# Blockchain Based Trust Model Using Tendermint in Vehicular Adhoc Networks
###### Abstract  
Blockchain is the consensus-based technology used to resolve conflicts in Byzantine environments. Vehicles validate the messages received from neighboring vehicles using the gradient boosting technique (GBT). Based on the validation results, the message source vehicle generates the ratings that are to be uploaded to roadside units (RSUs), and through that, the trust offset value can be calculated. All RSUs maintain the trust blockchain, and each RSU tries to add their blocks to the trust blockchain. We proposed a blockchain-based trust management model for the vehicular adhoc network (VANET) based on Tendermint. It eliminates the problem of malicious nodes entering the network, and will also overcome the problem of power consumption. Simulation results also show that the proposed system is 7.8% and 15.6% effective and efficient in terms of packet delivery ratio (PDR) and end-to-end delay (EED), respectively, to collect the trusted data between the vehicles. blockchain; vehicles; trust; traffic; consensus +
Footnote †: journal: Applied  
network. For example, a malicious node can broadcast a message that there is an accident on a road, claiming congestion, but there was no accident and traffic congestion. These types of misbehavior produce risk in the vehicular network. Therefore, trustworthiness is an important factor to deal with, which is a critical issue in the network [3]. In distributed systems, byzantine consensus is used to exchange the information between the vehicles using trust management [5]. The vehicular network helps to provide information about road accidents, traffic congestion, road conditions, etc., and this helps the vehicles to be aware of the critical situations, thus improving transportation safety [6; 7]. The trust management program allows vehicles to determine whether or not the received message is reliable [8; 9]. Normally, the vehicle's trust value can be determined based on the ratings produced by the vehicle's past behavior. Trust management can be categorized into two classes, i.e., centralized and decentralized [10; 11]. Centralized systems store confidence values on the central repository, e.g., the cloud repository. These central systems cannot fulfill the stringent quality of services (QoS) specifications because every time node has to ask the central server to test the trust value, which increases the latency of the network. Trust management is to be conducted at the vehicle or RSU level in decentralized trust management systems, so that the burden of interaction with the server is reduced to a great extent, which ultimately increases the efficiency of the system [12; 13; 14]. Moreover, we cannot rely on one node for trust management. Due to the dynamic network, it is difficult to trust each node for the ratings. Therefore, designing an effective decentralized network is still a challenge [14]. In [15], the authors has discussed about the families of consensus for the permissioned as well as permissionless blockchain which has been described in the literature. The proposed system works effectively by retaining the trustworthiness between the nodes in vehicular networks. The internet of vehicles, using big data, is also a trending area, and which explored by game theory, i.e., coalition games for spatial-temporal big data in the internet of vehicles, where the vehicles will be rewarded and penalized according to game rules [16]. Blockchain is one of the new innovations in the financial sector that establishes a clear and tamper-proof ledger without centralized banks, so people can transact with absolute trust [17; 18]. Therefore, due to the design of the blockchain's trust management system, it can be conveniently carried out between nodes with decentralized systems [19]. Automated-based contention-aware data forwarding has also been proposed, which is based on Baysian coalition game theory, which improves the routing parameters of VANET [17; 20]. The trust between the multiple parties can be generated with the help of Byzantine consensus [21; 22].