nassl

library5.4.0pypypiunverified

Experimental OpenSSL wrapper for Python 3.10+ and SSLyze, providing low-level access to SSL/TLS internals including X.509 certificate extraction, OCSP stapling, and custom handshake logic. Current version 5.4.0, released approximately quarterly.

auth-security http-networking serialization

pip install nassl

github ↗package ↗

INSTALL

IMPORT

SIG · NASSL

nassl

auth-securitypythonv5.4.0

Install

1.9s avg

Import

—

Disk

22MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v5.4.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.000s · 24.1MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.9s · import 0.000s · 25MB

22MB installed

● package 22MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

SslClient

✓ from nassl import SslClient

✗ from nassl import SslClient

Basic TLS handshake with Google and print Common Name.

from nassl import SslClient client = SslClient('www.google.com', 443) client.do_handshake() print('Server cert CN:', client.get_certificate_info().subject.get('CN')) client.close()

Debug

Known issues

breakingnassl v5 dropped support for Python <3.10. Upgrade your Python environment.

fix

Use Python 3.10+ or stay on nassl v4 if you must use older Python.

affects: >=5.0.0

gotchaSslClient.do_handshake() raises a custom 'Connection error' on failure, not a built-in exception. Catch nassl._nassl.OpenSSL_Error.

fix

from nassl._nassl import OpenSSL_Error
try: ...
except OpenSSL_Error: ...

affects: all

deprecatedOld API 'start_ssl_client' and 'get_certificate_chain' are deprecated and will be removed in v6. Use SslClient and SslClient.get_certificate_info().

fix

Replace start_ssl_client with SslClient(); use get_certificate_info().

affects: >=4.0.0

gotchaCalling do_handshake() on an already-closed client raises RuntimeError. Always check if client.is_connected before reusing.

fix

if not client.is_closed(): client.do_handshake()

affects: all

Upgrade

Version history

5.4.0latest on PyPI · released Dec 29, 2025

Audit

Dependencies

No dependency data recorded yet.

Agent activity

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Resources

githubhttps://github.com/nabla-c0d3/nassl ↗

packagehttps://pypi.org/project/nassl/ ↗