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Cipher Cove

Atbash Cipher

The Atbash cipher flips the alphabet: A becomes Z, B becomes Y and Z becomes A. Type or paste a message to encode or decode it, since both are the same step.

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How to use the Atbash translator

  1. Type or paste your message in the box. The Atbash version appears as you type.
  2. Press Copy to paste it anywhere.
  3. To decode, paste the coded message the same way. Atbash is its own reverse, so encoding a coded message gives back the original. The arrows between the labels only swap the boxes.

For example, HELLO WORLD becomes SVOOL DLIOW, and SVOOL DLIOW becomes HELLO WORLD again.

The Atbash alphabet

Write the alphabet forward, and under it the alphabet backward. Each letter swaps with the one under it:

  • Plain: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • Atbash: Z Y X W V U T S R Q P O N M L K J I H G F E D C B A

Every pair works both ways, so A and Z, B and Y, and M and N swap with each other. There are 13 pairs, and no letter stays the same.

History of the Atbash cipher

Atbash began as a way of writing the Hebrew alphabet backward. It appears in the Hebrew Bible: in the Book of Jeremiah, the name Sheshach is generally read as Babel (Babylon) written in Atbash. Scholars still debate whether it was meant to hide the name or was a form of wordplay.

Because it has no key, Atbash was never strong protection. It survives as a teaching cipher, as one of the classic codes in puzzle books, escape rooms and games, and in cryptograms like those in Gravity Falls.

Atbash and the Caesar cipher

Atbash and the Caesar cipher are both substitution ciphers: each letter always turns into the same other letter. The Caesar cipher shifts the alphabet along, so it has 25 possible keys. Atbash reverses the alphabet, so it has just one. If a coded message does not make sense in Atbash, try the Caesar cipher decoder, which tests all 25 shifts for you.

Frequently asked questions

How do you decode the Atbash cipher?

Swap each letter for its mirror in the alphabet: A and Z, B and Y, C and X, and so on. Decoding and encoding are the same step, so paste the coded message into the box above and the plain text appears.

Does Atbash have a key?

No. There is only one Atbash alphabet, so there is nothing to choose and nothing to keep secret. Anyone who knows the method can read the message, which makes it a puzzle cipher rather than a secure one.

Where does the name Atbash come from?

It is built from Hebrew letters. Aleph, the first letter, swaps with Tav, the last, and Bet, the second, swaps with Shin, the second last. Put together, A-T-B-SH gives Atbash.

Was Atbash used in Gravity Falls?

Yes. The cryptograms hidden in the end credits of Gravity Falls season one use several ciphers in turn: first a Caesar shift, then Atbash, then A1Z26, then a mix of all three. Paste one of the Atbash codes into the box to read it.

What happens to numbers and punctuation?

They stay as they are. Only the letters A to Z are swapped, and capital letters stay capital.

More translators and charts

Braille TranslatorEnglish to braille cells and back, with capitals, numbers and the braille alphabet chart.Caesar Cipher DecoderEncode with any shift, or decode without the key: all 25 shifts, most likely first.Vigenère CipherEncode and decode with a keyword, with a worked example and the Vigenère square.