ROT13 ("rotate by 13 places", sometimes hyphenated ROT-13) is a simple letter substitution cipher that replaces a letter with the letter 13 letters after it in the alphabet. ROT13 is an example of the Caesar cipher, developed in ancient Rome.
In the basic Latin alphabet, ROT13 is its own inverse; that is, to undo ROT13, the same algorithm is applied, so the same action can be used for encoding and decoding. The algorithm provides no cryptographic security, and is often cited as a canonical example of weak encryption.
This is a series of caches all being letterboxes, none of the hides are tough, just look in the obvious locations. Some of the micro sized containers, do not contain an ink pad, so please bring your own if you choose to stamp. Do not take the stamp or ink pad, they must stay in the container.