“But you could also think about a means of authentication that you could simply wear on your skin, every day for a week at a time, say an electronic tattoo.” (Regina Dugan, former DARPA head, now Google executive)
These future authentication tattoos would give people colorful, cool design options.
“This pill has a small chip inside of it with a switch. It also has what amounts to an inside-out potato battery. When you swallow it, the acids in your stomach serve as the electrolyte, and they power it up. And the switch goes on and off and it creates an 18-bit ECG-like signal in your body.” This means “essentially your entire body becomes your authentication token.”