"Holy Bat-phone, Batman!"

NEC develops biometrics technology that uses sound to distinguish individually unique ear cavity shape (NEC)

The new technology instantaneously measures (within approximately one second) acoustic characteristics determined by the shape of the ear, which is unique for each person, using an earphone with a built-in microphone to collect earphone-generated sounds as they resonate within ear cavities. This unique method for extracting features is useful for distinguishing individuals based on acoustic characteristics and enables rapid and highly accurate recognition (greater than 99% accuracy).