Research On Propagation Containment Strategy Of Worm In Multi-layer Coupled Network

With the rapid development of Internet technology,network security caused by Internet worm has increasingly highlighted.Worm propagation model is one of the important means for us to study worm propagation.In fact,the worm propagation environment always involves multiple different types of networks.Therefore,the worm propagation model based on one single network doesn't work well for the worm propagation in real world and how to accurately predict worm propagation behavior in real world has become an urgent issue to solve.Firstly,the fundamental knowledge about Internet worm and complex network are introduced.Then traditional worm propagation models,the characteristic of coupled network and several specific coupled networks are given.In this foundation,considering the real propagation environment of worm may be in two or more networks,we have developed two new worm propagation models:the worm propagation model under the effect of media and the worm propagation model in coupled network.The former is aimed at the multiple networks are physical independent,and the worm have to use propagation media to cross spread.The latter is aimed at there is the relationship of dependence and cooperation among the multiple networks and the worm don't need propagation media to cross spread.In these two models,we are introduced "immune" strategies to inhibit the propagation of worm.First of all,we have make theoretical analysis for these two models,respectively obtained the disease-free equilibriums and the basic reproductive numbers of the two worm propagation models.Then we use theory about the relationship between basic reproductive number and the stability of disease-free equilibrium to analyze the stability of disease-free equilibrium.The condition for the stability of disease-free equilibrium is obtained.When the basic reproduction number is less than 1,the disease-free equilibrium point is locally asymptotically stable.It is the best time to immunize.Otherwise,the disease-free equilibrium point is unstable.The worms are out of control and it's hard to completely eliminate.Finally,the experiments of these two models have designed and the related curves are given.The experiments have verified the correctness of theoretical analysis.From theoretical analysis and experiments we can get the following conclusions.In the case of worms using media spread across two physical independent networks,the increasing of immunization rate in one network can make great inhibition for the other network.When the inhibition condition is limited,we should give priority to the network with scale-free properties.For the coupled network,the impact of internal infection rates in sub-networks on the propagation of worms is greater than the cross infection rates between sub-networks.If there is one or more coupled mode presenting scale-free properties,the infection range of worms will be great.The impact of sub-network's network structures on the propagation of worms is greater than the coupled modes between sub-networks.The sub-network meet the scale-free properties are easier for the worm to spread.