Caesar Cipher

Encode or decode secret messages using the ancient Caesar Cipher. This is a substitution cipher which works by shifting all letters by a fixed number of positions. Julius Caesar used a shift of 3, but you can use any shift. To decode an N-shift code, you need to shift another C-N steps, where C is the number of characters in the alphabet. For N=13, and the usual 26-letter alphabet, the Caesar cipher is the ROT13 code which has been used to hide spoilers on the Internet.

FEATURES:
- Interactive change of shift with immediate update
- Customizable alphabet to allow for new languages or adding extra characters
- Swap button to move the encoded message to upper field, to become a deciphering challenge for someone else
- Cut and paste to and from other applications on iPhone OS 3.0 and later

Tested with iPhone OS 3.0