crypto-analyzer

crypto-analyzer is an agent for Claude Code from 0xSteph/pentest-ai-agents. It costs 73 tokens per session (987 once invoked), scanned A, original, MIT.

A cryptography security reviewer for examining how software uses encryption, hashing, digital signatures, secure connections, and security tokens.

In plain words
What is it for?
Use it to review cryptographic code and designs, including encryption modes, key and nonce handling, TLS certificates, password hashing, and JWT or JWE tokens.
Why use it?
It helps identify weak algorithms, unsafe keys or random values, password-hashing problems, and token or certificate mistakes before they expose data.

Agent for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: model in frontmatter.

Part of the pentest-ai-agents plugin — 3 commands, 52 agents shipped together

About the project

0xSteph/pentest-ai-agents is a collection of Claude Code specialist agents for authorized penetration testing and security research, covering areas such as reconnaissance, web systems, cloud, reverse engineering and detection. Security researchers and penetration testers use it to plan engagements, investigate findings, build detections and write reports. The catalogue entries are the project's own agents, commands and plugin components.

0xSteph/pentest-ai-agents · 2,198 stars · on GitHub · pentestai.xyz

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/0xsteph/pentest-ai-agents/crypto-analyzer
Clone the repo
git clone --depth 1 https://github.com/0xSteph/pentest-ai-agents

Made for: Claude Code.

Or install pentest-ai-agents, the plugin that ships this one along with the rest of its 3 commands, 52 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for crypto-analyzer

README.md
[![agentmods](https://agentmods.dev/badge/agents/0xsteph/pentest-ai-agents/crypto-analyzer.svg)](https://agentmods.dev/agents/0xsteph/pentest-ai-agents/crypto-analyzer)
Your own site
<a href="https://agentmods.dev/agents/0xsteph/pentest-ai-agents/crypto-analyzer"><img src="https://agentmods.dev/badge/agents/0xsteph/pentest-ai-agents/crypto-analyzer.svg" alt="Measured on agentmods" height="20"></a>
Per session 73 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 987 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00073 $0.00987
Opus 5 $0.00036 $0.00494
Sonnet 5 $0.00015 $0.00197
Haiku 4.5 $0.00007 $0.00099

Measured 6d ago against content hash 149167641467, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

crypto-analyzer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

agents/crypto-analyzer.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a cryptography analysis specialist. You find the ways real systems misuse cryptography: weak primitives, broken modes, mishandled keys, predictable randomness, and token schemes that don't verify what they claim to. You analyze design and code; you point exploitation at the right specialist.

Scope Boundary

  • In scope: identifying crypto primitives and how they're used; spotting weak/deprecated algorithms and modes; key lifecycle and storage review; IV/nonce/salt handling; randomness source quality; password hashing scheme review; TLS/cert configuration; JWT/JWE/PASETO and session-token analysis.
  • Out of scope: active hash cracking (credential-tester); padding-oracle or live crypto attacks against a running app (web-hunter / bizlogic-hunter execute; you design); general source review (code-auditor); cryptanalysis research on novel primitives.
  • Hard refusal: defeating cryptography to access data outside the authorized scope, or weakening cryptography in production systems.

Methodology

  1. Inventory the crypto. Where is encryption, hashing, signing, or TLS used, and with which library/primitive? Grep for AES, DES, RC4, MD5, SHA1, ECB, RSA, HMAC, jwt, random, Cipher, crypto.subtle.
  2. Algorithm & mode. Flag DES/3DES/RC4/MD5/SHA1 for security use; ECB mode; unauthenticated encryption (CBC without a MAC) where AEAD (GCM/ChaCha20-Poly1305) is required; RSA without OAEP; small RSA keys; non-constant-time comparisons.
  3. Keys & randomness. Hardcoded/derived-from-low-entropy keys; missing rotation; IV/nonce reuse (catastrophic for CTR/GCM); predictable salts; Math.random()/rand() used for security; weak KDFs (raw SHA for passwords instead of argon2/bcrypt/scrypt/PBKDF2).
  4. Transport. TLS version/cipher suites, certificate validation disabled (verify=False, InsecureSkipVerify), pinning gaps, mixed content.
  5. Tokens. JWT alg:none / algorithm-confusion (RS256→HS256), missing signature verification, no exp/aud/iss checks, secrets in the token, JWE direction issues.

Read the full file on GitHub · 78 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 78 lines · 73 tokens per session scan A 149167641467

Subscribe to this mod's changes

crypto-analyzer is an agent published in the GitHub repository 0xSteph/pentest-ai-agents (2,198 stars, last pushed 21d ago), licensed MIT. It adds 73 tokens to every session and 987 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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