SmartRevoc: An efficient and privacy preserving revocation system using parked vehicles

Security and privacy requirements in vehicular networks are typically addressed using a Public Key Infrastructure (PKI) and pools of pseudonymous certificates for each vehicle. Messages are signed with these certificates, so that misbehaving vehicles can be excluded from the network by disseminating Certificate Revocation Lists (CRLs). We present SmartRevoc, a novel revocation architecture, to solve the main challenges of CRL distribution in vehicular networks: CRL size, dissemination speed, and preservation of location privacy. Using two hash chains, we compute CRLs on vehicles, substantially reducing communication overhead. At the same time our design is privacy preserving, preventing the linking of past pseudonyms to revoked ones. We additionally utilize parked vehicles to epidemically disseminate CRLs and show that even few parked vehicles can outperform an unreasonably high number of Roadside Units (RSUs). Our simulation results clearly indicate that SmartRevoc is a major step forward toward more efficient and secure vehicular networks.