/rot ther'teen/ [Usenet: from "rotate alphabet 13 places"],

v. The simple Caesar-cypher encryption that replaces each

English letter with the one 13 places forward or back along

the alphabet, so that "The butler did it!" becomes "Gur ohgyre

qvq vg!" Most Usenet news reading and posting programs

include a rot13 feature. It is used to enclose the text in a

sealed wrapper that the reader must choose to open - e.g. for

posting things that might offend some readers, or spoilers.

A major advantage of rot13 over rot(N) for other N is that it

is self-inverse, so the same code can be used for encoding and

decoding.