Puzzle-based Clogging DoS-resilient Vehicular Communications

Abstract: In Vehicular Communication Systems (VCSs), authenticated safety beacons are used to deliver the vehicles’ status and provide necessary information for the applications. However, high rate safety beacons impose high processing overhead on the resource-constrained vehicular On-Board Units (OBUs). Therefore, the number of beacons that can be processed by a vehicle in a fixed period is limited. Denial of Service (DoS) attacks can be launched by broadcasting many bogus beacons in a high frequency, taking advantage of the weakness of the OBUs. The OBUs cannot verify all received beacons in a timely manner under a DoS attack, which affects the perception of surrounding vehicles’ status. This thesis proposes an efficient puzzle scheme built on pseudonymous authentication using hash functions to pre-authenticate all received beacons. This scheme enables the receiver to discover new benign neighbors and find potentially valid beacons among all received beacons even under DoS attack. We do both numerical analysis and experimental evaluation of the puzzle scheme. The results show that our scheme can guarantee low processing latency under different DoS attack models. We also show the advantage of our scheme compared to both the baseline pseudonymous authentication scheme and a cooperative scheme.