Fingerprint on top of a device to identify yourselve via your heartbeat....I guess apple can do the same overnight....by measuring the heartbeat through the phone and combine with Apple ID..how do you know you are voluntary wearing it...a high heartbeat?
Halifax is trialling technology which can authenticate user identities by analysing their unique heartbeat rhythm. The UK bank is working with Canadian firm Bionym to test the use of the firm's Nymi bracelet for logging on to online banking. The bracelet has an embedded sensor which recognises the wearer's unique electrocardiogram (ECG) and communicates their identity to terminal devices using Bluetooth. In September, Bionym raised $14 million on the back of a pre-launch order book for 10,000 of its wearable bracelets. The firm has already struck a deal with the Royal Bank of Canada and other Canadian banks to test the system in conjunction with contactless card use at the checkout.
http://www.finextra.com/news/fullstory.aspx?newsitemid=27108