ABCipher app for iPhone and iPad
ABCipher is a simple, yet clever, implementation of Lewis Carrolls Alphabet-Cipher.
Slide the (blue) dots up and down to create your secret message, select a Cipher Key, and tap ENCIPHER. The columns of letters will align themselves to spell-out the Cipher Key along the top; where the (now-red) dots lie indicate the encoded characters. Tap DECIPHER to reverse the process.