Best Crypto Libraries for Python Developers

This post provides some high-level introductions to cryptography libraries widely used in Python.

Contents

· M2Crypto · Cryptography · PyCryptodome · liboqs-python

M2Crypto

M2Crypto (M2 stands for “me, too!”) is a Python crypto and SSL toolkit. It is a wrapper of OpenSSL, providing a robust set of cryptographic functionalities, including encryption, digital signatures, certificates, and SSL/TLS support. It is one of the older Python cryptography libraries and offers low-level OpenSSL bindings.

M2Crypto is quite easy to use. As it is wrapped from OpenSSL, this library supports all functionalities that OpenSSL provides for symmetric cryptography, asymmetric cryptography, MAC, Certificate Managements, Secure Email Messaging, TLS, SSL, HTTPS, … that other libraries don’t provide. However, this library is currently in maintenance mode and Python developers are recommended to use a more modern alternative.

✅ Advantages

✔ Low-level APIs: Supports both simple and advanced use cases. ✔ TLS, X.509, and SSL support: Can handle certificates and secure communication. ✔ Uses OpenSSL: Provides high-performance cryptography.

❌ Disadvantages

❌ Requires OpenSSL: Installation issues may arise if OpenSSL libraries are missing. ❌ Outdated: No longer maintained.

Cryptography

Cryptography library is a more modern alternative to M2Crypto. It provides two levels: cryptographic recipes and cryptographic primitives.

Cryptographic recipes: a high level, that requires little to no configuration choices. These are safe and easy to use and don’t require developers to make many decisions. There are two packages in this layer:

• Fernet: implementations of symmetric authenticated cryptography
• X.509: APIs for PKI and X.509 certificates used to authenticate servers and clients (e.g., used in web servers using HTTPS)

Cryptographic primitives: a low-level, that is often dangerous if misused or incorrectly used. They require Python developers to make decisions and have an in-depth knowledge of the cryptographic concepts. Those primitives are in the cryptography.hazmat package, where “hazmat” stands for “hazardous materials” as of the potential danger in working at this level.

✅ Advantages

✔ Actively maintained: Secure and frequently updated. ✔ High-level & low-level APIs: Supports both simple and advanced use cases. ✔ TLS, X.509, and SSL support: Can handle certificates and secure communication. ✔ Uses OpenSSL: Provides high-performance cryptography. ✔ Compliant with security standards: Supports FIPS 140–2, NIST guidelines.

❌ Disadvantages

❌ Requires OpenSSL: Installation issues may arise if OpenSSL libraries are missing. ❌ Limited post-quantum support: Does not natively support post-quantum cryptography.

PyCryptodome

PyCryptodome, a fork of the old PyCrypto library, or PyCryptodomex, independent from PyCrypto, is pure Python and is known as the best for AES, RSA, and hashing. Unlike cryptography , PyCryptodomedoes not require OpenSSL. While it is a lightweight alternative, it does not support TLS or certificate handling. It thus is suitable for simple, standalone solutions for cryptographic primitives.

✅ Advantages

✔ Easy to install (pure Python, no OpenSSL dependency). ✔ Drop-in replacement for PyCrypto (legacy support). ✔ Supports AES, RSA, SHA, and password hashing. ✔ Good for offline/local encryption tasks.

❌ Disadvantages

❌ No TLS/SSL support (use cryptography for that). ❌ Limited support for X.509 certificates. ❌ No post-quantum cryptography.

liboqs-python

The Open Quantum Safe (OQS) project implements quantum-resistant cryptography. The core library liboqs was written in C, implementing KEM and digital signature algorithms. liboqs-python is a wrapper written in Python 3.

✅ Advantages

✔ Provides post-quantum security (NIST PQC algorithms). ✔ Faster than pure Python implementations (C backend). ✔ Supports both KEMs and digital signatures. ✔ Hybrid cryptography support (for classical-PQC transitions). ✔ Actively maintained by Open Quantum Safe (OQS) Project.

❌ Disadvantages

❌ Requires liboqs (C library) → Installation is harder than cryptography. ❌ Not as widely adopted as classical cryptography (still in transition phase).