Sending Passwords Through Fingerprints

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Computer scientists and electrical engineers from the University of Washington have devised a way to send passwords through the human body using benign, low-frequency transmissions generated by fingerprint sensors and touchpads on consumer devices.

These “on-body” transmissions offer a more secure way to transmit authenticating information between devices that touch parts of your body for example, smart doors lock or wearable medical devices and a phone or device that confirms your identity by asking you to type in a password.

“Fingerprint sensors have so far been used as an input device. What is cool is that we’ve shown for the first time that fingerprint sensors can be re-purposed to send out information that is confined to the body,” said senior author Shyam Gollakota, UW assistant professor of computer science and engineering.

The research team tested the technique on iPhone and other fingerprint sensors, in tests with 10 different subjects, they were able to generate usable on-body transmissions on people of different heights, weights and body types. The system also worked when subjects were in motion.

Normally, sensors use these signals to receive input about your finger. But the UW engineers devised a way to use these signals as output that corresponds to data contained in a password or access code. When entered on a smartphone, data that authenticates your identity can travel securely through your body to a receiver embedded in a device that needs to confirm who you are.

The team achieved bit rates of 50 bits per second on laptop touchpads and 25 bits per second with fingerprint sensors — fast enough to send a simple password or numerical code through the body and to a receiver within seconds. This represents only a first step, the researchers say. Data can be transmitted through the body even faster if fingerprint sensor manufacturers provide more access to their software.