The Atbash cipher is a simple substitution cipher where each letters is replaced by its equivalent in a reverse alphabet. For example, in the English alphabet, A becomes Z, B becomes Y, etc. Atbash was originally used for encrypting the Hebrew alphabet, but the method can be used with any alphabet.
- The Atbash cipher is a simple form of monoalphabetic substitution cipher.
- It is formed by taking the alphabet and mapping it to its reverse. For example, in the English alphabet, A becomes Z, B becomes Y, etc.
- The Atbash cipher was originally used to encrypt the Hebrew alphabet. It got its name from the Hebrew letters Aleph–Taw–Bet–Shin.
- Atbash cipher encryption and decryption is equivalent. If you encrypt a text twice, it becomes the original text again.
Atbash cipher, and variants of it, are often used in easy geocaching mystery caches, and easy logic puzzles. It can easily be detected using letter frequency analysis of the ciphertext, but it's usually easiest and quickest to just test if a text makes sense when decoded using Atbash.
OVG GSV TIVZG KOLG XLNNVMXV
The ciphertext above represents "LET THE GREAT PLOT COMMENCE" encrypted using Atbash.
See also: Code-Breaking overview | Adfgvx cipher | Adfgx cipher | Beaufort cipher | Bifid cipher | Caesar cipher | Columnar transposition | Cryptogram | Double transposition | Enigma machine | Four-square cipher | Gronsfeld cipher | Keyed caesar cipher | One-time pad | Pigpen cipher | Playfair cipher | Rail fence cipher | Rot13 | Trifid cipher | Variant beaufort cipher | Vigenère cipher