asn1 3.3.0

Encoding

If you want to encode data and retrieve its DER-encoded representation, use code such as:

import asn1

encoder = asn1.Encoder()
encoder.start()
encoder.write('1.2.3', asn1.Numbers.ObjectIdentifier)
encoded_bytes = encoder.output()

Decoding

If you want to decode ASN.1 from DER or BER encoded bytes, use code such as:

import asn1

decoder = asn1.Decoder()
decoder.start(encoded_bytes)
tag, value = decoder.read()

3.3.0 (2026-05-15)

• Fix #298 - Incorrect handling of indefinite form length when using ENTER/LEAVE

• Fix #296 - Support for writing IMPLICIT values

3.2.0 (2026-02-06)

• New API using a context manager

  • Support for using Encoder via context manager

  • Support for encoding sequences via context manager

  • Support for encoding sets via context manager

  • Support for using Decoder via context manager

• Add support of Python 3.14

• New way of installing old versions of Python in the Docker file. As a consequence, all versions of Python including 2.7 and from 3.5 to 3.14 are now properly tested.

3.1.0 (2025-05-16)

• #291 - Add support for mypy. As a consequence, the previous module has been migrated to a package.

3.0.1 (2025-05-02)

• Fix #288 - Use DER encoding by default as in previous versions

3.0.0 (2025-03-03)

• Encoding and decoding of the ASN.1 REAL type

• Support of indefinite lengths

• Encoding and decoding of complex data (lists, sets, …)

• Add support for streams (file-like objects) when encoding and decoding

• Optionally return the number of unused bits when decoding a BitString (see also #276)

• #286 - Add ASN.1:2008 compliance test suite

2.8.0 (2025-02-20)

• PR #285 - Use Enum with Tag for pretty representation (thanks to @Julien00859)

• Make explicit that Python 3.12 and 3.13 are supported

• Fix some links in the documentation

• Add a Docker file for testing

2.7.1 (2024-08-07)

• Fix OID encoding/decoding for the first octet according to ITU-T X.690 (thanks to Ian Neal)

2.7.0 (2023-01-17)

• Add context manager support (thanks to Mastermind-U)

2.6.0 (2022-07-15)

• Add support for GeneralizedTime (thanks to vollkorntomate)

2.5.0 (2022-03-03)

• Fixes to BitString decoding and encoding of IA5String and UTCTime (thanks to 0xbf00)

2.4.2 (2021-10-29)

• Fix a minor mistake in the dump.py example

• Add Python 3.9 and 3.10

2.4.1 (2020-07-16)

• Fix #89 - Replace explicit references to enum34 by enum-compat

2.4.0 (2020-06-23)

• Fix #21 - Invalid decoding in non-Universal classes

• Fix #57 - Invalid encoding of non-Universal classes

2.3.1 (2020-04-06)

• No change in code, only in packaging and in texts (README, …)

2.3.0 (2020-04-05)

• Tests: Replace nose by pytest

• Add Python 3.8, remove Python 3.4 support

• PR#26 (from rumbah): Add test for default (implicit) encoding types

• PR#25 (from thomwiggers): Attempt to support BIT STRING

• Fix wrong example code, see #27

• (from jcrowgey) Makes the package usable with pip install

• Remove support of Python 3.3 (some dependencies do not support 3.3)

• PR#15 (from ThePlasmaRailgun) Fix parsing of object identifier

• PR#10 (from robinleander): Allow user to determine decoding tagtype

2.2.0 (2017-10-30)

• Use “true” enums instead of classes. Use enun34 backport for old Python versions.

2.1.1 (2017-10-30)

• Fix a bug (#9): two’s complement corner case with values such as -32769. Add new test cases to test them.

2.1.0 (2016-12-18)

• Add more documentation

• Use (simulated) enumerations

• Add Python 2.6 in automated checks and tests

• Add type hints (for static checking) and fix some code

2.0.0 (2016-12-16)

• First public release by Sebastien Andrivet

• Support both python 2 and 3 (with Python-Future)

• All strings are now in unicode

• Add more ASN.1 tags (like PrintableString)

• Fix errors in the example (dump.py)

• Code reorganization

0.9 (2011-05-18)

• Initial public release by Geert Jansen