Free Toolkit

Atbash CipherEncrypt and decrypt text using the Atbash reverse-alphabet cipher.

Atbash Cipher illustration
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Atbash Cipher

Encrypt and decrypt text using the Atbash reverse-alphabet cipher.

How to Use
1

Enter Input

Type or paste your input.

2

View Output

Results appear in real time.

3

Copy Result

Click Copy to copy the output.

What Is Atbash Cipher?

Oldest known cipher from Hebrew alphabet (~500 BCE). Replaces each letter with its reverse: A-Z, B-Y, C-X. Name from Hebrew Aleph-Tav, Beth-Shin. Self-inverse (involution). Appears in the Book of Jeremiah. Pure JavaScript.

Why Use Our Atbash Cipher?

  • Fast, accurate processing
  • 100% client-side — data never leaves your browser
  • Free online tool with no signup required
  • Mobile-friendly with 44px touch targets

Common Use Cases

Development

Use in software development workflows.

Security

Cryptographic and security applications.

Education

Learn about algorithms and techniques.

Verification

Verify and validate data integrity.

Technical Guide

E(x) = 25-x. E(E(x)) = x (involution). Uppercase: 155-charCode. Lowercase: 219-charCode. Non-alphabetic unchanged. Equivalent to affine cipher a=25, b=25. One key — zero security.

Tips & Best Practices

  • 1
    All processing happens in your browser
  • 2
    Results are deterministic for the same input
  • 3
    Use Copy button to quickly grab output
  • 4
    Works on mobile devices with touch-friendly interface

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Frequently Asked Questions

QIs this tool free?
Yes, completely free with no signup required.
QIs my data secure?
Yes. All processing is 100% client-side.
QDoes it work on mobile?
Yes, with responsive design and touch-friendly controls.
QWhat browsers are supported?
All modern browsers including Chrome, Firefox, Safari, and Edge.
QCan I use this offline?
The tool requires an initial page load but processes data locally.

About Atbash Cipher

Atbash Cipher is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.