// kit 01

PQC Toolkit

Production-ready post-quantum crypto. Pick stack, pick primitive, copy the code.

$ pqc_kem.py
L3
PYTHON 
1# requires: pip install pqcrypto pynacl cryptography
2from pqcrypto.kem import ml_kem_768
3from nacl.public import PrivateKey
4from nacl.bindings import crypto_scalarmult
5from cryptography.hazmat.primitives import hashes
6from cryptography.hazmat.primitives.kdf.hkdf import HKDF
7 
8def digest(b: bytes) -> bytes:
9    h = hashes.Hash(hashes.SHA384()); h.update(b); return h.finalize()
10 
11def hybrid_keygen():
12    pq_pub, pq_priv = ml_kem_768.generate_keypair()
13    x_priv = PrivateKey.generate()
14    return {
15        "pq_pub": pq_pub, "pq_priv": pq_priv,
16        "x_pub":  bytes(x_priv.public_key), "x_priv": bytes(x_priv),
17    }
18 
19def hybrid_encaps(server_pub_pq: bytes, server_pub_x: bytes):
20    pq_ct, ss_pq = ml_kem_768.encrypt(server_pub_pq)
21    eph_priv = PrivateKey.generate()
22    eph_pub  = bytes(eph_priv.public_key)
23    ss_x     = crypto_scalarmult(bytes(eph_priv), server_pub_x)
24    transcript = digest(pq_ct + eph_pub)
25    session = HKDF(algorithm=hashes.SHA384(), length=32,
26                   salt=transcript, info=b"qbit404-hybrid").derive(ss_x + ss_pq)
27    return {"pq_ct": pq_ct, "eph_pub": eph_pub, "session": session}
28 
29def hybrid_decaps(pq_ct: bytes, client_pub_x: bytes, pq_priv: bytes, x_priv: bytes):
30    ss_pq = ml_kem_768.decrypt(pq_priv, pq_ct)
31    ss_x  = crypto_scalarmult(x_priv, client_pub_x)
32    transcript = digest(pq_ct + client_pub_x)
33    return HKDF(algorithm=hashes.SHA384(), length=32,
34                salt=transcript, info=b"qbit404-hybrid").derive(ss_x + ss_pq)
KEY SIZE
1184 B pub
SIG / CT
1088 B ct
NIST LEVEL
L3
NOTES

PQClean reference under the hood. Same hybrid construction as the Next.js version — wire-compatible.

  • Threading: generate_keypair is single-threaded; pool it.
  • Use secrets and os.urandom only.
  • For TLS-style use, feed session into AES-256-GCM with a per-direction nonce counter.