pqhybridsign (Python)

Python bindings for pqhybridsign, a suite of six hybrid classical / post-quantum signature schemes (H1 through H6), built on pyo3 over the workspace's type-erased pqhybridsign-abi crate.

H1 through H4 are stateless: sign and verify with bytes in, bytes out.

H5 and H6 pair a classical scheme with SHRINCS, a stateful hash-based scheme whose post-quantum half spends a one-time leaf per signature. Their secret key is StatefulSecretKey, not bytes: reusing a leaf is a total loss of the key's post-quantum security, so StatefulSecretKey refuses to be copied, deep-copied or pickled.

keygen_stateful_from_seed and load_stateful_secret_key both bind a journal to the StatefulSecretKey they return, for that key's whole lifetime; sign_stateful always spends leaves through that bound journal and takes no journal argument of its own. Loading the same exported key twice must reuse the same journal object, or the same durable store behind it, every time: two independent journals that have never seen the key both correctly report leaf 0 as next, and nothing in this crate can tell that apart from a legitimate restart. What binding a journal at construction does catch, the moment the key is asked to sign, is every case where a single journal was meant to be shared and was not kept in step: a stale blob loaded against an already-advanced journal, an advanced blob loaded against a journal that missed a commit, or two key objects sharing one journal instance where the second tries to sign after the first already has. Each of those raises CountersDivergedError.

keygen_from_seed returns the secret key as a Python bytes object. A bytes object is immutable. This binding cannot zeroize it once the caller holds it. The binding zeroizes every Rust copy it makes before that copy drops. That covers only the memory this crate controls. Callers that need the binding to zeroize the secret key on drop must use StatefulSecretKey or the C ABI.

import pqhybridsign as phs

sk, pk = phs.keygen_from_seed(phs.Suite.H1, seed)
sig = phs.sign(phs.Suite.H1, sk, b"message", b"context")
assert phs.verify(phs.Suite.H1, pk, b"message", b"context", sig)

Every wheel this crate ships is built against exactly one SHRINCS profile; compare pqhybridsign.profile_name() between the two sides of an integration before trusting anything on the wire.

Building

maturin develop

Testing

maturin develop
pytest