Keys and operations
Complete a cryptography review
Review goals, algorithms, libraries, formats, randomness, keys, failure behavior, migration, and recovery before relying on a cryptographic design.
8 minute lesson
A crypto review asks whether the complete system provides the intended property. Algorithm names alone are not enough.
Check the threat model, high-level construction, current guidance, nonce rules, authenticated context, key access, error handling, versioning, backup, revocation, and tests. Track standards changes, including post-quantum transitions, without inventing a premature hybrid protocol.
A webhook uses HMAC-SHA-256, so the team marks the design secure. The same secret is shared across environments, raw bytes are not preserved, replay is allowed, and failures leak which check failed.
The algorithm name is only one input. Review data formats, key access, nonce or replay rules, failure behavior, migration, recovery, and the authorization decision that follows verification.
Review one encrypted field or signed webhook and save a diagram plus a table of goals, library, format, keys, failures, migration, and remaining assumptions. Run successful verification and preserve the evidence. Then test tampering, replay, wrong context, old key version, and malformed input, and record that every failure is safe and observable.
Lesson completed