Cooperative Location Privacy in Vehicular Networks: Why Simple Mix Zones are Not Enough

Vehicular communications disclose rich information about the vehicles and their whereabouts. Pseudonymous authentication secures communication while enhancing user privacy. To enhance location privacy, cryptographic mix zones were proposed to facilitate covertly transition new ephemeral credentials. The resilience (syntactic semantic) pseudonym linking (attacks) highly depends on geometry of zones, mobility patterns, vehicle density, arrival rates. We introduce a tracking algorithm for pseudonyms before after cryptographically protected zone. Our experimental results show that an eavesdropper, leveraging standardized vehicular messages road layout, could successfully link ?73% during nonrush hours ?62% rush change in mitigate such inference attacks, we present novel cooperative zone scheme enhances privacy regardless rate A subset vehicles, termed relaying is selected be responsible emulating nonexisting vehicles. Such cooperatively disseminate decoy traffic without affecting safety-critical operations: with 50% as probability (for entire interval) drops from ?68% ?18%. On average, this imposes 28 ms extra computation overhead, per second, roadside unit (RSU) 4.67 (relaying) side; it also introduces 1.46 kB/s overhead by 45 RSUs dissemination traffic. Thus, enhanced at cost low overheads.