The security design of the system as implemented in tests so far will require a national certificate infrastructure much like that used for preventing domain spoofing and securing the Web. It will require a database of certificates—like the X.509 certificates used in public key infrastructure (PKI)—to verify that devices are legitimate and make it possible to rescind permissions to ensure that no one can send out spoofed messages. If a certificate were to become compromised or if a manufacturer misconfigured a batch of V2V systems, the certificate authority would be able to revoke the associated certificate. This prevents spoofing much in the way that DNS SEC prevents the “poisoning” of Internet domain address tables by a rogue Domain Name Service server.
The problem is that no one has ever developed a PKI system large enough to handle every vehicle in the United States—every car, truck, bus, and motorcycle. The revocation table for expired or compromised certificates would have to be distributed constantly to cars to make sure they weren’t victimized by recorded data attacks or other systems that used hacked hardware to spoof traffic.
So far, there hasn’t been any agreement yet on how this PKI would distribute its certificates. Proposals have included having roadside systems issue certificates as vehicles drive by and having certificates sent to vehicles out-of-band over cellular connections. The latter would mean that every car in the country would have to have its own integrated cellular phone or that drivers would have to connect their phones regularly to the systems to ensure they didn’t get shut out of the network.
Oh yes, please: let’s build a mass communications network dependent on a (largely) creaky Certificate system, deploy the devices to the attackers (i.e. car owners), and just trust that no one’s gonna hack a mass, nation-wide, Vehicle-to-Vehicle communications network.
Also: taking bets on it being an escrowed certificate system. For public safety and all that good stuff.