pyasn1-modules

0.4.2 · active · verified Sat Mar 28

pyasn1-modules is a collection of ASN.1-based protocol modules for Python, built upon the pyasn1 library. The current version is 0.4.2, released on March 28, 2025. The library is actively maintained, with updates addressing compatibility and support for newer Python versions.

Warnings

breaking Dropped support for Python 2.7, 3.6, and 3.7 in version 0.4.0.
Fix: Upgrade your Python environment to version 3.8 or later.
gotcha Importing modules directly without the pyasn1_modules prefix will result in ImportError.
Fix: Use the correct import statement: from pyasn1_modules import <module_name>.
gotcha Ensure that pyasn1 is installed, as it is a required dependency.
Fix: Install pyasn1 using pip install pyasn1.

Install

pip install pyasn1-modules Install pyasn1-modules

Imports

rfc2459
```
from pyasn1_modules import rfc2459
```
Direct imports without the pyasn1_modules prefix will fail.

Quickstart

Decoding a DER-encoded X.509 certificate using pyasn1-modules.

from pyasn1_modules import rfc2459
from pyasn1.codec.der import decoder

# Example DER-encoded certificate (incomplete for brevity)
der_encoded_cert = b'...'

# Decode the certificate
cert, _ = decoder.decode(der_encoded_cert, asn1Spec=rfc2459.Certificate())

# Access certificate fields
subject = cert['tbsCertificate']['subject']
print('Subject:', subject)

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