classical-cipher-analysis

Crack classical ciphers by applying a structured workflow that uses frequency analysis and IC evaluation to classify monoalphabetic, Vigenere, transposition, or XOR messages, then applies targeted attacks to recover plaintext.

Breaking a Vigenere cipher relies on Kasiski examination and index of coincidence evaluation to determine key length, followed by frequency analysis to deduce the specific key characters and extract the original plaintext message.

Crib dragging works by sliding a known plaintext fragment across the ciphertext to find alignment patterns, enabling a known-plaintext attack that reveals the remaining portions of monoalphabetic or XOR encrypted messages.

Frequency analysis is needed when deciphering monoalphabetic substitution ciphers, mapping the most common ciphertext characters to their likely plaintext equivalents by analyzing statistical letter distribution patterns.

Yes, known-plaintext attacks can recover XOR cipher flags by applying a known cleartext fragment against the ciphertext to extract the key, which then allows decrypting the entire encoded message to reveal the hidden flag.