An Improved PBFT-based Consensus for Securing Traffic Messages in VANETs

With the increasing number of autonomous vehicles, more intelligent applications and services are needed to build an efficient transportation system. That cannot be achieved without having an efficient and secure model for recording and sharing traffic-related data. Because of its important features in terms of architecture decentralization, data immutability, transparency of actions, and communications security, the blockchain technology has recently been proposed to mitigate early VANETs (Vehicular Ad Hoc Networks) designs' security issues. In this work, we design a new consensus protocol based on Practical Byzantine Fault Tolerance (PBFT), aiming at proposing a secure traffic-related data sharing system in VANETs. The proposed consensus intelligently selects a set of Road Side Units (RSUs) to validate the traffic events emitted by vehicles and subsequently maintain the blockchain ledger to further exploit its immutable data. In this paper, we also introduce the concept of micro-transactions to reduce the size of the blockchain ledger and minimize the communications overhead between nodes. The performance of the proposed solution is assessed by simulating real-world VANETs' settings. The experimental results validate the proposed work's high performance in terms of blockchain throughput, latency, communication load, and storage cost.