Research On Two Types Of Cybersecurity Problems

Cyberspace now plays a crucial role in every aspect of our lives.Many important infrastructures in human life,including transportation networks,communication networks,and the Internet,are part of cyberspace.However,cyberspace is a double-edged sword.The emergence of cyberspace has provided a platform for some cyberattacks.Some malicious attackers have used network infrastructure to carry out cyberattacks,causing serious consequences.Therefore,securing cyberspace is of great significance.Cyberspace has always been threatened by malicious spreading behavior.There are various types of malicious threats in cyberspace,among which computer viruses and rumors are two typical types of malicious spreading behavior.A computer virus is a malicious program that can spread through a computer network.It can cause the infected computer to paralyze or leak information,which can cause huge losses.Rumor is a kind of false information that can be spread through online social networks,it can cause serious consequences such as social panic and stock market shocks.In order to reduce the losses caused by these two types of security threats to cyberspace,they need to be studied in depth.Network spreading dynamics is a mature tool for studying propagation behavior,this article will use it to study two types of cyberspace problems,i.e.,computer viruses and rumors.The contributions of this thesis are sketched as follows.(1)The update process of viruses and patches is introduced,and the performance evaluation of patches on a class of homogeneous mixing computer networks is studiedTo contain the prevalence of computer virus on a network,we have to continuously inject new patches into the network.As the limited communication bandwidth restricts the patch injection rate,we need to evaluate the performance of a given patch injection rate in restraining computer infections.In this part,the paper focuses on the patch performance evaluation problem for homogeneous mixing computer networks.A virus–patch interacting model with patch injection mechanism is proposed,and the results of theoretical analysis show that this model admits a globally stable equilibrium.This result implies that the fraction of infected computers will approach a constant.Therefore,the asymptotic fraction of infected computers is recommended to serve as a measure of performance of the associated patch injection rate.This paper also examines the influence of different parameters on the asymptotic fraction of infected computers.In particular,it is found that patch injection mechanism is particularly effective for densely connected networks.This work takes the first step towards understanding the effectiveness of patch injection mechanism.(2)The influence of network topology on the spread of computer viruses is analyzed,and the problem of patch performance evaluation on a computer network of arbitrary topology is studiedTo cope with evolving computer viruses,antivirus programs must be periodically updated.However,due to the limited network bandwidth,new virus patches are typically injected into a small subset of computers in the network and then forwarded to the remaining computers.A static patching strategy consists of a fixed patch injection rate and a fixed patch forwarding rate.In this part,the paper focuses on evaluating the performance of a static patching strategy for arbitrary topological computer networks.First,a novel autonomous node-level virus-patch propagation model to characterize the effect of a static patching strategy is introduced.Then,it is proven in the article that the model is globally attracting,implying that regardless of the initial expected state of the network,the expected fraction of the infected computers converges to the same value.Therefore,the asymptotic expected fraction of the infected computers is recommended as the measure of performance of a static patching strategy.Finally,the influences of a few parameters on the performance of a static patching strategy is examined.The findings of this part provide a significant guidance for restraining malware propagation.(3)The influence of external environment on the spread of rumors is analyzed,and the control problem of rumor on online social networks is studiedHarmful rumors are a major concern in modern society.In this part,the paper is devoted to the design of a cost-effective rumor-refuting scheme for online social networks through optimal control approach.As online social network users receive rumors mainly through external environment and internal environment,therefore,this paper presents an individual-based rumor spreading model which considers the effect of both external and internal environment.In this work,the cost effectiveness of a rumor-refuting scheme is measured.Next,the original problem is reduced to an optimal control model.Through theoretical analysis,the solvable of the model is proved and the optimality system for the model is also presented.Finally,the paper shows that the resulting rumor-refuting scheme is cost-effective through extensive computer experiments.The study of this work provides a way to solve related problems.(4)A class of rumor and anti-rumor game-theoretic problem for online social networks is studiedA rumor about an entity can spread very rapidly through online social networks(OSNs),which may lead to serious consequence.In this part,the paper mainly studies how to mitigate the impact of a rumor when the rumormonger is strategic.Based on a novel rumor spreading model,the benefit of the rumormonger as well as the loss of the victim is estimated.On this basis,the original problem is reduced to a differential game-theoretic model.Next,a system for solving the model is derived.By solving the system,a dynamic rumor-refuting strategy can be obtained.Through extensive comparative experiments,it is shown that the proposed strategy is cost-effective in terms of the Nash equilibrium solution concept.To our knowledge,this is the first time this kind of problem is dealt with through differential game-theoretic approach.This work provides a significant guidance for restraining rumor on OSNs.