A Comprehensive Review on Blockchains for Internet of Vehicles: Challenges and Directions

Internet of Vehicles (IoVs) consist of smart vehicles, Autonomous Vehicles (AVs) as well as roadside units (RSUs) that communicate wirelessly to provide enhanced transportation services such as improved traffic efficiency and reduced traffic congestion and accidents. IoVs, however, suffer from issues of security, privacy and trust. Blockchain technology has been emerged as a decentralized approach for enhanced security without depending on trusted third parties to run services. Blockchain offers the benefits of trustworthiness, immutability, and mitigates the problem of single point of failure and other attacks. In this work, we present the state-of-the-art of Blockchain-enabled IoVs (BIoV) with a particular focus on their applications such as crowdsourcing-based applications, energy trading, traffic congestion reduction, collision and accident avoidance and infotainment and content cashing. We also present in-depth applications federated learning (FL) applications for BIoVs. The key challenges resulted from the integration of Blockchain with IoV is investigated in several domains such as edge computing, ML, and FL. Lastly, a number of open issues and challenges as well as future opportunities in the area of AI-enabled BIoV, hardware-assisted security for BIoV and quantum computing attacks on BIoV.