ctf-crypto

The ctf-crypto skill is a specialized cryptography reference and attack toolkit designed for Capture The Flag (CTF) competitions and security research scenarios. It provides guidance for analyzing and exploiting weaknesses in encryption schemes, hashing algorithms, digital signatures, pseudorandom number generators, zero-knowledge proof systems, and mathematical cryptography challenges. The skill focuses on practical offensive techniques used in CTF environments, helping users quickly identify applicable attack paths for RSA, AES, ECC, lattice-based cryptography, stream ciphers, block ciphers, padding oracles, nonce reuse issues, and number theory-based vulnerabilities.

The skill includes categorized references to both classical and modern cryptographic attacks, with supporting files covering techniques such as Vigenere analysis, XOR key recovery, AES padding oracle exploitation, AES-GCM nonce reuse attacks, ECB cut-and-paste manipulation, CBC bit-flipping, hash length extension, CRC32 forgery, RC4 bias exploitation, LFSR recovery, and multiple RSA attack methods including Wiener's attack, Pollard-based factorization, and small exponent attacks. It also documents required dependencies and tooling, including Python cryptography libraries, SageMath, Hashcat, Z3, and RsaCtfTool, enabling users to reproduce attacks and automate cryptographic analysis workflows.

This skill is intended for CTF participants, penetration testers, security researchers, and students studying applied cryptography. It is especially useful in environments where rapid identification of crypto weaknesses is required and where filesystem access, Python tooling, and command-line utilities are available. The documentation structure allows users to quickly locate relevant attack techniques while referencing more detailed implementation examples in supporting markdown files.