Classical Ciphers, Cryptanalysis & CTF Tools
Two thousand years of pen-and-paper cryptography — and the analysis tools that break it. Built for learning and Capture The Flag.
CAESAR · SHIFT
Caesar Cipher
Shift cipher with instant all-25 bruteforce
VIGENÈRE · POLYVigenère Cipher
The polyalphabetic cipher that resisted breaking for 300 years
ATBASH · AFFINEAtbash & Affine
Mirror-alphabet and modular substitution ciphers
RAIL FENCE · ZIGZAGRail Fence Cipher
Zigzag transposition across configurable rails
BACON · 5-BITBaconian Cipher
Francis Bacon's five-bit steganographic alphabet
POLYBIUS · 5×5Polybius & Tap Code
Coordinate ciphers from ancient Greece to POW camps
ANALYSIS · χ² · ICFrequency Analysis
Letter statistics, index of coincidence, chi-square
ENIGMA · M3Enigma Machine
The WWII cipher machine, with rotors, rings, and plugboard
PLAYFAIR · 5×5Playfair Cipher
The digraph cipher with a 5×5 keyed square
OTP · PADOne-Time Pad
The only provably unbreakable cipher — if used correctly