State-of-the-Art VANET Trust Models: Challenges and Recommendations

Research on trust models in Vehicular Ad-hoc Networks (VANET) was mainly focused on entity-centric, data-centric, and combined trust models until the latter half of the previous decade. There are a number of attacks these conventional trust models cannot hold back. The popularity of blockchain technology in the last few years resulted in the research on blockchain-based trust management models for VANET. Meanwhile, zero trust solutions claimed to overcome the problems of the traditional perimeter security model. With the perimeter security model, information systems within an organization's internal network are inherently trusted and the ones that belong outside the organization are consequently deemed untrusted. The zero trust architecture overcomes these flaws by simply not trusting any entity regardless of the entity belonging inside the organization's perimeter or outside. This paper discusses the various trust management models for VANET, their drawbacks and proposes a private blockchain technology to improve the performance and highlight the need for a central governing authority. The paper also investigates the challenges of implementing a zero-trust architecture for vehicular communications and brings forth the idea of using the concepts of zero trust to provide state-of-the-art security for VANET's supporting infrastructure. Additionally, this study surveys the benefits and challenges of developing the VANET architecture based on software-defined networking (SDN).