Atbash Cipher

Atbash replaces every letter with the letter at the same distance from the other end of the alphabet. In the Latin alphabet, A becomes Z, B becomes Y, C becomes X and so on, so “wizard” becomes “draziw”. There is no key and no setting: the alphabet simply runs backwards. This tool applies Atbash to Latin text and to Hebrew, where the cipher was born.

How it works

Write the alphabet forwards and, underneath it, backwards. Each letter is replaced by the one below it. Because the pairing is symmetrical, applying Atbash twice brings back the original, so the same step encrypts and decrypts. Capitals stay capitals, and spaces, digits and punctuation are not changed, unless you choose letters only or five-letter groups for a more cryptic look. The key under the tool shows both alphabets for checking by hand.

Hebrew origins

The name comes from the first letters of the pairs it uses in Hebrew: Aleph swaps with Tav, Bet with Shin — A-T-B-Sh. Atbash appears in the Hebrew Bible: in the Book of Jeremiah, Sheshach (ששך) is generally read as Atbash for Babel (בבל), and Leb Kamai as Atbash for Kasdim, the Chaldeans. Choose the Hebrew alphabet to apply it to the 22 Hebrew letters; final letter forms count as their regular letters.

A puzzle classic

Atbash is a staple of puzzle hunts, escape rooms, geocaches and children’s code books because it needs no key and can be decoded with pencil and paper once you know the trick. It is also used in fiction and games as a “secret language” that attentive readers can crack. The famous puzzle-filled cartoon Gravity Falls used Atbash alongside Caesar and A1Z26 codes in its end credits.

Spotting it

In Atbash text, common English letters turn into uncommon ones: e becomes v, t becomes g, a becomes z and o becomes l. A cipher full of v, g, z and l with otherwise normal word lengths is a strong hint. Paste it in; if it reads, you have found it.

Not a real cipher

With a single fixed substitution, Atbash offers no secrecy against anyone who knows it exists. Treat it as a game and a lesson in substitution, not as protection.

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A worked example

Encrypt “Hello world” with the Latin alphabet: H is the 8th letter, so it becomes the 8th letter from the end, S; e becomes v, l becomes o and o becomes l, giving “Svool dliow”. Paste “Svool dliow” back in and the same step returns “Hello world”, which shows that Atbash is its own inverse. With the five-letter groups style, the result is written SVOOL DLIOW, which looks the same here only because both words have five letters; longer messages lose their word lengths entirely.

Atbash in puzzle design

Because Atbash needs no key, it works well as the first step of a multi-stage puzzle: players who spot it move on quickly, while others get a satisfying moment when they realise the alphabet runs backwards. Combine it with A1Z26 numbers or a Pigpen drawing for a harder chain of clues.

Related tools

Shift the alphabet instead with the Caesar Cipher Solver or ROT13 Decoder, turn letters into numbers with the A1Z26 Cipher, or combine multiplication and shifting with the Affine Cipher, which includes Atbash as a special case.