The Study Of Trust Management For Wireless Sensor Networks

The wireless sensor networks (WSNs) are composed of a large amount of low-priced sensor nodes. The sensor nodes form a self-organization and multi-hop network system by wireless communication. Because of nodes own characters, WSNs not only have typical security issues, but also have other security issues. For examples: (1) Since sensor nodes are vulnerable to physical capture, an adversary can easily obtain the key of the node, and inject faulty data to destroy the network.(2) Because the sensor nodes are resource-constrained, they are vulnerable to system faults, which result in a large number of false data. Cryptographic and authentication1 mechanisms alone can not be used to solve the problems mentioned above.In this dissertation, we introduce the concept of trust and design an identity-based trust management for WSNs to solve those new security issues. It combines the knowledge of cryptography and statistics. In each node, it adds a model to calculate and manage the trust of its neighbor nodes. If a node wants to communicate with another, these steps should be followed. First, it needs to inquire the reputation of the next hop node from its neighbors. Second, combining with the trust of its own, it calculates and updates the reputation of the next hop node. Third, it decides whether to communicate according to application. Last, it monitors the behavior of the next hop node by monitoring module. The security and authentication of all the messages are depending on Identity-based public key cryptosystem. In this way, we can immediately identify and isolate the malice node, thereby creating a secure and reliable wireless sensor networks that can avoid some common attacks and ensure the security of the applications.In this dissertation, we give the communication process and the computation model as well as how each trust management mechanism works, and compare it with other exiting trust managements. We use Identity-based public key cryptosystem, hence, nodes don't need to exchange a lot of messages and do a lot of calculation, then we can ensure the reliability and credibility of message, reduce the complexity of computation, increase the security of communication. We solve the problem of the initialization of trust. Nodes have the same trust as the beginning of the network, and then by updating the reputation to build a network with trust. It has operability. Trust management and trust network we designed in line with the characters of WSNs, so it has practicability. It solves the problem of Multi-hop communication in trust network, and meets the applications of large-scale, so it has operability and feasibility.