crypto-architecture-review

Trace the key hierarchy from root keys to data-encryption keys, then verify AEAD binding, nonce uniqueness, and recovery flows against the product's claims. This Skill provides a ten-step workflow covering enrollment, sharing, revocation, and server influence.

Check whether the server can access or influence plaintext, keys, KDF parameters, public keys, or recovery secrets. The review flags server-controlled values that could silently capture future plaintext, which weakens any zero-knowledge claim.

Collect threat models, key hierarchy diagrams, client crypto call sites, serialized encrypted object formats, device enrollment code, and telemetry paths near secrets. Direct code and runtime evidence is preferred over diagrams alone.

Escalate when the system uses custom protocols, novel group ratchets, PAKEs, threshold recovery, post-quantum hybrids, key transparency, or formal security claims. Source review alone cannot establish cryptographic soundness for these cases.

Findings range from critical, where a server or operator can recover plaintext despite E2EE claims, down to low for bounded metadata leakage. Unclear documentation and missing rationale are recorded as limitations rather than findings.