A tongue-in-cheek article, written in early 2014 (below), mentioned the advantages of using body parts for identification, over a phone or credit card.  It says that: "anything", including one's forehead, can be turned into a "contactless payment device".  Revelation 13:16-17 mentions that the Mark of the Beast will be put "... in their right hand, or in their foreheads, and that no man may be able to buy or sell, save he who had the mark."

Swedish students are paying for things with their paws using Quixter, a palm scanner that reads the unique pattern of blood vessels in your hand.
People have turned to fortune tellers for millennia, but this palm reader is the first I can say with certainty that really does give you a glimpse of the future. Quixter is a palm reader that allows you to pay for things without your wallet simply by placing your hand on a scanner.
To pay for stuff with Quixter all you have to do is type in the last four numbers of your phone number at the cash register, then place your palm on a reader to scan the unique pattern of blood vessels in your hand.
Swedish start-up Quixter is the handiwork of Fredrik Leifland, an engineering student at Lund University in Sweden. There are now 15 stores and restaurants around the Lund University campus with the vein-matching biometric scanners installed, used by 1,600 palm-payers.
Hand over the cash
To start greasing palms, you sign up at a shop or venue with a Quixter reader. You hand over your social security number and phone number, then scan your palm three times. A text message with an activation link arrives so you can fill in more details and complete registration. Your purchases accumulate on an invoice, and then twice a month the money you've spent goes out of your account by direct debit.

You've got to hand it to this clever idea: parts of your body, whether your eye, finger or hand, have a number of advantages over a phone or credit card. You always have them with you -- unless your day has gone pretty wrong -- so you can buy stuff even if you've forgotten your wallet or mislaid your credit card. And thieves can't get their hands on your money -- unless your day has gone spectacularly wrong.
Wavey pay
In Britain, you can turn anything into a contactless payment device -- your phone, your shoe, your forehead, anything -- by plastering a Barclaycard PayTag NFC sticker on it. And PayPal Check-in wants you to buy things by checking in on an app then simply leaving the shop without taking out either wallet or phone.