Analysis And Research On User Behavior Based On Petri Net In Cloud Environment

In recent years,cloud computing has been developing rapidly and has impacted various aspects of our daily life.However,the security issue is one of the biggest challenges faced during the development of cloud computing.Cloud service providers hardware and software resources,and the user can access these resources directly.In cloud environment,user behavior often brings greater security risks to cloud service providers.So,thesis foucs on user identity authentication issues in cloud environment.The thesis proposes user behavior analysis method based on Petri net to guarantee the security of user indentity and resource in cloud environment.The contents and innovation of this thesis are listed as follows:(1)A user behavior analysis method based on Stochastic Petri Net(SPN)is proposed.According to the user behaviour characteristics in cloud environment,classifying user behaviour,and building up identity authentication model(IAM)by using SPN.This thesis proposes a behaviour authentication strategy,and using the improved K-modes algorithm to solve the user's behaviour standard.the weights of behaviour is obtained by AHP algorithm.Finally,the user behaviour credibility is obtained to judge user's identity.(2)In view of the behaviour of resource access and file operation in cloud environment,a user behaviour analysis method based on Privacy Petri Net(PPN).The resource access behavior is transformed into behavior path by using PPN.At the same time,the difference between behaviour paths is measured by using similarity distance.We build the short sequence model to analyse file operation behaviour in HDFS,and get the result of abnormal possibility and abnormal severity.According to these indexes,we can judge the malicious file operations.(3)Finally,a prototype system of user behavior analysis is designed and implemented.The thesis elaborates the algorithm and the design methods of each module.The experiment shows that the method proposed in this thesis can identify users' untrustworthy behavior effectively in cloud environment and warn them to cope with the security problems in cloud environment.