Research On The Key Managementfor Wireless Sensor Networks

Wireless sensor network is a wireless ad hoc network consisting of a large number of sensor nodes.It has many differences from traditional network,such as constrained energy resource, no fixed support network,and dynamic topology. Its purpose is to monitor, collect and deal with the information of monitored objects in the target area, and finally send it to the terminal users. WSN attracts more and more attention in the fieldof information collection.It is also easy to suffer more frequent and multiple attacks than general network.So the security problem is token much attention. Key managementbecomes the main content in WSN.It also is the basis of other security mechanisms.At present,there are many problems in key management scheme for wireless sensor network.Along with the communication and computation overhead generated in the key generation stage, the storage consumption generated in the key predistribution phase is always beyond the threshold of nodes.The leakage of shared key between nodes will also affect the resilience of WSN.The key information assigned randomly usually leads to the low network connectivity.In view of the existing problems,this thesis aims to design key management schemes which have high network connectivity and security,and also needs to take the overheadreducinginto account.The main contents and achievements of this thesis can be summarized as follows:1.A key pre-distribution scheme based on BIBD and multiple key spacesIn view of the contradiction between limited resources and network expansibility in centralized WSN,this thesis proposes a new key pre-distribution scheme based on BIBD andmultiple key spaces.The base station distributes a number of key spaces to each node using the hybrid symmetric BIBD.So the shared keybetween nodes can be established with high probability,and each node only needs to store a small amount of key spaces.The new nodes can establish secure links with nodes that already exist,as long as it completes the key pre-distribution process. So this scheme can achieve higher network connectivity,and it also improves the scalability of the network.2.A key pre-distribution scheme based on BIBD and the trivariate rotation symmetric polynomialIn order to solve the problem of large storage overhead.which is caused by the redundancy of key information.This thesis proposesa key pre-distribution scheme based on BIBD and the trivariate rotation symmetric polynomial.lt calculates the key by using the rotation symmetric of trivariate polynomial and the unidirectionality of Hash function.And the scheme assigns each node a number of random numbers as the parameter of trivariate polynomial, In this way,the base station only needs to reassign some random numbers for each node in the following key refresh process,then the communication key in the whole network will be changed.According to the theoretical analysis and simulation,we can see that the scheme not only reduces the storage overhead of nodes,but also achieves higher connectivity,and it also improves the network survivability.3.A key management scheme based on Chinese Remainder Theorem and trivariate convertible polynomialDue to the contradiction between storage overhead and network connectivity in the clustered wireless sensor network,we propose a key management scheme based on Chinese Remainder Theorem and trivariate convertible polynomial.In this scheme,the base station distributes necessary key information to ordinary nodes according to the Chinese Remainder Theorem.And each ordinary node is required to do only 2 modulo arithmetics,1 XOR operation and 1 Hash operation for each communication key. In this way, the computational overhead of ordinary nodes will be greatly reduced.The key between cluster heads is calculated according to the trivariate convertible polynomial and Hash function.So we can achieve a full connected network.In addition, according to the following analysis this scheme is a good solution to the contradiction between network connectivity and energy consumption of nodes.And it also improves the security of the network.