identifying-cryptographic-routines-in-binaries

identifying-cryptographic-routines-in-binaries is a skill for Claude Code, Codex from meltedinhex/analyst-ai-pack. It costs 80 tokens per session (696 once invoked), scanned A, original, Apache-2.0.

A malware-analysis guide for identifying cryptographic algorithms embedded in a binary by looking for recognizable constants and tables, such as those used by AES, SHA, MD5, ChaCha, CRC32, and Base64.

In plain words
What is it for?
Use it to scan a binary, report matching offsets, compare results with imports and strings, and locate the functions that use the routines.
Why use it?
It gives analysts a quick way to narrow down what encryption or hashing a sample may use before manually reversing the code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to scan a binary, report matching offsets, compare results with imports and strings, and locate the functions that use the routines.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries
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.

Any agent
npx skills add meltedinhex/analyst-ai-pack --skill identifying-cryptographic-routines-in-binaries
Clone the repo
git clone --depth 1 https://github.com/meltedinhex/analyst-ai-pack

Made for: Claude Code, Codex.

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 identifying-cryptographic-routines-in-binaries

README.md
[![agentmods](https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries/github.svg)](https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries)
Your own site
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

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Your own site · 80×15
<a href="https://agentmods.dev/skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries"><img src="https://agentmods.dev/badge/skills/meltedinhex/analyst-ai-pack/identifying-cryptographic-routines-in-binaries.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 696 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00080 $0.00696
Opus 5 $0.00040 $0.00348
Sonnet 5 $0.00016 $0.00139
Haiku 4.5 $0.00008 $0.00070

Measured 9d ago against content hash 274815871296, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

identifying-cryptographic-routines-in-binaries 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 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/analyst.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/identifying-cryptographic-routines-in-binaries/SKILL.md · 89 lines

What it actually says

Identifying Cryptographic Routines in Binaries

When to Use

  • You need to determine which cryptographic algorithms a sample implements (ransomware crypto, C2 encryption, config protection) by locating constant tables.
  • You want fast triage before manually reversing the crypto routine.

Do not use constant detection as proof of a specific mode/usage — it identifies the primitive, not how it is applied. This skill reads the binary statically and executes nothing.

Prerequisites

  • The binary (read inertly).

Safety & Handling

  • Read bytes statically; treat the sample as malicious data.

Workflow

Step 1: Scan for crypto constants

python scripts/analyst.py scan sample.bin

Searches for AES S-box/Te tables, SHA-256 H/K init constants, MD5 init, ChaCha/Salsa expand 32-byte k sigma, the CRC32 polynomial table, and the base64 alphabet, reporting offsets.

Step 2: Corroborate with imports/strings

Pair constant hits with crypto API imports (CryptDecrypt, BCryptEncrypt, EVP_*) or library strings to confirm.

Step 3: Locate the routine

Use the constant offset to find the referencing function for deeper reversing/key extraction.

Step 4: Document

Record which primitives are present and where, mapping to behavior (e.g., AES → file encryption).

Validation

  • Each hit references a real, named constant table (not a coincidental byte run).
  • Detected primitives are corroborated by imports/strings where possible.
  • Offsets point into the binary and can be navigated in a disassembler.

Pitfalls

  • Statically linked crypto libraries adding constants unused by the malware's logic.
  • Custom/modified S-boxes evading exact-match detection.
  • Assuming AES presence implies ransomware — corroborate with behavior.

References

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 89 lines · 80 tokens per session scan A 274815871296

Subscribe to this mod's changes

identifying-cryptographic-routines-in-binaries is a skill published in the GitHub repository meltedinhex/analyst-ai-pack (22 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 80 tokens to every session and 696 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 2026-09-03.

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