ctf-crypto

ctf-crypto is a skill for Claude Code, Codex from MateoBogo/CLEAVE. It costs 0 tokens per session (2,139 once invoked), scanned A, original, no licence file.

A collection of methods for solving cryptography challenges in capture-the-flag competitions, where participants find weaknesses in puzzles or systems.

In plain words
What is it for?
Use it for challenges involving RSA, AES, elliptic-curve cryptography, random-number generators, hashes, padding oracles, lattices, zero-knowledge proofs, and related schemes.
Why use it?
It helps choose an attack based on the encryption scheme, mathematical structure, or available oracle—a service that reveals limited information about a secret operation.

Skill for Claude CodeCodex

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 skills/mateobogo/cleave/ctf-crypto
Any agent
npx skills add MateoBogo/CLEAVE --skill ctf-crypto
Clone the repo
git clone --depth 1 https://github.com/MateoBogo/CLEAVE

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 ctf-crypto

README.md
[![agentmods](https://agentmods.dev/badge/skills/mateobogo/cleave/ctf-crypto.svg)](https://agentmods.dev/skills/mateobogo/cleave/ctf-crypto)
Your own site
<a href="https://agentmods.dev/skills/mateobogo/cleave/ctf-crypto"><img src="https://agentmods.dev/badge/skills/mateobogo/cleave/ctf-crypto.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,139 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00000 $0.02139
Opus 5 $0.00000 $0.01069
Sonnet 5 $0.00000 $0.00428
Haiku 4.5 $0.00000 $0.00214

Measured 5d ago against content hash 0172837b0594, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ctf-crypto 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 5d 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.

skills/ctf-crypto/SKILL.md · 83 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 5d ago First seen · 83 lines · 0 tokens per session scan A 0172837b0594

Subscribe to this mod's changes

ctf-crypto is a skill published in the GitHub repository MateoBogo/CLEAVE (4 stars, last pushed 3mo ago), with no licence file. It costs nothing until one of its globs matches a file; then it loads 2,139 tokens. 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 2026-08-31.

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