ctf-crypto

Solid

Provides cryptography attack techniques for CTF challenges. Use when attacking encryption, hashing, signatures, ZKP, PRNG, or mathematical crypto problems involving RSA, AES, ECC, lattices, LWE, CVP, number theory, Coppersmith, Pollard, Wiener, padding oracle, GCM, key derivation, or stream/block cipher weaknesses.

AI & Automation 2,250 stars 278 forks Updated 1 months ago MIT

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Skill Content

# CTF Cryptography Quick reference for crypto CTF challenges. Each technique has a one-liner here; see supporting files for full details with code. ## Prerequisites **Python packages (all platforms):** ```bash pip install pycryptodome z3-solver sympy gmpy2 hashpumpy fpylll py_ecc ``` **Linux (apt):** ```bash apt install hashcat sagemath ``` **macOS (Homebrew):** ```bash brew install hashcat ``` **Manual install:** - SageMath — Linux: `apt install sagemath`, macOS: `brew install --cask sage` - RsaCtfTool — `git clone https://github.com/RsaCtfTool/RsaCtfTool` (automated RSA attacks) > **Note:** `gmpy2` requires libgmp — Linux: `apt install libgmp-dev`, macOS: `brew install gmp`. ## Additional Resources - [classic-ciphers.md](classic-ciphers.md) - Classic ciphers: Vigenere (+ Kasiski examination), Atbash, substitution wheels, XOR variants (+ multi-byte frequency analysis), deterministic OTP, cascade XOR, book cipher, OTP key reuse / many-time pad, variable-length homophonic substitution, grid permutation cipher keyspace reduction, image-based Caesar shift ciphers, XOR key recovery via file format headers - [modern-ciphers.md](modern-ciphers.md) - Modern cipher attacks: AES (CFB-8, ECB leakage), CBC-MAC/OFB-MAC, padding oracle, S-box collisions, GF(2) elimination, LCG partial output recovery, affine cipher over composite modulus, AES-GCM with derived keys, AES-GCM nonce reuse (forbidden attack), Ascon-like reduced-round differential cryptanalysis, custom linear MAC forge...

Details

Author
ljagiello
Repository
ljagiello/ctf-skills
Created
3 months ago
Last Updated
1 months ago
Language
Python
License
MIT

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