Symmetric Cipher Attacks

This is a solid cryptanalysis reference for attacking symmetric encryption schemes in CTF challenges and authorized penetration tests. It covers the bread and butter attacks: CBC padding oracles with full byte-by-byte decryption walkthrough, CBC bit flipping for privilege escalation, ECB detection and cut-and-paste attacks including the classic byte-at-a-time oracle technique, and stream cipher key reuse exploits. The code samples are practical and ready to adapt, not pseudocode. What makes this useful is the attack selection table up front that maps observable behaviors to specific vulnerabilities, so you don't waste time trying ECB attacks on CBC mode. It also routes you to related skills for RSA and hash attacks when the symmetric crypto is wrapped in a larger scheme.