A device the size of a car-alarm remote could one day unlock cars and homes as well as validate credit card purchases and bank transactions-all by reading the user's fingerprint and wirelessly transmitting it to a third party for authentication. The tiny gizmo (photo) is the brainchild of Palm Beach Gardens, FL-based Cross Match Technologies, which specializes in fingerprint capture devices. The device will also sense blood flow patterns in the finger. This will add an extra layer of security to the device; not only must the finger be attached to a living person, but if the blood is flowing faster than normal (say, if the person attached to the finger is being held at gunpoint), the sensor can void the transaction. The sensitivity can be set for different applications, so runners could still unlock their doors after a jog but might have to wait 20 minutes to use the ATM. Cross Match hopes to build a working model in the next two and a half years. The company's target is a product selling for less than $50.