A Dependable and Efficient Decentralized Trust Management System Based on Consortium Blockchain for Intelligent Transportation Systems

The emergence of vehicular applications such as collision warning enhances traffic efficiency and the driving experience of users. Due to the features of decentralization, complexity, and heterogeneity in intelligent transportation systems, the key issue is ensuring the legality and trustworthiness of all participating parties. Traditional methodologies such as public key infrastructure provide services for verifying the legitimacy of entities with certificates. However, even if a vehicle is legally registered, trust in its behavior is not always assured. Recently decentralized trust management systems (DTMS) are proposed to solve the trust issue. However, achieving both dependability and efficiency remains a challenge. In this paper, we propose a novel DTMS based on the consortium blockchain. We in particular focus on the dependability of trust evaluation, where trust computation is performed on both vehicles and RSUs. To achieve a sustainable trust environment, we propose an incentive model whereby the raters can earn rewards for providing honest ratings. Instead of utilizing the consensus algorithm based on the Proof of Work (PoW) or Proof of Stake (PoS), we implement a verifiable delay function (VDF)-based consensus model within the trusted execution environment (TEE) to ensure efficiency and security for the consortium blockchain. In addition, we design a smart contract on top of the blockchain to assist the system in detecting a specific attack against the trust system, known as the on-off attack. Through extensive experiments, the results of trust assessment and blockchain performance demonstrate the dependability and efficiency of our proposed DTMS.