A survey of trust management in the Internet of Vehicles

In recent years, the emergence of the Internet of Vehicles (IoV) aims to enhance the users' quality of experience through proposing more sophisticated services ranging from guaranteeing the user safety to improving his comfort. The IoV ecosystem is complex, heterogeneous, and evolving. Many entities participate to compose its architecture (such as vehicles, humans, roadside units, ITS). Moreover, different communication types coexist to ensure the IoV connectivity and continuity. This diversity leads to new security requirements that seem more complex to take into account and enlarge the attack surface of such ecosystem. Many security mechanisms should be considered to enforce the security of IoV environment at many levels: data, entities, communications, storage, etc.. Trust management is one of the potential security mechanisms that aims to increase the reliability within the IoV environment. The topic has been widely explored within the vehicular ad hoc networks (VANETs). However, the VANET represents only one component of the IoV ecosystem. Thus, the approaches proposed for the VANET should be adapted to be applied for the IoV. Moreover, the advent of the emerging technologies like blockchain, cloud, SDN as well as artificial intelligence bring new opportunities to propose more relevant approaches within the trust management mechanisms within the IoV context. Accordingly, this survey deals with the literature about the trust management topic in vehicular environments. The scope considers the IoV environment as well as the relevant approaches proposed for the VANET context since it is one of the important component of the IoV ecosystem. We start by quickly reviewing the existing surveys about security of the vehicular environments. Then, we give a general overview about trust concepts. Afterwards, we present the security and trust challenges and attacks in the vehicular context. Later, we classify and compare the most relevant approaches related to the trust management for the IoV proposing a new taxonomy. We complete this survey by highlighting the open future directions and perspectives for research.