TypeError):
+            ctx.use_privatekey("")
+
+    def test_use_privatekey_file_missing(self, tmpfile):
+        """
+        `Context.use_privatekey_file` raises `OpenSSL.SSL.Error` when passed
+        the name of a file which does not exist.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            ctx.use_privatekey_file(tmpfile)
+
+    def _use_privatekey_file_test(self, pemfile, filetype):
+        """
+        Verify that calling ``Context.use_privatekey_file`` with the given
+        arguments does not raise an exception.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+
+        with open(pemfile, "wt") as pem:
+            pem.write(
+                dump_privatekey(FILETYPE_PEM, key).decode("ascii")
+            )
+
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_privatekey_file(pemfile, filetype)
+
+    @pytest.mark.parametrize('filetype', [object(), "", None, 1.0])
+    def test_wrong_privatekey_file_wrong_args(self, tmpfile, filetype):
+        """
+        `Context.use_privatekey_file` raises `TypeError` when called with
+        a `filetype` which is not a valid file encoding.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            ctx.use_privatekey_file(tmpfile, filetype)
+
+    def test_use_privatekey_file_bytes(self, tmpfile):
+        """
+        A private key can be specified from a file by passing a ``bytes``
+        instance giving the file name to ``Context.use_privatekey_file``.
+        """
+        self._use_privatekey_file_test(
+            tmpfile + NON_ASCII.encode(getfilesystemencoding()),
+            FILETYPE_PEM,
+        )
+
+    def test_use_privatekey_file_unicode(self, tmpfile):
+        """
+        A private key can be specified from a file by passing a ``unicode``
+        instance giving the file name to ``Context.use_privatekey_file``.
+        """
+        self._use_privatekey_file_test(
+            tmpfile.decode(getfilesystemencoding()) + NON_ASCII,
+            FILETYPE_PEM,
+        )
+
+    @skip_if_py3
+    def test_use_privatekey_file_long(self, tmpfile):
+        """
+        On Python 2 `Context.use_privatekey_file` accepts a filetype of
+        type `long` as well as `int`.
+        """
+        self._use_privatekey_file_test(tmpfile, long(FILETYPE_PEM))
+
+    def test_use_certificate_wrong_args(self):
+        """
+        `Context.use_certificate_wrong_args` raises `TypeError` when not passed
+        exactly one `OpenSSL.crypto.X509` instance as an argument.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            ctx.use_certificate("hello, world")
+
+    def test_use_certificate_uninitialized(self):
+        """
+        `Context.use_certificate` raises `OpenSSL.SSL.Error` when passed a
+        `OpenSSL.crypto.X509` instance which has not been initialized
+        (ie, which does not actually have any certificate data).
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            ctx.use_certificate(X509())
+
+    def test_use_certificate(self):
+        """
+        `Context.use_certificate` sets the certificate which will be
+        used to identify connections created using the context.
+        """
+        # TODO
+        # Hard to assert anything.  But we could set a privatekey then ask
+        # OpenSSL if the cert and key agree using check_privatekey.  Then as
+        # long as check_privatekey works right we're good...
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_certificate(
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM)
+        )
+
+    def test_use_certificate_file_wrong_args(self):
+        """
+        `Context.use_certificate_file` raises `TypeError` if the first
+        argument is not a byte string or the second argument is not an integer.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            ctx.use_certificate_file(object(), FILETYPE_PEM)
+        with pytest.raises(TypeError):
+            ctx.use_certificate_file(b"somefile", object())
+        with pytest.raises(TypeError):
+            ctx.use_certificate_file(object(), FILETYPE_PEM)
+
+    def test_use_certificate_file_missing(self, tmpfile):
+        """
+        `Context.use_certificate_file` raises `OpenSSL.SSL.Error` if passed
+        the name of a file which does not exist.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            ctx.use_certificate_file(tmpfile)
+
+    def _use_certificate_file_test(self, certificate_file):
+        """
+        Verify that calling ``Context.use_certificate_file`` with the given
+        filename doesn't raise an exception.
+        """
+        # TODO
+        # Hard to assert anything.  But we could set a privatekey then ask
+        # OpenSSL if the cert and key agree using check_privatekey.  Then as
+        # long as check_privatekey works right we're good...
+        with open(certificate_file, "wb") as pem_file:
+            pem_file.write(cleartextCertificatePEM)
+
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_certificate_file(certificate_file)
+
+    def test_use_certificate_file_bytes(self, tmpfile):
+        """
+        `Context.use_certificate_file` sets the certificate (given as a
+        `bytes` filename) which will be used to identify connections created
+        using the context.
+        """
+        filename = tmpfile + NON_ASCII.encode(getfilesystemencoding())
+        self._use_certificate_file_test(filename)
+
+    def test_use_certificate_file_unicode(self, tmpfile):
+        """
+        `Context.use_certificate_file` sets the certificate (given as a
+        `bytes` filename) which will be used to identify connections created
+        using the context.
+        """
+        filename = tmpfile.decode(getfilesystemencoding()) + NON_ASCII
+        self._use_certificate_file_test(filename)
+
+    @skip_if_py3
+    def test_use_certificate_file_long(self, tmpfile):
+        """
+        On Python 2 `Context.use_certificate_file` accepts a
+        filetype of type `long` as well as `int`.
+        """
+        pem_filename = tmpfile
+        with open(pem_filename, "wb") as pem_file:
+            pem_file.write(cleartextCertificatePEM)
+
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_certificate_file(pem_filename, long(FILETYPE_PEM))
+
+    def test_check_privatekey_valid(self):
+        """
+        `Context.check_privatekey` returns `None` if the `Context` instance
+        has been configured to use a matched key and certificate pair.
+        """
+        key = load_privatekey(FILETYPE_PEM, client_key_pem)
+        cert = load_certificate(FILETYPE_PEM, client_cert_pem)
+        context = Context(TLSv1_METHOD)
+        context.use_privatekey(key)
+        context.use_certificate(cert)
+        assert None is context.check_privatekey()
+
+    def test_check_privatekey_invalid(self):
+        """
+        `Context.check_privatekey` raises `Error` if the `Context` instance
+        has been configured to use a key and certificate pair which don't
+        relate to each other.
+        """
+        key = load_privatekey(FILETYPE_PEM, client_key_pem)
+        cert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        context = Context(TLSv1_METHOD)
+        context.use_privatekey(key)
+        context.use_certificate(cert)
+        with pytest.raises(Error):
+            context.check_privatekey()
+
+    def test_app_data(self):
+        """
+        `Context.set_app_data` stores an object for later retrieval
+        using `Context.get_app_data`.
+        """
+        app_data = object()
+        context = Context(TLSv1_METHOD)
+        context.set_app_data(app_data)
+        assert context.get_app_data() is app_data
+
+    def test_set_options_wrong_args(self):
+        """
+        `Context.set_options` raises `TypeError` if called with
+        a non-`int` argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_options(None)
+
+    def test_set_options(self):
+        """
+        `Context.set_options` returns the new options value.
+        """
+        context = Context(TLSv1_METHOD)
+        options = context.set_options(OP_NO_SSLv2)
+        assert options & OP_NO_SSLv2 == OP_NO_SSLv2
+
+    @skip_if_py3
+    def test_set_options_long(self):
+        """
+        On Python 2 `Context.set_options` accepts values of type
+        `long` as well as `int`.
+        """
+        context = Context(TLSv1_METHOD)
+        options = context.set_options(long(OP_NO_SSLv2))
+        assert options & OP_NO_SSLv2 == OP_NO_SSLv2
+
+    def test_set_mode_wrong_args(self):
+        """
+        `Context.set_mode` raises `TypeError` if called with
+        a non-`int` argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_mode(None)
+
+    def test_set_mode(self):
+        """
+        `Context.set_mode` accepts a mode bitvector and returns the
+        newly set mode.
+        """
+        context = Context(TLSv1_METHOD)
+        assert MODE_RELEASE_BUFFERS & context.set_mode(MODE_RELEASE_BUFFERS)
+
+    @skip_if_py3
+    def test_set_mode_long(self):
+        """
+        On Python 2 `Context.set_mode` accepts values of type `long` as well
+        as `int`.
+        """
+        context = Context(TLSv1_METHOD)
+        mode = context.set_mode(long(MODE_RELEASE_BUFFERS))
+        assert MODE_RELEASE_BUFFERS & mode
+
+    def test_set_timeout_wrong_args(self):
+        """
+        `Context.set_timeout` raises `TypeError` if called with
+        a non-`int` argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_timeout(None)
+
+    def test_timeout(self):
+        """
+        `Context.set_timeout` sets the session timeout for all connections
+        created using the context object. `Context.get_timeout` retrieves
+        this value.
+        """
+        context = Context(TLSv1_METHOD)
+        context.set_timeout(1234)
+        assert context.get_timeout() == 1234
+
+    @skip_if_py3
+    def test_timeout_long(self):
+        """
+        On Python 2 `Context.set_timeout` accepts values of type `long` as
+        well as int.
+        """
+        context = Context(TLSv1_METHOD)
+        context.set_timeout(long(1234))
+        assert context.get_timeout() == 1234
+
+    def test_set_verify_depth_wrong_args(self):
+        """
+        `Context.set_verify_depth` raises `TypeError` if called with a
+        non-`int` argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_verify_depth(None)
+
+    def test_verify_depth(self):
+        """
+        `Context.set_verify_depth` sets the number of certificates in
+        a chain to follow before giving up.  The value can be retrieved with
+        `Context.get_verify_depth`.
+        """
+        context = Context(TLSv1_METHOD)
+        context.set_verify_depth(11)
+        assert context.get_verify_depth() == 11
+
+    @skip_if_py3
+    def test_verify_depth_long(self):
+        """
+        On Python 2 `Context.set_verify_depth` accepts values of type `long`
+        as well as int.
+        """
+        context = Context(TLSv1_METHOD)
+        context.set_verify_depth(long(11))
+        assert context.get_verify_depth() == 11
+
+    def _write_encrypted_pem(self, passphrase, tmpfile):
+        """
+        Write a new private key out to a new file, encrypted using the given
+        passphrase.  Return the path to the new file.
+        """
+        key = PKey()
+        key.generate_key(TYPE_RSA, 512)
+        pem = dump_privatekey(FILETYPE_PEM, key, "blowfish", passphrase)
+        with open(tmpfile, 'w') as fObj:
+            fObj.write(pem.decode('ascii'))
+        return tmpfile
+
+    def test_set_passwd_cb_wrong_args(self):
+        """
+        `Context.set_passwd_cb` raises `TypeError` if called with a
+        non-callable first argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_passwd_cb(None)
+
+    def test_set_passwd_cb(self, tmpfile):
+        """
+        `Context.set_passwd_cb` accepts a callable which will be invoked when
+        a private key is loaded from an encrypted PEM.
+        """
+        passphrase = b"foobar"
+        pemFile = self._write_encrypted_pem(passphrase, tmpfile)
+        calledWith = []
+
+        def passphraseCallback(maxlen, verify, extra):
+            calledWith.append((maxlen, verify, extra))
+            return passphrase
+        context = Context(TLSv1_METHOD)
+        context.set_passwd_cb(passphraseCallback)
+        context.use_privatekey_file(pemFile)
+        assert len(calledWith) == 1
+        assert isinstance(calledWith[0][0], int)
+        assert isinstance(calledWith[0][1], int)
+        assert calledWith[0][2] is None
+
+    def test_passwd_callback_exception(self, tmpfile):
+        """
+        `Context.use_privatekey_file` propagates any exception raised
+        by the passphrase callback.
+        """
+        pemFile = self._write_encrypted_pem(b"monkeys are nice", tmpfile)
+
+        def passphraseCallback(maxlen, verify, extra):
+            raise RuntimeError("Sorry, I am a fail.")
+
+        context = Context(TLSv1_METHOD)
+        context.set_passwd_cb(passphraseCallback)
+        with pytest.raises(RuntimeError):
+            context.use_privatekey_file(pemFile)
+
+    def test_passwd_callback_false(self, tmpfile):
+        """
+        `Context.use_privatekey_file` raises `OpenSSL.SSL.Error` if the
+        passphrase callback returns a false value.
+        """
+        pemFile = self._write_encrypted_pem(b"monkeys are nice", tmpfile)
+
+        def passphraseCallback(maxlen, verify, extra):
+            return b""
+
+        context = Context(TLSv1_METHOD)
+        context.set_passwd_cb(passphraseCallback)
+        with pytest.raises(Error):
+            context.use_privatekey_file(pemFile)
+
+    def test_passwd_callback_non_string(self, tmpfile):
+        """
+        `Context.use_privatekey_file` raises `OpenSSL.SSL.Error` if the
+        passphrase callback returns a true non-string value.
+        """
+        pemFile = self._write_encrypted_pem(b"monkeys are nice", tmpfile)
+
+        def passphraseCallback(maxlen, verify, extra):
+            return 10
+
+        context = Context(TLSv1_METHOD)
+        context.set_passwd_cb(passphraseCallback)
+        # TODO: Surely this is the wrong error?
+        with pytest.raises(ValueError):
+            context.use_privatekey_file(pemFile)
+
+    def test_passwd_callback_too_long(self, tmpfile):
+        """
+        If the passphrase returned by the passphrase callback returns a string
+        longer than the indicated maximum length, it is truncated.
+        """
+        # A priori knowledge!
+        passphrase = b"x" * 1024
+        pemFile = self._write_encrypted_pem(passphrase, tmpfile)
+
+        def passphraseCallback(maxlen, verify, extra):
+            assert maxlen == 1024
+            return passphrase + b"y"
+
+        context = Context(TLSv1_METHOD)
+        context.set_passwd_cb(passphraseCallback)
+        # This shall succeed because the truncated result is the correct
+        # passphrase.
+        context.use_privatekey_file(pemFile)
+
+    def test_set_info_callback(self):
+        """
+        `Context.set_info_callback` accepts a callable which will be
+        invoked when certain information about an SSL connection is available.
+        """
+        (server, client) = socket_pair()
+
+        clientSSL = Connection(Context(TLSv1_METHOD), client)
+        clientSSL.set_connect_state()
+
+        called = []
+
+        def info(conn, where, ret):
+            called.append((conn, where, ret))
+        context = Context(TLSv1_METHOD)
+        context.set_info_callback(info)
+        context.use_certificate(
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+        context.use_privatekey(
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+
+        serverSSL = Connection(context, server)
+        serverSSL.set_accept_state()
+
+        handshake(clientSSL, serverSSL)
+
+        # The callback must always be called with a Connection instance as the
+        # first argument.  It would probably be better to split this into
+        # separate tests for client and server side info callbacks so we could
+        # assert it is called with the right Connection instance.  It would
+        # also be good to assert *something* about `where` and `ret`.
+        notConnections = [
+            conn for (conn, where, ret) in called
+            if not isinstance(conn, Connection)]
+        assert [] == notConnections, (
+            "Some info callback arguments were not Connection instances.")
+
+    def _load_verify_locations_test(self, *args):
+        """
+        Create a client context which will verify the peer certificate and call
+        its `load_verify_locations` method with the given arguments.
+        Then connect it to a server and ensure that the handshake succeeds.
+        """
+        (server, client) = socket_pair()
+
+        clientContext = Context(TLSv1_METHOD)
+        clientContext.load_verify_locations(*args)
+        # Require that the server certificate verify properly or the
+        # connection will fail.
+        clientContext.set_verify(
+            VERIFY_PEER,
+            lambda conn, cert, errno, depth, preverify_ok: preverify_ok)
+
+        clientSSL = Connection(clientContext, client)
+        clientSSL.set_connect_state()
+
+        serverContext = Context(TLSv1_METHOD)
+        serverContext.use_certificate(
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+        serverContext.use_privatekey(
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+
+        serverSSL = Connection(serverContext, server)
+        serverSSL.set_accept_state()
+
+        # Without load_verify_locations above, the handshake
+        # will fail:
+        # Error: [('SSL routines', 'SSL3_GET_SERVER_CERTIFICATE',
+        #          'certificate verify failed')]
+        handshake(clientSSL, serverSSL)
+
+        cert = clientSSL.get_peer_certificate()
+        assert cert.get_subject().CN == 'Testing Root CA'
+
+    def _load_verify_cafile(self, cafile):
+        """
+        Verify that if path to a file containing a certificate is passed to
+        `Context.load_verify_locations` for the ``cafile`` parameter, that
+        certificate is used as a trust root for the purposes of verifying
+        connections created using that `Context`.
+        """
+        with open(cafile, 'w') as fObj:
+            fObj.write(cleartextCertificatePEM.decode('ascii'))
+
+        self._load_verify_locations_test(cafile)
+
+    def test_load_verify_bytes_cafile(self, tmpfile):
+        """
+        `Context.load_verify_locations` accepts a file name as a `bytes`
+        instance and uses the certificates within for verification purposes.
+        """
+        cafile = tmpfile + NON_ASCII.encode(getfilesystemencoding())
+        self._load_verify_cafile(cafile)
+
+    def test_load_verify_unicode_cafile(self, tmpfile):
+        """
+        `Context.load_verify_locations` accepts a file name as a `unicode`
+        instance and uses the certificates within for verification purposes.
+        """
+        self._load_verify_cafile(
+            tmpfile.decode(getfilesystemencoding()) + NON_ASCII
+        )
+
+    def test_load_verify_invalid_file(self, tmpfile):
+        """
+        `Context.load_verify_locations` raises `Error` when passed a
+        non-existent cafile.
+        """
+        clientContext = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            clientContext.load_verify_locations(tmpfile)
+
+    def _load_verify_directory_locations_capath(self, capath):
+        """
+        Verify that if path to a directory containing certificate files is
+        passed to ``Context.load_verify_locations`` for the ``capath``
+        parameter, those certificates are used as trust roots for the purposes
+        of verifying connections created using that ``Context``.
+        """
+        makedirs(capath)
+        # Hash values computed manually with c_rehash to avoid depending on
+        # c_rehash in the test suite.  One is from OpenSSL 0.9.8, the other
+        # from OpenSSL 1.0.0.
+        for name in [b'c7adac82.0', b'c3705638.0']:
+            cafile = join_bytes_or_unicode(capath, name)
+            with open(cafile, 'w') as fObj:
+                fObj.write(cleartextCertificatePEM.decode('ascii'))
+
+        self._load_verify_locations_test(None, capath)
+
+    def test_load_verify_directory_bytes_capath(self, tmpfile):
+        """
+        `Context.load_verify_locations` accepts a directory name as a `bytes`
+        instance and uses the certificates within for verification purposes.
+        """
+        self._load_verify_directory_locations_capath(
+            tmpfile + NON_ASCII.encode(getfilesystemencoding())
+        )
+
+    def test_load_verify_directory_unicode_capath(self, tmpfile):
+        """
+        `Context.load_verify_locations` accepts a directory name as a `unicode`
+        instance and uses the certificates within for verification purposes.
+        """
+        self._load_verify_directory_locations_capath(
+            tmpfile.decode(getfilesystemencoding()) + NON_ASCII
+        )
+
+    def test_load_verify_locations_wrong_args(self):
+        """
+        `Context.load_verify_locations` raises `TypeError` if with non-`str`
+        arguments.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.load_verify_locations(object())
+        with pytest.raises(TypeError):
+            context.load_verify_locations(object(), object())
+
+    @pytest.mark.skipif(
+        not platform.startswith("linux"),
+        reason="Loading fallback paths is a linux-specific behavior to "
+        "accommodate pyca/cryptography manylinux1 wheels"
+    )
+    def test_fallback_default_verify_paths(self, monkeypatch):
+        """
+        Test that we load certificates successfully on linux from the fallback
+        path. To do this we set the _CRYPTOGRAPHY_MANYLINUX1_CA_FILE and
+        _CRYPTOGRAPHY_MANYLINUX1_CA_DIR vars to be equal to whatever the
+        current OpenSSL default is and we disable
+        SSL_CTX_SET_default_verify_paths so that it can't find certs unless
+        it loads via fallback.
+        """
+        context = Context(TLSv1_METHOD)
+        monkeypatch.setattr(
+            _lib, "SSL_CTX_set_default_verify_paths", lambda x: 1
+        )
+        monkeypatch.setattr(
+            SSL,
+            "_CRYPTOGRAPHY_MANYLINUX1_CA_FILE",
+            _ffi.string(_lib.X509_get_default_cert_file())
+        )
+        monkeypatch.setattr(
+            SSL,
+            "_CRYPTOGRAPHY_MANYLINUX1_CA_DIR",
+            _ffi.string(_lib.X509_get_default_cert_dir())
+        )
+        context.set_default_verify_paths()
+        store = context.get_cert_store()
+        sk_obj = _lib.X509_STORE_get0_objects(store._store)
+        assert sk_obj != _ffi.NULL
+        num = _lib.sk_X509_OBJECT_num(sk_obj)
+        assert num != 0
+
+    def test_check_env_vars(self, monkeypatch):
+        """
+        Test that we return True/False appropriately if the env vars are set.
+        """
+        context = Context(TLSv1_METHOD)
+        dir_var = "CUSTOM_DIR_VAR"
+        file_var = "CUSTOM_FILE_VAR"
+        assert context._check_env_vars_set(dir_var, file_var) is False
+        monkeypatch.setenv(dir_var, "value")
+        monkeypatch.setenv(file_var, "value")
+        assert context._check_env_vars_set(dir_var, file_var) is True
+        assert context._check_env_vars_set(dir_var, file_var) is True
+
+    def test_verify_no_fallback_if_env_vars_set(self, monkeypatch):
+        """
+        Test that we don't use the fallback path if env vars are set.
+        """
+        context = Context(TLSv1_METHOD)
+        monkeypatch.setattr(
+            _lib, "SSL_CTX_set_default_verify_paths", lambda x: 1
+        )
+        dir_env_var = _ffi.string(
+            _lib.X509_get_default_cert_dir_env()
+        ).decode("ascii")
+        file_env_var = _ffi.string(
+            _lib.X509_get_default_cert_file_env()
+        ).decode("ascii")
+        monkeypatch.setenv(dir_env_var, "value")
+        monkeypatch.setenv(file_env_var, "value")
+        context.set_default_verify_paths()
+
+        monkeypatch.setattr(
+            context,
+            "_fallback_default_verify_paths",
+            raiser(SystemError)
+        )
+        context.set_default_verify_paths()
+
+    @pytest.mark.skipif(
+        platform == "win32",
+        reason="set_default_verify_paths appears not to work on Windows.  "
+        "See LP#404343 and LP#404344."
+    )
+    def test_set_default_verify_paths(self):
+        """
+        `Context.set_default_verify_paths` causes the platform-specific CA
+        certificate locations to be used for verification purposes.
+        """
+        # Testing this requires a server with a certificate signed by one
+        # of the CAs in the platform CA location.  Getting one of those
+        # costs money.  Fortunately (or unfortunately, depending on your
+        # perspective), it's easy to think of a public server on the
+        # internet which has such a certificate.  Connecting to the network
+        # in a unit test is bad, but it's the only way I can think of to
+        # really test this. -exarkun
+        context = Context(SSLv23_METHOD)
+        context.set_default_verify_paths()
+        context.set_verify(
+            VERIFY_PEER,
+            lambda conn, cert, errno, depth, preverify_ok: preverify_ok)
+
+        client = socket()
+        client.connect(("encrypted.google.com", 443))
+        clientSSL = Connection(context, client)
+        clientSSL.set_connect_state()
+        clientSSL.set_tlsext_host_name(b"encrypted.google.com")
+        clientSSL.do_handshake()
+        clientSSL.send(b"GET / HTTP/1.0\r\n\r\n")
+        assert clientSSL.recv(1024)
+
+    def test_fallback_path_is_not_file_or_dir(self):
+        """
+        Test that when passed empty arrays or paths that do not exist no
+        errors are raised.
+        """
+        context = Context(TLSv1_METHOD)
+        context._fallback_default_verify_paths([], [])
+        context._fallback_default_verify_paths(
+            ["/not/a/file"], ["/not/a/dir"]
+        )
+
+    def test_add_extra_chain_cert_invalid_cert(self):
+        """
+        `Context.add_extra_chain_cert` raises `TypeError` if called with an
+        object which is not an instance of `X509`.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.add_extra_chain_cert(object())
+
+    def _handshake_test(self, serverContext, clientContext):
+        """
+        Verify that a client and server created with the given contexts can
+        successfully handshake and communicate.
+        """
+        serverSocket, clientSocket = socket_pair()
+
+        server = Connection(serverContext, serverSocket)
+        server.set_accept_state()
+
+        client = Connection(clientContext, clientSocket)
+        client.set_connect_state()
+
+        # Make them talk to each other.
+        # interact_in_memory(client, server)
+        for _ in range(3):
+            for s in [client, server]:
+                try:
+                    s.do_handshake()
+                except WantReadError:
+                    pass
+
+    def test_set_verify_callback_connection_argument(self):
+        """
+        The first argument passed to the verify callback is the
+        `Connection` instance for which verification is taking place.
+        """
+        serverContext = Context(TLSv1_METHOD)
+        serverContext.use_privatekey(
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+        serverContext.use_certificate(
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+        serverConnection = Connection(serverContext, None)
+
+        class VerifyCallback(object):
+            def callback(self, connection, *args):
+                self.connection = connection
+                return 1
+
+        verify = VerifyCallback()
+        clientContext = Context(TLSv1_METHOD)
+        clientContext.set_verify(VERIFY_PEER, verify.callback)
+        clientConnection = Connection(clientContext, None)
+        clientConnection.set_connect_state()
+
+        handshake_in_memory(clientConnection, serverConnection)
+
+        assert verify.connection is clientConnection
+
+    def test_x509_in_verify_works(self):
+        """
+        We had a bug where the X509 cert instantiated in the callback wrapper
+        didn't __init__ so it was missing objects needed when calling
+        get_subject. This test sets up a handshake where we call get_subject
+        on the cert provided to the verify callback.
+        """
+        serverContext = Context(TLSv1_METHOD)
+        serverContext.use_privatekey(
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+        serverContext.use_certificate(
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+        serverConnection = Connection(serverContext, None)
+
+        def verify_cb_get_subject(conn, cert, errnum, depth, ok):
+            assert cert.get_subject()
+            return 1
+
+        clientContext = Context(TLSv1_METHOD)
+        clientContext.set_verify(VERIFY_PEER, verify_cb_get_subject)
+        clientConnection = Connection(clientContext, None)
+        clientConnection.set_connect_state()
+
+        handshake_in_memory(clientConnection, serverConnection)
+
+    def test_set_verify_callback_exception(self):
+        """
+        If the verify callback passed to `Context.set_verify` raises an
+        exception, verification fails and the exception is propagated to the
+        caller of `Connection.do_handshake`.
+        """
+        serverContext = Context(TLSv1_2_METHOD)
+        serverContext.use_privatekey(
+            load_privatekey(FILETYPE_PEM, cleartextPrivateKeyPEM))
+        serverContext.use_certificate(
+            load_certificate(FILETYPE_PEM, cleartextCertificatePEM))
+
+        clientContext = Context(TLSv1_2_METHOD)
+
+        def verify_callback(*args):
+            raise Exception("silly verify failure")
+        clientContext.set_verify(VERIFY_PEER, verify_callback)
+
+        with pytest.raises(Exception) as exc:
+            self._handshake_test(serverContext, clientContext)
+
+        assert "silly verify failure" == str(exc.value)
+
+    def test_add_extra_chain_cert(self, tmpdir):
+        """
+        `Context.add_extra_chain_cert` accepts an `X509`
+        instance to add to the certificate chain.
+
+        See `_create_certificate_chain` for the details of the
+        certificate chain tested.
+
+        The chain is tested by starting a server with scert and connecting
+        to it with a client which trusts cacert and requires verification to
+        succeed.
+        """
+        chain = _create_certificate_chain()
+        [(cakey, cacert), (ikey, icert), (skey, scert)] = chain
+
+        # Dump the CA certificate to a file because that's the only way to load
+        # it as a trusted CA in the client context.
+        for cert, name in [(cacert, 'ca.pem'),
+                           (icert, 'i.pem'),
+                           (scert, 's.pem')]:
+            with tmpdir.join(name).open('w') as f:
+                f.write(dump_certificate(FILETYPE_PEM, cert).decode('ascii'))
+
+        for key, name in [(cakey, 'ca.key'),
+                          (ikey, 'i.key'),
+                          (skey, 's.key')]:
+            with tmpdir.join(name).open('w') as f:
+                f.write(dump_privatekey(FILETYPE_PEM, key).decode('ascii'))
+
+        # Create the server context
+        serverContext = Context(TLSv1_METHOD)
+        serverContext.use_privatekey(skey)
+        serverContext.use_certificate(scert)
+        # The client already has cacert, we only need to give them icert.
+        serverContext.add_extra_chain_cert(icert)
+
+        # Create the client
+        clientContext = Context(TLSv1_METHOD)
+        clientContext.set_verify(
+            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb)
+        clientContext.load_verify_locations(str(tmpdir.join("ca.pem")))
+
+        # Try it out.
+        self._handshake_test(serverContext, clientContext)
+
+    def _use_certificate_chain_file_test(self, certdir):
+        """
+        Verify that `Context.use_certificate_chain_file` reads a
+        certificate chain from a specified file.
+
+        The chain is tested by starting a server with scert and connecting to
+        it with a client which trusts cacert and requires verification to
+        succeed.
+        """
+        chain = _create_certificate_chain()
+        [(cakey, cacert), (ikey, icert), (skey, scert)] = chain
+
+        makedirs(certdir)
+
+        chainFile = join_bytes_or_unicode(certdir, "chain.pem")
+        caFile = join_bytes_or_unicode(certdir, "ca.pem")
+
+        # Write out the chain file.
+        with open(chainFile, 'wb') as fObj:
+            # Most specific to least general.
+            fObj.write(dump_certificate(FILETYPE_PEM, scert))
+            fObj.write(dump_certificate(FILETYPE_PEM, icert))
+            fObj.write(dump_certificate(FILETYPE_PEM, cacert))
+
+        with open(caFile, 'w') as fObj:
+            fObj.write(dump_certificate(FILETYPE_PEM, cacert).decode('ascii'))
+
+        serverContext = Context(TLSv1_METHOD)
+        serverContext.use_certificate_chain_file(chainFile)
+        serverContext.use_privatekey(skey)
+
+        clientContext = Context(TLSv1_METHOD)
+        clientContext.set_verify(
+            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT, verify_cb)
+        clientContext.load_verify_locations(caFile)
+
+        self._handshake_test(serverContext, clientContext)
+
+    def test_use_certificate_chain_file_bytes(self, tmpfile):
+        """
+        ``Context.use_certificate_chain_file`` accepts the name of a file (as
+        an instance of ``bytes``) to specify additional certificates to use to
+        construct and verify a trust chain.
+        """
+        self._use_certificate_chain_file_test(
+            tmpfile + NON_ASCII.encode(getfilesystemencoding())
+        )
+
+    def test_use_certificate_chain_file_unicode(self, tmpfile):
+        """
+        ``Context.use_certificate_chain_file`` accepts the name of a file (as
+        an instance of ``unicode``) to specify additional certificates to use
+        to construct and verify a trust chain.
+        """
+        self._use_certificate_chain_file_test(
+            tmpfile.decode(getfilesystemencoding()) + NON_ASCII
+        )
+
+    def test_use_certificate_chain_file_wrong_args(self):
+        """
+        `Context.use_certificate_chain_file` raises `TypeError` if passed a
+        non-byte string single argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.use_certificate_chain_file(object())
+
+    def test_use_certificate_chain_file_missing_file(self, tmpfile):
+        """
+        `Context.use_certificate_chain_file` raises `OpenSSL.SSL.Error` when
+        passed a bad chain file name (for example, the name of a file which
+        does not exist).
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            context.use_certificate_chain_file(tmpfile)
+
+    def test_set_verify_mode(self):
+        """
+        `Context.get_verify_mode` returns the verify mode flags previously
+        passed to `Context.set_verify`.
+        """
+        context = Context(TLSv1_METHOD)
+        assert context.get_verify_mode() == 0
+        context.set_verify(
+            VERIFY_PEER | VERIFY_CLIENT_ONCE, lambda *args: None)
+        assert context.get_verify_mode() == (VERIFY_PEER | VERIFY_CLIENT_ONCE)
+
+    @skip_if_py3
+    def test_set_verify_mode_long(self):
+        """
+        On Python 2 `Context.set_verify_mode` accepts values of type `long`
+        as well as `int`.
+        """
+        context = Context(TLSv1_METHOD)
+        assert context.get_verify_mode() == 0
+        context.set_verify(
+            long(VERIFY_PEER | VERIFY_CLIENT_ONCE), lambda *args: None
+        )  # pragma: nocover
+        assert context.get_verify_mode() == (VERIFY_PEER | VERIFY_CLIENT_ONCE)
+
+    @pytest.mark.parametrize('mode', [None, 1.0, object(), 'mode'])
+    def test_set_verify_wrong_mode_arg(self, mode):
+        """
+        `Context.set_verify` raises `TypeError` if the first argument is
+        not an integer.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_verify(mode=mode, callback=lambda *args: None)
+
+    @pytest.mark.parametrize('callback', [None, 1.0, 'mode', ('foo', 'bar')])
+    def test_set_verify_wrong_callable_arg(self, callback):
+        """
+        `Context.set_verify` raises `TypeError` if the second argument
+        is not callable.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_verify(mode=VERIFY_PEER, callback=callback)
+
+    def test_load_tmp_dh_wrong_args(self):
+        """
+        `Context.load_tmp_dh` raises `TypeError` if called with a
+        non-`str` argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.load_tmp_dh(object())
+
+    def test_load_tmp_dh_missing_file(self):
+        """
+        `Context.load_tmp_dh` raises `OpenSSL.SSL.Error` if the
+        specified file does not exist.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            context.load_tmp_dh(b"hello")
+
+    def _load_tmp_dh_test(self, dhfilename):
+        """
+        Verify that calling ``Context.load_tmp_dh`` with the given filename
+        does not raise an exception.
+        """
+        context = Context(TLSv1_METHOD)
+        with open(dhfilename, "w") as dhfile:
+            dhfile.write(dhparam)
+
+        context.load_tmp_dh(dhfilename)
+        # XXX What should I assert here? -exarkun
+
+    def test_load_tmp_dh_bytes(self, tmpfile):
+        """
+        `Context.load_tmp_dh` loads Diffie-Hellman parameters from the
+        specified file (given as ``bytes``).
+        """
+        self._load_tmp_dh_test(
+            tmpfile + NON_ASCII.encode(getfilesystemencoding()),
+        )
+
+    def test_load_tmp_dh_unicode(self, tmpfile):
+        """
+        `Context.load_tmp_dh` loads Diffie-Hellman parameters from the
+        specified file (given as ``unicode``).
+        """
+        self._load_tmp_dh_test(
+            tmpfile.decode(getfilesystemencoding()) + NON_ASCII,
+        )
+
+    def test_set_tmp_ecdh(self):
+        """
+        `Context.set_tmp_ecdh` sets the elliptic curve for Diffie-Hellman to
+        the specified curve.
+        """
+        context = Context(TLSv1_METHOD)
+        for curve in get_elliptic_curves():
+            if curve.name.startswith(u"Oakley-"):
+                # Setting Oakley-EC2N-4 and Oakley-EC2N-3 adds
+                # ('bignum routines', 'BN_mod_inverse', 'no inverse') to the
+                # error queue on OpenSSL 1.0.2.
+                continue
+            # The only easily "assertable" thing is that it does not raise an
+            # exception.
+            context.set_tmp_ecdh(curve)
+
+    def test_set_session_cache_mode_wrong_args(self):
+        """
+        `Context.set_session_cache_mode` raises `TypeError` if called with
+        a non-integer argument.
+        called with other than one integer argument.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_session_cache_mode(object())
+
+    def test_session_cache_mode(self):
+        """
+        `Context.set_session_cache_mode` specifies how sessions are cached.
+        The setting can be retrieved via `Context.get_session_cache_mode`.
+        """
+        context = Context(TLSv1_METHOD)
+        context.set_session_cache_mode(SESS_CACHE_OFF)
+        off = context.set_session_cache_mode(SESS_CACHE_BOTH)
+        assert SESS_CACHE_OFF == off
+        assert SESS_CACHE_BOTH == context.get_session_cache_mode()
+
+    @skip_if_py3
+    def test_session_cache_mode_long(self):
+        """
+        On Python 2 `Context.set_session_cache_mode` accepts values
+        of type `long` as well as `int`.
+        """
+        context = Context(TLSv1_METHOD)
+        context.set_session_cache_mode(long(SESS_CACHE_BOTH))
+        assert SESS_CACHE_BOTH == context.get_session_cache_mode()
+
+    def test_get_cert_store(self):
+        """
+        `Context.get_cert_store` returns a `X509Store` instance.
+        """
+        context = Context(TLSv1_METHOD)
+        store = context.get_cert_store()
+        assert isinstance(store, X509Store)
+
+    def test_set_tlsext_use_srtp_not_bytes(self):
+        """
+        `Context.set_tlsext_use_srtp' enables negotiating SRTP keying material.
+
+        It raises a TypeError if the list of profiles is not a byte string.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            context.set_tlsext_use_srtp(text_type('SRTP_AES128_CM_SHA1_80'))
+
+    def test_set_tlsext_use_srtp_invalid_profile(self):
+        """
+        `Context.set_tlsext_use_srtp' enables negotiating SRTP keying material.
+
+        It raises an Error if the call to OpenSSL fails.
+        """
+        context = Context(TLSv1_METHOD)
+        with pytest.raises(Error):
+            context.set_tlsext_use_srtp(b'SRTP_BOGUS')
+
+    def test_set_tlsext_use_srtp_valid(self):
+        """
+        `Context.set_tlsext_use_srtp' enables negotiating SRTP keying material.
+
+        It does not return anything.
+        """
+        context = Context(TLSv1_METHOD)
+        assert context.set_tlsext_use_srtp(b'SRTP_AES128_CM_SHA1_80') is None
+
+
+class TestServerNameCallback(object):
+    """
+    Tests for `Context.set_tlsext_servername_callback` and its
+    interaction with `Connection`.
+    """
+    def test_old_callback_forgotten(self):
+        """
+        If `Context.set_tlsext_servername_callback` is used to specify
+        a new callback, the one it replaces is dereferenced.
+        """
+        def callback(connection):  # pragma: no cover
+            pass
+
+        def replacement(connection):  # pragma: no cover
+            pass
+
+        context = Context(TLSv1_METHOD)
+        context.set_tlsext_servername_callback(callback)
+
+        tracker = ref(callback)
+        del callback
+
+        context.set_tlsext_servername_callback(replacement)
+
+        # One run of the garbage collector happens to work on CPython.  PyPy
+        # doesn't collect the underlying object until a second run for whatever
+        # reason.  That's fine, it still demonstrates our code has properly
+        # dropped the reference.
+        collect()
+        collect()
+
+        callback = tracker()
+        if callback is not None:
+            referrers = get_referrers(callback)
+            if len(referrers) > 1:  # pragma: nocover
+                pytest.fail("Some references remain: %r" % (referrers,))
+
+    def test_no_servername(self):
+        """
+        When a client specifies no server name, the callback passed to
+        `Context.set_tlsext_servername_callback` is invoked and the
+        result of `Connection.get_servername` is `None`.
+        """
+        args = []
+
+        def servername(conn):
+            args.append((conn, conn.get_servername()))
+        context = Context(TLSv1_METHOD)
+        context.set_tlsext_servername_callback(servername)
+
+        # Lose our reference to it.  The Context is responsible for keeping it
+        # alive now.
+        del servername
+        collect()
+
+        # Necessary to actually accept the connection
+        context.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+        context.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+
+        # Do a little connection to trigger the logic
+        server = Connection(context, None)
+        server.set_accept_state()
+
+        client = Connection(Context(TLSv1_METHOD), None)
+        client.set_connect_state()
+
+        interact_in_memory(server, client)
+
+        assert args == [(server, None)]
+
+    def test_servername(self):
+        """
+        When a client specifies a server name in its hello message, the
+        callback passed to `Contexts.set_tlsext_servername_callback` is
+        invoked and the result of `Connection.get_servername` is that
+        server name.
+        """
+        args = []
+
+        def servername(conn):
+            args.append((conn, conn.get_servername()))
+        context = Context(TLSv1_METHOD)
+        context.set_tlsext_servername_callback(servername)
+
+        # Necessary to actually accept the connection
+        context.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+        context.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+
+        # Do a little connection to trigger the logic
+        server = Connection(context, None)
+        server.set_accept_state()
+
+        client = Connection(Context(TLSv1_METHOD), None)
+        client.set_connect_state()
+        client.set_tlsext_host_name(b"foo1.example.com")
+
+        interact_in_memory(server, client)
+
+        assert args == [(server, b"foo1.example.com")]
+
+
+class TestNextProtoNegotiation(object):
+    """
+    Test for Next Protocol Negotiation in PyOpenSSL.
+    """
+    def test_npn_success(self):
+        """
+        Tests that clients and servers that agree on the negotiated next
+        protocol can correct establish a connection, and that the agreed
+        protocol is reported by the connections.
+        """
+        advertise_args = []
+        select_args = []
+
+        def advertise(conn):
+            advertise_args.append((conn,))
+            return [b'http/1.1', b'spdy/2']
+
+        def select(conn, options):
+            select_args.append((conn, options))
+            return b'spdy/2'
+
+        server_context = Context(TLSv1_METHOD)
+        server_context.set_npn_advertise_callback(advertise)
+
+        client_context = Context(TLSv1_METHOD)
+        client_context.set_npn_select_callback(select)
+
+        # Necessary to actually accept the connection
+        server_context.use_privatekey(
+            load_privatekey(FILETYPE_PEM, server_key_pem))
+        server_context.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+
+        # Do a little connection to trigger the logic
+        server = Connection(server_context, None)
+        server.set_accept_state()
+
+        client = Connection(client_context, None)
+        client.set_connect_state()
+
+        interact_in_memory(server, client)
+
+        assert advertise_args == [(server,)]
+        assert select_args == [(client, [b'http/1.1', b'spdy/2'])]
+
+        assert server.get_next_proto_negotiated() == b'spdy/2'
+        assert client.get_next_proto_negotiated() == b'spdy/2'
+
+    def test_npn_client_fail(self):
+        """
+        Tests that when clients and servers cannot agree on what protocol
+        to use next that the TLS connection does not get established.
+        """
+        advertise_args = []
+        select_args = []
+
+        def advertise(conn):
+            advertise_args.append((conn,))
+            return [b'http/1.1', b'spdy/2']
+
+        def select(conn, options):
+            select_args.append((conn, options))
+            return b''
+
+        server_context = Context(TLSv1_METHOD)
+        server_context.set_npn_advertise_callback(advertise)
+
+        client_context = Context(TLSv1_METHOD)
+        client_context.set_npn_select_callback(select)
+
+        # Necessary to actually accept the connection
+        server_context.use_privatekey(
+            load_privatekey(FILETYPE_PEM, server_key_pem))
+        server_context.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+
+        # Do a little connection to trigger the logic
+        server = Connection(server_context, None)
+        server.set_accept_state()
+
+        client = Connection(client_context, None)
+        client.set_connect_state()
+
+        # If the client doesn't return anything, the connection will fail.
+        with pytest.raises(Error):
+            interact_in_memory(server, client)
+
+        assert advertise_args == [(server,)]
+        assert select_args == [(client, [b'http/1.1', b'spdy/2'])]
+
+    def test_npn_select_error(self):
+        """
+        Test that we can handle exceptions in the select callback. If
+        select fails it should be fatal to the connection.
+        """
+        advertise_args = []
+
+        def advertise(conn):
+            advertise_args.append((conn,))
+            return [b'http/1.1', b'spdy/2']
+
+        def select(conn, options):
+            raise TypeError
+
+        server_context = Context(TLSv1_METHOD)
+        server_context.set_npn_advertise_callback(advertise)
+
+        client_context = Context(TLSv1_METHOD)
+        client_context.set_npn_select_callback(select)
+
+        # Necessary to actually accept the connection
+        server_context.use_privatekey(
+            load_privatekey(FILETYPE_PEM, server_key_pem))
+        server_context.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+
+        # Do a little connection to trigger the logic
+        server = Connection(server_context, None)
+        server.set_accept_state()
+
+        client = Connection(client_context, None)
+        client.set_connect_state()
+
+        # If the callback throws an exception it should be raised here.
+        with pytest.raises(TypeError):
+            interact_in_memory(server, client)
+        assert advertise_args == [(server,), ]
+
+    def test_npn_advertise_error(self):
+        """
+        Test that we can handle exceptions in the advertise callback. If
+        advertise fails no NPN is advertised to the client.
+        """
+        select_args = []
+
+        def advertise(conn):
+            raise TypeError
+
+        def select(conn, options):  # pragma: nocover
+            """
+            Assert later that no args are actually appended.
+            """
+            select_args.append((conn, options))
+            return b''
+
+        server_context = Context(TLSv1_METHOD)
+        server_context.set_npn_advertise_callback(advertise)
+
+        client_context = Context(TLSv1_METHOD)
+        client_context.set_npn_select_callback(select)
+
+        # Necessary to actually accept the connection
+        server_context.use_privatekey(
+            load_privatekey(FILETYPE_PEM, server_key_pem))
+        server_context.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+
+        # Do a little connection to trigger the logic
+        server = Connection(server_context, None)
+        server.set_accept_state()
+
+        client = Connection(client_context, None)
+        client.set_connect_state()
+
+        # If the client doesn't return anything, the connection will fail.
+        with pytest.raises(TypeError):
+            interact_in_memory(server, client)
+        assert select_args == []
+
+
+class TestApplicationLayerProtoNegotiation(object):
+    """
+    Tests for ALPN in PyOpenSSL.
+    """
+    # Skip tests on versions that don't support ALPN.
+    if _lib.Cryptography_HAS_ALPN:
+
+        def test_alpn_success(self):
+            """
+            Clients and servers that agree on the negotiated ALPN protocol can
+            correct establish a connection, and the agreed protocol is reported
+            by the connections.
+            """
+            select_args = []
+
+            def select(conn, options):
+                select_args.append((conn, options))
+                return b'spdy/2'
+
+            client_context = Context(TLSv1_METHOD)
+            client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+
+            server_context = Context(TLSv1_METHOD)
+            server_context.set_alpn_select_callback(select)
+
+            # Necessary to actually accept the connection
+            server_context.use_privatekey(
+                load_privatekey(FILETYPE_PEM, server_key_pem))
+            server_context.use_certificate(
+                load_certificate(FILETYPE_PEM, server_cert_pem))
+
+            # Do a little connection to trigger the logic
+            server = Connection(server_context, None)
+            server.set_accept_state()
+
+            client = Connection(client_context, None)
+            client.set_connect_state()
+
+            interact_in_memory(server, client)
+
+            assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+
+            assert server.get_alpn_proto_negotiated() == b'spdy/2'
+            assert client.get_alpn_proto_negotiated() == b'spdy/2'
+
+        def test_alpn_set_on_connection(self):
+            """
+            The same as test_alpn_success, but setting the ALPN protocols on
+            the connection rather than the context.
+            """
+            select_args = []
+
+            def select(conn, options):
+                select_args.append((conn, options))
+                return b'spdy/2'
+
+            # Setup the client context but don't set any ALPN protocols.
+            client_context = Context(TLSv1_METHOD)
+
+            server_context = Context(TLSv1_METHOD)
+            server_context.set_alpn_select_callback(select)
+
+            # Necessary to actually accept the connection
+            server_context.use_privatekey(
+                load_privatekey(FILETYPE_PEM, server_key_pem))
+            server_context.use_certificate(
+                load_certificate(FILETYPE_PEM, server_cert_pem))
+
+            # Do a little connection to trigger the logic
+            server = Connection(server_context, None)
+            server.set_accept_state()
+
+            # Set the ALPN protocols on the client connection.
+            client = Connection(client_context, None)
+            client.set_alpn_protos([b'http/1.1', b'spdy/2'])
+            client.set_connect_state()
+
+            interact_in_memory(server, client)
+
+            assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+
+            assert server.get_alpn_proto_negotiated() == b'spdy/2'
+            assert client.get_alpn_proto_negotiated() == b'spdy/2'
+
+        def test_alpn_server_fail(self):
+            """
+            When clients and servers cannot agree on what protocol to use next
+            the TLS connection does not get established.
+            """
+            select_args = []
+
+            def select(conn, options):
+                select_args.append((conn, options))
+                return b''
+
+            client_context = Context(TLSv1_METHOD)
+            client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+
+            server_context = Context(TLSv1_METHOD)
+            server_context.set_alpn_select_callback(select)
+
+            # Necessary to actually accept the connection
+            server_context.use_privatekey(
+                load_privatekey(FILETYPE_PEM, server_key_pem))
+            server_context.use_certificate(
+                load_certificate(FILETYPE_PEM, server_cert_pem))
+
+            # Do a little connection to trigger the logic
+            server = Connection(server_context, None)
+            server.set_accept_state()
+
+            client = Connection(client_context, None)
+            client.set_connect_state()
+
+            # If the client doesn't return anything, the connection will fail.
+            with pytest.raises(Error):
+                interact_in_memory(server, client)
+
+            assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+
+        def test_alpn_no_server(self):
+            """
+            When clients and servers cannot agree on what protocol to use next
+            because the server doesn't offer ALPN, no protocol is negotiated.
+            """
+            client_context = Context(TLSv1_METHOD)
+            client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+
+            server_context = Context(TLSv1_METHOD)
+
+            # Necessary to actually accept the connection
+            server_context.use_privatekey(
+                load_privatekey(FILETYPE_PEM, server_key_pem))
+            server_context.use_certificate(
+                load_certificate(FILETYPE_PEM, server_cert_pem))
+
+            # Do a little connection to trigger the logic
+            server = Connection(server_context, None)
+            server.set_accept_state()
+
+            client = Connection(client_context, None)
+            client.set_connect_state()
+
+            # Do the dance.
+            interact_in_memory(server, client)
+
+            assert client.get_alpn_proto_negotiated() == b''
+
+        def test_alpn_callback_exception(self):
+            """
+            We can handle exceptions in the ALPN select callback.
+            """
+            select_args = []
+
+            def select(conn, options):
+                select_args.append((conn, options))
+                raise TypeError()
+
+            client_context = Context(TLSv1_METHOD)
+            client_context.set_alpn_protos([b'http/1.1', b'spdy/2'])
+
+            server_context = Context(TLSv1_METHOD)
+            server_context.set_alpn_select_callback(select)
+
+            # Necessary to actually accept the connection
+            server_context.use_privatekey(
+                load_privatekey(FILETYPE_PEM, server_key_pem))
+            server_context.use_certificate(
+                load_certificate(FILETYPE_PEM, server_cert_pem))
+
+            # Do a little connection to trigger the logic
+            server = Connection(server_context, None)
+            server.set_accept_state()
+
+            client = Connection(client_context, None)
+            client.set_connect_state()
+
+            with pytest.raises(TypeError):
+                interact_in_memory(server, client)
+            assert select_args == [(server, [b'http/1.1', b'spdy/2'])]
+
+    else:
+        # No ALPN.
+        def test_alpn_not_implemented(self):
+            """
+            If ALPN is not in OpenSSL, we should raise NotImplementedError.
+            """
+            # Test the context methods first.
+            context = Context(TLSv1_METHOD)
+            with pytest.raises(NotImplementedError):
+                context.set_alpn_protos(None)
+            with pytest.raises(NotImplementedError):
+                context.set_alpn_select_callback(None)
+
+            # Now test a connection.
+            conn = Connection(context)
+            with pytest.raises(NotImplementedError):
+                conn.set_alpn_protos(None)
+
+
+class TestSession(object):
+    """
+    Unit tests for :py:obj:`OpenSSL.SSL.Session`.
+    """
+    def test_construction(self):
+        """
+        :py:class:`Session` can be constructed with no arguments, creating
+        a new instance of that type.
+        """
+        new_session = Session()
+        assert isinstance(new_session, Session)
+
+
+class TestConnection(object):
+    """
+    Unit tests for `OpenSSL.SSL.Connection`.
+    """
+    # XXX get_peer_certificate -> None
+    # XXX sock_shutdown
+    # XXX master_key -> TypeError
+    # XXX server_random -> TypeError
+    # XXX connect -> TypeError
+    # XXX connect_ex -> TypeError
+    # XXX set_connect_state -> TypeError
+    # XXX set_accept_state -> TypeError
+    # XXX do_handshake -> TypeError
+    # XXX bio_read -> TypeError
+    # XXX recv -> TypeError
+    # XXX send -> TypeError
+    # XXX bio_write -> TypeError
+
+    def test_type(self):
+        """
+        `Connection` and `ConnectionType` refer to the same type object and
+        can be used to create instances of that type.
+        """
+        assert Connection is ConnectionType
+        ctx = Context(TLSv1_METHOD)
+        assert is_consistent_type(Connection, 'Connection', ctx, None)
+
+    @pytest.mark.parametrize('bad_context', [object(), 'context', None, 1])
+    def test_wrong_args(self, bad_context):
+        """
+        `Connection.__init__` raises `TypeError` if called with a non-`Context`
+        instance argument.
+        """
+        with pytest.raises(TypeError):
+            Connection(bad_context)
+
+    def test_get_context(self):
+        """
+        `Connection.get_context` returns the `Context` instance used to
+        construct the `Connection` instance.
+        """
+        context = Context(TLSv1_METHOD)
+        connection = Connection(context, None)
+        assert connection.get_context() is context
+
+    def test_set_context_wrong_args(self):
+        """
+        `Connection.set_context` raises `TypeError` if called with a
+        non-`Context` instance argument.
+        """
+        ctx = Context(TLSv1_METHOD)
+        connection = Connection(ctx, None)
+        with pytest.raises(TypeError):
+            connection.set_context(object())
+        with pytest.raises(TypeError):
+            connection.set_context("hello")
+        with pytest.raises(TypeError):
+            connection.set_context(1)
+        assert ctx is connection.get_context()
+
+    def test_set_context(self):
+        """
+        `Connection.set_context` specifies a new `Context` instance to be
+        used for the connection.
+        """
+        original = Context(SSLv23_METHOD)
+        replacement = Context(TLSv1_METHOD)
+        connection = Connection(original, None)
+        connection.set_context(replacement)
+        assert replacement is connection.get_context()
+        # Lose our references to the contexts, just in case the Connection
+        # isn't properly managing its own contributions to their reference
+        # counts.
+        del original, replacement
+        collect()
+
+    def test_set_tlsext_host_name_wrong_args(self):
+        """
+        If `Connection.set_tlsext_host_name` is called with a non-byte string
+        argument or a byte string with an embedded NUL, `TypeError` is raised.
+        """
+        conn = Connection(Context(TLSv1_METHOD), None)
+        with pytest.raises(TypeError):
+            conn.set_tlsext_host_name(object())
+        with pytest.raises(TypeError):
+            conn.set_tlsext_host_name(b"with\0null")
+
+        if PY3:
+            # On Python 3.x, don't accidentally implicitly convert from text.
+            with pytest.raises(TypeError):
+                conn.set_tlsext_host_name(b"example.com".decode("ascii"))
+
+    def test_pending(self):
+        """
+        `Connection.pending` returns the number of bytes available for
+        immediate read.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        assert connection.pending() == 0
+
+    def test_peek(self):
+        """
+        `Connection.recv` peeks into the connection if `socket.MSG_PEEK` is
+        passed.
+        """
+        server, client = loopback()
+        server.send(b'xy')
+        assert client.recv(2, MSG_PEEK) == b'xy'
+        assert client.recv(2, MSG_PEEK) == b'xy'
+        assert client.recv(2) == b'xy'
+
+    def test_connect_wrong_args(self):
+        """
+        `Connection.connect` raises `TypeError` if called with a non-address
+        argument.
+        """
+        connection = Connection(Context(TLSv1_METHOD), socket())
+        with pytest.raises(TypeError):
+            connection.connect(None)
+
+    def test_connect_refused(self):
+        """
+        `Connection.connect` raises `socket.error` if the underlying socket
+        connect method raises it.
+        """
+        client = socket()
+        context = Context(TLSv1_METHOD)
+        clientSSL = Connection(context, client)
+        # pytest.raises here doesn't work because of a bug in py.test on Python
+        # 2.6: https://github.com/pytest-dev/pytest/issues/988
+        try:
+            clientSSL.connect(("127.0.0.1", 1))
+        except error as e:
+            exc = e
+        assert exc.args[0] == ECONNREFUSED
+
+    def test_connect(self):
+        """
+        `Connection.connect` establishes a connection to the specified address.
+        """
+        port = socket()
+        port.bind(('', 0))
+        port.listen(3)
+
+        clientSSL = Connection(Context(TLSv1_METHOD), socket())
+        clientSSL.connect(('127.0.0.1', port.getsockname()[1]))
+        # XXX An assertion?  Or something?
+
+    @pytest.mark.skipif(
+        platform == "darwin",
+        reason="connect_ex sometimes causes a kernel panic on OS X 10.6.4"
+    )
+    def test_connect_ex(self):
+        """
+        If there is a connection error, `Connection.connect_ex` returns the
+        errno instead of raising an exception.
+        """
+        port = socket()
+        port.bind(('', 0))
+        port.listen(3)
+
+        clientSSL = Connection(Context(TLSv1_METHOD), socket())
+        clientSSL.setblocking(False)
+        result = clientSSL.connect_ex(port.getsockname())
+        expected = (EINPROGRESS, EWOULDBLOCK)
+        assert result in expected
+
+    def test_accept(self):
+        """
+        `Connection.accept` accepts a pending connection attempt and returns a
+        tuple of a new `Connection` (the accepted client) and the address the
+        connection originated from.
+        """
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+        ctx.use_certificate(load_certificate(FILETYPE_PEM, server_cert_pem))
+        port = socket()
+        portSSL = Connection(ctx, port)
+        portSSL.bind(('', 0))
+        portSSL.listen(3)
+
+        clientSSL = Connection(Context(TLSv1_METHOD), socket())
+
+        # Calling portSSL.getsockname() here to get the server IP address
+        # sounds great, but frequently fails on Windows.
+        clientSSL.connect(('127.0.0.1', portSSL.getsockname()[1]))
+
+        serverSSL, address = portSSL.accept()
+
+        assert isinstance(serverSSL, Connection)
+        assert serverSSL.get_context() is ctx
+        assert address == clientSSL.getsockname()
+
+    def test_shutdown_wrong_args(self):
+        """
+        `Connection.set_shutdown` raises `TypeError` if called with arguments
+        other than integers.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        with pytest.raises(TypeError):
+            connection.set_shutdown(None)
+
+    def test_shutdown(self):
+        """
+        `Connection.shutdown` performs an SSL-level connection shutdown.
+        """
+        server, client = loopback()
+        assert not server.shutdown()
+        assert server.get_shutdown() == SENT_SHUTDOWN
+        with pytest.raises(ZeroReturnError):
+            client.recv(1024)
+        assert client.get_shutdown() == RECEIVED_SHUTDOWN
+        client.shutdown()
+        assert client.get_shutdown() == (SENT_SHUTDOWN | RECEIVED_SHUTDOWN)
+        with pytest.raises(ZeroReturnError):
+            server.recv(1024)
+        assert server.get_shutdown() == (SENT_SHUTDOWN | RECEIVED_SHUTDOWN)
+
+    def test_shutdown_closed(self):
+        """
+        If the underlying socket is closed, `Connection.shutdown` propagates
+        the write error from the low level write call.
+        """
+        server, client = loopback()
+        server.sock_shutdown(2)
+        with pytest.raises(SysCallError) as exc:
+            server.shutdown()
+        if platform == "win32":
+            assert exc.value.args[0] == ESHUTDOWN
+        else:
+            assert exc.value.args[0] == EPIPE
+
+    def test_shutdown_truncated(self):
+        """
+        If the underlying connection is truncated, `Connection.shutdown`
+        raises an `Error`.
+        """
+        server_ctx = Context(TLSv1_METHOD)
+        client_ctx = Context(TLSv1_METHOD)
+        server_ctx.use_privatekey(
+            load_privatekey(FILETYPE_PEM, server_key_pem))
+        server_ctx.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+        server = Connection(server_ctx, None)
+        client = Connection(client_ctx, None)
+        handshake_in_memory(client, server)
+        assert not server.shutdown()
+        with pytest.raises(WantReadError):
+            server.shutdown()
+        server.bio_shutdown()
+        with pytest.raises(Error):
+            server.shutdown()
+
+    def test_set_shutdown(self):
+        """
+        `Connection.set_shutdown` sets the state of the SSL connection
+        shutdown process.
+        """
+        connection = Connection(Context(TLSv1_METHOD), socket())
+        connection.set_shutdown(RECEIVED_SHUTDOWN)
+        assert connection.get_shutdown() == RECEIVED_SHUTDOWN
+
+    @skip_if_py3
+    def test_set_shutdown_long(self):
+        """
+        On Python 2 `Connection.set_shutdown` accepts an argument
+        of type `long` as well as `int`.
+        """
+        connection = Connection(Context(TLSv1_METHOD), socket())
+        connection.set_shutdown(long(RECEIVED_SHUTDOWN))
+        assert connection.get_shutdown() == RECEIVED_SHUTDOWN
+
+    def test_state_string(self):
+        """
+        `Connection.state_string` verbosely describes the current state of
+        the `Connection`.
+        """
+        server, client = socket_pair()
+        server = loopback_server_factory(server)
+        client = loopback_client_factory(client)
+
+        assert server.get_state_string() in [
+            b"before/accept initialization", b"before SSL initialization"
+        ]
+        assert client.get_state_string() in [
+            b"before/connect initialization", b"before SSL initialization"
+        ]
+
+    def test_app_data(self):
+        """
+        Any object can be set as app data by passing it to
+        `Connection.set_app_data` and later retrieved with
+        `Connection.get_app_data`.
+        """
+        conn = Connection(Context(TLSv1_METHOD), None)
+        assert None is conn.get_app_data()
+        app_data = object()
+        conn.set_app_data(app_data)
+        assert conn.get_app_data() is app_data
+
+    def test_makefile(self):
+        """
+        `Connection.makefile` is not implemented and calling that
+        method raises `NotImplementedError`.
+        """
+        conn = Connection(Context(TLSv1_METHOD), None)
+        with pytest.raises(NotImplementedError):
+            conn.makefile()
+
+    def test_get_certificate(self):
+        """
+        `Connection.get_certificate` returns the local certificate.
+        """
+        chain = _create_certificate_chain()
+        [(cakey, cacert), (ikey, icert), (skey, scert)] = chain
+
+        context = Context(TLSv1_METHOD)
+        context.use_certificate(scert)
+        client = Connection(context, None)
+        cert = client.get_certificate()
+        assert cert is not None
+        assert "Server Certificate" == cert.get_subject().CN
+
+    def test_get_certificate_none(self):
+        """
+        `Connection.get_certificate` returns the local certificate.
+
+        If there is no certificate, it returns None.
+        """
+        context = Context(TLSv1_METHOD)
+        client = Connection(context, None)
+        cert = client.get_certificate()
+        assert cert is None
+
+    def test_get_peer_cert_chain(self):
+        """
+        `Connection.get_peer_cert_chain` returns a list of certificates
+        which the connected server returned for the certification verification.
+        """
+        chain = _create_certificate_chain()
+        [(cakey, cacert), (ikey, icert), (skey, scert)] = chain
+
+        serverContext = Context(TLSv1_METHOD)
+        serverContext.use_privatekey(skey)
+        serverContext.use_certificate(scert)
+        serverContext.add_extra_chain_cert(icert)
+        serverContext.add_extra_chain_cert(cacert)
+        server = Connection(serverContext, None)
+        server.set_accept_state()
+
+        # Create the client
+        clientContext = Context(TLSv1_METHOD)
+        clientContext.set_verify(VERIFY_NONE, verify_cb)
+        client = Connection(clientContext, None)
+        client.set_connect_state()
+
+        interact_in_memory(client, server)
+
+        chain = client.get_peer_cert_chain()
+        assert len(chain) == 3
+        assert "Server Certificate" == chain[0].get_subject().CN
+        assert "Intermediate Certificate" == chain[1].get_subject().CN
+        assert "Authority Certificate" == chain[2].get_subject().CN
+
+    def test_get_peer_cert_chain_none(self):
+        """
+        `Connection.get_peer_cert_chain` returns `None` if the peer sends
+        no certificate chain.
+        """
+        ctx = Context(TLSv1_METHOD)
+        ctx.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+        ctx.use_certificate(load_certificate(FILETYPE_PEM, server_cert_pem))
+        server = Connection(ctx, None)
+        server.set_accept_state()
+        client = Connection(Context(TLSv1_METHOD), None)
+        client.set_connect_state()
+        interact_in_memory(client, server)
+        assert None is server.get_peer_cert_chain()
+
+    def test_get_session_unconnected(self):
+        """
+        `Connection.get_session` returns `None` when used with an object
+        which has not been connected.
+        """
+        ctx = Context(TLSv1_METHOD)
+        server = Connection(ctx, None)
+        session = server.get_session()
+        assert None is session
+
+    def test_server_get_session(self):
+        """
+        On the server side of a connection, `Connection.get_session` returns a
+        `Session` instance representing the SSL session for that connection.
+        """
+        server, client = loopback()
+        session = server.get_session()
+        assert isinstance(session, Session)
+
+    def test_client_get_session(self):
+        """
+        On the client side of a connection, `Connection.get_session`
+        returns a `Session` instance representing the SSL session for
+        that connection.
+        """
+        server, client = loopback()
+        session = client.get_session()
+        assert isinstance(session, Session)
+
+    def test_set_session_wrong_args(self):
+        """
+        `Connection.set_session` raises `TypeError` if called with an object
+        that is not an instance of `Session`.
+        """
+        ctx = Context(TLSv1_METHOD)
+        connection = Connection(ctx, None)
+        with pytest.raises(TypeError):
+            connection.set_session(123)
+        with pytest.raises(TypeError):
+            connection.set_session("hello")
+        with pytest.raises(TypeError):
+            connection.set_session(object())
+
+    def test_client_set_session(self):
+        """
+        `Connection.set_session`, when used prior to a connection being
+        established, accepts a `Session` instance and causes an attempt to
+        re-use the session it represents when the SSL handshake is performed.
+        """
+        key = load_privatekey(FILETYPE_PEM, server_key_pem)
+        cert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        ctx = Context(TLSv1_2_METHOD)
+        ctx.use_privatekey(key)
+        ctx.use_certificate(cert)
+        ctx.set_session_id("unity-test")
+
+        def makeServer(socket):
+            server = Connection(ctx, socket)
+            server.set_accept_state()
+            return server
+
+        originalServer, originalClient = loopback(
+            server_factory=makeServer)
+        originalSession = originalClient.get_session()
+
+        def makeClient(socket):
+            client = loopback_client_factory(socket)
+            client.set_session(originalSession)
+            return client
+        resumedServer, resumedClient = loopback(
+            server_factory=makeServer,
+            client_factory=makeClient)
+
+        # This is a proxy: in general, we have no access to any unique
+        # identifier for the session (new enough versions of OpenSSL expose
+        # a hash which could be usable, but "new enough" is very, very new).
+        # Instead, exploit the fact that the master key is re-used if the
+        # session is re-used.  As long as the master key for the two
+        # connections is the same, the session was re-used!
+        assert originalServer.master_key() == resumedServer.master_key()
+
+    def test_set_session_wrong_method(self):
+        """
+        If `Connection.set_session` is passed a `Session` instance associated
+        with a context using a different SSL method than the `Connection`
+        is using, a `OpenSSL.SSL.Error` is raised.
+        """
+        # Make this work on both OpenSSL 1.0.0, which doesn't support TLSv1.2
+        # and also on OpenSSL 1.1.0 which doesn't support SSLv3. (SSL_ST_INIT
+        # is a way to check for 1.1.0)
+        if SSL_ST_INIT is None:
+            v1 = TLSv1_2_METHOD
+            v2 = TLSv1_METHOD
+        elif hasattr(_lib, "SSLv3_method"):
+            v1 = TLSv1_METHOD
+            v2 = SSLv3_METHOD
+        else:
+            pytest.skip("Test requires either OpenSSL 1.1.0 or SSLv3")
+
+        key = load_privatekey(FILETYPE_PEM, server_key_pem)
+        cert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        ctx = Context(v1)
+        ctx.use_privatekey(key)
+        ctx.use_certificate(cert)
+        ctx.set_session_id("unity-test")
+
+        def makeServer(socket):
+            server = Connection(ctx, socket)
+            server.set_accept_state()
+            return server
+
+        def makeOriginalClient(socket):
+            client = Connection(Context(v1), socket)
+            client.set_connect_state()
+            return client
+
+        originalServer, originalClient = loopback(
+            server_factory=makeServer, client_factory=makeOriginalClient)
+        originalSession = originalClient.get_session()
+
+        def makeClient(socket):
+            # Intentionally use a different, incompatible method here.
+            client = Connection(Context(v2), socket)
+            client.set_connect_state()
+            client.set_session(originalSession)
+            return client
+
+        with pytest.raises(Error):
+            loopback(client_factory=makeClient, server_factory=makeServer)
+
+    def test_wantWriteError(self):
+        """
+        `Connection` methods which generate output raise
+        `OpenSSL.SSL.WantWriteError` if writing to the connection's BIO
+        fail indicating a should-write state.
+        """
+        client_socket, server_socket = socket_pair()
+        # Fill up the client's send buffer so Connection won't be able to write
+        # anything.  Only write a single byte at a time so we can be sure we
+        # completely fill the buffer.  Even though the socket API is allowed to
+        # signal a short write via its return value it seems this doesn't
+        # always happen on all platforms (FreeBSD and OS X particular) for the
+        # very last bit of available buffer space.
+        msg = b"x"
+        for i in range(1024 * 1024 * 64):
+            try:
+                client_socket.send(msg)
+            except error as e:
+                if e.errno == EWOULDBLOCK:
+                    break
+                raise
+        else:
+            pytest.fail(
+                "Failed to fill socket buffer, cannot test BIO want write")
+
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, client_socket)
+        # Client's speak first, so make it an SSL client
+        conn.set_connect_state()
+        with pytest.raises(WantWriteError):
+            conn.do_handshake()
+
+    # XXX want_read
+
+    def test_get_finished_before_connect(self):
+        """
+        `Connection.get_finished` returns `None` before TLS handshake
+        is completed.
+        """
+        ctx = Context(TLSv1_METHOD)
+        connection = Connection(ctx, None)
+        assert connection.get_finished() is None
+
+    def test_get_peer_finished_before_connect(self):
+        """
+        `Connection.get_peer_finished` returns `None` before TLS handshake
+        is completed.
+        """
+        ctx = Context(TLSv1_METHOD)
+        connection = Connection(ctx, None)
+        assert connection.get_peer_finished() is None
+
+    def test_get_finished(self):
+        """
+        `Connection.get_finished` method returns the TLS Finished message send
+        from client, or server. Finished messages are send during
+        TLS handshake.
+        """
+        server, client = loopback()
+
+        assert server.get_finished() is not None
+        assert len(server.get_finished()) > 0
+
+    def test_get_peer_finished(self):
+        """
+        `Connection.get_peer_finished` method returns the TLS Finished
+        message received from client, or server. Finished messages are send
+        during TLS handshake.
+        """
+        server, client = loopback()
+
+        assert server.get_peer_finished() is not None
+        assert len(server.get_peer_finished()) > 0
+
+    def test_tls_finished_message_symmetry(self):
+        """
+        The TLS Finished message send by server must be the TLS Finished
+        message received by client.
+
+        The TLS Finished message send by client must be the TLS Finished
+        message received by server.
+        """
+        server, client = loopback()
+
+        assert server.get_finished() == client.get_peer_finished()
+        assert client.get_finished() == server.get_peer_finished()
+
+    def test_get_cipher_name_before_connect(self):
+        """
+        `Connection.get_cipher_name` returns `None` if no connection
+        has been established.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        assert conn.get_cipher_name() is None
+
+    def test_get_cipher_name(self):
+        """
+        `Connection.get_cipher_name` returns a `unicode` string giving the
+        name of the currently used cipher.
+        """
+        server, client = loopback()
+        server_cipher_name, client_cipher_name = \
+            server.get_cipher_name(), client.get_cipher_name()
+
+        assert isinstance(server_cipher_name, text_type)
+        assert isinstance(client_cipher_name, text_type)
+
+        assert server_cipher_name == client_cipher_name
+
+    def test_get_cipher_version_before_connect(self):
+        """
+        `Connection.get_cipher_version` returns `None` if no connection
+        has been established.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        assert conn.get_cipher_version() is None
+
+    def test_get_cipher_version(self):
+        """
+        `Connection.get_cipher_version` returns a `unicode` string giving
+        the protocol name of the currently used cipher.
+        """
+        server, client = loopback()
+        server_cipher_version, client_cipher_version = \
+            server.get_cipher_version(), client.get_cipher_version()
+
+        assert isinstance(server_cipher_version, text_type)
+        assert isinstance(client_cipher_version, text_type)
+
+        assert server_cipher_version == client_cipher_version
+
+    def test_get_cipher_bits_before_connect(self):
+        """
+        `Connection.get_cipher_bits` returns `None` if no connection has
+        been established.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        assert conn.get_cipher_bits() is None
+
+    def test_get_cipher_bits(self):
+        """
+        `Connection.get_cipher_bits` returns the number of secret bits
+        of the currently used cipher.
+        """
+        server, client = loopback()
+        server_cipher_bits, client_cipher_bits = \
+            server.get_cipher_bits(), client.get_cipher_bits()
+
+        assert isinstance(server_cipher_bits, int)
+        assert isinstance(client_cipher_bits, int)
+
+        assert server_cipher_bits == client_cipher_bits
+
+    def test_get_protocol_version_name(self):
+        """
+        `Connection.get_protocol_version_name()` returns a string giving the
+        protocol version of the current connection.
+        """
+        server, client = loopback()
+        client_protocol_version_name = client.get_protocol_version_name()
+        server_protocol_version_name = server.get_protocol_version_name()
+
+        assert isinstance(server_protocol_version_name, text_type)
+        assert isinstance(client_protocol_version_name, text_type)
+
+        assert server_protocol_version_name == client_protocol_version_name
+
+    def test_get_protocol_version(self):
+        """
+        `Connection.get_protocol_version()` returns an integer
+        giving the protocol version of the current connection.
+        """
+        server, client = loopback()
+        client_protocol_version = client.get_protocol_version()
+        server_protocol_version = server.get_protocol_version()
+
+        assert isinstance(server_protocol_version, int)
+        assert isinstance(client_protocol_version, int)
+
+        assert server_protocol_version == client_protocol_version
+
+    def test_wantReadError(self):
+        """
+        `Connection.bio_read` raises `OpenSSL.SSL.WantReadError` if there are
+        no bytes available to be read from the BIO.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        with pytest.raises(WantReadError):
+            conn.bio_read(1024)
+
+    @pytest.mark.parametrize('bufsize', [1.0, None, object(), 'bufsize'])
+    def test_bio_read_wrong_args(self, bufsize):
+        """
+        `Connection.bio_read` raises `TypeError` if passed a non-integer
+        argument.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        with pytest.raises(TypeError):
+            conn.bio_read(bufsize)
+
+    def test_buffer_size(self):
+        """
+        `Connection.bio_read` accepts an integer giving the maximum number
+        of bytes to read and return.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        conn.set_connect_state()
+        try:
+            conn.do_handshake()
+        except WantReadError:
+            pass
+        data = conn.bio_read(2)
+        assert 2 == len(data)
+
+    @skip_if_py3
+    def test_buffer_size_long(self):
+        """
+        On Python 2 `Connection.bio_read` accepts values of type `long` as
+        well as `int`.
+        """
+        ctx = Context(TLSv1_METHOD)
+        conn = Connection(ctx, None)
+        conn.set_connect_state()
+        try:
+            conn.do_handshake()
+        except WantReadError:
+            pass
+        data = conn.bio_read(long(2))
+        assert 2 == len(data)
+
+
+class TestConnectionGetCipherList(object):
+    """
+    Tests for `Connection.get_cipher_list`.
+    """
+    def test_result(self):
+        """
+        `Connection.get_cipher_list` returns a list of `bytes` giving the
+        names of the ciphers which might be used.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        ciphers = connection.get_cipher_list()
+        assert isinstance(ciphers, list)
+        for cipher in ciphers:
+            assert isinstance(cipher, str)
+
+
+class VeryLarge(bytes):
+    """
+    Mock object so that we don't have to allocate 2**31 bytes
+    """
+    def __len__(self):
+        return 2**31
+
+
+class TestConnectionSend(object):
+    """
+    Tests for `Connection.send`.
+    """
+    def test_wrong_args(self):
+        """
+        When called with arguments other than string argument for its first
+        parameter, `Connection.send` raises `TypeError`.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        with pytest.raises(TypeError):
+            connection.send(object())
+
+    def test_short_bytes(self):
+        """
+        When passed a short byte string, `Connection.send` transmits all of it
+        and returns the number of bytes sent.
+        """
+        server, client = loopback()
+        count = server.send(b'xy')
+        assert count == 2
+        assert client.recv(2) == b'xy'
+
+    def test_text(self):
+        """
+        When passed a text, `Connection.send` transmits all of it and
+        returns the number of bytes sent. It also raises a DeprecationWarning.
+        """
+        server, client = loopback()
+        with pytest.warns(DeprecationWarning) as w:
+            simplefilter("always")
+            count = server.send(b"xy".decode("ascii"))
+            assert (
+                "{0} for buf is no longer accepted, use bytes".format(
+                    WARNING_TYPE_EXPECTED
+                ) == str(w[-1].message))
+        assert count == 2
+        assert client.recv(2) == b'xy'
+
+    def test_short_memoryview(self):
+        """
+        When passed a memoryview onto a small number of bytes,
+        `Connection.send` transmits all of them and returns the number
+        of bytes sent.
+        """
+        server, client = loopback()
+        count = server.send(memoryview(b'xy'))
+        assert count == 2
+        assert client.recv(2) == b'xy'
+
+    @skip_if_py3
+    def test_short_buffer(self):
+        """
+        When passed a buffer containing a small number of bytes,
+        `Connection.send` transmits all of them and returns the number
+        of bytes sent.
+        """
+        server, client = loopback()
+        count = server.send(buffer(b'xy'))
+        assert count == 2
+        assert client.recv(2) == b'xy'
+
+    @pytest.mark.skipif(
+        sys.maxsize < 2**31,
+        reason="sys.maxsize < 2**31 - test requires 64 bit"
+    )
+    def test_buf_too_large(self):
+        """
+        When passed a buffer containing >= 2**31 bytes,
+        `Connection.send` bails out as SSL_write only
+        accepts an int for the buffer length.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        with pytest.raises(ValueError) as exc_info:
+            connection.send(VeryLarge())
+        exc_info.match(r"Cannot send more than .+ bytes at once")
+
+
+def _make_memoryview(size):
+    """
+    Create a new ``memoryview`` wrapped around a ``bytearray`` of the given
+    size.
+    """
+    return memoryview(bytearray(size))
+
+
+class TestConnectionRecvInto(object):
+    """
+    Tests for `Connection.recv_into`.
+    """
+    def _no_length_test(self, factory):
+        """
+        Assert that when the given buffer is passed to `Connection.recv_into`,
+        whatever bytes are available to be received that fit into that buffer
+        are written into that buffer.
+        """
+        output_buffer = factory(5)
+
+        server, client = loopback()
+        server.send(b'xy')
+
+        assert client.recv_into(output_buffer) == 2
+        assert output_buffer == bytearray(b'xy\x00\x00\x00')
+
+    def test_bytearray_no_length(self):
+        """
+        `Connection.recv_into` can be passed a `bytearray` instance and data
+        in the receive buffer is written to it.
+        """
+        self._no_length_test(bytearray)
+
+    def _respects_length_test(self, factory):
+        """
+        Assert that when the given buffer is passed to `Connection.recv_into`
+        along with a value for `nbytes` that is less than the size of that
+        buffer, only `nbytes` bytes are written into the buffer.
+        """
+        output_buffer = factory(10)
+
+        server, client = loopback()
+        server.send(b'abcdefghij')
+
+        assert client.recv_into(output_buffer, 5) == 5
+        assert output_buffer == bytearray(b'abcde\x00\x00\x00\x00\x00')
+
+    def test_bytearray_respects_length(self):
+        """
+        When called with a `bytearray` instance, `Connection.recv_into`
+        respects the `nbytes` parameter and doesn't copy in more than that
+        number of bytes.
+        """
+        self._respects_length_test(bytearray)
+
+    def _doesnt_overfill_test(self, factory):
+        """
+        Assert that if there are more bytes available to be read from the
+        receive buffer than would fit into the buffer passed to
+        `Connection.recv_into`, only as many as fit are written into it.
+        """
+        output_buffer = factory(5)
+
+        server, client = loopback()
+        server.send(b'abcdefghij')
+
+        assert client.recv_into(output_buffer) == 5
+        assert output_buffer == bytearray(b'abcde')
+        rest = client.recv(5)
+        assert b'fghij' == rest
+
+    def test_bytearray_doesnt_overfill(self):
+        """
+        When called with a `bytearray` instance, `Connection.recv_into`
+        respects the size of the array and doesn't write more bytes into it
+        than will fit.
+        """
+        self._doesnt_overfill_test(bytearray)
+
+    def test_bytearray_really_doesnt_overfill(self):
+        """
+        When called with a `bytearray` instance and an `nbytes` value that is
+        too large, `Connection.recv_into` respects the size of the array and
+        not the `nbytes` value and doesn't write more bytes into the buffer
+        than will fit.
+        """
+        self._doesnt_overfill_test(bytearray)
+
+    def test_peek(self):
+        server, client = loopback()
+        server.send(b'xy')
+
+        for _ in range(2):
+            output_buffer = bytearray(5)
+            assert client.recv_into(output_buffer, flags=MSG_PEEK) == 2
+            assert output_buffer == bytearray(b'xy\x00\x00\x00')
+
+    def test_memoryview_no_length(self):
+        """
+        `Connection.recv_into` can be passed a `memoryview` instance and data
+        in the receive buffer is written to it.
+        """
+        self._no_length_test(_make_memoryview)
+
+    def test_memoryview_respects_length(self):
+        """
+        When called with a `memoryview` instance, `Connection.recv_into`
+        respects the ``nbytes`` parameter and doesn't copy more than that
+        number of bytes in.
+        """
+        self._respects_length_test(_make_memoryview)
+
+    def test_memoryview_doesnt_overfill(self):
+        """
+        When called with a `memoryview` instance, `Connection.recv_into`
+        respects the size of the array and doesn't write more bytes into it
+        than will fit.
+        """
+        self._doesnt_overfill_test(_make_memoryview)
+
+    def test_memoryview_really_doesnt_overfill(self):
+        """
+        When called with a `memoryview` instance and an `nbytes` value that is
+        too large, `Connection.recv_into` respects the size of the array and
+        not the `nbytes` value and doesn't write more bytes into the buffer
+        than will fit.
+        """
+        self._doesnt_overfill_test(_make_memoryview)
+
+
+class TestConnectionSendall(object):
+    """
+    Tests for `Connection.sendall`.
+    """
+    def test_wrong_args(self):
+        """
+        When called with arguments other than a string argument for its first
+        parameter, `Connection.sendall` raises `TypeError`.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        with pytest.raises(TypeError):
+            connection.sendall(object())
+
+    def test_short(self):
+        """
+        `Connection.sendall` transmits all of the bytes in the string
+        passed to it.
+        """
+        server, client = loopback()
+        server.sendall(b'x')
+        assert client.recv(1) == b'x'
+
+    def test_text(self):
+        """
+        `Connection.sendall` transmits all the content in the string passed
+        to it, raising a DeprecationWarning in case of this being a text.
+        """
+        server, client = loopback()
+        with pytest.warns(DeprecationWarning) as w:
+            simplefilter("always")
+            server.sendall(b"x".decode("ascii"))
+            assert (
+                "{0} for buf is no longer accepted, use bytes".format(
+                    WARNING_TYPE_EXPECTED
+                ) == str(w[-1].message))
+        assert client.recv(1) == b"x"
+
+    def test_short_memoryview(self):
+        """
+        When passed a memoryview onto a small number of bytes,
+        `Connection.sendall` transmits all of them.
+        """
+        server, client = loopback()
+        server.sendall(memoryview(b'x'))
+        assert client.recv(1) == b'x'
+
+    @skip_if_py3
+    def test_short_buffers(self):
+        """
+        When passed a buffer containing a small number of bytes,
+        `Connection.sendall` transmits all of them.
+        """
+        server, client = loopback()
+        server.sendall(buffer(b'x'))
+        assert client.recv(1) == b'x'
+
+    def test_long(self):
+        """
+        `Connection.sendall` transmits all the bytes in the string passed to it
+        even if this requires multiple calls of an underlying write function.
+        """
+        server, client = loopback()
+        # Should be enough, underlying SSL_write should only do 16k at a time.
+        # On Windows, after 32k of bytes the write will block (forever
+        # - because no one is yet reading).
+        message = b'x' * (1024 * 32 - 1) + b'y'
+        server.sendall(message)
+        accum = []
+        received = 0
+        while received < len(message):
+            data = client.recv(1024)
+            accum.append(data)
+            received += len(data)
+        assert message == b''.join(accum)
+
+    def test_closed(self):
+        """
+        If the underlying socket is closed, `Connection.sendall` propagates the
+        write error from the low level write call.
+        """
+        server, client = loopback()
+        server.sock_shutdown(2)
+        with pytest.raises(SysCallError) as err:
+            server.sendall(b"hello, world")
+        if platform == "win32":
+            assert err.value.args[0] == ESHUTDOWN
+        else:
+            assert err.value.args[0] == EPIPE
+
+
+class TestConnectionRenegotiate(object):
+    """
+    Tests for SSL renegotiation APIs.
+    """
+    def test_total_renegotiations(self):
+        """
+        `Connection.total_renegotiations` returns `0` before any renegotiations
+        have happened.
+        """
+        connection = Connection(Context(TLSv1_METHOD), None)
+        assert connection.total_renegotiations() == 0
+
+    def test_renegotiate(self):
+        """
+        Go through a complete renegotiation cycle.
+        """
+        server, client = loopback(
+            lambda s: loopback_server_factory(s, TLSv1_2_METHOD),
+            lambda s: loopback_client_factory(s, TLSv1_2_METHOD),
+        )
+
+        server.send(b"hello world")
+
+        assert b"hello world" == client.recv(len(b"hello world"))
+
+        assert 0 == server.total_renegotiations()
+        assert False is server.renegotiate_pending()
+
+        assert True is server.renegotiate()
+
+        assert True is server.renegotiate_pending()
+
+        server.setblocking(False)
+        client.setblocking(False)
+
+        client.do_handshake()
+        server.do_handshake()
+
+        assert 1 == server.total_renegotiations()
+        while False is server.renegotiate_pending():
+            pass
+
+
+class TestError(object):
+    """
+    Unit tests for `OpenSSL.SSL.Error`.
+    """
+    def test_type(self):
+        """
+        `Error` is an exception type.
+        """
+        assert issubclass(Error, Exception)
+        assert Error.__name__ == 'Error'
+
+
+class TestConstants(object):
+    """
+    Tests for the values of constants exposed in `OpenSSL.SSL`.
+
+    These are values defined by OpenSSL intended only to be used as flags to
+    OpenSSL APIs.  The only assertions it seems can be made about them is
+    their values.
+    """
+    @pytest.mark.skipif(
+        OP_NO_QUERY_MTU is None,
+        reason="OP_NO_QUERY_MTU unavailable - OpenSSL version may be too old"
+    )
+    def test_op_no_query_mtu(self):
+        """
+        The value of `OpenSSL.SSL.OP_NO_QUERY_MTU` is 0x1000, the value
+        of `SSL_OP_NO_QUERY_MTU` defined by `openssl/ssl.h`.
+        """
+        assert OP_NO_QUERY_MTU == 0x1000
+
+    @pytest.mark.skipif(
+        OP_COOKIE_EXCHANGE is None,
+        reason="OP_COOKIE_EXCHANGE unavailable - "
+        "OpenSSL version may be too old"
+    )
+    def test_op_cookie_exchange(self):
+        """
+        The value of `OpenSSL.SSL.OP_COOKIE_EXCHANGE` is 0x2000, the
+        value of `SSL_OP_COOKIE_EXCHANGE` defined by `openssl/ssl.h`.
+        """
+        assert OP_COOKIE_EXCHANGE == 0x2000
+
+    @pytest.mark.skipif(
+        OP_NO_TICKET is None,
+        reason="OP_NO_TICKET unavailable - OpenSSL version may be too old"
+    )
+    def test_op_no_ticket(self):
+        """
+        The value of `OpenSSL.SSL.OP_NO_TICKET` is 0x4000, the value of
+        `SSL_OP_NO_TICKET` defined by `openssl/ssl.h`.
+        """
+        assert OP_NO_TICKET == 0x4000
+
+    @pytest.mark.skipif(
+        OP_NO_COMPRESSION is None,
+        reason="OP_NO_COMPRESSION unavailable - OpenSSL version may be too old"
+    )
+    def test_op_no_compression(self):
+        """
+        The value of `OpenSSL.SSL.OP_NO_COMPRESSION` is 0x20000, the
+        value of `SSL_OP_NO_COMPRESSION` defined by `openssl/ssl.h`.
+        """
+        assert OP_NO_COMPRESSION == 0x20000
+
+    def test_sess_cache_off(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_OFF` 0x0, the value of
+        `SSL_SESS_CACHE_OFF` defined by `openssl/ssl.h`.
+        """
+        assert 0x0 == SESS_CACHE_OFF
+
+    def test_sess_cache_client(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_CLIENT` 0x1, the value of
+        `SSL_SESS_CACHE_CLIENT` defined by `openssl/ssl.h`.
+        """
+        assert 0x1 == SESS_CACHE_CLIENT
+
+    def test_sess_cache_server(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_SERVER` 0x2, the value of
+        `SSL_SESS_CACHE_SERVER` defined by `openssl/ssl.h`.
+        """
+        assert 0x2 == SESS_CACHE_SERVER
+
+    def test_sess_cache_both(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_BOTH` 0x3, the value of
+        `SSL_SESS_CACHE_BOTH` defined by `openssl/ssl.h`.
+        """
+        assert 0x3 == SESS_CACHE_BOTH
+
+    def test_sess_cache_no_auto_clear(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_NO_AUTO_CLEAR` 0x80, the
+        value of `SSL_SESS_CACHE_NO_AUTO_CLEAR` defined by
+        `openssl/ssl.h`.
+        """
+        assert 0x80 == SESS_CACHE_NO_AUTO_CLEAR
+
+    def test_sess_cache_no_internal_lookup(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_NO_INTERNAL_LOOKUP` 0x100,
+        the value of `SSL_SESS_CACHE_NO_INTERNAL_LOOKUP` defined by
+        `openssl/ssl.h`.
+        """
+        assert 0x100 == SESS_CACHE_NO_INTERNAL_LOOKUP
+
+    def test_sess_cache_no_internal_store(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_NO_INTERNAL_STORE` 0x200,
+        the value of `SSL_SESS_CACHE_NO_INTERNAL_STORE` defined by
+        `openssl/ssl.h`.
+        """
+        assert 0x200 == SESS_CACHE_NO_INTERNAL_STORE
+
+    def test_sess_cache_no_internal(self):
+        """
+        The value of `OpenSSL.SSL.SESS_CACHE_NO_INTERNAL` 0x300, the
+        value of `SSL_SESS_CACHE_NO_INTERNAL` defined by
+        `openssl/ssl.h`.
+        """
+        assert 0x300 == SESS_CACHE_NO_INTERNAL
+
+
+class TestMemoryBIO(object):
+    """
+    Tests for `OpenSSL.SSL.Connection` using a memory BIO.
+    """
+    def _server(self, sock):
+        """
+        Create a new server-side SSL `Connection` object wrapped around `sock`.
+        """
+        # Create the server side Connection.  This is mostly setup boilerplate
+        # - use TLSv1, use a particular certificate, etc.
+        server_ctx = Context(TLSv1_METHOD)
+        server_ctx.set_options(OP_NO_SSLv2 | OP_NO_SSLv3 | OP_SINGLE_DH_USE)
+        server_ctx.set_verify(
+            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT | VERIFY_CLIENT_ONCE,
+            verify_cb
+        )
+        server_store = server_ctx.get_cert_store()
+        server_ctx.use_privatekey(
+            load_privatekey(FILETYPE_PEM, server_key_pem))
+        server_ctx.use_certificate(
+            load_certificate(FILETYPE_PEM, server_cert_pem))
+        server_ctx.check_privatekey()
+        server_store.add_cert(load_certificate(FILETYPE_PEM, root_cert_pem))
+        # Here the Connection is actually created.  If None is passed as the
+        # 2nd parameter, it indicates a memory BIO should be created.
+        server_conn = Connection(server_ctx, sock)
+        server_conn.set_accept_state()
+        return server_conn
+
+    def _client(self, sock):
+        """
+        Create a new client-side SSL `Connection` object wrapped around `sock`.
+        """
+        # Now create the client side Connection.  Similar boilerplate to the
+        # above.
+        client_ctx = Context(TLSv1_METHOD)
+        client_ctx.set_options(OP_NO_SSLv2 | OP_NO_SSLv3 | OP_SINGLE_DH_USE)
+        client_ctx.set_verify(
+            VERIFY_PEER | VERIFY_FAIL_IF_NO_PEER_CERT | VERIFY_CLIENT_ONCE,
+            verify_cb
+        )
+        client_store = client_ctx.get_cert_store()
+        client_ctx.use_privatekey(
+            load_privatekey(FILETYPE_PEM, client_key_pem))
+        client_ctx.use_certificate(
+            load_certificate(FILETYPE_PEM, client_cert_pem))
+        client_ctx.check_privatekey()
+        client_store.add_cert(load_certificate(FILETYPE_PEM, root_cert_pem))
+        client_conn = Connection(client_ctx, sock)
+        client_conn.set_connect_state()
+        return client_conn
+
+    def test_memory_connect(self):
+        """
+        Two `Connection`s which use memory BIOs can be manually connected by
+        reading from the output of each and writing those bytes to the input of
+        the other and in this way establish a connection and exchange
+        application-level bytes with each other.
+        """
+        server_conn = self._server(None)
+        client_conn = self._client(None)
+
+        # There should be no key or nonces yet.
+        assert server_conn.master_key() is None
+        assert server_conn.client_random() is None
+        assert server_conn.server_random() is None
+
+        # First, the handshake needs to happen.  We'll deliver bytes back and
+        # forth between the client and server until neither of them feels like
+        # speaking any more.
+        assert interact_in_memory(client_conn, server_conn) is None
+
+        # Now that the handshake is done, there should be a key and nonces.
+        assert server_conn.master_key() is not None
+        assert server_conn.client_random() is not None
+        assert server_conn.server_random() is not None
+        assert server_conn.client_random() == client_conn.client_random()
+        assert server_conn.server_random() == client_conn.server_random()
+        assert server_conn.client_random() != server_conn.server_random()
+        assert client_conn.client_random() != client_conn.server_random()
+
+        # Export key material for other uses.
+        cekm = client_conn.export_keying_material(b'LABEL', 32)
+        sekm = server_conn.export_keying_material(b'LABEL', 32)
+        assert cekm is not None
+        assert sekm is not None
+        assert cekm == sekm
+        assert len(sekm) == 32
+
+        # Export key material for other uses with additional context.
+        cekmc = client_conn.export_keying_material(b'LABEL', 32, b'CONTEXT')
+        sekmc = server_conn.export_keying_material(b'LABEL', 32, b'CONTEXT')
+        assert cekmc is not None
+        assert sekmc is not None
+        assert cekmc == sekmc
+        assert cekmc != cekm
+        assert sekmc != sekm
+        # Export with alternate label
+        cekmt = client_conn.export_keying_material(b'test', 32, b'CONTEXT')
+        sekmt = server_conn.export_keying_material(b'test', 32, b'CONTEXT')
+        assert cekmc != cekmt
+        assert sekmc != sekmt
+
+        # Here are the bytes we'll try to send.
+        important_message = b'One if by land, two if by sea.'
+
+        server_conn.write(important_message)
+        assert (
+            interact_in_memory(client_conn, server_conn) ==
+            (client_conn, important_message))
+
+        client_conn.write(important_message[::-1])
+        assert (
+            interact_in_memory(client_conn, server_conn) ==
+            (server_conn, important_message[::-1]))
+
+    def test_socket_connect(self):
+        """
+        Just like `test_memory_connect` but with an actual socket.
+
+        This is primarily to rule out the memory BIO code as the source of any
+        problems encountered while passing data over a `Connection` (if
+        this test fails, there must be a problem outside the memory BIO code,
+        as no memory BIO is involved here).  Even though this isn't a memory
+        BIO test, it's convenient to have it here.
+        """
+        server_conn, client_conn = loopback()
+
+        important_message = b"Help me Obi Wan Kenobi, you're my only hope."
+        client_conn.send(important_message)
+        msg = server_conn.recv(1024)
+        assert msg == important_message
+
+        # Again in the other direction, just for fun.
+        important_message = important_message[::-1]
+        server_conn.send(important_message)
+        msg = client_conn.recv(1024)
+        assert msg == important_message
+
+    def test_socket_overrides_memory(self):
+        """
+        Test that `OpenSSL.SSL.bio_read` and `OpenSSL.SSL.bio_write` don't
+        work on `OpenSSL.SSL.Connection`() that use sockets.
+        """
+        context = Context(TLSv1_METHOD)
+        client = socket()
+        clientSSL = Connection(context, client)
+        with pytest.raises(TypeError):
+            clientSSL.bio_read(100)
+        with pytest.raises(TypeError):
+            clientSSL.bio_write("foo")
+        with pytest.raises(TypeError):
+            clientSSL.bio_shutdown()
+
+    def test_outgoing_overflow(self):
+        """
+        If more bytes than can be written to the memory BIO are passed to
+        `Connection.send` at once, the number of bytes which were written is
+        returned and that many bytes from the beginning of the input can be
+        read from the other end of the connection.
+        """
+        server = self._server(None)
+        client = self._client(None)
+
+        interact_in_memory(client, server)
+
+        size = 2 ** 15
+        sent = client.send(b"x" * size)
+        # Sanity check.  We're trying to test what happens when the entire
+        # input can't be sent.  If the entire input was sent, this test is
+        # meaningless.
+        assert sent < size
+
+        receiver, received = interact_in_memory(client, server)
+        assert receiver is server
+
+        # We can rely on all of these bytes being received at once because
+        # loopback passes 2 ** 16 to recv - more than 2 ** 15.
+        assert len(received) == sent
+
+    def test_shutdown(self):
+        """
+        `Connection.bio_shutdown` signals the end of the data stream
+        from which the `Connection` reads.
+        """
+        server = self._server(None)
+        server.bio_shutdown()
+        with pytest.raises(Error) as err:
+            server.recv(1024)
+        # We don't want WantReadError or ZeroReturnError or anything - it's a
+        # handshake failure.
+        assert type(err.value) in [Error, SysCallError]
+
+    def test_unexpected_EOF(self):
+        """
+        If the connection is lost before an orderly SSL shutdown occurs,
+        `OpenSSL.SSL.SysCallError` is raised with a message of
+        "Unexpected EOF".
+        """
+        server_conn, client_conn = loopback()
+        client_conn.sock_shutdown(SHUT_RDWR)
+        with pytest.raises(SysCallError) as err:
+            server_conn.recv(1024)
+        assert err.value.args == (-1, "Unexpected EOF")
+
+    def _check_client_ca_list(self, func):
+        """
+        Verify the return value of the `get_client_ca_list` method for
+        server and client connections.
+
+        :param func: A function which will be called with the server context
+            before the client and server are connected to each other.  This
+            function should specify a list of CAs for the server to send to the
+            client and return that same list.  The list will be used to verify
+            that `get_client_ca_list` returns the proper value at
+            various times.
+        """
+        server = self._server(None)
+        client = self._client(None)
+        assert client.get_client_ca_list() == []
+        assert server.get_client_ca_list() == []
+        ctx = server.get_context()
+        expected = func(ctx)
+        assert client.get_client_ca_list() == []
+        assert server.get_client_ca_list() == expected
+        interact_in_memory(client, server)
+        assert client.get_client_ca_list() == expected
+        assert server.get_client_ca_list() == expected
+
+    def test_set_client_ca_list_errors(self):
+        """
+        `Context.set_client_ca_list` raises a `TypeError` if called with a
+        non-list or a list that contains objects other than X509Names.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            ctx.set_client_ca_list("spam")
+        with pytest.raises(TypeError):
+            ctx.set_client_ca_list(["spam"])
+
+    def test_set_empty_ca_list(self):
+        """
+        If passed an empty list, `Context.set_client_ca_list` configures the
+        context to send no CA names to the client and, on both the server and
+        client sides, `Connection.get_client_ca_list` returns an empty list
+        after the connection is set up.
+        """
+        def no_ca(ctx):
+            ctx.set_client_ca_list([])
+            return []
+        self._check_client_ca_list(no_ca)
+
+    def test_set_one_ca_list(self):
+        """
+        If passed a list containing a single X509Name,
+        `Context.set_client_ca_list` configures the context to send
+        that CA name to the client and, on both the server and client sides,
+        `Connection.get_client_ca_list` returns a list containing that
+        X509Name after the connection is set up.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        cadesc = cacert.get_subject()
+
+        def single_ca(ctx):
+            ctx.set_client_ca_list([cadesc])
+            return [cadesc]
+        self._check_client_ca_list(single_ca)
+
+    def test_set_multiple_ca_list(self):
+        """
+        If passed a list containing multiple X509Name objects,
+        `Context.set_client_ca_list` configures the context to send
+        those CA names to the client and, on both the server and client sides,
+        `Connection.get_client_ca_list` returns a list containing those
+        X509Names after the connection is set up.
+        """
+        secert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        clcert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        sedesc = secert.get_subject()
+        cldesc = clcert.get_subject()
+
+        def multiple_ca(ctx):
+            L = [sedesc, cldesc]
+            ctx.set_client_ca_list(L)
+            return L
+        self._check_client_ca_list(multiple_ca)
+
+    def test_reset_ca_list(self):
+        """
+        If called multiple times, only the X509Names passed to the final call
+        of `Context.set_client_ca_list` are used to configure the CA
+        names sent to the client.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        secert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        clcert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        cadesc = cacert.get_subject()
+        sedesc = secert.get_subject()
+        cldesc = clcert.get_subject()
+
+        def changed_ca(ctx):
+            ctx.set_client_ca_list([sedesc, cldesc])
+            ctx.set_client_ca_list([cadesc])
+            return [cadesc]
+        self._check_client_ca_list(changed_ca)
+
+    def test_mutated_ca_list(self):
+        """
+        If the list passed to `Context.set_client_ca_list` is mutated
+        afterwards, this does not affect the list of CA names sent to the
+        client.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        secert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        cadesc = cacert.get_subject()
+        sedesc = secert.get_subject()
+
+        def mutated_ca(ctx):
+            L = [cadesc]
+            ctx.set_client_ca_list([cadesc])
+            L.append(sedesc)
+            return [cadesc]
+        self._check_client_ca_list(mutated_ca)
+
+    def test_add_client_ca_wrong_args(self):
+        """
+        `Context.add_client_ca` raises `TypeError` if called with
+        a non-X509 object.
+        """
+        ctx = Context(TLSv1_METHOD)
+        with pytest.raises(TypeError):
+            ctx.add_client_ca("spam")
+
+    def test_one_add_client_ca(self):
+        """
+        A certificate's subject can be added as a CA to be sent to the client
+        with `Context.add_client_ca`.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        cadesc = cacert.get_subject()
+
+        def single_ca(ctx):
+            ctx.add_client_ca(cacert)
+            return [cadesc]
+        self._check_client_ca_list(single_ca)
+
+    def test_multiple_add_client_ca(self):
+        """
+        Multiple CA names can be sent to the client by calling
+        `Context.add_client_ca` with multiple X509 objects.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        secert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        cadesc = cacert.get_subject()
+        sedesc = secert.get_subject()
+
+        def multiple_ca(ctx):
+            ctx.add_client_ca(cacert)
+            ctx.add_client_ca(secert)
+            return [cadesc, sedesc]
+        self._check_client_ca_list(multiple_ca)
+
+    def test_set_and_add_client_ca(self):
+        """
+        A call to `Context.set_client_ca_list` followed by a call to
+        `Context.add_client_ca` results in using the CA names from the
+        first call and the CA name from the second call.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        secert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        clcert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        cadesc = cacert.get_subject()
+        sedesc = secert.get_subject()
+        cldesc = clcert.get_subject()
+
+        def mixed_set_add_ca(ctx):
+            ctx.set_client_ca_list([cadesc, sedesc])
+            ctx.add_client_ca(clcert)
+            return [cadesc, sedesc, cldesc]
+        self._check_client_ca_list(mixed_set_add_ca)
+
+    def test_set_after_add_client_ca(self):
+        """
+        A call to `Context.set_client_ca_list` after a call to
+        `Context.add_client_ca` replaces the CA name specified by the
+        former call with the names specified by the latter call.
+        """
+        cacert = load_certificate(FILETYPE_PEM, root_cert_pem)
+        secert = load_certificate(FILETYPE_PEM, server_cert_pem)
+        clcert = load_certificate(FILETYPE_PEM, server_cert_pem)
+
+        cadesc = cacert.get_subject()
+        sedesc = secert.get_subject()
+
+        def set_replaces_add_ca(ctx):
+            ctx.add_client_ca(clcert)
+            ctx.set_client_ca_list([cadesc])
+            ctx.add_client_ca(secert)
+            return [cadesc, sedesc]
+        self._check_client_ca_list(set_replaces_add_ca)
+
+
+class TestInfoConstants(object):
+    """
+    Tests for assorted constants exposed for use in info callbacks.
+    """
+    def test_integers(self):
+        """
+        All of the info constants are integers.
+
+        This is a very weak test.  It would be nice to have one that actually
+        verifies that as certain info events happen, the value passed to the
+        info callback matches up with the constant exposed by OpenSSL.SSL.
+        """
+        for const in [
+            SSL_ST_CONNECT, SSL_ST_ACCEPT, SSL_ST_MASK,
+            SSL_CB_LOOP, SSL_CB_EXIT, SSL_CB_READ, SSL_CB_WRITE, SSL_CB_ALERT,
+            SSL_CB_READ_ALERT, SSL_CB_WRITE_ALERT, SSL_CB_ACCEPT_LOOP,
+            SSL_CB_ACCEPT_EXIT, SSL_CB_CONNECT_LOOP, SSL_CB_CONNECT_EXIT,
+            SSL_CB_HANDSHAKE_START, SSL_CB_HANDSHAKE_DONE
+        ]:
+            assert isinstance(const, int)
+
+        # These constants don't exist on OpenSSL 1.1.0
+        for const in [
+            SSL_ST_INIT, SSL_ST_BEFORE, SSL_ST_OK, SSL_ST_RENEGOTIATE
+        ]:
+            assert const is None or isinstance(const, int)
+
+
+class TestRequires(object):
+    """
+    Tests for the decorator factory used to conditionally raise
+    NotImplementedError when older OpenSSLs are used.
+    """
+    def test_available(self):
+        """
+        When the OpenSSL functionality is available the decorated functions
+        work appropriately.
+        """
+        feature_guard = _make_requires(True, "Error text")
+        results = []
+
+        @feature_guard
+        def inner():
+            results.append(True)
+            return True
+
+        assert inner() is True
+        assert [True] == results
+
+    def test_unavailable(self):
+        """
+        When the OpenSSL functionality is not available the decorated function
+        does not execute and NotImplementedError is raised.
+        """
+        feature_guard = _make_requires(False, "Error text")
+
+        @feature_guard
+        def inner():  # pragma: nocover
+            pytest.fail("Should not be called")
+
+        with pytest.raises(NotImplementedError) as e:
+            inner()
+
+        assert "Error text" in str(e.value)
+
+
+class TestOCSP(object):
+    """
+    Tests for PyOpenSSL's OCSP stapling support.
+    """
+    sample_ocsp_data = b"this is totally ocsp data"
+
+    def _client_connection(self, callback, data, request_ocsp=True):
+        """
+        Builds a client connection suitable for using OCSP.
+
+        :param callback: The callback to register for OCSP.
+        :param data: The opaque data object that will be handed to the
+            OCSP callback.
+        :param request_ocsp: Whether the client will actually ask for OCSP
+            stapling. Useful for testing only.
+        """
+        ctx = Context(SSLv23_METHOD)
+        ctx.set_ocsp_client_callback(callback, data)
+        client = Connection(ctx)
+
+        if request_ocsp:
+            client.request_ocsp()
+
+        client.set_connect_state()
+        return client
+
+    def _server_connection(self, callback, data):
+        """
+        Builds a server connection suitable for using OCSP.
+
+        :param callback: The callback to register for OCSP.
+        :param data: The opaque data object that will be handed to the
+            OCSP callback.
+        """
+        ctx = Context(SSLv23_METHOD)
+        ctx.use_privatekey(load_privatekey(FILETYPE_PEM, server_key_pem))
+        ctx.use_certificate(load_certificate(FILETYPE_PEM, server_cert_pem))
+        ctx.set_ocsp_server_callback(callback, data)
+        server = Connection(ctx)
+        server.set_accept_state()
+        return server
+
+    def test_callbacks_arent_called_by_default(self):
+        """
+        If both the client and the server have registered OCSP callbacks, but
+        the client does not send the OCSP request, neither callback gets
+        called.
+        """
+        def ocsp_callback(*args, **kwargs):  # pragma: nocover
+            pytest.fail("Should not be called")
+
+        client = self._client_connection(
+            callback=ocsp_callback, data=None, request_ocsp=False
+        )
+        server = self._server_connection(callback=ocsp_callback, data=None)
+        handshake_in_memory(client, server)
+
+    def test_client_negotiates_without_server(self):
+        """
+        If the client wants to do OCSP but the server does not, the handshake
+        succeeds, and the client callback fires with an empty byte string.
+        """
+        called = []
+
+        def ocsp_callback(conn, ocsp_data, ignored):
+            called.append(ocsp_data)
+            return True
+
+        client = self._client_connection(callback=ocsp_callback, data=None)
+        server = loopback_server_factory(socket=None)
+        handshake_in_memory(client, server)
+
+        assert len(called) == 1
+        assert called[0] == b''
+
+    def test_client_receives_servers_data(self):
+        """
+        The data the server sends in its callback is received by the client.
+        """
+        calls = []
+
+        def server_callback(*args, **kwargs):
+            return self.sample_ocsp_data
+
+        def client_callback(conn, ocsp_data, ignored):
+            calls.append(ocsp_data)
+            return True
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+        handshake_in_memory(client, server)
+
+        assert len(calls) == 1
+        assert calls[0] == self.sample_ocsp_data
+
+    def test_callbacks_are_invoked_with_connections(self):
+        """
+        The first arguments to both callbacks are their respective connections.
+        """
+        client_calls = []
+        server_calls = []
+
+        def client_callback(conn, *args, **kwargs):
+            client_calls.append(conn)
+            return True
+
+        def server_callback(conn, *args, **kwargs):
+            server_calls.append(conn)
+            return self.sample_ocsp_data
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+        handshake_in_memory(client, server)
+
+        assert len(client_calls) == 1
+        assert len(server_calls) == 1
+        assert client_calls[0] is client
+        assert server_calls[0] is server
+
+    def test_opaque_data_is_passed_through(self):
+        """
+        Both callbacks receive an opaque, user-provided piece of data in their
+        callbacks as the final argument.
+        """
+        calls = []
+
+        def server_callback(*args):
+            calls.append(args)
+            return self.sample_ocsp_data
+
+        def client_callback(*args):
+            calls.append(args)
+            return True
+
+        sentinel = object()
+
+        client = self._client_connection(
+            callback=client_callback, data=sentinel
+        )
+        server = self._server_connection(
+            callback=server_callback, data=sentinel
+        )
+        handshake_in_memory(client, server)
+
+        assert len(calls) == 2
+        assert calls[0][-1] is sentinel
+        assert calls[1][-1] is sentinel
+
+    def test_server_returns_empty_string(self):
+        """
+        If the server returns an empty bytestring from its callback, the
+        client callback is called with the empty bytestring.
+        """
+        client_calls = []
+
+        def server_callback(*args):
+            return b''
+
+        def client_callback(conn, ocsp_data, ignored):
+            client_calls.append(ocsp_data)
+            return True
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+        handshake_in_memory(client, server)
+
+        assert len(client_calls) == 1
+        assert client_calls[0] == b''
+
+    def test_client_returns_false_terminates_handshake(self):
+        """
+        If the client returns False from its callback, the handshake fails.
+        """
+        def server_callback(*args):
+            return self.sample_ocsp_data
+
+        def client_callback(*args):
+            return False
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+
+        with pytest.raises(Error):
+            handshake_in_memory(client, server)
+
+    def test_exceptions_in_client_bubble_up(self):
+        """
+        The callbacks thrown in the client callback bubble up to the caller.
+        """
+        class SentinelException(Exception):
+            pass
+
+        def server_callback(*args):
+            return self.sample_ocsp_data
+
+        def client_callback(*args):
+            raise SentinelException()
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+
+        with pytest.raises(SentinelException):
+            handshake_in_memory(client, server)
+
+    def test_exceptions_in_server_bubble_up(self):
+        """
+        The callbacks thrown in the server callback bubble up to the caller.
+        """
+        class SentinelException(Exception):
+            pass
+
+        def server_callback(*args):
+            raise SentinelException()
+
+        def client_callback(*args):  # pragma: nocover
+            pytest.fail("Should not be called")
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+
+        with pytest.raises(SentinelException):
+            handshake_in_memory(client, server)
+
+    def test_server_must_return_bytes(self):
+        """
+        The server callback must return a bytestring, or a TypeError is thrown.
+        """
+        def server_callback(*args):
+            return self.sample_ocsp_data.decode('ascii')
+
+        def client_callback(*args):  # pragma: nocover
+            pytest.fail("Should not be called")
+
+        client = self._client_connection(callback=client_callback, data=None)
+        server = self._server_connection(callback=server_callback, data=None)
+
+        with pytest.raises(TypeError):
+            handshake_in_memory(client, server)
diff --git a/tests/test_tsafe.py b/tests/test_tsafe.py
new file mode 100644
index 0000000..8ffe35a
--- /dev/null
+++ b/tests/test_tsafe.py
@@ -0,0 +1,23 @@
+# Copyright (C) Jean-Paul Calderone
+# See LICENSE for details.
+
+"""
+Unit tests for `OpenSSL.tsafe`.
+"""
+
+from OpenSSL.SSL import TLSv1_METHOD, Context
+from OpenSSL.tsafe import Connection
+
+
+class TestConnection(object):
+    """
+    Tests for `OpenSSL.tsafe.Connection`.
+    """
+    def test_instantiation(self):
+        """
+        `OpenSSL.tsafe.Connection` can be instantiated.
+        """
+        # The following line should not throw an error.  This isn't an ideal
+        # test.  It would be great to refactor the other Connection tests so
+        # they could automatically be applied to this class too.
+        Connection(Context(TLSv1_METHOD), None)
diff --git a/tests/test_util.py b/tests/test_util.py
new file mode 100644
index 0000000..91847e0
--- /dev/null
+++ b/tests/test_util.py
@@ -0,0 +1,18 @@
+import pytest
+
+from OpenSSL._util import exception_from_error_queue, lib
+
+
+class TestErrors(object):
+    """
+    Tests for handling of certain OpenSSL error cases.
+    """
+    def test_exception_from_error_queue_nonexistent_reason(self):
+        """
+        :func:`exception_from_error_queue` raises ``ValueError`` when it
+        encounters an OpenSSL error code which does not have a reason string.
+        """
+        lib.ERR_put_error(lib.ERR_LIB_EVP, 0, 1112, b"", 10)
+        with pytest.raises(ValueError) as exc:
+            exception_from_error_queue(ValueError)
+        assert exc.value.args[0][0][2] == ""
diff --git a/tests/util.py b/tests/util.py
new file mode 100644
index 0000000..4464379
--- /dev/null
+++ b/tests/util.py
@@ -0,0 +1,158 @@
+# Copyright (C) Jean-Paul Calderone
+# Copyright (C) Twisted Matrix Laboratories.
+# See LICENSE for details.
+"""
+Helpers for the OpenSSL test suite, largely copied from
+U{Twisted<http://twistedmatrix.com/>}.
+"""
+
+from six import PY3
+
+
+# This is the UTF-8 encoding of the SNOWMAN unicode code point.
+NON_ASCII = b"\xe2\x98\x83".decode("utf-8")
+
+
+def is_consistent_type(theType, name, *constructionArgs):
+    """
+    Perform various assertions about *theType* to ensure that it is a
+    well-defined type.  This is useful for extension types, where it's
+    pretty easy to do something wacky.  If something about the type is
+    unusual, an exception will be raised.
+
+    :param theType: The type object about which to make assertions.
+    :param name: A string giving the name of the type.
+    :param constructionArgs: Positional arguments to use with
+        *theType* to create an instance of it.
+    """
+    assert theType.__name__ == name
+    assert isinstance(theType, type)
+    instance = theType(*constructionArgs)
+    assert type(instance) is theType
+    return True
+
+
+class EqualityTestsMixin(object):
+    """
+    A mixin defining tests for the standard implementation of C{==} and C{!=}.
+    """
+
+    def anInstance(self):
+        """
+        Return an instance of the class under test.  Each call to this method
+        must return a different object.  All objects returned must be equal to
+        each other.
+        """
+        raise NotImplementedError()
+
+    def anotherInstance(self):
+        """
+        Return an instance of the class under test.  Each call to this method
+        must return a different object.  The objects must not be equal to the
+        objects returned by C{anInstance}.  They may or may not be equal to
+        each other (they will not be compared against each other).
+        """
+        raise NotImplementedError()
+
+    def test_identicalEq(self):
+        """
+        An object compares equal to itself using the C{==} operator.
+        """
+        o = self.anInstance()
+        assert (o == o)
+
+    def test_identicalNe(self):
+        """
+        An object doesn't compare not equal to itself using the C{!=} operator.
+        """
+        o = self.anInstance()
+        assert not (o != o)
+
+    def test_sameEq(self):
+        """
+        Two objects that are equal to each other compare equal to each other
+        using the C{==} operator.
+        """
+        a = self.anInstance()
+        b = self.anInstance()
+        assert (a == b)
+
+    def test_sameNe(self):
+        """
+        Two objects that are equal to each other do not compare not equal to
+        each other using the C{!=} operator.
+        """
+        a = self.anInstance()
+        b = self.anInstance()
+        assert not (a != b)
+
+    def test_differentEq(self):
+        """
+        Two objects that are not equal to each other do not compare equal to
+        each other using the C{==} operator.
+        """
+        a = self.anInstance()
+        b = self.anotherInstance()
+        assert not (a == b)
+
+    def test_differentNe(self):
+        """
+        Two objects that are not equal to each other compare not equal to each
+        other using the C{!=} operator.
+        """
+        a = self.anInstance()
+        b = self.anotherInstance()
+        assert (a != b)
+
+    def test_anotherTypeEq(self):
+        """
+        The object does not compare equal to an object of an unrelated type
+        (which does not implement the comparison) using the C{==} operator.
+        """
+        a = self.anInstance()
+        b = object()
+        assert not (a == b)
+
+    def test_anotherTypeNe(self):
+        """
+        The object compares not equal to an object of an unrelated type (which
+        does not implement the comparison) using the C{!=} operator.
+        """
+        a = self.anInstance()
+        b = object()
+        assert (a != b)
+
+    def test_delegatedEq(self):
+        """
+        The result of comparison using C{==} is delegated to the right-hand
+        operand if it is of an unrelated type.
+        """
+        class Delegate(object):
+            def __eq__(self, other):
+                # Do something crazy and obvious.
+                return [self]
+
+        a = self.anInstance()
+        b = Delegate()
+        assert (a == b) == [b]
+
+    def test_delegateNe(self):
+        """
+        The result of comparison using C{!=} is delegated to the right-hand
+        operand if it is of an unrelated type.
+        """
+        class Delegate(object):
+            def __ne__(self, other):
+                # Do something crazy and obvious.
+                return [self]
+
+        a = self.anInstance()
+        b = Delegate()
+        assert (a != b) == [b]
+
+
+# The type name expected in warnings about using the wrong string type.
+if PY3:
+    WARNING_TYPE_EXPECTED = "str"
+else:
+    WARNING_TYPE_EXPECTED = "unicode"
diff --git a/tox.ini b/tox.ini
new file mode 100644
index 0000000..8bef9e3
--- /dev/null
+++ b/tox.ini
@@ -0,0 +1,85 @@
+[tox]
+envlist = {pypy,pypy3,py27,py34,py35,py36,py37}{,-cryptographyMaster,-cryptographyMinimum},py27-twistedMaster,pypi-readme,check-manifest,flake8,docs,coverage-report
+
+[testenv]
+whitelist_externals =
+    openssl
+passenv = ARCHFLAGS CFLAGS LC_ALL LDFLAGS PATH LD_LIBRARY_PATH TERM
+extras =
+    test
+deps =
+    coverage>=4.2
+    cryptographyMaster: git+https://github.com/pyca/cryptography.git
+    cryptographyMinimum: cryptography==2.3.0
+setenv =
+    # Do not allow the executing environment to pollute the test environment
+    # with extra packages.
+    PYTHONPATH=
+    PIP_NO_BINARY=cryptography
+commands =
+    openssl version
+    coverage run --parallel -m OpenSSL.debug
+    coverage run --parallel -m pytest -v {posargs}
+
+[testenv:py27-twistedMaster]
+deps =
+    # [tls,conch] syntax doesn't work here so we enumerate all dependencies.
+    git+https://github.com/twisted/twisted
+    idna
+    service_identity
+    bcrypt
+passenv = ARCHFLAGS CFLAGS LC_ALL LDFLAGS PATH LD_LIBRARY_PATH TERM
+commands =
+    python -c "import OpenSSL.SSL; print(OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION))"
+    python -c "import cryptography; print(cryptography.__version__)"
+    python -m twisted.trial --reporter=text twisted
+
+[testenv:py35-urllib3Master]
+basepython=python3.5
+deps =
+    pyasn1
+    ndg-httpsclient
+passenv = ARCHFLAGS CFLAGS LC_ALL LDFLAGS PATH LD_LIBRARY_PATH TERM TRAVIS_INFRA
+whitelist_externals =
+    rm
+commands =
+    python -c "import OpenSSL.SSL; print(OpenSSL.SSL.SSLeay_version(OpenSSL.SSL.SSLEAY_VERSION))"
+    python -c "import cryptography; print(cryptography.__version__)"
+    {toxinidir}/.travis/install_urllib3.sh
+    pytest urllib3/test
+    rm -rf ./urllib3
+
+[testenv:flake8]
+deps =
+     flake8
+skip_install = true
+commands =
+     flake8 src tests examples setup.py
+
+[testenv:pypi-readme]
+deps =
+    readme_renderer
+skip_install = true
+commands =
+    python setup.py check -r -s
+
+[testenv:check-manifest]
+deps =
+    check-manifest
+skip_install = true
+commands =
+    check-manifest
+
+[testenv:docs]
+extras =
+    docs
+basepython = python2.7
+commands =
+     sphinx-build -W -b html doc doc/_build/html
+
+[testenv:coverage-report]
+deps = coverage>=4.2
+skip_install = true
+commands =
+    coverage combine
+    coverage report