Researchers at The University of Washington’s Networks and Mobile Systems Lab are experimenting with technology that sends signals such as passcodes through the skin. Touchpads and fingerprint readers create the signals that are then transmitted through the body. Unlike wireless broadcasts, these electrical transmissions cannot be intercepted in the air.
The science requires an individual to touch a transmitter, such as a fingerprint reader on an iPhone, when they are within distance or in contact with a receiver. That touch then initiates a signal or electromagnetic pulse that is detected by the end device after transmission just below the skin of the individual or conduit. TechInsider gives the example of a door knob that can be opened only by the person with the paired signaling device, such as a smartphone or a wearable.
For an in-depth paper on the research, go to http://onbody.cs.washington.edu/files/bodycomm.pdf