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Caesar Cipher / ROT13
Shift letters by any amount to encode or decode a classic Caesar cipher, with a one-click ROT13 preset.
Input
Result
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Frequently asked questions
What is a Caesar cipher?＋
A simple substitution cipher that shifts each letter a fixed number of places in the alphabet. ROT13 is the special case with a shift of 13.
Is it secure?＋
No — it's a classic puzzle cipher and is trivially broken. Never use it to protect real secrets.
Why is ROT13 self-reversing?＋
Because the alphabet has 26 letters, shifting by 13 twice returns the original, so the same operation both encodes and decodes.