And you thought a fingerprint scanner was advanced? Think again. Now users in the US can unlock their Moto X by touching it against a digital tattoo.
The digital tatts are made by VivaLnk.com, and are the size of a small coin. Don't worry if you're not a fan of the needle: they're only temporary.
Intended to stick to your skin for five days, the tatts will even stay on while you shower, swim, or do other exercise.
NFC technology is harnessed to communicate with your phone. NFC is currently used in speakers and other accessories, and allows a phone to 'pair' with a single tap, which means there's no need for a passcode or fingerprint scanner.
The tattoos are sold in packs of 10, and cost $9.99. There's no word if or when they'll be available in the UK.
VivaLnk.com has said it's looking to make the tattoos compatible with other handsets in future.
Devices like the iPhone 5S, Samsung Galaxy S5, and HTC One Max feature fingerprint scanners that allow you to unlock them without entering a passcode.