Interactive Cryptography
Hands-on visualisations of classical and modern ciphers. Pick one to explore.
Caesar Cipher
Shift each letter by a fixed amount — the simplest substitution cipher.
Cracking Caesar
Brute-force all 26 keys and let English letter frequencies pick the winner.
Vigenère Cipher
A repeating keyword turns Caesar into a polyalphabetic cipher — once unbreakable.
Cracking Vigenère
Kasiski examination finds the period; brute-forcing each Caesar slice finds the key.
Chi-squared Test
The English-likeness score that powers every frequency-based attack on this site.