| With the rapid development of embedded systems,wireless communications,MEMS(Micro-Electro-Mechanical-System)and other technologies,wireless sensor network(WSN)composed of sensors with sensing,computing and wireless communication capabilities have also been rapidly developed and applied to many areas,such as:environmental monitoring,medical and health care.Security is a key problem for WSN to be solved.However,WSN are faced with various security threats and challenges due to the limitations of wireless communication,resources and unattended.The security research of WSN has been widely concerned by scholars at home and abroad.It is one of the hot and difficult research topics.For the security of WSN,the security mechanism based on cryptographic system and authentication technology can only resist the intrusion and destruction caused by external attack.But it cannot solve the attack by the internal malicious nodes attack,because the internal malicious nodes have been controlled the network communication key and authentication information,which can participate in the data processing and communication in all stages of the network as legal nodes and easily launch a higher concealment attack.The security threat of internal malicious nodes involves topology control,node communication,data fusion,routing and so on.So how to design the corresponding security mechanism to resist the internal attack is an important aspect of the security research of WSN.This paper takes cluster wireless sensor network as the research object,trust is the major basis of my thesis,the study of internal security was focused on by this dissertation from aspects of clustering,node communication,data fusion and routing.The main research work of this paper is as follows:(1)A secure multi-layer non-uniform clustering algorithm(SMNCA)is proposed.This algorithm uses multi-layer heterogeneous clustering topology network structure,which can realize the load balancing and prolong the lifetime of the whole network effectively.In the cluster head selection,the relative energy,relative density,relative centrality and trust value of nodes are considered synthetically by fuzzy logic and trust model to ensure the rationality and security of cluster head selection and cluster building.Finally,the cluster heads are selected among different layers to establish a secure transmission path to realize the transmission of data.The algorithm adopts multi-layer non-uniform clustering design and considers the priority and trust value of nodes to select cluster heads,which can effectively improve the lifetime of the network and ensure the security of the network.(2)A dynamic trust evaluation model(DTEM)for WSN is proposed.The trust evaluation mechanism between nodes is established by monitoring the behavior of nodes to effectively identify malicious nodes in the network.The calculation of trust includes direct trust and indirect trust.The direct trust is calculated considering multi-trust including communication trust and energy trust with the punishment factor and regulating function.The indirect trust is evaluated conditionally by the trusted recommendations from a third party.Moreover,the integrated trust is measured by assigning dynamic weights for direct trust and indirect trust and combing them.Finally,we propose an update mechanism by a sliding window based on induced ordered weighted averaging operator to enhance flexibility.We can dynamically adapt the parameters and the number of the windows according to the actual needs of the network to realize dynamic update of trust value.Simulation results indicate that the proposed dynamic trust model is an efficient dynamic and attack-resistant trust evaluation model,which can accurately identify multiple types of malicious nodes in the network.(3)A trust-based secure data aggregation algorithm(TSDAA)for WSN is proposed.To resist the influence of the behavior of the internal malicious attack and the fault node on the data accuracy and integrity,a trust evaluation model based on abnormal data filtering is established,which can effectively resist data related malicious attack nodes,abnormal nodes and other internal malicious attacks.Secondly,the intra-cluster trust evaluation is established to realize the selection of the trusted nodes,the cluster heads and the fusion nodes in the cluster.The inter-cluster trust evaluation is established to identify abnormal cluster heads.Finally,the data of trusted nodes are fused based on trust values.The algorithm can effectively identify a variety of malicious and abnormal nodes and consider the security of cluster heads and fusion nodes to achieve secure data fusion.(4)A trust-based secure fault-tolerant routing algorithm(TSFRA)is proposed.This algorithm firstly analyzes the routing security problems caused by the node failure or node captured in WSN,especially for routing attacks.To select trusted routing nodes,a trust model is established to identify various malicious nodes.Secondly,considering the fault tolerance of routing,several redundant fault-tolerant routing paths composed of different layers of trusted cluster heads are established between the source node and the destination node.Finally,the optimal path selection strategy is established to select the optimal path as the transmission path among the redundant routing paths,and a maintenance mechanism based on the fallback strategy is proposed.The routing algorithm adopts the layered routing strategy to realize the network load balance,and effectively guarantees the reliability and security of the routing. |
