A Security Mechanism For Cluster-based WSN Against Selective Forwarding

Wireless sensor network(WSN)is a self-organize network formed by plenty of sensor nodes distributed in the monitoring area,and its research work is full of challenging because of the characteristics of the sensor node like energy constrained,low ability of computing and communicating,limited storage space and so on.In recent years,the WSN,mainly about the wireless communication protocol,routing mechanism,network topology and security algorithm,has always been a hot research topic in the field of communication.The security of a WSN is particularly vital for its wide range applications especially in the field of military,on which this thesis based to lucubrate the security defense technology of a WSN.The attack types to WSN include insider attack and outsider attack: the traditional encryption technology can only resist outsider attacks;but to the insider attack,currently,especially the selective forwarding cannot be defended well.Interrelated study work focusing on the selective forwarding is carried out in this thesis and we calculate some corresponding conclusions.The full text work is as follows:1.The research direction.Analyzing the research situation of recent years in WSN,we choose the selective forwarding,the hardest one to be identified and defended among insider attacks,as the research direction of this thesis.Through summarizing,we calculate that the proposed mechanism should have the following features: detecting malicious node quickly and accurately,giving feedback and updating the routing in time,low energy consumption,and possessing the ability of settling a variety of insider attacks.2.The security mechanism.The proposed mechanism is based on the advantages of the Watchdog and the neighbor monitoring mechanism.The novelty of our scheme is that a node in cluster is selected to act as inspector node,ascertaining the cluster node working properly,and the radius of the cluster is set to half of the node's communication radius so that the inspector node can cover the whole cluster to improve the work efficiency.3.The new network layout.A new network layout corresponding to our security mechanism is put forward.Firstly,setting the shape of the cluster to square;then,calculating the density of nodes distribution through analyzing the node's energy consumption of each layer;then,combining the energy consumption of a single node and that of the entire network to calculate the optimal period of updating the cluster head and inspector node;lastly,calculating the specific parameters of the new network layout.4.Simulation results indicate that the proposed scheme can detect the malicious node accurately,the false alarm rate is lowered by 25.7% compared with Watchdog,and the network lifespan is prolonged by 54.84% compared with LEACH.