Security Policy Specification And Analysis Method For Privacy Information Flows In Web Service Compositions

As a distributed computing paradigm based on Internet,Web services are suitable for being published and used as an independent and open entity in the Internet environment.The functions of a single Web service are often limited.In order to realize more complex business logic,a feasible method is to form more powerful composite services by effectively integrating Web services distributed on the Internet.To use the functions provided by services,users need to provide the necessary personal privacy information.However,due to the open,dynamic and autonomous nature of Web services,once private information is collected,it is difficult for users to control how services use and expose the information.Especially in the case of service composition,user privacy information is exposed to member services through a composite service.Due to the lack of relevant agreement for the use of private information between users and member services,how to prevent the illegal disclosure of privacy information has become a key issue in implementing secure service compositions.Information flow control technology can control the propagation of information according to a security policy,and can guarantee the end-to-end security of information.Implementing a privacy information flow security control mechanism will greatly increase users' confidence in using services.Although researchers at home and abroad have conducted some research on privacy protection based on the information flow control mechanism,they have not proposed privacy information flow security policies and corresponding enforcement mechanisms for behavior-based privacy protection features.In view of the shortcomings of current research work,this thesis focuses on the issues related to security analysis of privacy information flows in a service composition.The main research contents and contributions are as follows:(1)Aiming at how to protect users' privacy information by using information flow control technology,a framework for the security analysis of privacy information flows in service compositions is proposed.This framework support the generation of a privacy information flow security policy according to the features of behavior-oriented privacy protection,and validates the security of privacy information flows by analyzing the paths of a service composition.At the same time,the framework supports the analysis of the security of privacy information flows in the evolution environment,and provides guidance for the specific evolutionary implementation so that the security of the privacy information flows in a service composition can be preserved.(2)Behavior-oriented privacy protection is essentially a control policy for user privacy information and a mechanism to ensure that this policy is not violated during the service execution.Unlike traditional information control policies,behavior-oriented privacy information control policies mainly focus on the dimensions such as privacy data,data users,retention,and purpose.To this end,a security policy is proposed on three aspects: data sensitivity/service reputation,retention and purpose according to the characteristics of behavior-oriented privacy protection.(3)A static analysis method for the privacy information flows in a service composition is proposed based on the security policy.First,a privacy work flow net is proposed by extending the data modeling capability and privacy semantics of work flow nets to formally model the privacy behaviors of a service composition.Thus,the information flows in a service composition can be analyzed with fine granularity.Next,a privacy flow security control mechanism is proposed including analysis of privacy data item combination,acquisition method for path set to be analyzed,security class binding,and information flow control rules.Then,analysis algorithm for secure privacy information flows is presented.Finally,a case study is included to demonstrate the effectiveness of the proposed method.Compared with the existing relevant works,this analysis method can deal with issues caused by the combination of privacy data items.Therefore,the application of this method can prevent the information leakage more efficiently.(4)In order to adapt to changes in the environment and continuously meet user requirement,service compositions will continue to evolve.It is an important evolutionary requirement to preserve the security of privacy information flows.Hence,an analysis method for verifying the security of privacy information flows under evolutionary environment is proposed.When we initially analyze the security of privacy information flows,the dependency relationships among privacy data items are analyzed,and the privacy data usage set and the security scope of each member service are recorded.Then,for the changes of user privacy requirement and the privacy policy of a member service,the security of privacy information flows are analyzed,and evolution operation criterion are proposed,respectively.The security of privacy information flows can be preserved with use of these criterion,which can avoid complete reanalysis after evolution and improve the efficiency of security analysis.(5)Based on the above theories and methods,a prototype tool for analyzing the security of privacy information flows in service compositions is designed and implemented.This tool can help service compositors analyze the security of privacy information flows and guide the evolution to preserve the security of privacy information flows.