How do I use the Atbash Cipher?

Enter or paste your input value, select the source and target formats, then click Convert. The result appears instantly. All conversions run locally in your browser — no data is sent to any server.

Is the Atbash Cipher free to use?

Yes, this tool is completely free with no signup required. Everything runs locally: your input is processed on your device, never sent to a server — ensuring complete privacy and security.

Is there a file size limit for the Atbash Cipher?

Since all conversions happen locally in your browser, the limit depends on your device's memory. Most typical inputs are processed instantly. Very large files may take longer but will still work without server upload.

Atbash Cipher

Free online Atbash Cipher encoder/decoder - reverse alphabet substitution cipher, instant encode/decode with bulk text processing.

Reverse alphabet substitution cipher — one of the oldest monoalphabetic ciphers

🔤 Encode / Decode (Atbash is symmetric — same operation for both)

📖 Substitution Table

What is Atbash Cipher?

Atbash Cipher is a free online tool that runs entirely in your browser. No download or signup needed — just paste your text and convert it instantly. All data is processed locally.

Use Cases

Reverse plaintext alphabet substitution to encrypt or decrypt messages
Solve puzzles and riddles that use the Atbash cipher
Decode historical texts or cipher challenges
Teach the basics of monoalphabetic substitution ciphers

Key Features

Completely Free: No registration, no limits
Privacy Safe: Data never leaves your browser
Cross-Platform: Any modern browser
Zero Dependencies: Open and use