Atbash Cipher Tool
NewEncode or decode text with the Atbash cipher — a mirror-alphabet substitution (A↔Z, B↔Y...) that is its own inverse.
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Atbash maps each letter to its mirror position in the alphabet — A becomes Z, B becomes Y, and so on. Because the mapping is symmetric, running the exact same transformation a second time restores the original text, so there's no separate "decrypt" mode needed. Digits, punctuation, and spaces pass through unchanged.
Frequently Asked Questions
What makes Atbash different from a Caesar or Vigenère cipher?
A Caesar cipher shifts every letter by a fixed amount and a Vigenère cipher shifts by an amount that varies with a keyword; Atbash instead reverses the entire alphabet — the first letter swaps with the last, the second with the second-to-last, and so on — with no shift amount or key involved at all.
Why is there no separate "decrypt" button?
Atbash is its own inverse: mirroring the alphabet twice returns every letter to its original position, so running the exact same transformation on already-encoded text decodes it back to the original — there's no different operation needed for the reverse direction.
Is Atbash cipher actually secure?
No — it's one of the oldest and simplest substitution ciphers (originally used for the Hebrew alphabet), with no key at all, so it offers essentially no real security; it's used here for historical interest, word puzzles, and basic obfuscation, not for protecting sensitive information.
What happens to digits, spaces, and punctuation?
They pass through completely unchanged — only letters A-Z and a-z are mirrored, with case preserved in the output.
What does the mirror alphabet reference table show?
Every letter A through Z paired directly above its Atbash mirror partner, so you can look up any single letter's substitution without needing to type anything into the main tool.