Or if a hacker gets access to your computer and can read your digital key, he’s home free because he can transfer the car on the block chain to a key that he controls. If he does, your car keys will instantly stop working. Not only can he drive off with your car, but he owns it outright. After all, the block chain says he does. As far as anyone can tell, you sold your car, and you can’t do anything to prove otherwise. Bear in mind that the block chain has no real names or identities, so it doesn’t give you a way to trace the theft, much less prosecute the thief. Suddenly, anonymous transactions don’t sound quite so appealing.