The Research On The Models Of Email Networks And Spreading Of Malicious Codes

At present, it is probably that the email is the one of most widely used application in Internet. However, in recent years, the popularization of the Internet and the spreading of information provide the enormous convenience for the diffusing of the malicious codes. The one of most common reasons which causes the ubiquitous spam emails and messages in the Internet is email virus, and the worms and backdoor programs in the attachment are the major ways of spreading the virus in the Internet. All of those factors are seriously threating security and safety of internet. Therefore,the email network is getting increasing attention of researchers and scientists from all kinds of fields. Actually,the toplogy of email network is a type of Directed Scale-Free network which is similar to other kinds of Complex networks.However, here are some assumptions that cannot be totally convinced about the transmission process of the virus and malicious codes in the email network. At first, in order to simplify the model,they think the email network is a Undirected Scale-Free Network. Whereas according to the Investigation from Newman and Ebel,we can conclude that the email network is a Directed Scale-free network.Secondly,they assume that the implementation of immunization strategies is before the brginning of the process which malicious codes spread in email network. But actually ,in most cases,when facing the outbreak of email virus,there often have a certain delay time before performing the immunization strategies. Therefore, the current models can not effectively simulate the diffuse process of virus in the email network.Taking into account the current research status about the spreading process of malicious codes in email network , the paper made the following improvements: This takes into account the malicious code research at the e-mail network status, the essay made the following improvements:1. Based on this conclusion,we extend the BA Model and created a Directed network model. We simulated the evolution process of this model and observed the degree-distribution of this model. At last,we verified this model and sure that it is a Direced sale-free network .2. Through adjusting the parameters of this model,we make the power law distribution of in-degree and out-degree in this network model correspond the statistics of real email networks. Based on this model, we simulated the diffusing process of three typical e-mail virus in email networks by SHIS methodology. Those simulation results will give us some clues about how to arrange the immunization strategy in the current email network.