Abstract:

Vehicular ad-hoc networks (VANET) have attracted a lot of attention because of their great potential to improve road safety and traffic efficiency.However,in the VANET,the trust assessment of emergency messages by vehicles needs to meet both low latency and high accuracy.In order to solve the problem of high latency and low accuracy of the existing trust management scheme in the VANET in the process of emergency message trust assessment,the author proposes a scheme for blockchain-assisted emergency message trust evaluation in the VANET.In this scheme,first,the blockchain technology is used to store the vehicle trust value in a distributed manner to realize trusted storage of the vehicle trust value; next,the pre-caching strategy and post-query caching strategy are designed,which are combined with the smart contract to design the trust value query algorithm respectively to query the vehicle trust value with low latency; and then,based on the proposed query algorithm,vehicle trust values are introduced,and vehicle location and message freshness are combined as reference factors for emergency message trust evaluation.Finally,low latency and high accuracy in emergency message trust evaluation is achieved.Compared with the existing solutions,the proposed solution improves the trust value query efficiency by about 79.9%~98.9% and the trust evaluation accuracy by about 4.71%.In addition,the author compares the two proposed caching strategies,with the pre-caching strategy improving the query efficiency by about 56.9% but increasing the storage space overhead by about 23.7%~86.2% as compared with the post-query caching strategy.

Key words: vehicular ad-hoc networks, emergency message, blockchain, smart contract, trust evaluation