Add kdf module: Key Derivation Function API (JEP 510, final in JDK 25), HKDF, RFC 5869 vectors, interop with Python cryptography and openssl, per-tenant keys

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_017ic4b7rnC7jppGGdHGESvy

kdf/interop/gen_cases.py

@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+"""Generate interop/cases.tsv: random HKDF inputs plus the expected OKM from Python's `cryptography` package
+(a thin wrapper over OpenSSL's HKDF). Deterministic: fixed seed, so the file is byte-stable.
+Columns: hash <TAB> ikm <TAB> salt <TAB> info <TAB> length <TAB> okm   (hex; an empty field is an empty value)"""
+import random, sys
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.kdf.hkdf import HKDF
+
+HASHES = {"SHA256": hashes.SHA256, "SHA384": hashes.SHA384, "SHA512": hashes.SHA512}
+SIZE = {"SHA256": 32, "SHA384": 48, "SHA512": 64}
+rnd = random.Random(5869)
+
+def rb(n): return bytes(rnd.getrandbits(8) for _ in range(n))
+
+rows = []
+for h in HASHES:
+    for i in range(100):
+        ikm = rb(rnd.choice([1, 16, 22, 32, 64, 100]))
+        salt = b"" if i % 5 == 0 else rb(rnd.choice([1, 13, 32, 80]))
+        info = b"" if i % 7 == 0 else rb(rnd.choice([1, 10, 40, 80]))
+        length = rnd.choice([1, 16, 32, 42, SIZE[h], SIZE[h] + 1, 82, 255 * SIZE[h]]) if i % 10 else 255 * SIZE[h]
+        okm = HKDF(algorithm=HASHES[h](), length=length, salt=salt or None, info=info).derive(ikm)
+        rows.append((h, ikm.hex(), salt.hex(), info.hex(), str(length), okm.hex()))
+
+with open(sys.argv[1], "w") as f:
+    for r in rows: f.write("\t".join(r) + "\n")
+print(f"wrote {len(rows)} cases")