Atbash Cipher

Encryption replaces each letter in the alphabet with the letter at its mirrored position, counting from the opposite end.

Here $m$ is the plaintext letter, encoded as an integer 0 (a) to 25 (z).

Originally devised for the Hebrew alphabet, then applied to Latin and other alphabets.

Breaking the Atbash Cipher

There is no key to search: the mapping is fixed, so recovering the plaintext is a single substitution away once Atbash is suspected.