Caesar, ROT13, Atbash & Vigenère

Classic cipher toolkit

100% local — nothing is uploaded
Shift: 3
Output
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How to use

  1. Pick a cipher: Caesar, ROT13, Atbash or Vigenère.
  2. Set the shift (Caesar) or the letter key (Vigenère).
  3. Choose encode or decode.
  4. Copy the transformed text.

FAQ

Are these ciphers secure?

No — they are historical and trivially broken by frequency analysis. Use them for puzzles and learning, never for real secrets.

What is ROT13?

A Caesar cipher with a shift of 13. Applying it twice returns the original text, so encoding and decoding are identical.