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resultsaudit-latest.md

1. Verification of the 8 Hardening Items

  1. Full Windows parity (VirtualLock + VirtualProtect in secure_alloc.rs / memory_guard.py)
  1. Mandatory ML-DSA manifest signing + full PQ ratchet beacon (ML-KEM-1024 integrated into ratchet path)
  • Status: Fully Implemented
  • Is it correctly wired into production paths? Yes
  • Reachability: production
  • Evidence: Mandatory signing in meow_decoder/manifest_signing.py; encoder fail-closed on missing ML-DSA backend in meow_decoder/encode.py; decoder enforces signature by default in meow_decoder/decode_gif.py. PQ ratchet beacon logic exists in meow_decoder/ratchet.py and meow_decoder/ratchet.py. Encoder now passes receiver_pq_public_key (ML-KEM-1024 keys only, 1568 bytes) to EncoderRatchet in meow_decoder/encode.py; decoder now constructs a PQBeaconKeyPair from the HybridKeyPair and passes it as receiver_pq_keypair to DecoderRatchet via _ratchet_params in meow_decoder/decode_gif.py.
  • Any remaining weakness, stub, or incomplete integration? Signing can be disabled via MEOW_MANIFEST_SIGNING=off, which weakens mandatory enforcement (meow_decoder/decode_gif.py). PQ ratchet beacons are silently skipped for ML-KEM-768 keys (1184 bytes) since the beacon implementation is ML-KEM-1024-only; paranoid mode (--paranoid) is required for PQ ratchet beacons.
  1. On-screen randomized keyboard + mouse-gesture password auth (full working implementation)
  • Status: Fully Implemented
  • Is it correctly wired into production paths? Yes
  • Reachability: production
  • Evidence: Randomized on-screen keyboard and mouse-gesture implementation in meow_decoder/secure_keyboard.py; CLI password modes invoking secure keyboard and mouse gesture in meow_decoder/encode.py.
  • Any remaining weakness, stub, or incomplete integration? None observed.
  1. Active tamper detection + silent poisoning (fail-closed, no side-effect leaks)
  • Status: Fully Implemented
  • Is it correctly wired into production paths? Yes (PyInstaller runtime)
  • Reachability: production (packed binary), optional in non-packed runs
  • Evidence: Poison output path in meow_decoder/tamper_detection.py; runtime hook aborts on tamper detection in scripts/pyinstaller_runtime_hook.py.
  • Any remaining weakness, stub, or incomplete integration? Tamper protections are activated automatically only in the PyInstaller runtime hook; non-packed executions rely on manual invocation.
  1. Adversarial carrier generation + stego algorithm rotation (integrated into encode path)
  • Status: Partially Implemented
  • Is it correctly wired into production paths? Yes, but only when stego is enabled and set to PARANOID level
  • Reachability: production (optional path)
  • Evidence: Rotation schedule and adversarial embed in meow_decoder/stego_advanced.py; encode path applies stego pipeline in meow_decoder/encode.py.
  • Any remaining weakness, stub, or incomplete integration? Rotation and adversarial embedding only occur at PARANOID level; default stego levels do not invoke adversarial noise.
  1. Shamir-style multi-GIF split redundancy (threshold secret sharing with CLI workflow)
  • Status: Fully Implemented
  • Is it correctly wired into production paths? Yes
  • Reachability: production
  • Evidence: Shamir split implementation in meow_decoder/shamir_split.py; CLI flags and split-to-files integration in meow_decoder/encode.py.
  • Any remaining weakness, stub, or incomplete integration? None observed.
  1. Portable single-executable mode + isolation checks (PyInstaller single binary + env safety)
  • Status: Fully Implemented
  • Is it correctly wired into production paths? Yes for PyInstaller builds; optional for non-packed runs
  • Reachability: production (packed binary), optional in standard Python runs
  • Evidence: PyInstaller runtime hook and env safety inclusion in meow_decoder.spec; runtime hook enforces env safety and tamper checks in scripts/pyinstaller_runtime_hook.py; strict isolation path in meow_decoder/main.py.
  • Any remaining weakness, stub, or incomplete integration? Non-packed runs do not automatically enable env_safety unless MEOW_STRICT_ISOLATION=1 is set.
  1. Expanded formal verification (Verus proofs for timing/expiry/tamper/secure_alloc) + public bounty program in README

2. Cryptographic Correctness Audit

  • AES-GCM nonce generation and reuse prevention

    • Status: Mixed
    • Findings: Observed random nonce generation in production encrypt path, not deterministic HKDF nonces as described in protocol docs. Observed per-process reuse guard.
    • Severity: Medium
    • Evidence / reachability: Random nonces in production encryption meow_decoder/crypto.py; deterministic NonceGenerator exists but is not referenced in production meow_decoder/nonce.py; protocol doc claims deterministic HKDF-derived nonce docs/PROTOCOL.md.

  • Argon2id usage and domain separation

    • Status: Implemented
    • Findings: Observed Argon2id parameters from presets and handle-based derivation; observed domain separation constants for HMAC and keyfile mixing.
    • Severity: Low
    • Evidence / reachability: Presets and parameters in meow_decoder/crypto.py; canonical AAD layout and domain separation constants in meow_decoder/crypto.py; handle-based derivation in meow_decoder/crypto.py.

  • Ratchet forward secrecy (including PQ beacon integration)

    • Status: Implemented
    • Findings: Ratchet supports asymmetric rekey and PQ hybrid fold with ML-KEM-1024. Production CLI now wires ML-KEM-1024 key material into both EncoderRatchet and DecoderRatchet when paranoid PQ mode is used.
    • Severity: Low
    • Evidence / reachability: PQ beacon logic in meow_decoder/ratchet.py and meow_decoder/ratchet.py; encoder now passes receiver_pq_public_key to EncoderRatchet meow_decoder/encode.py; decoder now passes receiver_pq_keypair (as PQBeaconKeyPair) to DecoderRatchet via _ratchet_params meow_decoder/decode_gif.py.

  • Manifest signing, AAD binding, and HMAC verification

  • Zeroization and memory wiping reliability

  • Constant-time guarantees across decode paths

  • Side-channel leaks (timing, cache, branch prediction)

    • Status: Partially mitigated
    • Findings: Assumption that Rust backend provides constant-time primitives; observed equalize_timing used to reduce timing variance but no formal side-channel guarantees are provided.
    • Severity: Medium
    • Evidence / reachability: equalize_timing in meow_decoder/constant_time.py; timing uniformity notes in crypto_core/src/verus_kdf_proofs.rs.

3. Steganography & Indistinguishability Audit

  • Adversarial carrier generation and stego algorithm rotation

    • Status: Implemented (Paranoid mode only)
    • Findings: Observed rotation schedule and adversarial carrier embedding used when stealth level is PARANOID.
    • Severity: Low
    • Evidence / reachability: rotation and adversarial embed in meow_decoder/stego_advanced.py; encode path calls stego pipeline in meow_decoder/encode.py.

  • Statistical indistinguishability (single vs dual mode, inter-file correlation)

    • Status: Best-effort
    • Findings: Observed adversarial carrier module explicitly documents limitations; no evidence of formal indistinguishability proof.
    • Severity: Medium
    • Evidence / reachability: limitations and threat model in meow_decoder/adversarial_carrier.py.

  • Fixed-size padding, fixed QR parameters, decorrelation

    • Status: Partially implemented
    • Findings: Observed length padding at encryption; QR parameters are configurable rather than fixed.
    • Severity: Low
    • Evidence / reachability: length padding in production encrypt path meow_decoder/crypto.py; QR parameters configured in encoder meow_decoder/encode.py.

  • Resistance to common steganalysis techniques

    • Status: Best-effort
    • Findings: Observed adversarial carrier noise targets chi-square and LSB steganalysis but explicitly notes detection is still possible.
    • Severity: Medium
    • Evidence / reachability: adversarial carrier threat model and limitations meow_decoder/adversarial_carrier.py.

4. General Bug & Regression Hunt

  • Finding: PQ ratchet beacons are now wired into production CLI paths. (FIXED)

    • Severity: Resolved
    • Evidence: Encoder passes ML-KEM-1024 public key as receiver_pq_public_key to EncoderRatchet meow_decoder/encode.py; decoder converts HybridKeyPair to PQBeaconKeyPair and passes as receiver_pq_keypair in _ratchet_params to DecoderRatchet meow_decoder/decode_gif.py. Keys are only wired for ML-KEM-1024 (1568-byte public key, paranoid mode); ML-KEM-768 silently skips PQ beacons.

  • Finding: Protocol documentation claims deterministic HKDF nonces, but production encryption uses random nonces.

  • Finding: Environment safety checks are enforced only in PyInstaller runtime hook or when MEOW_STRICT_ISOLATION=1 is set.

  • Finding: Manifest signing can be disabled via environment policy, weakening mandatory guarantees.

5. Documentation Verification

  • Overclaim/inconsistency: README states post-quantum is default while threat model says PQ requires explicit opt-in.

    • Quote: "ML-KEM-768 (default, Signal PQXDH)" in README.md
    • Counter-evidence: "not default; requires explicit opt-in" in docs/THREAT_MODEL.md
    • Corrected wording (prose): Post-quantum features are available but only enabled when the user sets --pq (and --paranoid for ML-KEM-1024), not by default.

  • Overclaim/inconsistency: Protocol spec mandates deterministic HKDF nonces, while production encryption uses random nonces.

    • Quote: "Nonce: 12 bytes deterministic via HKDF" in docs/PROTOCOL.md
    • Counter-evidence: random nonce generation in meow_decoder/crypto.py
    • Corrected wording (prose): Production encryption currently uses random 96-bit nonces with a reuse guard; deterministic HKDF nonces are implemented in nonce.py but not used in the main encrypt path.

  • Overclaim/inconsistency: Formal verification claims vs implementation notes.

    • Quote: "Verus ... Complete" in formal/README.md
    • Counter-evidence: "Verus proofs are stubs" for AEAD in crypto_core/src/lib.rs and SECURITY_INVARIANTS notes AEAD proofs are not Verus-proven docs/SECURITY_INVARIANTS.md
    • Corrected wording (prose): Verus proofs are complete for guarded-buffer memory safety; AEAD proofs are not machine-checked and are enforced via type system and tests.

6. Final Independent Verdict

  • Overall security score out of 10 (conservative): 7.7/10
  • Is the current implementation ready for high-stakes use? No, not without resolving the nonce-specification mismatch between code and documentation.
  • Remaining Critical/High issues that must be addressed before release:
  • Resolved issues:
    • FIXED (was High): PQ ratchet beacons now wired into production encode/decode flows: encoder passes ML-KEM-1024 key via receiver_pq_public_key, decoder constructs PQBeaconKeyPair and passes via receiver_pq_keypair in _ratchet_params.
  • One-sentence recommendation before release: Align nonce derivation behavior between code and protocol documentation (either document that random nonces are intentional or wire in the existing deterministic NonceGenerator).