Atbash

Atbash is a monoalphabetic substitution cipher originally used to encode the Hebrew alphabet. It is created by substituting the first letter of the alphabet for the last, the second letter for the second to last, and so on, reversing the alphabet. In the Hebrew alphabet, the first letter Aleph (א) is substituted with the last letter Tav (ת), the second letter Beth (ב) with Shin (ש), and so forth.

The term "Atbash" itself is derived from the Hebrew letters representing the substitution key: Aleph (א), Tav (ת), Beth (ב), and Shin (ש). These are combined to create the word "Atbash," signifying the substitution method.

While originally applied to the Hebrew alphabet, the Atbash cipher can be used with any known alphabet. In the English alphabet, 'A' would become 'Z', 'B' would become 'Y', 'C' would become 'X', and so on. Decryption is identical to encryption, as applying the Atbash substitution again restores the original text.

The Atbash cipher is a very simple cipher and provides little security. It is easily broken using frequency analysis or by simply knowing the algorithm. It is often used as a basic example in cryptography or puzzle-solving.