A Reliable Trust Computing Mechanism based on Multi-source Feedback and Fog Computing in Social Sensor Cloud

Social sensor cloud (SSC) is combined with social network, wireless sensor network, cloud computing, and fog computing, which is currently a new type of Internet of Things (IoT). In order to provide a convenient, open, and highly reliable SSC services, the devices of fog computing are distributed at the edge of cloud computing. The devices of fog computing can independently process and store data, and feedback more quickly in SSC. The sensing layer of SSC faces different types of physical attacks and communication attacks, such as message forgery, message tampering, reply attacks, hidden data attacks, etc., lead to the lack of trust between social sensors and cloud data centers in SSC. Therefore, the trust evaluation between the sensing layer and the network layer is necessary. However, computing the reliability of the social sensor data in cloud data centers will generate a large amount of trust computing overhead, communication overhead, and communication delay, which hinder the widespread application of SSC services. To combat this issue, a reliable trust computing mechanism (RTCM) based on multisource feedback and fog computing fusion is proposed. First, a new metric is designed for the trust of social sensor nodes, and multisource feedback trust value collection is performed at the sensing layer to improve the detection of malicious feedback nodes. Second, the trust feedback information of the sensing layer is collected by the devices of fog computing, and the recommendation trust calculation is performed, which reduces the communication delay and computing overhead. Third, a fusion algorithm is designed to aggregate different types of feedback trust values, which overcomes the limitation of trust weights in artificial weighting and subjective weighting in traditional trust mechanisms. Theoretical analyses and simulation results show that the proposed trust computing mechanism has better computational efficiency and higher reliability compared with existing methods.