- node:crypto scrypt (N=16384, r=8, p=1, 32-byte output) — zero new dependencies (D-08)
- 16-byte random salt per hash; PHC-encoded format: scrypt$N$r$p$salt_b64url$hash_b64url
- timingSafeEqual for constant-time comparison (prevents timing oracle attacks, T-19-01)
- verifyPassword returns false on any error (never throws); passwords never logged
- All 5 unit tests pass (round-trip, wrong-pw, unique-salt, malformed-hash, PHC-shape)