Tattoo technology can also be used for authentication purposes, as an alternative to traditional computer passwords. The mobile devices could then be used to confirm the owner’s identity and log them in to accounts automatically. This would prevent thieves and other people from being able to access a phone, or individual apps on the device, if it is stolen or lost. The circuits in tattoo, which also contain antennae and built-in sensors, could be adapted to work with mobile phones and tablets.