Atbash Cipher Encode & Decode
An ancient mirror cipher: A↔Z, B↔Y — encode and decode are the same. This tool does both encode and decode on one page — just pick a mode, paste your text, and click. Everything runs on your device, nothing is sent to a server.
Everything runs in your browser. Your data is never sent to our servers.
Example
Example Input
Hello
Example Output
Svool
How to Use
- 1Choose Encode or Decode mode at the top.
- 2Type or paste your text into the Input field.
- 3Click the button (or press Ctrl+Enter) to process. The result appears in the Output field.
- 4Click Copy to copy the result, or "Swap input/output" to quickly reverse the operation.
About Atbash Cipher
Atbash is an ancient substitution cipher (originating in Hebrew) that reverses the alphabet: A becomes Z, B becomes Y, and so on. Because it is symmetric, encoding and decoding use the same operation.
How it works: each letter maps to its mirror pair (distance from the start of the alphabet becomes distance from the end). Digits and symbols are left untouched.
Atbash is one of the oldest known ciphers and appears in historical texts. Today it is used for education, puzzles, and word games — not for security.
FAQ
Can this Atbash Cipher tool both encode and decode?
Yes. This is a single page with a toggle — use Encode mode to transform text, and Decode mode to reverse it. No need for two separate pages.
Is my data sent to a server?
No. Atbash Cipher is processed entirely in your browser. The text you enter never leaves your device.