Rust Crypto Safety

rust-crypto-safety

Implementation-safety auditor for cryptographic Rust code.

When to Use

• Auditing Rust crates that implement or wrap cryptographic primitives
• Reviewing secret handling, constant-time behavior, and memory lifecycle
• Checking unsafe, raw pointers, _unchecked entrypoints, or manual concurrency traits
• Reviewing cargo features, dependencies, and panic/error behavior on crypto paths

When NOT to Use

• Building protocol context before the code paths are identified
• Reviewing circuit constraints or verifier equations in ZK systems
• Declaring a finding confirmed without end-to-end verification

Core Review Areas

1. Secret-dependent control flow and memory access
2. Secret lifecycle and zeroization
3. unsafe, unchecked constructors, and trait soundness
4. Panic, overflow, cast, and feature-flag hazards
5. Supply-chain and tool-assisted review

Workflow

Phase 1: Checklist pass

• Read references/rust-checklist.md
• Trace secret-bearing types through parsing, arithmetic, cloning, sharing, and drop paths
• Mark every unsafe, _unchecked, unwrap, expect, and as cast on the critical path

Phase 2: Pattern hunt

• Read references/finding-patterns.md
• Treat secret-dependent timing, zeroization gaps, unsafe deserialization, and unsound Send/Sync as active search targets
• Check feature-flagged code separately; hidden security semantics count as real audit surface

Phase 3: Tool-assisted review

• Read references/toolchain.md
• Run the smallest relevant tool set for the crate under review: static analysis first, then fuzzing, side-channel checks, and dependency inspection
• Use audit-common testing evidence language when describing gaps in coverage or missing negative tests

Phase 4: Handoff

• Send suspected findings to crypto-fp-check
• Use zkbugs-index only after the finding survives verification and is suitable for indexing

Output Contract

Produce an implementation-safety handoff that includes:

• The relevant secret-bearing types, unsafe paths, or dependency surfaces
• Concrete timing, zeroization, panic, cast, or concurrency hazards observed
• Tool-assisted evidence already gathered
• The next verification or reporting route

Reference Index

• references/rust-checklist.md
• references/finding-patterns.md
• references/toolchain.md