Apple, always the innovator, is looking for the key to your heart. Security is a major concern in computing, particularly with smaller mobile devices becoming more capable. Apple thinks it has the answer. The patent describes a method of detecting an authorized user by the pulse in the veins and arteries in the hand holding the device. A sensor built into the device would detect your heart rhythm, apparently as unique as a fingerprint or retina. Other uses have been suggested, such as mood detection or managing user profiles. I’ve not heard much about cardiac signatures before, but this strikes…