rot13

/rot therteen/ , n.,v. [Usenet: from rotate alphabet 13 places ] 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 spoiler s. 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. See also spoiler space , which has partly displaced
rot13 since non-Unix-based newsreaders became common.

