feat: ML-DSA-65, did:key, named hash algorithm, model provenance, log tiles and witnesses

- hashing.algorithm names the hash function in every document; a consumer refuses one it does not implement (doc.hash.algorithm)
- ML-DSA-65 (FIPS 204) is an implemented signature scheme: pure-Python reference in tools/oracle/mldsa.py checked against NIST ACVP vectors, a receipt signed by the new roster key dana, and signature vectors for key generation and a deterministic signature
- roster keys may carry a did:key, which the validator checks against the public key (doc.roster.did), and a witness purpose for parties that cosign log checkpoints
- model provenance: a correction's author and an annotation's generator name the model with provider, version and the hashes of its weights, prompt and parameters, and where it ran
- the transparency log gains the tlog-tiles static layout (fixtures/records/log/), a project settings.log with origin, witnesses and threshold, and an acceptance rule; the fixture checkpoint is cosigned by a witness
- store.sql: roster_keys accepts cose and ml-dsa-65 and gains a did column
- spec chapters 01, 08, 11, 18, 20 and 23, the rationale, glossary, fixture, vector and tool guides updated; stress harness covers ML-DSA

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/stress.py

@@ -34,7 +34,7 @@ from tools.oracle import align as AL  # noqa: E402
 from tools.oracle import anchors as AN  # noqa: E402
 from tools.oracle import corrections as CO  # noqa: E402
 from tools.oracle import crypto, fingerprint as FP, hashing, jcs, receipts as RC, rights as RI, targets as TG  # noqa: E402
-from tools.oracle import keys as K, log as LG, vrf  # noqa: E402
+from tools.oracle import keys as K, log as LG, mldsa, vrf  # noqa: E402
 from tools.oracle import package as PK  # noqa: E402
 from tools.oracle.model import LABELLED, LEAVES, Doc  # noqa: E402
 from tools.oracle.notation import fold_math  # noqa: E402
@@ -672,6 +672,24 @@ def stress_checkpoints(rng, rounds):
         ok("checkpoints", p2 is None or len(v2) < len(verified), "an edited note still fully verifies: %r" % bad[max(0, k - 5):k + 5])
 
 
+def stress_mldsa(rng, rounds):
+    """ML-DSA-65 signs deterministically and verifies; a flipped bit anywhere, another message or another key fails."""
+    for _ in range(max(3, rounds // 50)):
+        seed = os.urandom(32)
+        pk, sk = mldsa.keygen(seed)
+        msg = os.urandom(rng.randint(0, 100))
+        sig = mldsa.sign(sk, msg)
+        ok("ml-dsa", len(pk) == mldsa.PK_SIZE and len(sk) == mldsa.SK_SIZE and len(sig) == mldsa.SIG_SIZE, "sizes")
+        ok("ml-dsa", mldsa.verify(pk, msg, sig) and mldsa.sign(sk, msg) == sig, "a signature does not verify or is not deterministic")
+        bad = bytearray(sig)
+        bad[rng.randrange(len(bad))] ^= 1 << rng.randrange(8)
+        ok("ml-dsa", not mldsa.verify(pk, msg, bytes(bad)), "a tampered signature verifies")
+        ok("ml-dsa", not mldsa.verify(pk, msg + b"x", sig) and not mldsa.verify(mldsa.keygen(os.urandom(32))[0], msg, sig),
+           "a signature verifies for another message or key")
+        ok("ml-dsa", not mldsa.verify(pk, msg, os.urandom(mldsa.SIG_SIZE)) and not mldsa.verify(os.urandom(mldsa.PK_SIZE), msg, sig),
+           "garbage verifies")
+
+
 def main():
     ap = argparse.ArgumentParser(description=__doc__.splitlines()[0])
     ap.add_argument("--seed", type=int, default=20261014, help="the random seed (default 20261014)")
@@ -699,6 +717,7 @@ def main():
     stress_vrf(rng, a.rounds)
     stress_proofs(rng, a.rounds)
     stress_checkpoints(rng, a.rounds)
+    stress_mldsa(rng, a.rounds)
     for k in sorted(COUNTS):
         print("%-17s %6d checks" % (k, COUNTS[k]))
     if FAILS: