Mitigating Blackhole and Greyhole Routing Attacks in Vehicular Ad Hoc Networks Using Blockchain Based Smart Contracts

The rapid increase in vehicle traffic volume in modern societies has raised the need to develop innovative solutions to reduce traffic congestion and enhance traffic management efficiency. Revolutionary advanced technology, such as Intelligent Transportation Systems (ITS), enables improved traffic management, helps eliminate congestion, and supports a safer environment. ITS provides real-time information on vehicle traffic and transportation systems that can improve decision-making for road users. However, ITS suffers from routing issues at the network layer when utilising Vehicular Ad Hoc Networks (VANETs). This is because each vehicle plays the role of a router in this network, which leads to a complex vehicle communication network, causing issues such as repeated link breakages between vehicles resulting from the mobility of the network and rapid topological variation. This may lead to loss or delay in packet transmissions; this weakness can be exploited in routing attacks, such as black-hole and gray-hole attacks, that threaten the availability of ITS services. In this paper, a Blockchain-based smart contracts model is proposed to offer convenient and comprehensive security mechanisms, enhancing the trustworthiness between vehicles. Self-Classification Blockchain-Based Contracts (SCBC) and Voting-Classification BlockchainBased Contracts (VCBC) are utilised in the proposed protocol. The results show that VCBC succeeds in attaining better results in PDR and TP performance even in the presence of Blackhole and Grayhole attacks.