ROT13 / Caesar Cipher
Play with the classic shift cipher used by Julius Caesar, or ROT13 for hiding spoilers.
Runs in your browser. Nothing is uploaded Free, no sign-up Works on mobile
Shift (13 = ROT13)
Mode
How to use ROT13 / Caesar Cipher
- Type your message.
- Choose a shift (13 for ROT13) and encrypt or decrypt.
- To crack a message, tick “Show all 25 shifts” and look for readable text.
Frequently asked questions
Is a Caesar cipher secure?
No. There are only 25 possible shifts, so it can be cracked instantly. Use AES encryption for real secrets.
What is ROT13?
A Caesar cipher with a shift of 13. Applying it twice returns the original text.
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