Atbash Cipher

The Atbash Cipher tool applies one of the oldest substitution ciphers known, originally devised for the Hebrew alphabet and later adapted to Latin letters.

The rule is beautifully simple: each letter is swapped for its mirror image in the alphabet, so A becomes Z, B becomes Y, C becomes X, and so on, with the two halves of the alphabet folding onto each other.

Because the mapping is symmetrical, the same operation both encodes and decodes — there is no separate key or direction to choose.

Type or paste your text and the output updates live as you go.

The letter case of your message is preserved, so capitals stay capital and lower-case stays lower-case, and everything that is not an A–Z letter — digits, spaces, punctuation, accented characters and emoji — passes straight through untouched.

That keeps the shape of your message intact while scrambling the letters.

To read an Atbash message back, just paste the ciphertext into the same box: running Atbash twice returns the original text exactly.

Like all classical substitution ciphers, Atbash is a learning and puzzle tool rather than real security, since the fixed mapping is trivial to reverse.

It shows up in word games, escape rooms, cryptography lessons and even some historical texts.

Everything runs locally in your browser, so your text never leaves your device.