classical-cipher-analysis

To identify and decrypt an unknown classical ciphertext, analyze character set cues, perform frequency analysis, calculate the Index of Coincidence, and apply Kasiski examination to detect the cipher family and recover the plaintext.

Breaking a Vigenère cipher with frequency analysis involves using the Index of Coincidence and Kasiski examination to infer key length, then applying chi-squared statistical scoring to recover the polyalphabetic substitution key and plaintext.

Cracking XOR ciphertext with known plaintext is done through crib dragging, where you drag the expected plaintext fragment across the ciphertext to compute and recover the repeating XOR key.

Yes, you can detect base64, Morse code, or true classical ciphers by examining character set cues and performing statistical frequency analysis to distinguish standard encodings from monoalphabetic or polyalphabetic substitution ciphers.

Cracking columnar transposition and rail fence ciphers requires identifying the structured transposition pattern and applying cipher-specific cracking steps to rearrange the ciphertext blocks back into the correct plaintext order.

Recovering a monoalphabetic substitution cipher key requires frequency analysis and chi-squared statistical scoring to map ciphertext characters to plaintext letters based on standard language frequency distributions.