Atbash Cipher
The alphabet, reversed. Paste text to encode or decode — it is the same operation in both directions.
ABCDEFGHIJKLMNOPQRSTUVWXYZZYXWVUTSRQPONMLKJIHGFEDCBA
How to use Atbash by hand
Write the alphabet forwards, then backwards underneath it, as shown above. To encode, find each letter on the top row and write the letter under it. To decode, do exactly the same thing. Numbers, spaces and punctuation are left unchanged.
Atbash is common in puzzle hunts and escape rooms because it looks scrambled but needs no key. If a puzzle text is not Atbash, try the cipher identifier or brute-force every Caesar shift.
Questions people ask
What is the Atbash cipher?
Atbash reverses the alphabet: A becomes Z, B becomes Y, C becomes X and so on. It has no key, and applying it twice returns the original text.
Where does Atbash come from?
It was originally used with the Hebrew alphabet; the name comes from its first and last letter pairs, aleph–tav and bet–shin. Scholars have identified Atbash substitutions in the Book of Jeremiah, where “Sheshach” stands for Babel.
Is Atbash a Caesar cipher?
No. A Caesar cipher shifts the alphabet; Atbash mirrors it. Both are simple substitution ciphers, and both are trivial to break.