The development of vehicular ad hoc networks (VANETs) is facing great challenges. Due to the open environment in VANETs, the false information sent by malicious vehicles not only affects the fairness of information interaction but also seriously threatens the driving safety of normal vehicles. Therefore, the study of trust evaluation and management in VANETs has become hot topics in recent years. In this paper, we propose a trust management model of VANETs based on blockchain. In this model, a hidden markov model (HMM) based vehicle trust evaluation method that improve the accuracy on the detection of malicious behavior is proposed. Besides, a trust management method based on the alliance chain is designed, which greatly improves the efficiency of trust updating and querying on the premise of security. Simulation results show that the model is promising and feasible, effective in the aspects of trust evaluation and trust management.

车辆自组织网络（VANET）的发展面临着巨大的挑战。由于VANET的开放环境，恶意车辆发送的虚假信息不仅影响信息交互的公平性，而且严重威胁普通车辆的行驶安全。因此，近年来对VANET中信任评估和管理的研究已成为热门话题。本文提出了一种基于区块链的VANET信任管理模型。在该模型中，提出了一种基于隐马尔可夫模型（HMM）的车辆信任评估方法，该方法提高了恶意行为检测的准确性。另外，设计了一种基于联盟链的信任管理方法，大大提高了安全性前提下信任更新和查询的效率。