VANETs are a type of mobile ad-hoc network that are used in a wide variety of applications. Establishing reliable communication, especially in safety and emergency applications, remains a significant challenge for VANETs. Applying trust management has emerged as a crucial approach to address this challenge. This paper has proposed a cooperation-based RSU-assisted trust management model (CTVAN), which is easily integrated with other protocols for establishing reliable communication in VANETs. In CTVAN, vehicles observe the cooperation in forwarding ( \(\:CF\) ) of other vehicles to calculate direct trusts of vehicles and then report their observations to RSUs, where indirect trusts of vehicles are calculated and maintained in the distributed ledger of a blockchain. CTVAN incorporates an effective monitoring process to evaluate the cooperation of vehicles in packet forwarding, which detects forwarding-related attacks and retransmits packets that may have failed to be correctly forwarded. It encourages and evaluates vehicle cooperation in reporting ( \(\:CR\) ), which can significantly improve the accuracy of trust management. It utilizes a pair-reporting mechanism that assesses the reports against reporting-related attacks and incorporates the evaluation results into the indirect trust calculation. The simulation results demonstrated significant improvements in the trust management of the TGRV protocol when integrated with CTVAN for trust management and communication establishment. In an urban scenario, there was a notable 5.5% increase in the packet delivery ratio and a substantial 17% reduction in end-to-end delay. Furthermore, the results indicate that TGRV with CTVAN outperforms the RTRV protocol. The cost analysis showed that memory, communication, and computational overheads of CTVAN are acceptable. Also, the security analysis showed that CTVAN is resistant and resilient to important trust-based attacks.
