Security
ROT13 / ROT47 Cipher
Input
ROT13: Shifts letters A–Z by 13 positions. Non-letters unchanged.
Run apply repeatedly to decode/encode with the same mode.
Result
Frequently Asked Questions
What is ROT13?
ROT13 (Rotate by 13) is a simple letter-substitution cipher that replaces each letter with the letter 13 positions ahead in the alphabet. A→N, B→O, N→A, etc. Because the alphabet has 26 letters, applying ROT13 twice returns the original text. Non-letter characters are unchanged.
Is ROT13 a form of encryption?
No. ROT13 is trivially reversible with no key — it provides zero security against anyone who knows it (which is everyone). It is used for light obfuscation of spoilers, puzzle answers, and offensive words in online communities, not for protecting sensitive information.
What is ROT47?
ROT47 extends the rotation to 94 printable ASCII characters (codes 33–126), shifting each by 47 positions. Unlike ROT13 (letters only), ROT47 also rotates digits, punctuation, and symbols. The same self-inverse property applies: ROT47 applied twice restores the original.