BIOACOUSTIC AUTHENTICATION

According to various, but not necessarily all, embodiments there is provided an apparatus comprising means for: determining at least two locations at which a user touches a device; selecting a first location and a second location from the at least two locations to define a transmission path for an acoustic signal through the user; applying an acoustic signal to the user through the first location; detecting an acoustic signal transmitted through the user at the second location; and analysing the detected acoustic signal to determine if it is indicative of transmission of the applied acoustic signal through an authorised user based on a known bioacoustic signature of the authorised user.