Atbash Cipher - Backwards/Reverse Alphabet - Online Decoder/Translator (2024)

Atbash cipher (also called mirror cipher or backwards alphabet or reverse alphabet) is the name given to a monoalphabetical substitution cipher which owes its name and origins to the Hebrew alphabet.

Atbash replaces each letter with its symmetrical one in the alphabet, that is, A becomes Z, B becomes Y, and so on.

Atbash encryption uses a substitution alphabet and its reciprocal, a combination of the normal alphabet and its reverse alphabet (mirrored).

Example: The latin alphabet ABCDEFGHIJKLMNOPQRSTUVWXYZ and its reverse: ZYXWVUTSRQPONMLKJIHGFEDCBA are combine in the substitution table:

Encryption consists in replacing letters from the first with letters from the other one, with is equivalent to replace the first letter of the alphabet A with the last one Z, the second one B with the penultimate Y etc.

Example: MIRROR becomes NRIILI

Decryption is identical to encryption because of the reversible alphabet (due to the symmetry of the backwards alphabet)

Example: ZGYZHS is decrypted ATBASH

dCode offers an encoder and a decoder, but they are actually one and the same Atbash converter.

An Atbash ciphertext has a coincidence index similar to an unencrypted text.

If the encryption used the classical latin alphabet, letters V,G,R,L,M appear the most frequently.

Otherwise the presence of Hebrew characters or a reference to the Dead Sea can be a clue.

The notions of mirror, reflection, opposite, axis, direction, word written in reverse (hsabta) are also clues.

There are a small number of words that have an existing Atbash equivalent in the English dictionary.

Example: GIRTH & TRIGS, GIRL & TRIO, GLOW & TOLD, HOLD & SLOW, HORN & SLIM, WILD & DROW, ZARA & AZIZ

In Hebrew, this situation is more common (notably because the alphabet has no vowels).

Atbash is adaptable to any alphabet, so using the Hebrew alphabet is possible.

The atbash cipher is equivalent to an affine cipher with $ a = -1 $ and $ b = -1 $

The atbash cipher is equivalent to a monoalphabetic substitution with the alphabet ZYXWVUTSRQPONMLKJIHGFEDCBA