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atbash-cipher

The Atbash cipher is one of the oldest known substitution ciphers — originally used in Hebrew (Aleph ↔ Tav, Beth ↔ Shin) and adapted to any alphabet — that maps each letter to its mirror across the alphabet (A ↔ Z, B ↔ Y, ..., M ↔ N). Like ROT13, it is self-inverse: applying Atbash twice returns the original. The ZTools Atbash tool encodes and decodes Latin (English), Hebrew, and Greek alphabets, preserves case, passes non-letters through unchanged, and is suitable for educational demos, puzzles, and casual obfuscation — never for real security.

Use cases​

Religious / historical study​

Atbash appears in the Hebrew Bible (Jeremiah uses "Sheshach" as Atbash for Babel). Demonstrate the cipher for Bible-study or history classes.

Cryptography 101​

Teaching substitution ciphers — Atbash is even simpler than Caesar (no shift parameter to choose). One mapping, fixed.

Puzzles and escape rooms​

Hide a clue with Atbash. Solvers decode without needing a key beyond the alphabet itself.

Hidden spoilers / jokes​

Lighter than ROT13 in some communities; same purpose: read only if you choose to decode.

How it works​

  1. Pick alphabet — Latin (A–Z), Hebrew (22 letters), Greek (24 letters).
  2. Paste text — Text in the chosen alphabet. Other characters pass through.
  3. Apply Atbash — Each letter maps to its mirror (1st ↔ last, 2nd ↔ second-to-last, etc.).
  4. Inspect — Side-by-side original / encoded view.
  5. Decode — Apply Atbash again — self-inverse, so the same operation undoes it.

Examples​

Input: HELLO

Output: SVOOL

Input: SVOOL

Output: HELLO (self-inverse)

Input: BABEL → Hebrew Atbash

Output: SHESHACH (Biblical reference: Jeremiah 25:26)

Frequently asked questions​

How is Atbash different from Caesar?

Caesar shifts every letter by the same number (configurable 1–25). Atbash mirrors the alphabet — no parameter, fixed mapping. Caesar with shift = 25 looks similar but is not the same; only the symmetric mirror is "Atbash".

Why is it self-inverse?

Because mirroring twice returns the original position. If A → Z then Z → A; both operations use the same rule.

Is Atbash secure?

No — trivially broken by frequency analysis or guessing once you suspect it. Use only for fun and education.

Does it work on lowercase?

Yes — case is preserved. "hello" → "svool".

What about Hebrew or Greek?

Yes — the tool supports both. Hebrew Atbash maps Aleph ↔ Tav. Greek maps Alpha ↔ Omega. Same self-inverse property.

Will it handle accented letters (é, ñ)?

No — they pass through unchanged. Atbash is defined only on the chosen base alphabet.

Tips​

  • For puzzles, pair Atbash with another step — alone it is too easy.
  • For Bible study, demonstrate the Sheshach example — a memorable real-world appearance.
  • For mixed alphabets, run each segment through its corresponding alphabet setting.
  • Use sparingly — once readers know the cipher, decoding takes seconds.
  • For real obfuscation, pair with Caesar at a non-13 shift; combinations are slightly more puzzle-friendly.

Try it now​

The full atbash-cipher runs in your browser at https://ztools.zaions.com/atbash-cipher — no signup, no upload, no data leaves your device.

Open the tool ↗

Last updated: 2026-05-05 · Author: Ahsan Mahmood · Edit this page on GitHub