asn1crypto

Fast ASN.1 parser and serializer with definitions for private keys, public keys, certificates, CRL, OCSP, CMS, PKCS#3, PKCS#7, PKCS#8, PKCS#12, PKCS#5, X.509 and TSP

asn1crypto Permissive license MIT Active ★ 362 v1.5.1 released 2022-03-15

Install

asn1crypto on PyPI

pip

pip install asn1crypto

uv

uv add asn1crypto

poetry

poetry add asn1crypto

Package facts

License	MIT (permissive)
Python support	not specified
Install friction	low — pure-Python wheel
Runtime dependencies	none
Maintenance	actively maintained — 1,612 days since the last release
Last repo commit	2026-07-18
First released	2015-10-20
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: asn1crypto-1.5.1-py2.py3-none-any.whl

Keywords: asn1, crypto, pki, x509, certificate, rsa, dsa, ec, dh

Development Status :: 5 - Production/StableIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseProgramming Language :: PythonProgramming Language :: Python :: 2Programming Language :: Python :: 2.6Programming Language :: Python :: 2.7Programming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.2Programming Language :: Python :: 3.3Programming Language :: Python :: 3.4Programming Language :: Python :: 3.5Programming Language :: Python :: 3.6Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: Security :: Cryptography

About asn1crypto

from the package's own PyPI description — quoted content, verbatim

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
Security Policy
Documentation
Continuous Integration
Testing
Development
CI Tasks

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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...

Read as markdown · JSON record · Source repository · Homepage

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

asn1crypto parses and serializes ASN.1 structures used in cryptography standards including X.509 certificates, CRLs, CSRs, OCSP, and PKCS formats, with a focus on performance and Pythonic APIs.

Installation is straightforward with no runtime dependencies and a pure-Python wheel. The project remains actively maintained with recent commits.

MIT license is permissive and imposes no restrictions on use, modification, or distribution in proprietary or open-source contexts.

Usage

pip install asn1crypto

from asn1crypto import x509
cert = x509.Certificate.load(cert_der_bytes)
subject = cert.subject

Verdict: asn1crypto is a production-ready, dependency-free ASN.1 library with strong cryptographic standards support and no known vulnerabilities. Active repository status and recent commits indicate ongoing maintenance.

Needs verification

Whether the gap since the 2022-03-15 release reflects intentional stability or reduced development activity
Current adoption breadth and whether performance claims versus alternative libraries remain valid

asn1 parser serializerx509 certificate parsingpkcs key handlingasn.1 ber der decodercryptography certificate structurescrl ocsp parsingpython asn1 library