Atbash

The Atbash cipher is a substitution cipher where each letter of the plaintext is replaced by its counterpart in the reverse alphabet.

Preserve Capitals

Preserve Symbols

Preserve Whitespace

Encode

Input Message

Output Message

Explanation

The Atbash cipher is a mono-alphabetic substitution cipher and is one of the simplest and oldest forms of encryption.

Encryption involves replacing each letter with its reverse counterpart. i.e. A becomes Z, B becomes Y, etc.

Decryption is performed using the same formula as encryption.

Atbash cipher can effectively obscure the meaning of a message to those unfamiliar with the technique. However, it's very vulnerable to cryptanalysis, especially frequency analysis, and it provides very little security against modern decryption techniques.

Facts

The Atbash cipher is one of the oldest known substitution ciphers. It is believed to have been used in ancient Hebrew texts as far back as 500-600 B.C.

It gets its name from a technique using the Hebrew alphabet, where the first letter 'Aleph' is replaced with the last latter 'Tav', 'Bet' is replaced with 'shin', etc.

It is a special case of the Affine cipher with a = 25 and b = 25.