Atbash Cipher Encoder & Decoder
Encode and decode messages using the Atbash cipher — one of the oldest known ciphers, originating in ancient Hebrew. Atbash reverses the alphabet so A maps to Z, B maps to Y, C maps to X, and so on. Because the cipher is its own inverse, the same process encodes and decodes.
About Atbash Cipher
The Atbash cipher is a substitution cipher that maps each letter to its reverse in the alphabet: A→Z, B→Y, C→X, D→W, and so on. The name comes from the first and last Hebrew letters: Aleph–Taw–Beth–Shin (ATBS). It was used in the Hebrew Bible, notably in the Book of Jeremiah where ‘Sheshach’ is Atbash for ‘Babel’.
Because the alphabet reversal is symmetric, Atbash is its own inverse — applying it twice returns the original message. This makes it both extremely simple and completely self-decoding. Like all simple substitution ciphers, Atbash is trivially broken with frequency analysis but remains popular for puzzles, games, and creative writing.
Our Atbash tool handles both upper and lowercase letters independently, preserving case. Numbers, spaces, and punctuation are passed through unchanged. The same button encodes and decodes — just paste your Atbash text and click decode to reveal the original message.