The digital tattoo will rely on copper, where it will see its purpose accomplished alongside NFC technology, letting your Moto X unlock without the need to key in a passcode or swipe the display with a predesignated pattern. And fret not about the temporary nature of this tattoo, it will remain on your body even if you would like to take a swim, since it last up to five days thereabouts. A packet of 10 of such digital tattoos will retail for $9.99, and each of these is roughly the size of a nickel. It works only with the Moto X at the moment, although Vivalnk, the company behind this digital tattoo, might churn out versions that are compatible with other smartphone models if there is sufficient demand.