Atbash Cipher

What Is a Atbash Cipher?

The Atbash Cipher tool replaces each letter with its opposite in the alphabet: A becomes Z, B becomes Y, and so on. It is a simple substitution cipher that appears in historical texts such as the Bible and is an involution — applying it twice returns the original. This free online tool is useful for Atbash cipher, Atbash encoder, Atbash decoder online. Common use cases include classical cryptography, puzzles, historical texts, and educational exercises. It is designed for quick browser-based hashing, encoding, decoding, encryption testing, checksum comparison, identifier generation, and cryptography education. For production security, follow the algorithm's current standards, key-management requirements, and application-specific security guidance.