Atbash cipher online

Atbash cipher online. Enter text, choose settings and encrypt or decrypt immediately. Learn how it works, its history, an example and its limitations.

How does the Atbash cipher work?

What is this method?

Reverses the alphabet: A becomes Z, B becomes Y, and so on.

How does it work step by step?

The first alphabet letter maps to the last, the second to the penultimate, and so on. The transformation is reciprocal, so the same keyless operation both encrypts and decrypts.

Example and practical use

Atbash changes “REBUS” into “IVYFH”. Applying the same operation again restores the original text.

How to use the tool

Choose encryption or decryption, enter a message and set the parameters required by the Atbash cipher. The result is calculated locally in your browser and can be copied or shared without sending the text to a server.

History of the cipher

Atbash comes from the Hebrew tradition and appears in interpretations of the Book of Jeremiah. Its name joins the first with the last and the second with the penultimate Hebrew letter.

Security and limitations

This tool is educational. Classical ciphers can usually be broken with frequency analysis, repetition patterns or a small search through possible keys, so they should not protect confidential information.