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Study On Temporal Role Delegation Graph Model And Its Analysis

Posted on:2005-09-21Degree:DoctorType:Dissertation
Country:ChinaCandidate:X M WangFull Text:PDF
GTID:1118360155475902Subject:Computer software and theory
Abstract/Summary:PDF Full Text Request
Access control is one of the kernel policies of information system security, and it constitutes the security infrastructure used for saving, processing and transmissing data in information system with cryptography, authentication, auditing, intrusion detection, system recovery, risk analysis and assurance technique togethor. The infrastructure provides an effecttive mechanism to provent nonauthorized users from accessing system resource and from leaking data, and to ensure country politics, military, economy and personal private information.Access control model is used to express the access control policies of information system security, to verify the consistance among them, and to provide the effective mechanism for enforcing the access control policies. The main method to enforce access control policies is authorization. Because it has many advantages, such as the policy neutrality, the effective authorization management and the natural mapping relations between organization structure and access control space, the role-based access control (RBAC) proposed in the early days of 1990s is thinked as a new promising access control model, and deeply studied and generally used. The existing RBAC models have a common hypothesis: the authorization management tasks, such as creating roles, assigning roles and revoking roles, are only carried out by authorization management users, and the other regullar users only have the rights for using roles, but do not have the rights for managing roles. However, in distributed system, network and cooperative computing system, the numbers of users, permissiones and resources usually are large or huge, and the relations between them are very complicated. Thus RBAC, a central authorization model, can not meet the authorization management need of distributed system, network and cooperative computing systems. Access control model must have the power for regular users to transmiss thier right discretionarily, and such a right transmission should be controlled to ensure distributed authorization management and to enhance the flexibility and validity of the access control of distributed and wide-scope information system. The right transmission between users is called right delegation.First, in this paper, I deeply analyze the drawbacks of the existing role-based delegation authorization models, and propose several novel role delegation principles. Second, with graph theory, first order predicate logic, and event algebra theory, I propose a temporal role delegation graph model (TRDG) based on the model ARABC97, which is deeply studied and generally used currently. Because graph model has an inherent distributed modeling characteristic, TRDG must have the power of modeling role delegation in distributed way. Third, I present a series of new role delegation concepts, and define novel authorization supporting relation and authorization chain, and study thier properties. Forth, I propose several novel role delegation policies and delegation revoke policies, and decribe the algorithms for enforing the proposed policies. Forth, I study role delegation constraints. Fifth, I analyse the properties of TRDG. Final, I discuss the key techniques, the data flow and the main data structures for designing and realizing a prototype of TRDG.The main innovations of this paper are as follows:(i) I propose eight novel role delegation principles, and they form a more complete role delegation principle framework with the seven existing role delegation principles.(ii ) I define a series of new delegation concepts and relations, and propose a graph model of role delegation. My method is to define the authorization relation of role delegation as a seven-tuple: (delegation time, delegated role, directly supporting role of delegated role, delegating user, delegated user, directly suporting user of delegation) original temporal role of delegation dependence). The proposed authorization support relation describes the local dependence relation among delegations, and the authorization chain concept expresses the overall dependence relation among delegations. Regular users may create new roles based on the temporal roles held by them. As a result, total and partial role delegation and repeatable role delegation can be realized.(iii) I propose the monotonic role delegation policy and the nonmonotonic role delegation policy, the time-triggering role delegation revoke policy, the candidating and noncandidating role delegation revoke policies, and the authorization dependence role delegation revoke policies with priority class, and describe the algorithms for enforcing the proposed policies.(iv) I deeply study temporal role delegation constraints. I express periodic time by calendar time and interval time, and propose the new temporal role and sub-role concepts to realize the periodic time constraint in role delegation. We can control the role delegation depth and width by the cardinality constraint proposed in this paper. In addition, I propose the authorization control flow dependence constraint, the seperation of duty constraint, and the coordination of duty constraint in role delegation, and expand the constraint mechanism of the seperation of duty of RBAC. We also can effectively express role delegation history constraint by the role delegation support relation proposed in this paper.(v) I introduce event algebra theory into the research on role delegation, and expand the tranditional triger mechanism to adapt to the environment of role delegation, so that TRDG has an active service mechanism to a certain extent, and it can effectively express the order dependence relation of the delegation event occurence.(vi) I analyze and discuss the properties of TRDG. I define the concepts of the consistence, the completeness, the correctness, the secirity, and the secure role delegation desision of TRDG. and present the verifiable security theorem of TRDG, and give the related-delegation or revoke algorithm.(vn) I also design and realize a web access control server prototype of TRDG to verify the validity and correctness of the proposed theory and method in this paper.In summary, the model TRDG is a more complete role delegation model, which is proposed on the basis of the study of the national natural science foundation of China under grant No.90204012, the national High-Tech research and development plan of China under grant No.2002AA143012 and the national defense foundation of China under grant No.EP010240-10, and it has a general theoretical idea and an important application value in the access controls of WfMS, DBS, network security system, fault tolerance system, operation system and distributed application system.
Keywords/Search Tags:Information system security, access control, RBAC, role, delegation, model, constraint, graph, algorithm, first-order predicate logic, event algebra
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