Wycheproof
Validates cryptographic implementations against Project Wycheproof's test vectors...
Install
npx skills add trailofbits/skills --skill wycheproof -g -a claude-code -y- Repository
- trailofbits/skills7.9k
- Category
- Testing
- Updated
- 7d ago
- License
- CC-BY-SA-4.0
- Context cost
- Mediumabout 3,000 tokens
- Runs scripts
- No, instructions only
What it does
Validates cryptographic implementations against Project Wycheproof's test vectors, which encode known attacks and edge cases across AES, RSA, ECDSA, ECDH, and more. Covers loading test vectors, mapping result flags onto pass and fail expectations, and reading a failure. Use when testing a crypto implementation against known attacks, checking a library against standard test vectors, or investigating why two implementations disagree on the same input.
Wycheproof
Wycheproof is an extensive collection of test vectors designed to verify the correctness of cryptographic implementations and test against known attacks. Originally developed by Google, it is now a community-managed project where contributors can add test vectors for specific cryptographic constructions.
Background
Key Concepts
| Concept | Description |
|---|---|
| Test vector | Input/output pair for validating crypto implementation correctness |
| Test group | Collection of test vectors sharing attributes (key size, IV size, curve) |
| Result flag | Indicates if test should pass (valid), fail (invalid), or is acceptable |
| Edge case testing | Testing for known vulnerabilities and attack patterns |
Why This Matters
Cryptographic implementations are notoriously difficult to get right. Even small bugs can:
- Expose private keys
- Allow signature forgery
- Enable message decryption
- Create consensus problems when different implementations accept/reject the same inputs
Wycheproof has found vulnerabilities in major libraries including OpenJDK's SHA1withDSA, Bouncy Castle's ECDHC, and the elliptic npm package.
When to Use
Apply Wycheproof when:
- Testing cryptographic implementations (AES-GCM, ECDSA, ECDH, RSA, etc.)
- Validating that crypto code handles edge cases correctly
- Verifying implementations against known attack vectors
- Setting up CI/CD for cryptographic libraries
- Auditing third-party crypto code for correctness
Consider alternatives when:
- Testing for timing side-channels (use constant-time testing tools instead)
- Finding new unknown bugs (use fuzzing instead)
- Testing custom/experimental cryptographic algorithms (Wycheproof only covers established algorithms)
