diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 85f8447..4506a46 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -24,8 +24,26 @@
   and :class:`~cryptography.hazmat.primitives.kdf.concatkdf.ConcatKDFHMAC`.
 * Raise a ``TypeError`` when passing objects that are not text as the value to
   :class:`~cryptography.x509.NameAttribute`.
+* Add support for :class:`~cryptography.x509.OtherName` as a general name
+  type.
+* Added new X.509 extension support in :class:`~cryptography.x509.Certificate`
+  The following new extensions are now supported:
+
+  * :class:`~cryptography.x509.OCSPNoCheck`
+  * :class:`~cryptography.x509.InhibitAnyPolicy`
+  * :class:`~cryptography.x509.IssuerAlternativeName`
+  * :class:`~cryptography.x509.NameConstraints`
+
+* Extension support was added to
+  :class:`~cryptography.x509.CertificateSigningRequest`.
 * Add support for creating certificate signing requests with
-  :class:`~cryptography.x509.CertificateSigningRequestBuilder`.
+  :class:`~cryptography.x509.CertificateSigningRequestBuilder`. This includes
+  support for the following extensions:
+
+  * :class:`~cryptography.x509.BasicConstraints`
+  * :class:`~cryptography.x509.ExtendedKeyUsage`
+  * :class:`~cryptography.x509.KeyUsage`
+  * :class:`~cryptography.x509.SubjectAlternativeName`
 
 0.9.3 - 2015-07-09
 ~~~~~~~~~~~~~~~~~~
diff --git a/docs/development/test-vectors.rst b/docs/development/test-vectors.rst
index ea44a46..d400e66 100644
--- a/docs/development/test-vectors.rst
+++ b/docs/development/test-vectors.rst
@@ -233,6 +233,8 @@
 * ``cp_user_notice_no_explicit_text.pem`` - An RSA 2048 bit self-signed
   certificate containing a certificate policies extension with a user notice
   with no explicit text.
+* ``cp_invalid.pem`` - An RSA 2048 bit self-signed certificate containing a
+  certificate policies extension with invalid data.
 * ``ian_uri.pem`` - An RSA 2048 bit certificate containing an issuer
   alternative name extension with a ``URI`` general name.
 * ``ocsp_nocheck.pem`` - An RSA 2048 bit self-signed certificate containing
diff --git a/docs/installation.rst b/docs/installation.rst
index 96e1e8d..becab6b 100644
--- a/docs/installation.rst
+++ b/docs/installation.rst
@@ -45,28 +45,18 @@
     $ pip install cryptography
 
 If you prefer to compile it yourself you'll need to have OpenSSL installed.
-There are `pre-compiled binaries`_ available. If your installation is in an
-unusual location set the ``LIB`` and ``INCLUDE`` environment variables to
-include the corresponding locations.For example:
+You can compile OpenSSL yourself as well or use the binaries we build for our
+release infrastructure (`32-bit`_ and `64-bit`_). Wherever you place your copy
+of OpenSSL you'll need to set the ``LIB`` and ``INCLUDE`` environment variables
+to include the proper locations. For example:
 
 .. code-block:: console
 
     C:\> \path\to\vcvarsall.bat x86_amd64
-    C:\> set LIB=C:\OpenSSL\lib\VC\static;C:\OpenSSL\lib;%LIB%
-    C:\> set INCLUDE=C:\OpenSSL\include;%INCLUDE%
+    C:\> set LIB=C:\OpenSSL-win64\lib;%LIB%
+    C:\> set INCLUDE=C:\OpenSSL-win64\include;%INCLUDE%
     C:\> pip install cryptography
 
-You can also choose to build statically or dynamically using the
-``PYCA_WINDOWS_LINK_TYPE`` variable. Allowed values are ``static`` (default)
-and ``dynamic``.
-
-.. code-block:: console
-
-    C:\> \path\to\vcvarsall.bat x86_amd64
-    C:\> set LIB=C:\OpenSSL\lib\VC\static;C:\OpenSSL\lib;%LIB%
-    C:\> set INCLUDE=C:\OpenSSL\include;%INCLUDE%
-    C:\> set PYCA_WINDOWS_LINK_TYPE=dynamic
-    C:\> pip install cryptography
 
 Building cryptography on Linux
 ------------------------------
@@ -186,6 +176,7 @@
 
 .. _`Homebrew`: http://brew.sh
 .. _`MacPorts`: http://www.macports.org
-.. _`pre-compiled binaries`: https://www.openssl.org/related/binaries.html
+.. _`32-bit`: https://jenkins.cryptography.io/job/openssl-win32-release/
+.. _`64-bit`: https://jenkins.cryptography.io/job/openssl-win64-release/
 .. _`bug in conda`: https://github.com/conda/conda-recipes/issues/110
 .. _`Greg Wilson's blog post`: http://software-carpentry.org/blog/2014/04/mr-biczo-was-right.html
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 5e58886..799126b 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -565,6 +565,25 @@
             >>> isinstance(csr.signature_hash_algorithm, hashes.SHA1)
             True
 
+    .. attribute:: extensions
+
+        :type: :class:`Extensions`
+
+        The extensions encoded in the certificate signing request.
+
+        :raises cryptography.x509.DuplicateExtension: If more than one
+            extension of the same type is found within the certificate signing request.
+
+        :raises cryptography.x509.UnsupportedExtension: If the certificate signing request
+            contains an extension that is not supported.
+
+        :raises cryptography.x509.UnsupportedGeneralNameType: If an extension
+            contains a general name that is not supported.
+
+        :raises UnicodeError: If an extension contains IDNA encoding that is
+            invalid or not compliant with IDNA 2008.
+
+
     .. method:: public_bytes(encoding)
 
         .. versionadded:: 1.0
diff --git a/src/_cffi_src/build_openssl.py b/src/_cffi_src/build_openssl.py
index dac3e4d..6a5bf2d 100644
--- a/src/_cffi_src/build_openssl.py
+++ b/src/_cffi_src/build_openssl.py
@@ -4,7 +4,6 @@
 
 from __future__ import absolute_import, division, print_function
 
-import os
 import sys
 
 from _cffi_src.utils import build_ffi_for_binding, extra_link_args
@@ -19,20 +18,8 @@
         # (http://marc.info/?l=openssl-users&m=135361825921871)
         return ["ssl", "crypto"]
     else:
-        link_type = os.environ.get("PYCA_WINDOWS_LINK_TYPE", "static")
-        return _get_openssl_windows_libraries(link_type)
-
-
-def _get_openssl_windows_libraries(link_type):
-    if link_type == "dynamic":
-        return ["libeay32", "ssleay32", "advapi32"]
-    elif link_type == "static" or link_type == "":
-        return ["libeay32mt", "ssleay32mt", "advapi32",
+        return ["libeay32", "ssleay32", "advapi32",
                 "crypt32", "gdi32", "user32", "ws2_32"]
-    else:
-        raise ValueError(
-            "PYCA_WINDOWS_LINK_TYPE must be 'static' or 'dynamic'"
-        )
 
 
 _OSX_PRE_INCLUDE = """
diff --git a/src/_cffi_src/openssl/asn1.py b/src/_cffi_src/openssl/asn1.py
index 5f8ca69..96eff7d 100644
--- a/src/_cffi_src/openssl/asn1.py
+++ b/src/_cffi_src/openssl/asn1.py
@@ -125,7 +125,9 @@
 """
 
 MACROS = """
+ASN1_BIT_STRING *ASN1_BIT_STRING_new(void);
 void ASN1_BIT_STRING_free(ASN1_BIT_STRING *);
+int i2d_ASN1_BIT_STRING(ASN1_BIT_STRING *, unsigned char **);
 /* This is not a macro, but is const on some versions of OpenSSL */
 int ASN1_BIT_STRING_get_bit(ASN1_BIT_STRING *, int);
 ASN1_TIME *M_ASN1_TIME_dup(void *);
diff --git a/src/_cffi_src/openssl/err.py b/src/_cffi_src/openssl/err.py
index eebf19b..73ce4e3 100644
--- a/src/_cffi_src/openssl/err.py
+++ b/src/_cffi_src/openssl/err.py
@@ -230,6 +230,7 @@
 static const int RSA_R_BLOCK_TYPE_IS_NOT_01;
 static const int RSA_R_BLOCK_TYPE_IS_NOT_02;
 static const int RSA_R_PKCS_DECODING_ERROR;
+static const int RSA_F_RSA_SIGN;
 """
 
 FUNCTIONS = """
diff --git a/src/_cffi_src/openssl/x509.py b/src/_cffi_src/openssl/x509.py
index 6bd117b..bdcc171 100644
--- a/src/_cffi_src/openssl/x509.py
+++ b/src/_cffi_src/openssl/x509.py
@@ -325,6 +325,8 @@
 int sk_ASN1_OBJECT_num(Cryptography_STACK_OF_ASN1_OBJECT *);
 ASN1_OBJECT *sk_ASN1_OBJECT_value(Cryptography_STACK_OF_ASN1_OBJECT *, int);
 void sk_ASN1_OBJECT_free(Cryptography_STACK_OF_ASN1_OBJECT *);
+Cryptography_STACK_OF_ASN1_OBJECT *sk_ASN1_OBJECT_new_null(void);
+int sk_ASN1_OBJECT_push(Cryptography_STACK_OF_ASN1_OBJECT *, ASN1_OBJECT *);
 """
 
 CUSTOMIZATIONS = """
diff --git a/src/_cffi_src/openssl/x509v3.py b/src/_cffi_src/openssl/x509v3.py
index 8e42b65..a61ad32 100644
--- a/src/_cffi_src/openssl/x509v3.py
+++ b/src/_cffi_src/openssl/x509v3.py
@@ -33,6 +33,7 @@
 typedef ... Cryptography_STACK_OF_POLICYINFO;
 typedef ... Cryptography_STACK_OF_ASN1_INTEGER;
 typedef ... Cryptography_STACK_OF_GENERAL_SUBTREE;
+typedef ... EXTENDED_KEY_USAGE;
 
 typedef struct {
     X509 *issuer_cert;
@@ -200,6 +201,8 @@
 
 int i2d_GENERAL_NAMES(GENERAL_NAMES *, unsigned char **);
 
+int i2d_EXTENDED_KEY_USAGE(EXTENDED_KEY_USAGE *, unsigned char **);
+
 int sk_GENERAL_NAME_num(struct stack_st_GENERAL_NAME *);
 int sk_GENERAL_NAME_push(struct stack_st_GENERAL_NAME *, GENERAL_NAME *);
 GENERAL_NAME *sk_GENERAL_NAME_value(struct stack_st_GENERAL_NAME *, int);
@@ -220,19 +223,42 @@
 const X509V3_EXT_METHOD *X509V3_EXT_get(X509_EXTENSION *);
 const X509V3_EXT_METHOD *X509V3_EXT_get_nid(int);
 
+Cryptography_STACK_OF_DIST_POINT *sk_DIST_POINT_new_null(void);
 void sk_DIST_POINT_free(Cryptography_STACK_OF_DIST_POINT *);
 int sk_DIST_POINT_num(Cryptography_STACK_OF_DIST_POINT *);
 DIST_POINT *sk_DIST_POINT_value(Cryptography_STACK_OF_DIST_POINT *, int);
+int sk_DIST_POINT_push(Cryptography_STACK_OF_DIST_POINT *, DIST_POINT *);
 
 void sk_POLICYINFO_free(Cryptography_STACK_OF_POLICYINFO *);
 int sk_POLICYINFO_num(Cryptography_STACK_OF_POLICYINFO *);
 POLICYINFO *sk_POLICYINFO_value(Cryptography_STACK_OF_POLICYINFO *, int);
+int sk_POLICYINFO_push(Cryptography_STACK_OF_POLICYINFO *, POLICYINFO *);
+Cryptography_STACK_OF_POLICYINFO *sk_POLICYINFO_new_null(void);
+
+POLICYINFO *POLICYINFO_new(void);
+void POLICYINFO_free(POLICYINFO *);
+
+POLICYQUALINFO *POLICYQUALINFO_new(void);
+void POLICYQUALINFO_free(POLICYQUALINFO *);
+
+NOTICEREF *NOTICEREF_new(void);
+void NOTICEREF_free(NOTICEREF *);
+
+USERNOTICE *USERNOTICE_new(void);
+void USERNOTICE_free(USERNOTICE *);
+
+int i2d_CERTIFICATEPOLICIES(Cryptography_STACK_OF_POLICYINFO *,
+                            unsigned char **);
 
 void sk_POLICYQUALINFO_free(Cryptography_STACK_OF_POLICYQUALINFO *);
 int sk_POLICYQUALINFO_num(Cryptography_STACK_OF_POLICYQUALINFO *);
 POLICYQUALINFO *sk_POLICYQUALINFO_value(Cryptography_STACK_OF_POLICYQUALINFO *,
                                         int);
+int sk_POLICYQUALINFO_push(Cryptography_STACK_OF_POLICYQUALINFO *,
+                           POLICYQUALINFO *);
+Cryptography_STACK_OF_POLICYQUALINFO *sk_POLICYQUALINFO_new_null(void);
 
+Cryptography_STACK_OF_GENERAL_SUBTREE *sk_GENERAL_SUBTREE_new_null(void);
 void sk_GENERAL_SUBTREE_free(Cryptography_STACK_OF_GENERAL_SUBTREE *);
 int sk_GENERAL_SUBTREE_num(Cryptography_STACK_OF_GENERAL_SUBTREE *);
 GENERAL_SUBTREE *sk_GENERAL_SUBTREE_value(
@@ -244,8 +270,14 @@
 void sk_ASN1_INTEGER_free(Cryptography_STACK_OF_ASN1_INTEGER *);
 int sk_ASN1_INTEGER_num(Cryptography_STACK_OF_ASN1_INTEGER *);
 ASN1_INTEGER *sk_ASN1_INTEGER_value(Cryptography_STACK_OF_ASN1_INTEGER *, int);
+int sk_ASN1_INTEGER_push(Cryptography_STACK_OF_ASN1_INTEGER *, ASN1_INTEGER *);
 
 X509_EXTENSION *X509V3_EXT_i2d(int, int, void *);
+
+DIST_POINT *DIST_POINT_new(void);
+void DIST_POINT_free(DIST_POINT *);
+
+int i2d_CRL_DIST_POINTS(Cryptography_STACK_OF_DIST_POINT *, unsigned char **);
 """
 
 CUSTOMIZATIONS = """
diff --git a/src/cryptography/hazmat/backends/openssl/backend.py b/src/cryptography/hazmat/backends/openssl/backend.py
index c190f59..0176de2 100644
--- a/src/cryptography/hazmat/backends/openssl/backend.py
+++ b/src/cryptography/hazmat/backends/openssl/backend.py
@@ -108,7 +108,7 @@
     subject = backend._lib.X509_NAME_new()
     for attribute in attributes:
         value = attribute.value.encode('utf8')
-        obj = _txt2obj(backend, attribute.oid.dotted_string)
+        obj = _txt2obj_gc(backend, attribute.oid.dotted_string)
         res = backend._lib.X509_NAME_add_entry_by_OBJ(
             subject,
             obj,
@@ -134,10 +134,53 @@
     name = name.encode('ascii')
     obj = backend._lib.OBJ_txt2obj(name, 1)
     assert obj != backend._ffi.NULL
+    return obj
+
+
+def _txt2obj_gc(backend, name):
+    obj = _txt2obj(backend, name)
     obj = backend._ffi.gc(obj, backend._lib.ASN1_OBJECT_free)
     return obj
 
 
+def _encode_key_usage(backend, key_usage):
+    set_bit = backend._lib.ASN1_BIT_STRING_set_bit
+    ku = backend._lib.ASN1_BIT_STRING_new()
+    ku = backend._ffi.gc(ku, backend._lib.ASN1_BIT_STRING_free)
+    res = set_bit(ku, 0, key_usage.digital_signature)
+    assert res == 1
+    res = set_bit(ku, 1, key_usage.content_commitment)
+    assert res == 1
+    res = set_bit(ku, 2, key_usage.key_encipherment)
+    assert res == 1
+    res = set_bit(ku, 3, key_usage.data_encipherment)
+    assert res == 1
+    res = set_bit(ku, 4, key_usage.key_agreement)
+    assert res == 1
+    res = set_bit(ku, 5, key_usage.key_cert_sign)
+    assert res == 1
+    res = set_bit(ku, 6, key_usage.crl_sign)
+    assert res == 1
+    if key_usage.key_agreement:
+        res = set_bit(ku, 7, key_usage.encipher_only)
+        assert res == 1
+        res = set_bit(ku, 8, key_usage.decipher_only)
+        assert res == 1
+    else:
+        res = set_bit(ku, 7, 0)
+        assert res == 1
+        res = set_bit(ku, 8, 0)
+        assert res == 1
+
+    pp = backend._ffi.new('unsigned char **')
+    r = backend._lib.i2d_ASN1_BIT_STRING(ku, pp)
+    assert r > 0
+    pp = backend._ffi.gc(
+        pp, lambda pointer: backend._lib.OPENSSL_free(pointer[0])
+    )
+    return pp, r
+
+
 def _encode_basic_constraints(backend, basic_constraints):
     constraints = backend._lib.BASIC_CONSTRAINTS_new()
     constraints = backend._ffi.gc(
@@ -167,89 +210,7 @@
     )
 
     for alt_name in san:
-        if isinstance(alt_name, x509.DNSName):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            gn.type = backend._lib.GEN_DNS
-
-            ia5 = backend._lib.ASN1_IA5STRING_new()
-            assert ia5 != backend._ffi.NULL
-
-            if alt_name.value.startswith(u"*."):
-                value = b"*." + idna.encode(alt_name.value[2:])
-            else:
-                value = idna.encode(alt_name.value)
-
-            res = backend._lib.ASN1_STRING_set(ia5, value, len(value))
-            assert res == 1
-            gn.d.dNSName = ia5
-        elif isinstance(alt_name, x509.RegisteredID):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            gn.type = backend._lib.GEN_RID
-            obj = backend._lib.OBJ_txt2obj(
-                alt_name.value.dotted_string.encode('ascii'), 1
-            )
-            assert obj != backend._ffi.NULL
-            gn.d.registeredID = obj
-        elif isinstance(alt_name, x509.DirectoryName):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            name = _encode_name(backend, alt_name.value)
-            gn.type = backend._lib.GEN_DIRNAME
-            gn.d.directoryName = name
-        elif isinstance(alt_name, x509.IPAddress):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            ipaddr = _encode_asn1_str(
-                backend, alt_name.value.packed, len(alt_name.value.packed)
-            )
-            gn.type = backend._lib.GEN_IPADD
-            gn.d.iPAddress = ipaddr
-        elif isinstance(alt_name, x509.OtherName):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            other_name = backend._lib.OTHERNAME_new()
-            assert other_name != backend._ffi.NULL
-
-            type_id = backend._lib.OBJ_txt2obj(
-                alt_name.type_id.dotted_string.encode('ascii'), 1
-            )
-            assert type_id != backend._ffi.NULL
-            data = backend._ffi.new("unsigned char[]", alt_name.value)
-            data_ptr_ptr = backend._ffi.new("unsigned char **")
-            data_ptr_ptr[0] = data
-            value = backend._lib.d2i_ASN1_TYPE(
-                backend._ffi.NULL, data_ptr_ptr, len(alt_name.value)
-            )
-            if value == backend._ffi.NULL:
-                backend._consume_errors()
-                raise ValueError("Invalid ASN.1 data")
-            other_name.type_id = type_id
-            other_name.value = value
-            gn.type = backend._lib.GEN_OTHERNAME
-            gn.d.otherName = other_name
-        elif isinstance(alt_name, x509.RFC822Name):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            asn1_str = _encode_asn1_str(
-                backend, alt_name._encoded, len(alt_name._encoded)
-            )
-            gn.type = backend._lib.GEN_EMAIL
-            gn.d.rfc822Name = asn1_str
-        elif isinstance(alt_name, x509.UniformResourceIdentifier):
-            gn = backend._lib.GENERAL_NAME_new()
-            assert gn != backend._ffi.NULL
-            asn1_str = _encode_asn1_str(
-                backend, alt_name._encoded, len(alt_name._encoded)
-            )
-            gn.type = backend._lib.GEN_URI
-            gn.d.uniformResourceIdentifier = asn1_str
-        else:
-            raise ValueError(
-                "{0} is an unknown GeneralName type".format(alt_name)
-            )
-
+        gn = _encode_general_name(backend, alt_name)
         res = backend._lib.sk_GENERAL_NAME_push(general_names, gn)
         assert res != 0
 
@@ -262,6 +223,112 @@
     return pp, r
 
 
+def _encode_general_name(backend, name):
+    if isinstance(name, x509.DNSName):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        gn.type = backend._lib.GEN_DNS
+
+        ia5 = backend._lib.ASN1_IA5STRING_new()
+        assert ia5 != backend._ffi.NULL
+
+        if name.value.startswith(u"*."):
+            value = b"*." + idna.encode(name.value[2:])
+        else:
+            value = idna.encode(name.value)
+
+        res = backend._lib.ASN1_STRING_set(ia5, value, len(value))
+        assert res == 1
+        gn.d.dNSName = ia5
+    elif isinstance(name, x509.RegisteredID):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        gn.type = backend._lib.GEN_RID
+        obj = backend._lib.OBJ_txt2obj(
+            name.value.dotted_string.encode('ascii'), 1
+        )
+        assert obj != backend._ffi.NULL
+        gn.d.registeredID = obj
+    elif isinstance(name, x509.DirectoryName):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        dir_name = _encode_name(backend, name.value)
+        gn.type = backend._lib.GEN_DIRNAME
+        gn.d.directoryName = dir_name
+    elif isinstance(name, x509.IPAddress):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        ipaddr = _encode_asn1_str(
+            backend, name.value.packed, len(name.value.packed)
+        )
+        gn.type = backend._lib.GEN_IPADD
+        gn.d.iPAddress = ipaddr
+    elif isinstance(name, x509.OtherName):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        other_name = backend._lib.OTHERNAME_new()
+        assert other_name != backend._ffi.NULL
+
+        type_id = backend._lib.OBJ_txt2obj(
+            name.type_id.dotted_string.encode('ascii'), 1
+        )
+        assert type_id != backend._ffi.NULL
+        data = backend._ffi.new("unsigned char[]", name.value)
+        data_ptr_ptr = backend._ffi.new("unsigned char **")
+        data_ptr_ptr[0] = data
+        value = backend._lib.d2i_ASN1_TYPE(
+            backend._ffi.NULL, data_ptr_ptr, len(name.value)
+        )
+        if value == backend._ffi.NULL:
+            backend._consume_errors()
+            raise ValueError("Invalid ASN.1 data")
+        other_name.type_id = type_id
+        other_name.value = value
+        gn.type = backend._lib.GEN_OTHERNAME
+        gn.d.otherName = other_name
+    elif isinstance(name, x509.RFC822Name):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        asn1_str = _encode_asn1_str(
+            backend, name._encoded, len(name._encoded)
+        )
+        gn.type = backend._lib.GEN_EMAIL
+        gn.d.rfc822Name = asn1_str
+    elif isinstance(name, x509.UniformResourceIdentifier):
+        gn = backend._lib.GENERAL_NAME_new()
+        assert gn != backend._ffi.NULL
+        asn1_str = _encode_asn1_str(
+            backend, name._encoded, len(name._encoded)
+        )
+        gn.type = backend._lib.GEN_URI
+        gn.d.uniformResourceIdentifier = asn1_str
+    else:
+        raise ValueError(
+            "{0} is an unknown GeneralName type".format(name)
+        )
+
+    return gn
+
+
+def _encode_extended_key_usage(backend, extended_key_usage):
+    eku = backend._lib.sk_ASN1_OBJECT_new_null()
+    eku = backend._ffi.gc(eku, backend._lib.sk_ASN1_OBJECT_free)
+    for oid in extended_key_usage:
+        obj = _txt2obj(backend, oid.dotted_string)
+        res = backend._lib.sk_ASN1_OBJECT_push(eku, obj)
+        assert res >= 1
+
+    pp = backend._ffi.new('unsigned char **')
+    r = backend._lib.i2d_EXTENDED_KEY_USAGE(
+        backend._ffi.cast("EXTENDED_KEY_USAGE *", eku), pp
+    )
+    assert r > 0
+    pp = backend._ffi.gc(
+        pp, lambda pointer: backend._lib.OPENSSL_free(pointer[0])
+    )
+    return pp, r
+
+
 @utils.register_interface(CipherBackend)
 @utils.register_interface(CMACBackend)
 @utils.register_interface(DERSerializationBackend)
@@ -971,10 +1038,14 @@
                 pp, r = _encode_basic_constraints(self, extension.value)
             elif isinstance(extension.value, x509.SubjectAlternativeName):
                 pp, r = _encode_subject_alt_name(self, extension.value)
+            elif isinstance(extension.value, x509.KeyUsage):
+                pp, r = _encode_key_usage(self, extension.value)
+            elif isinstance(extension.value, x509.ExtendedKeyUsage):
+                pp, r = _encode_extended_key_usage(self, extension.value)
             else:
                 raise NotImplementedError('Extension not yet supported.')
 
-            obj = _txt2obj(self, extension.oid.dotted_string)
+            obj = _txt2obj_gc(self, extension.oid.dotted_string)
             extension = self._lib.X509_EXTENSION_create_by_OBJ(
                 self._ffi.NULL,
                 obj,
@@ -983,7 +1054,7 @@
             )
             assert extension != self._ffi.NULL
             res = self._lib.sk_X509_EXTENSION_push(extensions, extension)
-            assert res == 1
+            assert res >= 1
         res = self._lib.X509_REQ_add_extensions(x509_req, extensions)
         assert res == 1
 
@@ -991,7 +1062,11 @@
         res = self._lib.X509_REQ_sign(
             x509_req, private_key._evp_pkey, evp_md
         )
-        assert res > 0
+        if res == 0:
+            errors = self._consume_errors()
+            assert errors[0][1] == self._lib.ERR_LIB_RSA
+            assert errors[0][3] == self._lib.RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY
+            raise ValueError("Digest too big for RSA key")
 
         return _CertificateSigningRequest(self, x509_req)
 
@@ -1609,13 +1684,15 @@
             if format is serialization.PrivateFormat.PKCS8:
                 write_bio = self._lib.PEM_write_bio_PKCS8PrivateKey
                 key = evp_pkey
-            elif format is serialization.PrivateFormat.TraditionalOpenSSL:
+            else:
+                assert format is serialization.PrivateFormat.TraditionalOpenSSL
                 if evp_pkey.type == self._lib.EVP_PKEY_RSA:
                     write_bio = self._lib.PEM_write_bio_RSAPrivateKey
                 elif evp_pkey.type == self._lib.EVP_PKEY_DSA:
                     write_bio = self._lib.PEM_write_bio_DSAPrivateKey
-                elif (self._lib.Cryptography_HAS_EC == 1 and
-                      evp_pkey.type == self._lib.EVP_PKEY_EC):
+                else:
+                    assert self._lib.Cryptography_HAS_EC == 1
+                    assert evp_pkey.type == self._lib.EVP_PKEY_EC
                     write_bio = self._lib.PEM_write_bio_ECPrivateKey
 
                 key = cdata
@@ -1632,7 +1709,8 @@
                 return self._private_key_bytes_traditional_der(
                     evp_pkey.type, cdata
                 )
-            elif format is serialization.PrivateFormat.PKCS8:
+            else:
+                assert format is serialization.PrivateFormat.PKCS8
                 write_bio = self._lib.i2d_PKCS8PrivateKey_bio
                 key = evp_pkey
         else:
@@ -1657,7 +1735,8 @@
         elif (self._lib.Cryptography_HAS_EC == 1 and
               key_type == self._lib.EVP_PKEY_EC):
             write_bio = self._lib.i2d_ECPrivateKey_bio
-        elif key_type == self._lib.EVP_PKEY_DSA:
+        else:
+            assert key_type == self._lib.EVP_PKEY_DSA
             write_bio = self._lib.i2d_DSAPrivateKey_bio
 
         bio = self._create_mem_bio()
@@ -1672,7 +1751,8 @@
         if format is serialization.PublicFormat.SubjectPublicKeyInfo:
             if encoding is serialization.Encoding.PEM:
                 write_bio = self._lib.PEM_write_bio_PUBKEY
-            elif encoding is serialization.Encoding.DER:
+            else:
+                assert encoding is serialization.Encoding.DER
                 write_bio = self._lib.i2d_PUBKEY_bio
 
             key = evp_pkey
@@ -1681,7 +1761,8 @@
             assert evp_pkey.type == self._lib.EVP_PKEY_RSA
             if encoding is serialization.Encoding.PEM:
                 write_bio = self._lib.PEM_write_bio_RSAPublicKey
-            elif encoding is serialization.Encoding.DER:
+            else:
+                assert encoding is serialization.Encoding.DER
                 write_bio = self._lib.i2d_RSAPublicKey_bio
 
             key = cdata
diff --git a/src/cryptography/hazmat/backends/openssl/rsa.py b/src/cryptography/hazmat/backends/openssl/rsa.py
index 21414c0..822c730 100644
--- a/src/cryptography/hazmat/backends/openssl/rsa.py
+++ b/src/cryptography/hazmat/backends/openssl/rsa.py
@@ -268,8 +268,9 @@
                     self._backend._lib.RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE):
                 reason = ("Salt length too long for key size. Try using "
                           "MAX_LENGTH instead.")
-            elif (errors[0].reason ==
-                    self._backend._lib.RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY):
+            else:
+                assert (errors[0].reason ==
+                        self._backend._lib.RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY)
                 reason = "Digest too large for key size. Use a larger key."
             assert reason is not None
             raise ValueError(reason)
diff --git a/src/cryptography/hazmat/backends/openssl/x509.py b/src/cryptography/hazmat/backends/openssl/x509.py
index 472d8a7..ee9a3bb 100644
--- a/src/cryptography/hazmat/backends/openssl/x509.py
+++ b/src/cryptography/hazmat/backends/openssl/x509.py
@@ -234,7 +234,15 @@
                         "{0} is not currently supported".format(oid), oid
                     )
             else:
-                value = handler(backend, ext)
+                d2i = backend._lib.X509V3_EXT_d2i(ext)
+                if d2i == backend._ffi.NULL:
+                    backend._consume_errors()
+                    raise ValueError(
+                        "The {0} extension is invalid and can't be "
+                        "parsed".format(oid)
+                    )
+
+                value = handler(backend, d2i)
                 extensions.append(x509.Extension(oid, critical, value))
 
             seen_oids.add(oid)
@@ -358,12 +366,8 @@
         return self._backend._read_mem_bio(bio)
 
 
-def _decode_certificate_policies(backend, ext):
-    cp = backend._ffi.cast(
-        "Cryptography_STACK_OF_POLICYINFO *",
-        backend._lib.X509V3_EXT_d2i(ext)
-    )
-    assert cp != backend._ffi.NULL
+def _decode_certificate_policies(backend, cp):
+    cp = backend._ffi.cast("Cryptography_STACK_OF_POLICYINFO *", cp)
     cp = backend._ffi.gc(cp, backend._lib.sk_POLICYINFO_free)
     num = backend._lib.sk_POLICYINFO_num(cp)
     certificate_policies = []
@@ -386,7 +390,8 @@
                         pqi.d.cpsuri.data, pqi.d.cpsuri.length
                     )[:].decode('ascii')
                     qualifiers.append(cpsuri)
-                elif pqualid == x509.OID_CPS_USER_NOTICE:
+                else:
+                    assert pqualid == x509.OID_CPS_USER_NOTICE
                     user_notice = _decode_user_notice(
                         backend, pqi.d.usernotice
                     )
@@ -431,12 +436,8 @@
     return x509.UserNotice(notice_reference, explicit_text)
 
 
-def _decode_basic_constraints(backend, ext):
-    bc_st = backend._lib.X509V3_EXT_d2i(ext)
-    assert bc_st != backend._ffi.NULL
-    basic_constraints = backend._ffi.cast(
-        "BASIC_CONSTRAINTS *", bc_st
-    )
+def _decode_basic_constraints(backend, bc_st):
+    basic_constraints = backend._ffi.cast("BASIC_CONSTRAINTS *", bc_st)
     basic_constraints = backend._ffi.gc(
         basic_constraints, backend._lib.BASIC_CONSTRAINTS_free
     )
@@ -447,19 +448,13 @@
     if basic_constraints.pathlen == backend._ffi.NULL:
         path_length = None
     else:
-        path_length = _asn1_integer_to_int(
-            backend, basic_constraints.pathlen
-        )
+        path_length = _asn1_integer_to_int(backend, basic_constraints.pathlen)
 
     return x509.BasicConstraints(ca, path_length)
 
 
-def _decode_subject_key_identifier(backend, ext):
-    asn1_string = backend._lib.X509V3_EXT_d2i(ext)
-    assert asn1_string != backend._ffi.NULL
-    asn1_string = backend._ffi.cast(
-        "ASN1_OCTET_STRING *", asn1_string
-    )
+def _decode_subject_key_identifier(backend, asn1_string):
+    asn1_string = backend._ffi.cast("ASN1_OCTET_STRING *", asn1_string)
     asn1_string = backend._ffi.gc(
         asn1_string, backend._lib.ASN1_OCTET_STRING_free
     )
@@ -468,13 +463,9 @@
     )
 
 
-def _decode_authority_key_identifier(backend, ext):
-    akid = backend._lib.X509V3_EXT_d2i(ext)
-    assert akid != backend._ffi.NULL
+def _decode_authority_key_identifier(backend, akid):
     akid = backend._ffi.cast("AUTHORITY_KEYID *", akid)
-    akid = backend._ffi.gc(
-        akid, backend._lib.AUTHORITY_KEYID_free
-    )
+    akid = backend._ffi.gc(akid, backend._lib.AUTHORITY_KEYID_free)
     key_identifier = None
     authority_cert_issuer = None
     authority_cert_serial_number = None
@@ -499,15 +490,9 @@
     )
 
 
-def _decode_authority_information_access(backend, ext):
-    aia = backend._lib.X509V3_EXT_d2i(ext)
-    assert aia != backend._ffi.NULL
-    aia = backend._ffi.cast(
-        "Cryptography_STACK_OF_ACCESS_DESCRIPTION *", aia
-    )
-    aia = backend._ffi.gc(
-        aia, backend._lib.sk_ACCESS_DESCRIPTION_free
-    )
+def _decode_authority_information_access(backend, aia):
+    aia = backend._ffi.cast("Cryptography_STACK_OF_ACCESS_DESCRIPTION *", aia)
+    aia = backend._ffi.gc(aia, backend._lib.sk_ACCESS_DESCRIPTION_free)
     num = backend._lib.sk_ACCESS_DESCRIPTION_num(aia)
     access_descriptions = []
     for i in range(num):
@@ -521,13 +506,9 @@
     return x509.AuthorityInformationAccess(access_descriptions)
 
 
-def _decode_key_usage(backend, ext):
-    bit_string = backend._lib.X509V3_EXT_d2i(ext)
-    assert bit_string != backend._ffi.NULL
+def _decode_key_usage(backend, bit_string):
     bit_string = backend._ffi.cast("ASN1_BIT_STRING *", bit_string)
-    bit_string = backend._ffi.gc(
-        bit_string, backend._lib.ASN1_BIT_STRING_free
-    )
+    bit_string = backend._ffi.gc(bit_string, backend._lib.ASN1_BIT_STRING_free)
     get_bit = backend._lib.ASN1_BIT_STRING_get_bit
     digital_signature = get_bit(bit_string, 0) == 1
     content_commitment = get_bit(bit_string, 1) == 1
@@ -551,11 +532,8 @@
     )
 
 
-def _decode_general_names_extension(backend, ext):
-    gns = backend._ffi.cast(
-        "GENERAL_NAMES *", backend._lib.X509V3_EXT_d2i(ext)
-    )
-    assert gns != backend._ffi.NULL
+def _decode_general_names_extension(backend, gns):
+    gns = backend._ffi.cast("GENERAL_NAMES *", gns)
     gns = backend._ffi.gc(gns, backend._lib.GENERAL_NAMES_free)
     general_names = _decode_general_names(backend, gns)
     return general_names
@@ -573,11 +551,8 @@
     )
 
 
-def _decode_name_constraints(backend, ext):
-    nc = backend._ffi.cast(
-        "NAME_CONSTRAINTS *", backend._lib.X509V3_EXT_d2i(ext)
-    )
-    assert nc != backend._ffi.NULL
+def _decode_name_constraints(backend, nc):
+    nc = backend._ffi.cast("NAME_CONSTRAINTS *", nc)
     nc = backend._ffi.gc(nc, backend._lib.NAME_CONSTRAINTS_free)
     permitted = _decode_general_subtrees(backend, nc.permittedSubtrees)
     excluded = _decode_general_subtrees(backend, nc.excludedSubtrees)
@@ -602,12 +577,8 @@
     return subtrees
 
 
-def _decode_extended_key_usage(backend, ext):
-    sk = backend._ffi.cast(
-        "Cryptography_STACK_OF_ASN1_OBJECT *",
-        backend._lib.X509V3_EXT_d2i(ext)
-    )
-    assert sk != backend._ffi.NULL
+def _decode_extended_key_usage(backend, sk):
+    sk = backend._ffi.cast("Cryptography_STACK_OF_ASN1_OBJECT *", sk)
     sk = backend._ffi.gc(sk, backend._lib.sk_ASN1_OBJECT_free)
     num = backend._lib.sk_ASN1_OBJECT_num(sk)
     ekus = []
@@ -621,14 +592,9 @@
     return x509.ExtendedKeyUsage(ekus)
 
 
-def _decode_crl_distribution_points(backend, ext):
-    cdps = backend._ffi.cast(
-        "Cryptography_STACK_OF_DIST_POINT *",
-        backend._lib.X509V3_EXT_d2i(ext)
-    )
-    assert cdps != backend._ffi.NULL
-    cdps = backend._ffi.gc(
-        cdps, backend._lib.sk_DIST_POINT_free)
+def _decode_crl_distribution_points(backend, cdps):
+    cdps = backend._ffi.cast("Cryptography_STACK_OF_DIST_POINT *", cdps)
+    cdps = backend._ffi.gc(cdps, backend._lib.sk_DIST_POINT_free)
     num = backend._lib.sk_DIST_POINT_num(cdps)
 
     dist_points = []
@@ -716,12 +682,8 @@
     return x509.CRLDistributionPoints(dist_points)
 
 
-def _decode_inhibit_any_policy(backend, ext):
-    asn1_int = backend._ffi.cast(
-        "ASN1_INTEGER *",
-        backend._lib.X509V3_EXT_d2i(ext)
-    )
-    assert asn1_int != backend._ffi.NULL
+def _decode_inhibit_any_policy(backend, asn1_int):
+    asn1_int = backend._ffi.cast("ASN1_INTEGER *", asn1_int)
     asn1_int = backend._ffi.gc(asn1_int, backend._lib.ASN1_INTEGER_free)
     skip_certs = _asn1_integer_to_int(backend, asn1_int)
     return x509.InhibitAnyPolicy(skip_certs)
@@ -789,33 +751,33 @@
         return self._backend._read_mem_bio(bio)
 
 
+_EXTENSION_HANDLERS = {
+    x509.OID_BASIC_CONSTRAINTS: _decode_basic_constraints,
+    x509.OID_SUBJECT_KEY_IDENTIFIER: _decode_subject_key_identifier,
+    x509.OID_KEY_USAGE: _decode_key_usage,
+    x509.OID_SUBJECT_ALTERNATIVE_NAME: _decode_subject_alt_name,
+    x509.OID_EXTENDED_KEY_USAGE: _decode_extended_key_usage,
+    x509.OID_AUTHORITY_KEY_IDENTIFIER: _decode_authority_key_identifier,
+    x509.OID_AUTHORITY_INFORMATION_ACCESS: (
+        _decode_authority_information_access
+    ),
+    x509.OID_CERTIFICATE_POLICIES: _decode_certificate_policies,
+    x509.OID_CRL_DISTRIBUTION_POINTS: _decode_crl_distribution_points,
+    x509.OID_OCSP_NO_CHECK: _decode_ocsp_no_check,
+    x509.OID_INHIBIT_ANY_POLICY: _decode_inhibit_any_policy,
+    x509.OID_ISSUER_ALTERNATIVE_NAME: _decode_issuer_alt_name,
+    x509.OID_NAME_CONSTRAINTS: _decode_name_constraints,
+}
+
+
 _CERTIFICATE_EXTENSION_PARSER = _X509ExtensionParser(
     ext_count=lambda backend, x: backend._lib.X509_get_ext_count(x),
     get_ext=lambda backend, x, i: backend._lib.X509_get_ext(x, i),
-    handlers={
-        x509.OID_BASIC_CONSTRAINTS: _decode_basic_constraints,
-        x509.OID_SUBJECT_KEY_IDENTIFIER: _decode_subject_key_identifier,
-        x509.OID_KEY_USAGE: _decode_key_usage,
-        x509.OID_SUBJECT_ALTERNATIVE_NAME: _decode_subject_alt_name,
-        x509.OID_EXTENDED_KEY_USAGE: _decode_extended_key_usage,
-        x509.OID_AUTHORITY_KEY_IDENTIFIER: _decode_authority_key_identifier,
-        x509.OID_AUTHORITY_INFORMATION_ACCESS: (
-            _decode_authority_information_access
-        ),
-        x509.OID_CERTIFICATE_POLICIES: _decode_certificate_policies,
-        x509.OID_CRL_DISTRIBUTION_POINTS: _decode_crl_distribution_points,
-        x509.OID_OCSP_NO_CHECK: _decode_ocsp_no_check,
-        x509.OID_INHIBIT_ANY_POLICY: _decode_inhibit_any_policy,
-        x509.OID_ISSUER_ALTERNATIVE_NAME: _decode_issuer_alt_name,
-        x509.OID_NAME_CONSTRAINTS: _decode_name_constraints,
-    }
+    handlers=_EXTENSION_HANDLERS
 )
 
 _CSR_EXTENSION_PARSER = _X509ExtensionParser(
     ext_count=lambda backend, x: backend._lib.sk_X509_EXTENSION_num(x),
     get_ext=lambda backend, x, i: backend._lib.sk_X509_EXTENSION_value(x, i),
-    handlers={
-        x509.OID_BASIC_CONSTRAINTS: _decode_basic_constraints,
-        x509.OID_SUBJECT_ALTERNATIVE_NAME: _decode_subject_alt_name,
-    }
+    handlers=_EXTENSION_HANDLERS
 )
diff --git a/src/cryptography/x509.py b/src/cryptography/x509.py
index 9f6cda1..a831506 100644
--- a/src/cryptography/x509.py
+++ b/src/cryptography/x509.py
@@ -1575,12 +1575,16 @@
         """
         if isinstance(extension, BasicConstraints):
             extension = Extension(OID_BASIC_CONSTRAINTS, critical, extension)
+        elif isinstance(extension, ExtendedKeyUsage):
+            extension = Extension(OID_EXTENDED_KEY_USAGE, critical, extension)
         elif isinstance(extension, SubjectAlternativeName):
             extension = Extension(
                 OID_SUBJECT_ALTERNATIVE_NAME, critical, extension
             )
         elif isinstance(extension, KeyUsage):
             extension = Extension(OID_KEY_USAGE, critical, extension)
+        elif isinstance(extension, InhibitAnyPolicy):
+            extension = Extension(OID_INHIBIT_ANY_POLICY, critical, extension)
         else:
             raise NotImplementedError('Unsupported X.509 extension.')
         # TODO: This is quadratic in the number of extensions
diff --git a/tests/hazmat/backends/test_openssl.py b/tests/hazmat/backends/test_openssl.py
index 5b611cd..c2a4f54 100644
--- a/tests/hazmat/backends/test_openssl.py
+++ b/tests/hazmat/backends/test_openssl.py
@@ -36,6 +36,20 @@
 from ...utils import load_vectors_from_file, raises_unsupported_algorithm
 
 
+def skip_if_libre_ssl(openssl_version):
+    if u'LibreSSL' in openssl_version:
+        pytest.skip("LibreSSL hard-codes RAND_bytes to use arc4random.")
+
+
+class TestLibreSkip(object):
+    def test_skip_no(self):
+        assert skip_if_libre_ssl(u"OpenSSL 0.9.8zf 19 Mar 2015") is None
+
+    def test_skip_yes(self):
+        with pytest.raises(pytest.skip.Exception):
+            skip_if_libre_ssl(u"LibreSSL 2.1.6")
+
+
 @utils.register_interface(Mode)
 class DummyMode(object):
     name = "dummy-mode"
@@ -218,6 +232,19 @@
         bn = backend._int_to_bn(0)
         assert backend._bn_to_int(bn) == 0
 
+    def test_actual_osrandom_bytes(self, monkeypatch):
+        skip_if_libre_ssl(backend.openssl_version_text())
+        sample_data = (b"\x01\x02\x03\x04" * 4)
+        length = len(sample_data)
+
+        def notrandom(size):
+            assert size == length
+            return sample_data
+        monkeypatch.setattr(os, "urandom", notrandom)
+        buf = backend._ffi.new("char[]", length)
+        backend._lib.RAND_bytes(buf, length)
+        assert backend._ffi.buffer(buf)[0:length] == sample_data
+
 
 class TestOpenSSLRandomEngine(object):
     def teardown_method(self, method):
diff --git a/tests/hazmat/bindings/test_openssl.py b/tests/hazmat/bindings/test_openssl.py
index f3f2eaf..75a8e3f 100644
--- a/tests/hazmat/bindings/test_openssl.py
+++ b/tests/hazmat/bindings/test_openssl.py
@@ -4,27 +4,11 @@
 
 from __future__ import absolute_import, division, print_function
 
-import os
-
 import pytest
 
 from cryptography.hazmat.bindings.openssl.binding import Binding
 
 
-def skip_if_libre_ssl(openssl_version):
-    if b'LibreSSL' in openssl_version:
-        pytest.skip("LibreSSL hard-codes RAND_bytes to use arc4random.")
-
-
-class TestLibreSkip(object):
-    def test_skip_no(self):
-        assert skip_if_libre_ssl(b"OpenSSL 0.9.8zf 19 Mar 2015") is None
-
-    def test_skip_yes(self):
-        with pytest.raises(pytest.skip.Exception):
-            skip_if_libre_ssl(b"LibreSSL 2.1.6")
-
-
 class TestOpenSSL(object):
     def test_binding_loads(self):
         binding = Binding()
@@ -108,20 +92,6 @@
         with pytest.raises(RuntimeError):
             b._register_osrandom_engine()
 
-    def test_actual_osrandom_bytes(self, monkeypatch):
-        b = Binding()
-        skip_if_libre_ssl(b.ffi.string(b.lib.OPENSSL_VERSION_TEXT))
-        sample_data = (b"\x01\x02\x03\x04" * 4)
-        length = len(sample_data)
-
-        def notrandom(size):
-            assert size == length
-            return sample_data
-        monkeypatch.setattr(os, "urandom", notrandom)
-        buf = b.ffi.new("char[]", length)
-        b.lib.RAND_bytes(buf, length)
-        assert b.ffi.buffer(buf)[0:length] == sample_data
-
     def test_ssl_ctx_options(self):
         # Test that we're properly handling 32-bit unsigned on all platforms.
         b = Binding()
diff --git a/tests/test_utils.py b/tests/test_utils.py
index f71264e..210e929 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -3045,8 +3045,13 @@
     assert expected == load_kasvs_dh_vectors(vector_data)
 
 
+def test_load_kasvs_ecdh_vectors_empty_vector_data():
+    assert [] == load_kasvs_ecdh_vectors([])
+
+
 def test_load_kasvs_ecdh_vectors():
     vector_data = textwrap.dedent("""
+    #  CAVS 11.0
     #  Parameter set(s) supported: EA EB EC ED EE
     #  CAVSid: CAVSid (in hex: 434156536964)
     #  IUTid: In hex: a1b2c3d4e5
diff --git a/tests/test_x509.py b/tests/test_x509.py
index fb58396..ac20f64 100644
--- a/tests/test_x509.py
+++ b/tests/test_x509.py
@@ -1306,6 +1306,20 @@
             x509.SubjectAlternativeName([x509.DNSName(u"cryptography.io")]),
             critical=False,
         ).add_extension(
+            x509.InhibitAnyPolicy(0),
+            critical=False
+        )
+        with pytest.raises(NotImplementedError):
+            builder.sign(private_key, hashes.SHA256(), backend)
+
+    def test_key_usage(self, backend):
+        private_key = RSA_KEY_2048.private_key(backend)
+        builder = x509.CertificateSigningRequestBuilder()
+        request = builder.subject_name(
+            x509.Name([
+                x509.NameAttribute(x509.OID_COUNTRY_NAME, u'US'),
+            ])
+        ).add_extension(
             x509.KeyUsage(
                 digital_signature=True,
                 content_commitment=True,
@@ -1318,9 +1332,82 @@
                 decipher_only=False
             ),
             critical=False
+        ).sign(private_key, hashes.SHA256(), backend)
+        assert len(request.extensions) == 1
+        ext = request.extensions.get_extension_for_oid(x509.OID_KEY_USAGE)
+        assert ext.critical is False
+        assert ext.value == x509.KeyUsage(
+            digital_signature=True,
+            content_commitment=True,
+            key_encipherment=False,
+            data_encipherment=False,
+            key_agreement=False,
+            key_cert_sign=True,
+            crl_sign=False,
+            encipher_only=False,
+            decipher_only=False
         )
-        with pytest.raises(NotImplementedError):
-            builder.sign(private_key, hashes.SHA256(), backend)
+
+    def test_key_usage_key_agreement_bit(self, backend):
+        private_key = RSA_KEY_2048.private_key(backend)
+        builder = x509.CertificateSigningRequestBuilder()
+        request = builder.subject_name(
+            x509.Name([
+                x509.NameAttribute(x509.OID_COUNTRY_NAME, u'US'),
+            ])
+        ).add_extension(
+            x509.KeyUsage(
+                digital_signature=False,
+                content_commitment=False,
+                key_encipherment=False,
+                data_encipherment=False,
+                key_agreement=True,
+                key_cert_sign=True,
+                crl_sign=False,
+                encipher_only=False,
+                decipher_only=True
+            ),
+            critical=False
+        ).sign(private_key, hashes.SHA256(), backend)
+        assert len(request.extensions) == 1
+        ext = request.extensions.get_extension_for_oid(x509.OID_KEY_USAGE)
+        assert ext.critical is False
+        assert ext.value == x509.KeyUsage(
+            digital_signature=False,
+            content_commitment=False,
+            key_encipherment=False,
+            data_encipherment=False,
+            key_agreement=True,
+            key_cert_sign=True,
+            crl_sign=False,
+            encipher_only=False,
+            decipher_only=True
+        )
+
+    def test_add_two_extensions(self, backend):
+        private_key = RSA_KEY_2048.private_key(backend)
+        builder = x509.CertificateSigningRequestBuilder()
+        request = builder.subject_name(
+            x509.Name([x509.NameAttribute(x509.OID_COUNTRY_NAME, u'US')])
+        ).add_extension(
+            x509.SubjectAlternativeName([x509.DNSName(u"cryptography.io")]),
+            critical=False,
+        ).add_extension(
+            x509.BasicConstraints(ca=True, path_length=2), critical=True
+        ).sign(private_key, hashes.SHA1(), backend)
+
+        assert isinstance(request.signature_hash_algorithm, hashes.SHA1)
+        public_key = request.public_key()
+        assert isinstance(public_key, rsa.RSAPublicKey)
+        basic_constraints = request.extensions.get_extension_for_oid(
+            x509.OID_BASIC_CONSTRAINTS
+        )
+        assert basic_constraints.value.ca is True
+        assert basic_constraints.value.path_length == 2
+        ext = request.extensions.get_extension_for_oid(
+            x509.OID_SUBJECT_ALTERNATIVE_NAME
+        )
+        assert list(ext.value) == [x509.DNSName(u"cryptography.io")]
 
     def test_set_subject_twice(self):
         builder = x509.CertificateSigningRequestBuilder()
@@ -1440,6 +1527,42 @@
         with pytest.raises(ValueError):
             builder.sign(private_key, hashes.SHA256(), backend)
 
+    def test_extended_key_usage(self, backend):
+        private_key = RSA_KEY_2048.private_key(backend)
+        builder = x509.CertificateSigningRequestBuilder()
+        request = builder.subject_name(
+            x509.Name([x509.NameAttribute(x509.OID_COUNTRY_NAME, u'US')])
+        ).add_extension(
+            x509.ExtendedKeyUsage([
+                x509.OID_CLIENT_AUTH,
+                x509.OID_SERVER_AUTH,
+                x509.OID_CODE_SIGNING,
+            ]), critical=False
+        ).sign(private_key, hashes.SHA256(), backend)
+
+        eku = request.extensions.get_extension_for_oid(
+            x509.OID_EXTENDED_KEY_USAGE
+        )
+        assert eku.critical is False
+        assert eku.value == x509.ExtendedKeyUsage([
+            x509.OID_CLIENT_AUTH,
+            x509.OID_SERVER_AUTH,
+            x509.OID_CODE_SIGNING,
+        ])
+
+    @pytest.mark.requires_backend_interface(interface=RSABackend)
+    def test_rsa_key_too_small(self, backend):
+        private_key = rsa.generate_private_key(65537, 512, backend)
+        builder = x509.CertificateSigningRequestBuilder()
+        builder = builder.subject_name(
+            x509.Name([x509.NameAttribute(x509.OID_COUNTRY_NAME, u'US')])
+        )
+
+        with pytest.raises(ValueError) as exc:
+            builder.sign(private_key, hashes.SHA512(), backend)
+
+        assert str(exc.value) == "Digest too big for RSA key"
+
 
 @pytest.mark.requires_backend_interface(interface=DSABackend)
 @pytest.mark.requires_backend_interface(interface=X509Backend)
diff --git a/tests/test_x509_ext.py b/tests/test_x509_ext.py
index 7b13582..890709a 100644
--- a/tests/test_x509_ext.py
+++ b/tests/test_x509_ext.py
@@ -2853,3 +2853,18 @@
             x509.OID_INHIBIT_ANY_POLICY
         ).value
         assert iap.skip_certs == 5
+
+
+@pytest.mark.requires_backend_interface(interface=RSABackend)
+@pytest.mark.requires_backend_interface(interface=X509Backend)
+class TestInvalidExtension(object):
+    def test_invalid_certificate_policies_data(self, backend):
+        cert = _load_cert(
+            os.path.join(
+                "x509", "custom", "cp_invalid.pem"
+            ),
+            x509.load_pem_x509_certificate,
+            backend
+        )
+        with pytest.raises(ValueError):
+            cert.extensions
diff --git a/tests/utils.py b/tests/utils.py
index 5083d48..7e7abdf 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -539,8 +539,8 @@
             elif line.startswith("Qy = "):
                 key_data["y"] = int(line.split("=")[1], 16)
 
-    if key_data is not None:
-        vectors.append(key_data)
+    assert key_data is not None
+    vectors.append(key_data)
 
     return vectors
 
@@ -559,9 +559,6 @@
     for line in vector_data:
         line = line.strip()
 
-        if not line or line.startswith("#"):
-            continue
-
         curve_match = curve_rx.match(line)
         if curve_match:
             curve_name = _ECDSA_CURVE_NAMES[curve_match.group("curve")]
@@ -593,8 +590,8 @@
             elif line.startswith("Result = "):
                 data["fail"] = line.split("=")[1].strip()[0] == "F"
 
-    if data is not None:
-        vectors.append(data)
+    assert data is not None
+    vectors.append(data)
     return vectors
 
 
diff --git a/vectors/cryptography_vectors/x509/custom/cp_invalid.pem b/vectors/cryptography_vectors/x509/custom/cp_invalid.pem
new file mode 100644
index 0000000..b7bcc07
--- /dev/null
+++ b/vectors/cryptography_vectors/x509/custom/cp_invalid.pem
@@ -0,0 +1,16 @@
+-----BEGIN CERTIFICATE-----
+MIIC8TCCAdmgAwIBAgITBmsoYWX1PCELRmm8qB2WJ2QdDjANBgkqhkiG9w0BAQUFADASMRAwDgYD
+VQQDDAdQeUNBIENBMB4XDTE1MDUxMTE4NTc0NVoXDTE2MDUxMDE4NTc0NVowEjEQMA4GA1UEAwwH
+UHlDQSBDQTCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAK3FTRITEY4b/Y1Uv4CtH61Y
+19TPxK2+H/XuqHwtYlPRyD35LLFES0wykf0V2m1DUmf9jQa9R63jBZxzCgJ/oIJzV28PgSg9P/Nn
+417fNASDduY2GPvYuwwKXcLY2fBBFjBrz7z/5tyXCADjLDkzoUTzQlYPbhOrFU5QwaqlckXBgt/4
+8GRDujoHy4RSMEDNjLUDgwx7Z/JK2ujbGJDguLRuBsHirk2h6xXEmSWxquKDXw4NnakwBqp8kKhQ
+2xTSWXxabNps8FCBM4sC78gKgONy3lbYdHFt/2BU4yAMyowJwtDEYHCqe1g4sVsB839Ol0SXb6vl
+eXQ6dx+zbi8UzTsCAwEAAaNAMD4wPAYDVR0gBDUwMzAxBgtghkgB4DkBAgMEATAiMCAGCCsGAQUF
+BwICFhRodHRwOi8vb3RoZXIuY29tL2NwczANBgkqhkiG9w0BAQUFAAOCAQEADpZIjHvu02euPNI8
+nzzDufRXEnjrF09xc9pudxTjWU2mSVApXPmTDyWzOD+2HmsNKHRE6sWjca5qPDeDbGq4JOw+TzYq
+9eoqwK2Sh0QHUpg5ZaAmIJ1qe5/sNETH5RFlXrlzW9S0rwViLgUaJp6MreTdGZbxdpNsfdkuNd+S
+Tz0MA/3ScbdUcj6uwQQ4JxQiTuPwD35pKwxfUzHjeTmqIEHDuCk17KqIRORdbeD3vFx0R5IQ3mQ6
+9zSGY2AGB0A9oS0qQ2/Mh59A6xyjbPH3Rr7g5MW58PPTWp2FSXkloy7Ze+doQ7wXE6PVmaeKz5qA
+9OGaCHIiC2iG9UcqWxfeWw==
+-----END CERTIFICATE-----