What Is the Atbash Cipher?
Atbash is one of the oldest known ciphers, originally used with the Hebrew alphabet. This guide explains the reversed-alphabet idea and why it is easy to crack today.
What is the Atbash Cipher?
Atbash Cipher swaps each letter for its mirror image in the alphabet: A becomes Z, B becomes Y, and so on. Because the swap is its own reverse, encoding a message twice returns the original text.
How to use it
- Type or paste your message into the box.
- Click Encode.
- Copy the encoded message.
Worked example
For 'Hello World', the output is 'Svool Dliow'.
Is Atbash secure for private messages?
No. There is only one possible Atbash alphabet, so anyone who recognises the pattern can decode a message instantly. It is fine for puzzles, but never use it for anything genuinely private.
Frequently asked questions
How do I decode an Atbash message?
Run it through the tool again. Atbash is symmetric, so encoding the encoded message returns the original.
Does it change numbers and punctuation?
No. Only letters are swapped; numbers, spaces, and punctuation pass through unchanged.