What it does
ROT13 ("rotate by 13") replaces each letter with the one 13 positions further in the alphabet, wrapping around after Z. Because the alphabet has 26 letters, applying ROT13 twice returns the original text — so encoding and decoding are literally the same operation.
It's commonly used to casually obscure text (like spoilers or puzzle answers) — never for actual security.
Try it
How it works
This is simply a Caesar cipher with a fixed shift of exactly 13 — half of the 26-letter alphabet. Letter case is preserved and non-letter characters are left untouched.
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