Unlocking your smartphone is not that hard. But wouldn’t it be nice if you could do it with a digital tattoo? That way only you would be able to unlock your phone. Motorola has come up with a similar idea. It has partnered with VivaLnk to launch a NFC based skin tag that can unlock your phone with a quick tap. It can stay on your body for up to 5 days. You are going to have to pay $10 for packs of 10 tattoos, so it’s not a cheap solution. This is not a permanent tattoo and does not make your phone hack-proof as we mentioned earlier. Nevertheless, the idea is interesting to further explore.