Amazon was just granted a patent for tech that unlocks your smartphone with your ears. By now, most of us are familiar with Touch ID, the fingerprint recognition system on the newer iPhones. Retinal scanners, too, have been around since the early ’80s. But this new technology could eventually be a game-changer in biometrics. For one, our ears (like our fingerprints) are unique; no two are alike, which makes them ideal for personal identification. In addition to simply confirming the identity of a phone user, Amazon wants to use data accumulated by this new tech to personalize users’ experiences. For instance, if someone is consistently holding his phone around his left ear, he’s probably using his left hand, and would benefit from a customized layout of buttons designed for left-handed people.