v4.2.0 - Jura

New features

• New module Crypto.PublicKey.MLKEM, for ML-KEM keys (FIPS 203).
  It is based on the portable C code of
  mlkem-native <https://github.com/pq-code-package/mlkem-native>_ (v2.0.0),
  with the Keccak code of PyCryptodome, also compiled for AVX2 and BMI2 (with 4-way SHA-3).
  The keys can be exported and imported as PKCS#8 DER or PEM files.
• New module Crypto.PublicKey.Hybrid, to model hybrid keys (post-quantum + traditional).
  It supports the hybrid KEM MLKEM768-X25519 (X-Wing), which combines ML-KEM-768 and X25519.
  For now, hybrid keys can only be generated and used with HPKE: they cannot be exported or imported.
• Crypto.Protocol.HPKE accepts ML-KEM keys and X-Wing keys,
  for post-quantum HPKE (draft-ietf-hpke-pq), in the Base and PSK modes.