【作者】 钱俊磊；

【导师】 董晓蕾；

【作者基本信息】 上海交通大学 ， 计算机软件与理论， 2011， 硕士

【摘要】 信息分布存储系统中需要复杂的访问结构控制以及被保护信息的多种属性标签。在传统系统中,为了实现访问结构控制,由一台服务器明文存储所以信息,并作为控制服务器接受信息的访问请求。信息是以明文形式存储在服务器上,攻击者如果直接访问存储介质即可获取信息。Sahai和Waters提出的属性基密码方案(ABE),恰好迎合了这种信息访问控制的需求。属性基密码方案是将访问控制结构以及属性集合分别与私钥或密文相结合,存储服务器上的信息都已密文形式存储,用户可以直接取得密文而不在需要认证服务器,是否能获得秘密信息取决于属性集合是否满足访问控制结构。应用了这样一个系统后,同时解决了数据存储服务器的压力与信息的访问控制问题。除了访问控制问题,在有些情况下,用户可能在获得访问权限后又遇到必须剥夺该权限的问题,例如付费电视等的互联网应用。因此,还需要在密钥系统中加入私钥撤销的密钥操作功能。之前的属性基加密系统多是在选择安全模型下规约证明的,并且都没有是想用户私钥的撤销机制。该论文将提出一个属性基加密系统,该系统将应用双系统加密的技术来实现完全安全模型下的可证明安全,并且实现了私钥的撤销功能。主要贡献如下:1.我们将应用双系统加密技术来帮助我们的属性基密码系统实现完全安全模型下的可证明安全。2.方案的安全性证明将应用游戏序列的证明方式即逐步将方案中的密文和询问私钥都转变为半状态模式。3.我们将应用完全二叉树技术来实现用户私钥的撤销管理功能。更多还原

【Abstract】 Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally, to enforce the access control, a file server is used to restore all data and acts as a reference to check the user. Apparently, the drawback of this system’s security is based on the file server and the data is restored in plaintext. Attribute based encryption(ABE) was introduced first by Sahai and Waters that enables an access control mechanism over encrypted data by specifying the users’ attributes. Employs this mechanism, even the file server is compromised, we can still keep the security of the data. Besides the access control, user may be deprived of the ability in some situation, for example pay TV. More previous ABE constructions were proven secure in the selective model of security, and few of them realize revocation of the users’ key. This paper will present an ABE scheme that supports revocation and has full security by adapting the dual system encryption methodology.The major contributions include:1. We adapt the dual system encryption technique to ABE case to gain full security. 2. The proof employs a sequence of security games which the ciphertext and queried keys are changed to semi-functional one by one.3. We add the Complete Binary Tree technique to realize user’s revocation.更多还原