Atbash Cipher Encoder & Decoder
The Atbash Cipher is an ancient monoalphabetic substitution cipher originally used to encrypt the Hebrew alphabet. It maps the first letter of the alphabet to the last, the second to the second-to-last, and so on (A↔Z, B↔Y). It is a symmetric cipher, meaning the same algorithm is used for both encryption and decryption. Famous for its use in Biblical texts like the Book of Jeremiah, it is one of the earliest known examples of cryptography.
Cipher
Cipher Settings
Processed Text
Cipher Settings
Atbash Cipher
Replaces each letter with its opposite in the alphabet
Mapping:
- A↔Z, B↔Y, C↔X, D↔W, E↔V, F↔U, G↔T, H↔S, I↔R, J↔Q, K↔P, L↔O, M↔N
- No key needed - fixed substitution
- Self-reversing (same algorithm for encrypt/decrypt)
- Example: "HELLO" → "SVOOL", "WORLD" → "DLIOW"
Who Uses This Tool
- • Theology students studying Biblical codes
- • Puzzle enthusiasts solving substitution riddles
- • History buffs interested in ancient communication
- • Escape room designers creating 'mirror' puzzles
- • Linguistics students studying alphabet reversion
Key Features
- ✓ Symmetric substitution (A becomes Z, Z becomes A)
- ✓ No key required (Fixed mapping)
- ✓ Preserves punctuation and numbers
- ✓ Simple bi-directional mirroring
- ✓ Instant client-side conversion
- ✓ Historical significance (600 B.C.)
Frequently Asked Questions
Where does the name 'Atbash' come from?
It comes from the first, last, second, and second-to-last letters of the Hebrew alphabet: Aleph-Tav-Bet-Shin (A-T-B-Sh).
Do I need a key to decode Atbash?
No. Atbash is a 'fixed' substitution cipher. The rule is always the same: valid for any standard Latin alphabet where A↔Z, B↔Y, etc. If you know it is Atbash, you can decode it instantly.
Is it secure?
No. It offers no security against anyone who knows the method, and it is trivial to break with frequency analysis even if the method is unknown. It is strictly a historical curiosity or puzzle element.
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