Enlarge (credit: Getty Images) Researchers have devised a low-cost smartphone attack that cracks the authentication fingerprint used to unlock the screen and perform other sensitive actions on a range of Android devices in as little as 45 minutes. Dubbed BrutePrint by its creators, the attack requires an adversary to have physical control of a device when it is lost, stolen, temporarily surrendered, or unattended, for instance, while the owner is asleep.