【作者】 张伟；

【导师】 林作铨；

【作者基本信息】 北京大学 ， 应用数学， 2013， 博士

【摘要】 基于角色的访问控制（RBAC）是目前访问控制领域的主流模型。与传统访问控制模型相比，它有效降低了安全管理的成本，大幅提高了系统效率。然而，在复杂应用环境中，RBAC模型本身的一些局限和不足也逐渐暴露出来。本文着重研究了RBAC模型存在的一些问题，并提出了一个基于答集程序设计（ASP）的框架对这些问题加以解决，主要工作包括：1.提出基于ASP的RBAC形式化框架。由于RBAC缺少一个形式化的框架来支持知识的表示与推理，访问控制规则的制定、执行与维护均易于出错，从而带来许多安全隐患。我们基于ASP对ANSI RBAC参考模型中的四大模型组件进行了形式化，并举例说明了这一框架能够很好地支持访问控制规则的制定和执行。2.提出基于ASP的授权框架，使RBAC支持复杂策略及策略的组合。访问控制策略是一系列规则的组合，对复杂策略的支持可以保证访问控制授权决策的推理和执行。我们首先提出一个基于ASP的负授权RBAC模型，扩展ANSIRBAC标准来使其支持负授权策略；其次，对主要的策略分别进行形式化并加以整合，提出了一个可灵活支持各类访问控制策略的授权框架；最后，对这一框架的安全性及可行性进行了证明。3.提出一种基于ASP的方法来解决域间角色映射（IDRM）问题。我们通过扩展RBAC形式化框架，使其能够有效地支持分布式环境下的域间角色映射问题。基于ASP，我们借助图的染色问题提出了一种IDRM问题的求解方法。最后，对域间角色映射带来的冲突问题进行讨论，并给出了冲突消解规则。更多还原

【Abstract】 Role Based Access Control (RBAC) is recognized as the predominant model in the ac-cess control field nowadays.Compared with traditional access control models, RBACobviously reduces the security administration cost and improves the system efficiency.However, many limitations of RBAC model surface in complex application environ-ment. In this dissertation, we study the disadvantages of RBAC model, and present aframework based on answer set programming (ASP) to address the issues. The maincontributions of this thesis are as follows:1. Present an ASP-based RBAC formalization framework. Access control rulesare error-prone due to the lack of a formalization framework for knowledge represen-tation and reasoning. We represent the model components of ANSI RBAC referencemodel, and illustrate that our logic framework is flexible and efficient for access controlreasonings.2. Propose an ASP-based authorization framework to support complicated andcombined policies. Policies are sets of specific access control rules. The support forflexible policies ensures the authorization decisions in RBAC systems. We proposean ASP-based RBAC extended model for negative authorization first. Then the fourmajor groups of policies are represented and integrated as an authorization framework.Finally, we prove the systems based on our framework are both safe and available.3. Propose an ASP-based approach for Inter-domain Role Mapping (IDRM) prob-lem. We extend the ASP-based RBAC framework to support the IDRM problem indistributed environments. Based on ASP, we employ the graph coloring problem andput forward an approach to solve IDRM problem. Conflicts that brought by IDRM arediscuss in the following, with sets of rules for conflict resolution.更多还原