DETECTING SYBIL ATTACK SUSING PROOFS OF WORK AND LOCATION INVANETS

Abstract

Vehicular Ad Hoc Networks(VANETs) has the potential to enable the next-generation Intelligent Transportation Systems (ITS). In
ITS, data contributed from vehicles can build a spatiotemporal view of traffic statistics, which can consequently improve road safety
and reduce slow traffic and jams. To preserve vehicles’ privacy, vehicles should use multiple pseudonyms instead of only one identity. However, vehicles may exploit this abundance of pseudonyms and launch Sybil attacks by pretending to be multiple vehicles. Then, these Sybil (or fake) vehicles report falsedata, e.g., to create fake congestion or pollute traffic management data. In this paper, we propose a Sybil attack detection scheme using proofs of work and location. The idea is that each road side unit (RSU) issues a signed time-stamped tag as a proof forthe vehicle’s anonymous location. Proofs sent from multiple consecutive RSUs isused to create vehicle trajectory which is used as vehicle anonymous identity. Also,one RSU is not able to issue trajectories for vehicles, rather the contributions ofseveral RSUs are needed. By this way, attackers need to compromise an infeasiblenumber of RSUs to create fake trajectories. Moreover, upon receiving the proof oflocation from an RSU, the vehicle should solve a computational puzzle by runningproof of work (PoW) algorithm. So, it should providea valid solution (proof ofwork) to the next RSU before it can obtain a proof of location. Using the PoW canprevent the vehicles from creating multiple trajectories in case of lowdense RSUs.Then, during any reported event, e.g., road congestion, the event manager uses amatching technique to identify the trajectories sent from Sybil vehicles. The schemedepends on the fact that the Sybil trajectories are bounded physically to one vehicle; therefore,their trajectories should overlap.