Atbash Cipher

📖 Tool Introduction

The Atbash cipher is one of the oldest known substitution ciphers, and its name comes from combining the first and last letters of the Hebrew alphabet, Aleph and Tav. Its rule is wonderfully simple: mirror the whole alphabet so that the first letter becomes the last, the second becomes the second to last, and so on. Translated into the Latin alphabet, this means A becomes Z, B becomes Y, C becomes X, all the way to M becoming N, which makes exactly fourteen pairs. Because this mapping is symmetric, encrypting once produces the ciphertext, and running the very same operation a second time restores the plaintext, which means the tool is simultaneously the encryptor and the decryptor and needs no key at all. Across the top of the interface a row of small cards shows all fourteen letter pairs at a glance, so you can see the mirroring logic from A to Z immediately. After you type your text and click Reverse letters, every Latin letter is mirrored according to its own case, while digits, punctuation, spaces and even CJK characters are left untouched and do not participate in the mapping. Since the operation is fully self-inverse, you can convert back and forth freely without ever worrying about which direction you picked. Everything runs locally in your browser, which makes the tool a natural fit for classroom demonstrations, introductory cryptography lessons and lighthearted word games. It also pairs beautifully with other classical ciphers: you can first Atbash a message and then Caesar-shift it, and experimenting with these layers is a hands-on way to feel how early ciphers evolved toward stronger schemes. The pair strip at the top is not decorative: you can point at any row and immediately read which letter mirrors to which, which turns an abstract substitution into something you can verify by eye. Because the transform costs nothing and needs no key, it is also a fun way to disguise a short note while still being trivially reversible by anyone who knows the trick, which makes it popular in puzzles and escape-room clues.

✨ Key Features

• Alphabet mirror: fourteen pairs from A↔Z up to M↔N
• Self-inverse: encrypt and decrypt are the same operation, twice restores text
• Visual mapping: a full letter pair strip is shown at the top
• Case preserved: upper and lowercase mirror on separate tables
• Non-letters kept: digits, punctuation, spaces and CJK stay as-is
• Fully offline: pure in-browser math, copy and download, private

📝 How to Use

1. Type the text you want to process into the input area
2. Read the letter pair strip above to understand the mirror rule
3. Click Reverse letters, or press Ctrl+Enter
4. Inspect the result in the output area
5. Click again to restore the original, then copy or download if needed

⚠️ Notes

• Empty input: running with nothing typed shows a friendly prompt
• Latin only: CJK characters and digits are not mirrored and stay as-is
• Self-inverse: there is no direction to pick; two passes always restore text
• For teaching: Atbash is trivial and must not protect real secrets
• Reversible: applying it twice to the output always returns the original