For a couple of years now, I've had my eye on the community of people who've had RFID or NFC chips implanted somewhere in their bodies, usually in the back of the hand.  If you've ever used a badge to unlock a door at work or tapped your phone on a point-of-sale terminal to buy something, you've used one of these two technologies in your everyday life to do something useful.  What I've wanted to do for a while was use an implanted chip as a second authentication factor to my servers for better security.  As for why I couldn't …