That's the idea behind startup Bionym's Nymi bracelet, a so-called "wearable authentication device." It's still in the prototype stage, but Bionym is hoping investors will fall for the idea of a world where you can walk into a room and have all your devices unlock for you.
Using the same technology as an electrocardiograph, Nymi monitors your heart's unique electrical activity. When your wrist comes within a certain distance from your computer or cell phone, it will automatically authenticate those devices for you. If another person tries to use your devices, it would sense that person is not you and lock them out.
The first group of Nymis would be confined to Android, iOS, Macs, and Windows devices, meaning that users could unlock them without touching the keyboard. But Bionym would eventually like Nymi to work seamlessly with other everyday products -- like cars or television sets.
Nymi bracelets are available for a special pre-order price of $79, though they'll ultimately cost $99.