Research On Multilevel Security Model Based On BTG Strategy

Along with the distributed systems and network technology of rapid growth,information sharing becomes increasingly commonplace.Informatization brings not only convenience to people's life,but more importantly,it makes information safety a problem that cannot be neglected.The classical multilevel security model is still in use today after being put forward.It can ensure information accurate delivery,and guarantees the confidentiality and integrity of data.However,the traditional multilevel security models pay much attention to the security of the system but ignore the requirement of dynamic access in the rapidly changing environment.It is not applicable to manage permission in multi-domain environment and also not able to meet the requirement of security maintenance well.Thus,how to flexibly balance the security of the multilevel security model and the way to handling the permission management problems in emergency has important practical significance.On the basis of the above reasons,this paper makes research on the problems that access control system is lack of context-sensitivity,it cannot provide dynamic access rules and redesigns the multilevel access model BLP and Biba.The paper mainly concerns on the cross-domain access problems and the authorization control in emergency and aims to realize a fine-grained,high-compatibility and high-available information protection system.Its research approaches are quite different with the general multilevel security model improvement theory.This paper makes the following innovation:First,this paper puts forward a model termed BTG-BLP which integrates Break the Glass strategies into the classical multilevel BLP model.It is context-aware and can implement a fine-grained type of access control,thus BTG-BLP effectively processes access requests in emergency,which improves the flexibility and availability of the system.The paper formally defines the improved access control policies and then theoretically proof the security of BTG-BLP model through mathematics method.Second,an approach is presented in this work for integrating Break the Glass strategies into the Biba model.This research proposes a model,BTG-Biba,which is context aware and solves the problem the traditional models lack of dynamic polices.Besides,this paper formally defines the access control policy of BTG-Biba,which can efficiently solves cross-domain access problems and improves the flexibility and availability of the system.This paper introduces a new access control strategy for multilevel model rather than only making addition or modification of access polices,which proposes a feasible idea to deal with the emergency in the system.Moreover this work incorporates flexibility function into the traditional multilevel security model very well combined with posterior characteristics of BTG strategies.BTG makes the security models have a good dynamism and be suitable in the current changeable information environment.To sum up,this paper takes the dynamic access requirement of the classical multilevel security model in the rapidly changing environment as the starting point,and makes research on the approach to improve theory and practical application of traditional MLS model based on BTG strategies.The proposed model BTG-BLP and BTG-Biba shows a brand new idea to deal with the emergency in the system and solves the cross-domain problem.Finally,this paper presents and implements a multi-level file management system based on BTG-BLP model then designs an experiment to illustrate the running process under emergency situation and show the feasibility of the improved models.The research achievement of this work not only provides support for the research of multilevel security model but also provides a certain reference for the research of the BTG strategies.