[ItisaReligionofPeace]

what is ROT-13? Thanks.

[JRandomFreeper]

ROT-13 is an encryption method developed by Caesar. Rotate every letter 13 letters to the right. A becomes M, B becomes N etc.

/john

[justlurking]

what is ROT-13?

It's a simple substitution cipher:

abcdefghijklmnopqrstuvwxyz
nopqrstuvwxyzabcdefgjijklm

The quick brown fox jumped over the lazy dog.
Gur dhvpx oebja sbk whzcrq bire gur ynml qbt.

ROT is short for "Rotate", and -13 means substitute the 13th character after the plaintext character. Since there are 26 characters in the alphabet, two rounds of ROT-13 yields the original plaintext.