Pyber – ML-KEM

A pure Python implementation of ML-KEM (FIPS 203), built to understand the underlying mathematics and cryptography.

Validated against ACVP and C2SP test vectors for all three parameter sets (ML-KEM-512, ML-KEM-768, ML-KEM-1024).

Caution

This project is for educational purposes only. It is not hardened, not audited, and must not be used in real cryptographic applications.

Installation

git clone https://github.com/valentinfrm/pyber.git
cd pyber
uv sync

Using pyber

Exposed functions in kem.py:

• keygen(): generate a keypair (ek, dk)
• keygen_checked(): generate a keypair (ek, dk) with fault attack resistance
• encaps(ek): generate a key and ciphertext pair (key, c)
• decaps(dk, c): generate the symmetric key

Example

from pyber.kem import keygen, keygen_checked, encaps, decaps

# Key generation (use keygen_checked() for fault attack resistance)
public_key, private_key = keygen()

# Encapsulation
symmetric_key, ciphertext = encaps(public_key)

# Decapsulation
symmetric_key_dec = decaps(private_key, ciphertext)

assert symmetric_key == symmetric_key_dec

Performance

Fastest observed runtime over 20 runs on APPLE m1:

References

• FIPS 203 - ML-KEM Standard — NIST
• Kyber and Dilithium — Alfred Menezes, University of Waterloo
• Conceptual Review on Number Theoretic Transform and Comprehensive Review on Its Implementations
• kyber-py