| commit | aaa2c5a523ca0484365ee38b7d522b85a6f03509 | [log] [tgz] |
|---|---|---|
| author | wbond <will@wbond.net> | Tue Sep 04 06:53:53 2018 -0400 |
| committer | wbond <will@wbond.net> | Tue Sep 04 06:53:53 2018 -0400 |
| tree | 4d6a0a07f8b72666943e73286ab4590da2b84a4e | |
| parent | ba72f7177a713d4e9b468c005f6c4306cbca5cc5 [diff] |
Try caching homebrew on CircleCI
- .circleci/
- asn1crypto/
- dev/
- docs/
- requires/
- tests/
- .gitignore
- .travis.yml
- appveyor.yml
- changelog.md
- codecov.json
- LICENSE
- MANIFEST.in
- readme.md
- run.py
- setup.cfg
- setup.py
- tox.ini
asn1crypto
A fast, pure Python library for parsing and serializing ASN.1 structures.
- Features
- Why Another Python ASN.1 Library?
- Related Crypto Libraries
- Current Release
- Dependencies
- Installation
- License
- Documentation
- Continuous Integration
- Testing
- Development
Features
In addition to an ASN.1 BER/DER decoder and DER serializer, the project includes a bunch of ASN.1 structures for use with various common cryptography standards:
| Standard | Module | Source |
|---|---|---|
| X.509 | asn1crypto.x509 | RFC 5280 |
| CRL | asn1crypto.crl | RFC 5280 |
| CSR | asn1crypto.csr | RFC 2986, RFC 2985 |
| OCSP | asn1crypto.ocsp | RFC 6960 |
| PKCS#12 | asn1crypto.pkcs12 | RFC 7292 |
| PKCS#8 | asn1crypto.keys | RFC 5208 |
| PKCS#1 v2.1 (RSA keys) | asn1crypto.keys | RFC 3447 |
| DSA keys | asn1crypto.keys | RFC 3279 |
| Elliptic curve keys | asn1crypto.keys | SECG SEC1 V2 |
| PKCS#3 v1.4 | asn1crypto.algos | PKCS#3 v1.4 |
| PKCS#5 v2.1 | asn1crypto.algos | PKCS#5 v2.1 |
| CMS (and PKCS#7) | asn1crypto.cms | RFC 5652, RFC 2315 |
| TSP | asn1crypto.tsp | RFC 3161 |
| PDF signatures | asn1crypto.pdf | PDF 1.7 |
Why Another Python ASN.1 Library?
Python has long had the pyasn1 and pyasn1_modules available for parsing and serializing ASN.1 structures. While the project does include a comprehensive set of tools for parsing and serializing, the performance of the library can be very poor, especially when dealing with bit fields and parsing large structures such as CRLs.
After spending extensive time using pyasn1, the following issues were identified:
- Poor performance
- Verbose, non-pythonic API
- Out-dated and incomplete definitions in pyasn1-modules
- No simple way to map data to native Python data structures
- No mechanism for overridden universal ASN.1 types
The pyasn1 API is largely method driven, and uses extensive configuration objects and lowerCamelCase names. There were no consistent options for converting types of native Python data structures. Since the project supports out-dated versions of Python, many newer language features are unavailable for use.
Time was spent trying to profile issues with the performance, however the architecture made it hard to pin down the primary source of the poor performance. Attempts were made to improve performance by utilizing unreleased patches and delaying parsing using the Any type. Even with such changes, the performance was still unacceptably slow.
Finally, a number of structures in the cryptographic space use universal data types such as BitString and OctetString, but interpret the data as other types. For instance, signatures are really byte strings, but are encoded as BitString. Elliptic curve keys use both BitString and OctetString to represent integers. Parsing these structures as the base universal types and then re-interpreting them wastes computation.
asn1crypto uses the following techniques to improve performance, especially when extracting one or two fields from large, complex structures:
- Delayed parsing of byte string values
- Persistence of original ASN.1 encoded data until a value is changed
- Lazy loading of child fields
- Utilization of high-level Python stdlib modules
While there is no extensive performance test suite, the CRLTests.test_parse_crl test case was used to parse a 21MB CRL file on a late 2013 rMBP. asn1crypto parsed the certificate serial numbers in just under 8 seconds. With pyasn1, using definitions from pyasn1-modules, the same parsing took over 4,100 seconds.
For smaller structures the performance difference can range from a few times faster to an order of magnitude of more.
Related Crypto Libraries
asn1crypto is part of the modularcrypto family of Python packages:
Current Release
0.24.0 - changelog
Dependencies
Python 2.6, 2.7, 3.2, 3.3, 3.4, 3.5, 3.6 or pypy. No third-party packages required.
Installation
pip install asn1crypto
License
asn1crypto is licensed under the terms of the MIT license. See the LICENSE file for the exact license text.
Documentation
The documentation for asn1crypto is composed of tutorials on basic usage and links to the source for the various pre-defined type classes.
Tutorials
Reference
- Universal types,
asn1crypto.core - Digest, HMAC, signed digest and encryption algorithms,
asn1crypto.algos - Private and public keys,
asn1crypto.keys - X509 certificates,
asn1crypto.x509 - Certificate revocation lists (CRLs),
asn1crypto.crl - Online certificate status protocol (OCSP),
asn1crypto.ocsp - Certificate signing requests (CSRs),
asn1crypto.csr - Private key/certificate containers (PKCS#12),
asn1crypto.pkcs12 - Cryptographic message syntax (CMS, PKCS#7),
asn1crypto.cms - Time stamp protocol (TSP),
asn1crypto.tsp - PDF signatures,
asn1crypto.pdf
Continuous Integration
- Windows via AppVeyor
- OS X via CircleCI
- Linux via Travis CI
- Test Coverage via Codecov
Testing
Tests are written using unittest and require no third-party packages:
python run.py tests
To run only some tests, pass a regular expression as a parameter to tests.
python run.py tests ocsp
Development
To install the package used for linting, execute:
pip install --user -r requires/lint
The following command will run the linter:
python run.py lint
Support for code coverage can be installed via:
pip install --user -r requires/coverage
Coverage is measured by running:
python run.py coverage
To install the necessary packages for releasing a new version on PyPI, run:
pip install --user -r requires/release
Releases are created by:
Making a git tag in semver format
Running the command:
python run.py release
Existing releases can be found at https://pypi.org/project/asn1crypto/.
CI Tasks
A task named deps exists to download and stage all necessary testing dependencies. On posix platforms, curl is used for downloads and on Windows PowerShell with Net.WebClient is used. This configuration sidesteps issues related to getting pip to work properly and messing with site-packages for the version of Python being used.
The ci task runs lint (if flake8 is available for the version of Python) and coverage (or tests if coverage is not available for the version of Python). If the current directory is a clean git working copy, the coverage data is submitted to codecov.io.
python run.py deps python run.py ci