A comprehensive survey on SDN and blockchain-based secure vehicular networks

Internet of Vehicles (IoV), as an emerging technology, has gained much attention in recent years due to rapid advancements in computing paradigms, vehicular and wireless technologies. IoV integrates vehicles with the internet using a computing paradigm and enables vehicle-to-everything (V2X) communication. However, the increase in density and the highly dynamic nature of vehicles have led to exponential complexity in traffic management, data exchange, and route scheduling. Moreover, rapid advancements in vehicular technologies to manage, store, and exchange data have led to serious security concerns. Software-defined networking (SDN), as an emerging networking architecture, has been adopted to control and manage the dynamic nature of vehicles and provide diverse quality of service and security (QoSS). These services include better transportation, resource sharing, network verification, and secure programmability of SDN-based applications. It consists of a centralized controller which uses OpenFlow (OF) protocol and achieves a global view of all the devices in a domain area. However, the network is vulnerable to single point of failure (SPoF), network topology poisoning, denial of service attacks, etc. To counter these attacks, a distributed control plane architecture has been adopted. However, it brings many challenges, and one of the biggest challenges is achieving consensus on information exchange among the controllers controlling different domain areas. Therefore, adopting blockchain technology in SDN-based vehicular network (SDVN) is a viable solution to address the mentioned challenges. The inherent features of blockchain such as decentralization, trust-free, immutability, public auditing and consensus algorithms offer various security services to vehicular networks. Therefore, this survey focuses on different SDN control plane architectures, security services, and challenges in SDVNs. The state-of-the-art blockchain-based schemes focusing on security requirements in vehicular networks have been discussed. A summary of blockchain-based SDVNs have been presented. An analysis of SDN controllers, simulation tools, and blockchain platforms for Vehicular Ad-hoc NETworks (VANETs) is made. Finally, future research issues, challenges, and lessons learnt have been discussed.