Ciphers
Caesar, Vigenère, Atbash and A1Z26 ciphers explained, with tools to encode, decode and crack them.
Translators
Caesar Cipher
Shift by any amount, ROT13, and crack it with all 25 shifts.
Vigenère Cipher
Keyword cipher that keeps case, spaces and punctuation.
Atbash Cipher
Mirror the alphabet: A ↔ Z, B ↔ Y.
Letter to Number Cipher (A1Z26)
A = 1 … Z = 26, with your choice of separator.
Guides
Code vs. Cipher: What Is the Difference?
A code replaces whole words with agreed symbols. A cipher transforms every letter by a rule. Morse code is technically a code; Caesar is a cipher.
Easy Ciphers for Kids
Five simple ciphers kids can use without a computer: Caesar shift, A1Z26 (A=1), reverse alphabet, pigpen, and the rail fence.
Vigenère Cipher Explained
The Vigenère cipher uses a keyword to change the shift for each letter. HELLO encrypted with key KEY becomes RIJVS. Much harder to crack than Caesar.
How to Crack a Caesar Cipher
Two methods crack a Caesar cipher: try all 25 shifts (brute force) or use frequency analysis — E appears in 12.7% of English text.
Caesar Cipher Explained
A Caesar cipher shifts every letter by a fixed number. HELLO with shift 3 becomes KHOOR. Julius Caesar used this cipher for military messages.