【作者】 刘玲；

【导师】 杨秋伟；

【作者基本信息】 湖南大学 ， 计算机科学与技术， 2011， 硕士

【摘要】 基于网络跨越多个组织的大规模应用系统具有分布性、开放性和动态性等特征,跨越多个管理域的分散组织通过Internet动态结盟进行综合协作的过程中,如何对服务提供者拥有资源的访问进行有效控制成为亟待解决的安全问题。其中,基于角色的访问控制模型是研究的热点。在传统的分布式访问控制模型中,往往采用“乐观”模式,服务请求者将能力或主体属性等披露给服务提供者。但是这些能力和主体属性等通常携带了大量隐私信息,无限制的披露势必会给多域环境中的互操作带来许多安全隐患和风险。因此,如何保护这些隐私信息的内容敏感及拥有敏感,研究多域互操作的访问控制模型具有较大的意义。首先介绍了基于角色的访问控制发展历程,分析了已有访问控制模型研究隐私保护方面的优点和不足。在传统基于角色的访问控制模型基础上,结合基于身份的加密思想,提出了一种支持隐私保护的角色访问控制模型,以支持安全目标除机密性、完整性、可用性之外对隐私保护方面的扩展。该方案以角色布尔变元来描述策略表达式,将策略表达式转化为析取范式,建立访问控制决策与策略布尔表达式取值之间的映射；服务提供者在加密阶段将策略隐涵在公钥中,请求者的解密密钥包含了个体的授权指派,当且仅当请求者拥有加密公钥对应的私钥才能够正确解密,解密过程隐涵着策略和用户所拥有的角色的一致性验证。该方案不泄露除了用户1D以外的其它信息,并且在服务请求者与提供者交互时一次通信就完成了数据交换。对模型的隐私保护逻辑进行了详细的阐述,并重点描述了系统初始化、授权指派、策略定制及响应、加密处理、消息恢复及验证五个组成部分。最后,采用随机预言机模型证明本方案满足IND-CCA2语义安全；通过算法复杂度分析,并且与其他方案的计算代价相比较,本方案对比传统模型并没有显著增加运算量,在执行效率方面影响很小。更多还原

【Abstract】 The large-scale application systems based on Internet have special features such as distributed, open-ended and dynamic, how to control the access the resources which belong to the service providers become urgent security problems during the procedure of spanning multiple administrative domains through the internet dynamic alliance organizational collaboration, and the role-based access control model is the more important research hot spot. In the traditional distributed access control model, often using optimistic mode, the requester for service always disclosed its ability or subject property to the service provider. However, the ability and subject property of the requester usually carry a lot of private information, so the unlimited disclosures of the requesters will bring many security risks for multi-domain interoperability environment. Therefore, how to protect sensitive and private information with multi-domain interoperability of access control model have great significance.In this paper, we firstly introduce the development history of the role-based access control, as well as analyze the strengths and weaknesses of the current researches about the privacy protection. Based on the traditional role-based access control model, combining the identity-based encryption idea, we propose an role access control model to support safety goal except the confidentiality, integrity, availability and extension of privacy protection.The model describes the role of policy expression by Boolean variables, then transforms it to disjunctive normal expression, based on it the map between the access control policy strategy and the Boolean expression is established. In the encryption stage the access control strategy is embedded implicitly in public key by the service providers, so the decryption key of the requester contains the individual authorization assignment, if and only if the requester who has the corresponding private key encryption public key can decrypt correctly, mean while the consistency between the strategy and the role of the user can be validated during the decryption process. In addition, this model does not disclose the other information other than the user ID, and completes the data exchange during the interacting between the requester of the resource and the provider of the resource. Last we discuss the privacy protection logic mainly, and describe the five stage of the model, such as system initialization, authorized assignment, customized strategies and response, encryption, message recovery and verification in detail. In the end, We assess the security of the model by the success probability of adversary attacking protocol and the computational cost, using random oracle model to certificate the model meeting the IND-CCA2semantic security, and analysis the complexity of the algorithm, comparing the cost with other programs. The experiments show that the model does not significantly increase the amount of the computation and executing more efficiency.更多还原