An attacker walks up to a car stopped at a traffic light and tries to open the driver’s door. The driver discreetly presses a specific fingerprint onto the start button, and the cars around them begin building evidence.

 

That scene comes from a patent filing discovered by Carmoses, granted to Audi in Germany this month. Audi calls the press a “Biometric Duress Signature,” but the fingerprint is only one way in. What it protected is a network of witness cars that forms on the spot and locks in proof that the footage is untouched, while the video stays put until the law says otherwise.