Apply ROT13 and other Caesar cipher rotations to text. ROT13 is its own inverse — encoding and decoding use the same operation.
ROT13 is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Since the alphabet has 26 letters, applying ROT13 twice returns the original text — making it its own inverse. It's commonly used on internet forums to hide spoilers, puzzle answers, and mildly obscure content.
ROT13 is a special case of the Caesar cipher, one of the earliest known encryption techniques. Julius Caesar used a rotation of 3 (ROT3) to encrypt military messages. While trivially breakable today, it was effective in an era when most people couldn't read at all.
Absolutely not. ROT13 provides zero security — it's trivially reversed. It should never be used for actual encryption. Use AES-256 for real security. ROT13 is only useful for casually obscuring text (like spoilers).