Trust Management Research In Wireless Sensor Networks Based On Subject Logic

With the recent advances in micro electro-mechanical systems(MEMS) technology, wireless communications, and digital electronics, the design and development of low-cost, low-power, multifunctional sensor nodes that are small in size and communicate untethered in short distances have become feasible. The ever-increasing capabilities of these tiny sensor nodes, which include sensing, data processing, and communicating, enable the realization of wireless sensor networks (WSNs) based on the collaborative effort of a large number of sensor nodes.WSNs have a wide range of applications,and are slowly becoming an integral part of our lives. Recently, considerable amounts of research efforts have enabled the actual implementation and deployment of sensor networks tailored to the unique requirements of certain sensing and monitoring applications.There are more and more security problems in Wireless Sensor Networks because sensor nodes are resource-constrained and usually deployed in a bad environment. Encryption-based security mechanisms can resist external attacks, but they can't resolve internal attacks that caused by nodes been captured sometimes. Therefore, it is quite necessary to build and development security structure of wireless sensor networks by introducing security mechanism based on trust management.In this paper, we will give the summary of trust management of WSNs, and illustrate the calculating method for trust values which is in the centre of the system architecture of WSNs, and then we indicate the importance of evaluating and updating the trust value of sensor nodes. By analyzing the classical Reputation-based Framework for Sensor Networks (RFSN), we point out the distortion of trust updating.To solve the distortion of trust updating for Reputation-based Framework for Sensor Networks (RFSN), a algorithm of trust updating using subject logic is presented. Firstly, the process of trust updating in RFSN is recognized and decomposed. It is pointed out that the prime reason in the distortion of trust updating is the partial reflection of current behavior tendency of the node owning to the representation of trust in expectation of reputation variable, and the general design model is constructed. Then, the trust updating based on the expectation of reputation random variable is adjusted adaptively by overlooking the trust updating with comparatively weaker support about current behavior tendency importing the subject logic opinion so as to avoid the distortion caused by using long-term behavior tendency oriented trust updating to reflect the current behavior tendency of the node. Finally, by J-Sim, the function of representing the long-term behavior tendency as well as reflecting the current behavior tendency of the node to some extent of the presented algorithm is demonstrated.