Remembering passwords can always be a drag, especially because it's so common to place emphasis on remembering the wrong things. Luckily, scientists at MIT are working on a much simpler system: skulls. Your skull, specifically.
That's what three scientists from the University of Stuttgart, Saarland University, and the Max Planck Institute have done with SkullConduct, which they describe as "a biometric system that uses bone conduction of
sound through the user's skull as well as a microphone readily
integrated into many of these devices, such as Google
They're claiming their system can identify users with a 97% accuracy using bone conduction. In their paper, the team notes that there are two methods for a person to receive sound: the most common form is hearing, of course, but the second is called bone conduction. Bone conduction is when sound travels to the inner through the bones of skull. It's been theorized that it's the reason your voice sounds different to you when you hear a recording of yourself.
These scientists aren't the first to bring bone conduction technology to the market. Bone conduction technology was crucial in the raid that killed Osama bin Laden. Headphones being marketed with bone conduction were being sold in the early 2000's, and a company called Afterrshockz sells high-end models for as low as $60.
But it's a trait unique to each human, similar to fingerprints, that hasn't been used in privacy before. SkullConduct is being built around products like Google Glass, and it works like this: when audio is being played through your head with bone conduction, your head is modified by the sound waves. SkullConduct would send a white noise signal through to your bones, and then monitor your skull's response to that signal. The human skull is so unique, with slight structural differences and the brain, that it would be almost impossible to replicate.
The system is still in its early stages, and the paper notes some serious work has to be done before SkullConduct is ready for sale, including testing it in situations where there is outside noise such as a crowded cafe or a concert. There's also the question of what happens if a user's skull is damaged in an accident, and if that change would affect SkullConduct. But the underlying technology appears to be on very stable ground.