I'm not certain how the ring works. Perhaps there is some sort of chip in there that sends a message to the iPhone that the key is in the lock so to speak. It reminds me of the days when messages had to be sealed with wax and a specially molded ring.
Granted, the ring in the video looks like something that only Green Lantern would wear, but if it could be put on a normal-sized ring, like a wedding ring or class ring, then we have a marketable iPhone accessory with the bonus of some added mobile phone security!
