Atbash Cipher

Paste text to apply Atbash - it encodes and decodes with the same operation.

Encode Decode

Enter text on the left and click Apply Atbash to begin.

How to use

What is the origin of the Atbash cipher?

Atbash originated in ancient Hebrew and is used in the Bible. The name comes from the first and last Hebrew letters.

Is Atbash self-inverse like ROT13?

Yes. Applying Atbash twice returns the original text, making encoding and decoding the same operation.

Does Atbash work on numbers?

This implementation only shifts letters A-Z. Numbers and punctuation pass through unchanged.

How secure is Atbash?

Not at all. It is a monoalphabetic substitution cipher, trivially broken with frequency analysis.