- 7 deterministic tests: AES-256-CBC encrypt/decrypt, empty, HMAC-SHA256, HMAC verify, SHA-256 x2 - Fixed IV vectors for reproducible results (no randomness) - HMAC golden value cross-verified with openssl (file input) and Python hmac module - SHA-256 values match FORMAT.md Section 12.3 known vectors Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>