While this may sound stupid the science behind the idea is sound. Every ear is unique, very much the same way we have unique fingerprints or eyes. By using the way sound resonated within your ear canal, the headphones create a unique sound, something that can be measured and compared.
Reported to have 99% accuracy and only taking a second to do the measurements needed, listening to all that music may actually help you unlock your phone. The system is praised by the general manager of NEC saying that as it doesn’t “require particular actions such as scanning a part of the body over an authentication device” it would enable “a natural way of conducting continuous authentication”.
This solution may be a few years out though with the company behind it, NEC, saying that they are looking to commercialize the system for the 2018 fiscal year. So looking forward to listening to music while you bank? Take your headphones out to talk to someone and your phone will start to doubt if you truly are who you say you are.