qcrypto 0.2.0

Quantum-safe cryptography utilities built on top of liboqs-python

qcrypto

Version: 0.1.2

qcrypto is a lightweight Python library providing simple, Pythonic wrappers around post-quantum cryptography (PQC) algorithms using the official liboqs-python bindings from the Open Quantum Safe project.

The library currently includes:

• Kyber Key Encapsulation Mechanism (KEM)
• Dilithium digital signatures
• A hybrid PQC + AES-GCM encryption scheme
• Clean utility classes and exception handling

qcrypto is suitable for learning PQC, research, prototyping, and experiments involving quantum-safe primitives.

Features

Kyber KEM

• Public/secret key generation
• Encapsulation (ciphertext + shared secret)
• Decapsulation (recover shared secret)
• Supports Kyber512, Kyber768, Kyber1024

Dilithium Signatures

• Keypair generation
• Message signing
• Signature verification
• Supports Dilithium2, Dilithium3, Dilithium5

Hybrid PQC + AES Encryption

A simple hybrid model where:

• Kyber encapsulates a symmetric key
• AES-256-GCM encrypts the message
• Result is (kem_ciphertext, aes_ciphertext)

Installation

Requires Python 3.8+.

pip install qcrypto

This installs liboqs-python automatically.

Usage

Usage examples are available in the examples/ directory

Implementation Notes

• Uses liboqs-python, which bundles OQS C library implementations.
• Hybrid encryption uses AES-256-GCM.
• Pure Python package, no compiled extensions.
• Modern PEP 621 src/ layout.

Changelog

v0.2.0 — Hybrid API Rewrite, Key Serialization, Ciphertext Format

• Added encrypt() and decrypt() as the new high-level hybrid PQC API
• Introduced a single-blob ciphertext format:
  • version byte
  • algorithm identifier
  • Kyber ciphertext length
  • Kyber ciphertext
  • AES-GCM nonce
  • AES-GCM ciphertext+tag
• Added key serialization helpers:
  • save_public_key(), save_private_key()
  • KyberKEM.load_public_key(), KyberKEM.load_private_key()
• decapsulate() now accepts a private key directly
• Legacy API (encrypt_for_recipient, decrypt_from_sender) retained for compatibility
• Updated example usage and documentation
• Cleaned internal attribute naming (private_key rather than secret_key)

Disclaimer

This library is for educational, experimental, and research use.
It is not a production security component and has not undergone cryptographic review.

License

MIT License.

Resources

• Open Quantum Safe Project: https://openquantumsafe.org
• liboqs-python: https://github.com/open-quantum-safe/liboqs-python