Encrypt Wheel-An Magic Prop

How to use this app to perform magic:

1.Make setting ”Hide Compass“ on
2.You and Your Friend face to face
3.Open this app to input some words and press left button to encrypt
4 Press "key" button to decrypt, means you can decrypt
5 Encrypt the text again and pass your iPhone to your friend
6 Your friend try to decrypt the message, but failed
Magical thing happened !!

Of cause, it's the compass contribution!