Group-based Key Management Scheme For Wireless Sensor Networks

Wireless sensor network is a new network for the purpose of collecting and sending data.It is composed of mass sensor nodes which deployed in practical area. Due to thecharacteristic of wireless sensor network, it has a few limitations such as complex topologicalstructure, self-organizing structure, computing power, memory capacity, etc. And theselimitations make some existing technologies in general network can not be directly applied toit. Therefore it is necessary to establish the communication model and security model specificto wireless sensor network.The core issue of the wireless sensor network security is its key management scheme.This paper proposed a secure and efficient random key pre-distribution management modelbased on grouping. The idea of this model is in accordance with the main stages in keymanagement processes in wireless sensor network, including the middle-key pool and sub-keypool allocation rules, the shared key pool generation, the key agreement, the key Renewal andthe joining of new node. At first, by comparing several basic group-based models wedetermined the hexagonal group-based model. Next we divided all the groups into two layers:middle-group layer and sub-group layer, and divided the sub groups into core groups andsensor groups, then we designed a whole algorithm for key pool allocation. Through themathematical proof, the results showed that this algorithm can not only save the nodes storage,and can also enhance the node connectivity probability.In addition, this scheme applied the pre-shared key pool structure based on one-way hashfunction with the time variable. With this structure even the attacker mastered the algorithmand the leaked key, still he can not figure out the next updated key. This design can establish asecure communication link in the key agreement process. Also it can prevent an attackerpretending a new node to launch security attacks when a new node joins the network, in orderto ensure that old node and new node can establish a secure communication key. Moreoverthis design can removed the unreliable key from the key pool timely to prevent an attackerpretending the old node. for these reasons, this group-based key management schemeguaranteed the Forward security and backward security of the pre-shared key. the analysisshowed that the entire scheme increased a little computing and communications consumption.But it significantly enhanced the network connectivity, security and scalability, which are allsuperior to the basic random key pre-distribution scheme.