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crypto-audit

Audit cryptography implementation — algorithm choice, key sizes, KDF parameters, IV/nonce handling, signature verification, randomness, TLS configuration, and key rotation. Deeper than owasp-audit A04. Use when the user mentions 'crypto review,' 'cryptography audit,' 'encryption review,' 'KDF,' 'PBKDF2,' 'Argon2,' 'bcrypt cost,' 'IV reuse,' 'nonce reuse,' 'AES mode,' 'AES-GCM,' 'AES-ECB,' 'signature verification,' 'TLS configuration,' 'cipher suites,' 'key rotation,' 'libsodium,' 'BoringSSL,' or 'is this crypto right.'

Quality

94%

Does it follow best practices?

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SecuritybySnyk

Low

Low-risk findings worth noting

SKILL.md
Quality
Evals
Security

Quality

Content

88%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A strong, highly actionable audit skill: concrete thresholds, grep patterns, and commands throughout, with a well-sequenced verify-then-record-validate workflow and a real, well-structured reference bundle. The main costs are minor: a few trimmable known-concept explanations and noticeable duplication of the shared findings-format content that lives in references/.

Suggestions

Trim explanations of concepts Claude already knows (e.g., the "< 50 people on Earth" flourish, the Mersenne Twister aside, the ECB block-pattern parenthetical) — keep the verdict and the threshold, drop the rationale.

Drop the restated verdict semantics, JSON-first rule, and validate/SARIF command blocks that duplicate references/findings-format.md; keep the crypto-specific verdict examples and a single pointer.

Move the ~40-line Output Format report template into a reference file (e.g., references/report-template.md), leaving a short inline summary of the section headings.

DimensionReasoningScore

Conciseness

The body is dominated by dense, non-obvious audit specifics (grep patterns, OWASP 2024 iteration floors, the Java/PyCryptodome default-ECB gotchas, fingerprint rules), but includes a few trimmable explanations of concepts Claude already knows: "There are < 50 people on Earth who can design new crypto safely, and they don't work at your company", "Math.random() (Node — Mersenne Twister, predictable)", and the ECB block-pattern aside. Not 3 because the unnecessary explanation is minor relative to the high-signal content.

4 / 5

Actionability

Fully executable throughout: per-category grep patterns (`AES.*ECB`, `pkcs1_v1_5`, `jwt.decode`, `mt_rand`), runnable commands (`testssl.sh https://target`, `sslyze --regular target`, `aws kms get-key-policy`, `node references/validate-findings.mjs findings.json`, `curl --tlsv1.3 --tls-max 1.3`), exact thresholds (PBKDF2 ≥ 600,000 iterations, bcrypt cost ≥ 12, scrypt N=2^17, 96-bit GCM nonces, 128-bit token floor), and concrete confirmed/needs_validation/rejected examples with real file paths. Not 4: copy-paste-ready guidance covers the common cases end to end.

5 / 5

Workflow Clarity

Clear sequence with explicit validation checkpoints: checklist greps → refutation pass ("Before anything is `confirmed`, run the refutation pass in references/verification.md") → findings.json sorted by fingerprint and validated before rendering → runtime fix verification ("Test encryption / decryption round-trip after every change", rehash-on-login migration plans, testssl verification of TLS changes). Not 4: checkpoints and feedback loops are explicit at every stage, including fix-time.

5 / 5

Progressive Disclosure

All six referenced bundle files exist, are one level deep, and are clearly signaled with links and a stated purpose at each point of use; the core crypto checklist appropriately stays in SKILL.md. Not 5: the body restates verdict semantics, the JSON-first rule, and the exact validate/SARIF commands already covered by references/findings-format.md, and the ~40-line Output Format report template is inlined rather than split out — minor organization gaps against the actual bundle structure.

4 / 5

Total

18

/

20

Passed

Description

100%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A model description: concrete capability enumeration, an explicit differentiation from the related baseline skill, and a long, natural trigger list covering synonyms, technical keywords, and colloquial phrasing. Both 'what' and 'when' are answered explicitly.

DimensionReasoningScore

Specificity

"Audit cryptography implementation — algorithm choice, key sizes, KDF parameters, IV/nonce handling, signature verification, randomness, TLS configuration, and key rotation" lists eight concrete audit areas with comprehensive coverage of the domain. Not 4: no meaningful gaps in coverage within the niche.

5 / 5

Completeness

Explicitly answers both: 'what' (audit of algorithm choice, key sizes, KDF parameters, IV/nonce handling, signature verification, randomness, TLS, rotation) and 'when' via an explicit "Use when the user mentions…" clause with concrete trigger phrases.

5 / 5

Trigger Term Quality

Triggers include natural phrases ('crypto review', 'encryption review', 'is this crypto right'), synonyms ('cryptography audit', 'nonce reuse' next to 'IV reuse'), technical terms ('AES-GCM', 'PBKDF2', 'Argon2', 'bcrypt cost', 'libsodium', 'BoringSSL') — comprehensive coverage including variations users would actually say.

5 / 5

Distinctiveness Conflict Risk

"Deeper than owasp-audit A04" explicitly differentiates it from the closest sibling skill, and trigger terms like 'AES-ECB', 'bcrypt cost', 'libsodium' are distinctive to this niche. Not 4: the differentiation is stated up front and the triggers are unlikely to fire for the wrong skill.

5 / 5

Total

20

/

20

Passed

Validation

93%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 15 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

allowed_tools_field

'allowed-tools' contains unusual tool name(s)

Warning

Total

15

/

16

Passed

Repository

briiirussell/cybersecurity-skills

Path

skills/crypto-audit/SKILL.md

Reviewed

Table of Contents

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