Atbash Cipher Decoder & Encoder
beginnerReverses the alphabet: A↔Z, B↔Y, etc.
What is Atbash Cipher?
Atbash is one of the oldest ciphers, originating in Hebrew tradition around 600 BC. The name comes from the Hebrew letters Aleph-Tav-Beth-Shin, indicating the substitution pattern. It reverses the alphabet: A becomes Z, B becomes Y, C becomes X, and so on.
How Atbash Cipher Works
Replace each letter with its mirror in the alphabet: A↔Z, B↔Y, C↔X, D↔W, and so forth. The cipher is perfectly symmetrical — encoding and decoding use the exact same operation. HELLO becomes SVOOL, and SVOOL becomes HELLO.
Atbash Cipher in Pop Culture
Atbash is used in the TV show "Gravity Falls" for hiding secret messages in the credits. It appears in several Dan Brown novels and is popular in escape room design.
How to Break Atbash Cipher
Apply Atbash again — since it's self-reciprocal, decoding it IS encoding it. Alternatively, frequency analysis on the reversed alphabet reveals the pattern immediately.
Frequently Asked Questions
How do I decode Atbash Cipher?
Enter your ciphertext in the tool above, select "Atbash Cipher" from the dropdown, choose Decode mode, and click the button. Results appear instantly.
What is Atbash Cipher used for?
Atbash Cipher was used since ~600 BC for secret communication. While not secure by modern standards, it's widely used in puzzles, escape rooms, and educational contexts.
How secure is Atbash Cipher?
Atbash Cipher is not secure by modern standards — it can be broken quickly with basic cryptanalysis or brute force. Use it for puzzles and learning, not sensitive data.
Who invented Atbash Cipher?
Atbash Cipher was invented by Hebrew scribes around ~600 BC.