Abstract: To solve the problem of malicious devices or malicious data in edge computing,this paper proposes a method of node trust evaluation based on edge computing.Firstly,the blockchain technology and the method of building a cloud-edge framework are used to establish the trust relationship between edge devices.Secondly,a trust-based consensus mechanism is added to the overall trust evaluation method,and a time-sensitive function is introduced to determine the timeliness of trust value requirements in different scenarios.Finally,in order to avoid deviations caused by subjective factors in calculating the trust value,a method of adding stability coefficients is proposed to ensure the reliability of the trust value.Simulation experiments validate that the proposed trust evaluation method has a higher success rate of node interaction than other traditional trust evaluation methods at different malicious node ratios.When the malicious node ratio is 20%,the proposed method is similar to other methods,while when the malicious node ratio is 40%,the success rate is 0.82,and when the malicious node ratio is 60%,the success rate is 0.68%.As the normal nodes and malicious nodes’ trust values change over time,they follow opposite trends.The trust value of normal nodes reaches 0.9 in the end,while the trust value of malicious nodes decreases to 0.2.To better observe the change of trust va-lues of nodes,this paper sets the probability of malicious nodes performing malicious behaviors at 50%.The results also show that the proposed trust evaluation method can effectively respond to malicious nodes.Finally,the time consumption is compared in different node conditions,and the results show that the proposed method has lesser time consumption than traditional trust evaluation methods when dealing with a larger number of nodes.Therefore,the proposed method can make effective trust evaluations when facing a large number of malicious nodes.This method aims to determine how to select trusted nodes as target nodes for data storage and transmission,calculate the trust value of edge nodes,and reduce the impact of malicious nodes.

Key words: Edge computing, Blockchain, Trust evaluation, Identity authentication