identification microchips

Former DARPA director and current Google executive Regina Dugan wants you to swallow identification microchips.

She explains how the microchip works when it is in the body. Inside the pill is a small chip with a switch. When you swallow the pill, the acids in your stomach act as an electrolyte that powers the chip. The switch turns on and off and generates an 18-bit ECG signal in your body so that your whole body becomes your authenticator.
"You put your hand to your computer, your phone, your doorbell-and you're authenticated."

FYI, the video was filmed in 2012, so you can imagine the technology already exists.