Research On Key-Management Scheme For Wireless Sensor Networks

Wireless sensor network(WSN) has been widely used in areas such as military field, environmental monitoring and medical industry, meanwhile it has attracted an increasing number of researchers. Different from traditional networks, wireless sensor network is a network structure formed by number of tiny sensor nodes over multi-hop and self-organized way, in which nodes are randomly deployed. Sensor nodes cooperate with each other for real-time observation, perception and collection of data within a specific area. Since wireless sensor network is often deployed in the harsh environment even the enemy's theater that people can not reach, so network security has been attracted more and more attention. As an important service for safe function, key management plays a very important role in information encryption and certification, which has also become one of the hotspots in the information technology field.The thesis first outlines basic knowledge of wireless sensor network, including its characteristics, the differences between it and the wireless Ad Hoc networks and its research focus etc. Then key management solutions and their improvement schemes for wireless sensor network are discussed. After analysis of existing typical key management schemes, two improved schemes are put forward at last based on deficiency of existing schemes.The two key management schemes proposed in the thesis are based on original scheme called LKH and key management schemes for clustering wireless sensor network. The multicast key management scheme forms the key binary tree according to residual energy of nodes. Nodes with high energy enter into construction of the key tree with high probability and nodes with different energy generate different multicast keys in the scheme. In the second key management scheme on hierarchical tree assuming that one cluster head exists in a cluster and all nodes of a cluster form one tree according to certain rules and the cluster head works as the root. The formed tree is called intra-cluster hierarchical tree. Then one cluster head is selected from all cluster heads as a leader, which is also the root of a tree .The tree is called inter-cluster hierarchical tree. Firstly one key is produced for the leader node and keys generation of residual nodes are from top to bottom in the tree. In the process, children keys are produced by use of keys of their respective fathers and identification of their own. By analysis and simulation on key storage and key update, it proves that schemes in the thesis need less storage cost and key updates when nodes leave the network or fail. They are also available for scalable wireless sensor networks, which also prove that schemes in the thesis have good performance.