Secure Routing Mechanism For Opportunistic Network Based On The Evaluation Of The Nodes Reputation Value

In the mobile era of rapid technological development,the Opportunistic Network,in which there is no complete communication path between the source node and the destination node,relies on the cooperation of nodes to complete the message delivery.It has attracted the attention of many scholars and been successfully applied in many fields,such as wildlife tracking,pocket switch network and so on.The nodes in opportunistic network have different characteristics and attribute preferences.The process of message forwarding is actually the result of nodes resources optimal allocation.Due to the limited resources of nodes,when there are no sufficient resources some selfish behaviors are shown to influence nodes cooperation.In addition,nodes may initiate malicious attacks to the network,so network security will be seriously threatened.In the presence of these factors,it proposes a secure routing mechanism based on resource allocation and the reputation evaluation to measure the message forwarding mechanism of non-cooperative nodes.The thesis first describes the research background and typical applications of opportunistic network,analyzes the research hotspots of opportunistic network in recent years,then emphatically expounds the necessity of introducing nodes reputation evaluation in opportunistic network and existing nodes reputation value evaluation method.Secondly,it proposes a kind of security routing mechanism based on supply-demand relation,making full use of node's active degree,node's cache degree,node's trust degree,and node's energy degree in the nearest interval and establish the relation between forwarding price and message quota of meeting nodes.The message balance quota is obtained by using the message supply curve and the message demand curve to reasonably determine the allocation of the message quota from the node.The simulation results show that the proposed method can effectively improve the network performance.Thirdly,in order to further improve the accuracy of node trust quantification,in the light of non cooperative behaviors in opportunistic network,a message forwarding mechanism is proposed to predict the reputation value of nodes using autoregressive time series.The operation cycle of opportunistic network is divided into several time slots.In each time slot,feedback information and recommendation information about evaluation object nodes are collected by evaluation agent nodes,and reputation values are quantized.Then the reputation value of nodes is predicted by time series to determine malicious nodes.The hypothesis testing method is used to test whether the reputation value of malicious nodes is improved significantly,so as to improve the accuracy of malicious nodes detection.Simulation results show that the proposed message forwarding mechanism can effectively reduce the negative impact of non cooperative behavior on opportunistic network.Finally,the research contents are summarized and the future research work is presented.