Security of Vehicular Ad Hoc Networks using blockchain: A comprehensive review

The most advanced and emerging component of an intelligent transportation system (ITS) is the vehicular ad hoc network (VANET). Vehicles communicate with nearby vehicles or road side units (RSUs) in order to provide safety or non-safety information. This information containing vehicle ID, current position, speed and vehicle status is shared periodically among nearby vehicles. VANET provides tremendous benefits to drivers, but due to its inherent characteristics, it is important to address security and privacy issues before it can be fully adopted. It is required to authenticate the vehicles participating in the network and held responsible in case any type of misbehavior is encountered in the network. Traditional centralized security solutions are not suitable in VANET because of high speed of vehicles, minimal communication resources and delay sensitive applications. Blockchain is a decentralized and distributed computing platform that makes it easier to record and manage resources without relying on a centralized trusted authority. Therefore, blockchain based solution is expedient in VANET scenario which provides transparency, tamper resistance and immutableness. This paper aims to envision a comprehensive review on applications of blockchain in VANET security. We first present the introduction of VANET security and blockchain. Then, we conduct a literature review on the existing security solutions using blockchain in VANET by considering the technical issues and research problems. At last, we highlight some future research issues by reviewing the characteristics of both blockchain and VANET.