A New York Times report that protecting driverless cars from cyber attacks is the “primary challenge will be preventing hackers from getting into the heart of the car’s crucial computing system, called a CAN (or computer area network).” The June 7, 2017 report entitled “Electronic Setups of Driverless Cars Vulnerable to Hackers” included this proposal from the National Highway Traffic Safety Administration

…that V2V equipment be installed in all cars in the future. But that channel, and all the equipment involved, open millions more access points for would-be attackers.

Also the New York Times made these predictions:

It will be five to 10 years — or even more — before a truly driverless car, without a steering wheel, hits the market. In the meantime, digital automobile security experts will have to solve problems that the cybersecurity industry still has not quite figured out.

Protecting V2V from cyber attacks will clearly be a challenge!