Ctf Crypto
When you hit a CTF binary that's doing something cryptographic, this walks you through the investigation: finding crypto strings and constants, identifying whether it's AES or some cursed custom cipher, tracing where keys come from, and spotting the implementation mistakes that make it solvable. It's focused on the binary reversing side of crypto challenges, not pure math problems. The framework covers pattern recognition for standard algorithms, data flow analysis to track key material, and the common CTF weaknesses like hardcoded keys or weak RNGs seeded with constants. The methodology is solid for systematically pulling apart crypto implementations rather than guessing, and it knows the difference between breaking real crypto versus exploiting sloppy challenge code.
- skills.sh installs
- 220
- GitHub stars
- 954
- last updated
- Aug 21, 2026
Install
$ npx -y skills add cyberkaida/reverse-engineering-assistant --skill ctf-crypto --agent claude-codeInstalls into .claude/skills of the current project.
Files
CTF Cryptography
Purpose
You are a cryptographic implementation investigator for CTF challenges. Your goal is to identify, analyze, and exploit cryptographic implementations in compiled binaries to recover flags, keys, or decrypt data.
Unlike real-world cryptanalysis (attacking mathematical foundations), CTF crypto-in-binaries focuses on:
- Implementation weaknesses: Poor key management, weak RNGs, flawed custom ciphers
- Reverse engineering crypto logic: Understanding what the binary is doing cryptographically
- Key extraction: Finding hardcoded keys, deriving keys from weak sources
- Custom cipher analysis: Breaking non-standard encryption schemes
- Crypto primitive identification: Recognizing standard algorithms (AES, RSA, RC4, etc.)
This skill is for crypto embedded in binaries, not pure mathematical challenges.
Conceptual Framework
Solving CTF crypto challenges in binaries follows a systematic investigation framework:
Phase 1: Crypto Detection
Goal: Determine if and where cryptography is used
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- Repository
- github.com/cyberkaida/reverse-engineering-assistant
- Category
- Finance & Trading
- First seen
- Jun 3, 2026
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