Rot13 Cipher app for iPhone and iPad

The Rot 13 Cipher is a cool way to encode and decode messages quickly on the iPhone. You can type a message into the app to encode it and then somebody else with the same app can type the encoded message into their app to decode it. This is also a useful way to hide spoilers. Since encoded messages look like random letters, the only way to read an encoded message is to go out of your way to decode it first.

The cipher works by exchanging every letter to the letter that comes 13 after it (wrapping around if need be). Because there are exactly 26 letters in the alphabet, performing this twice leaves you with the letter you started with. This is why the same cipher can be used to both encode and decode the messages!

A - N
B - O
C - P
D - Q
E - R
F - S
G - T
H - U
I - V
J - W
K - X
L - Y
M - Z