Atbash Cipher
Atbash Cipher Overview
Reverse alphabet substitution encryption
The Atbash Cipher is one of the oldest known substitution ciphers, originally used to encode the Hebrew alphabet. It works on a simple symmetrical principle: the first letter of the alphabet is substituted with the last, the second with the second-to-last, and so on. In English, 'A' becomes 'Z', 'B' becomes 'Y', and 'C' becomes 'X'. Because the cipher is entirely symmetric, the same process is used for both encryption and decryption—applying the cipher to an encrypted message will return the original plain text. While it offers no real security against modern cryptanalysis, it is excellent for learning about the history of cryptography, creating simple puzzles, or understanding the basics of substitution encryption.
How to Use Atbash Cipher
- Type or paste your text into the 'Input' box.
- The tool calculates the transformation instantly as you type.
- The encrypted (or decrypted) text appears in the 'Result' box.
- Click 'Copy Result' to save the output to your clipboard.
- To decrypt, simply paste the encrypted text back into the Input box.
Frequently Asked Questions
- Is Atbash secure?
- No. Atbash is a monoalphabetic substitution cipher with a fixed key. Anyone who knows it is Atbash can decrypt it instantly. Do not use it for sensitive data.
- Do I need a key?
- No. Unlike the Caesar Cipher which requires a shift number, Atbash always uses the same fixed reversal (A↔Z).
- Why is 'A' becoming 'Z'?
- Atbash maps the alphabet backwards. Index 0 (A) maps to Index 25 (Z), Index 1 (B) maps to Index 24 (Y), etc.
- Does it work with numbers?
- This tool passes numbers and special characters through unchanged. It only encrypts English letters (A-Z).
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