多属性机构的属性加密研究-密码学专业论文.docxVIP

摘 摘 要 万方数据 万方数据 万方数据 万方数据 摘 要 基于属性的加密体制是基于身份加密的一个重要分支。在基于属性的加密体 制中，身份被一系列描述性的属性取而代之，同时添加了一个灵活的访问结构。 我们大致可以把它分为两大类：密钥策略的和密文策略的属性加密。当且仅当属 性集合和访问结构相匹配时，才能成功解密。这种加密体制最突出的优点就是不 需指定是谁解密，只要接收方符合相应条件便可解密。属性加密在实际中有广泛 的应用场景，比如分布式计算，网络存储等。 但是现有的属性加密方案(ABE)在实际环境中很难得到应用，其中一个原因就 是属性机构的管理问题。Lin 等人提出了一个无中心的多属性机构属性加密方案 (MA-ABE)，去除了安全性较差的中心机构，实现了分布式要求，且所有属性机构 之间地位平等。在他的方案中还引入了秘密共享机制，大大提高了属性加密方案 的实用性，本文在此基础上使用了另一个秘密共享方案，不但可以去除中心机构， 还可以对属性机构进行灵活的增加和删除。另一个原因是一些无中心的属性加密 方案不能抵抗合谋攻击。Lin 等人的方案是通过对用户数量的严格的限制来防止用 户的合谋攻击，针对这个问题我们加入一个哈希函数对用户 GID 进行隐藏，使得 任意数量的用户之间不能进行合谋攻击，从而保证加密方案的安全。 关键词: 基于属性的加密 中心机构 多机构 共谋攻击 Abst Abstract 万方数据 万方数据 万方数据 万方数据 Abstract Attribute based encryption (ABE) is an important branch of identity based encryption. In this system,a series of description attributes instead of the identity, and a more flexible access structure is added to this system. There are two kinds of attribute based encryption：key-policy based and ciphertext-policy based. If and only if attributes match access structure, we can get decryption. The most advantage of the system is that sender does not need to know the specific receiver, and receiver who is consistent with the corresponding conditions can decrypt the message from the sender. Attribute based encryption can be widely adopted in many application scenarios such as distributed computing and network storage. But the existing attribute-based encryption (ABE) is too weak to get application in the actual environment. One of the reasons is the management problems of attribute authorities. Lin presented a threshold multi authority attribute based encryption(MA—ABE)scheme without a central authority. It removed the central authority which has the decryption ability and meets the requirements of a distributed environment. And it made all the authority have the coequal status. He used a secret sharing system in attribute-based encryption, so that it improved usability. On the basis of his scheme, we use another secret sharing system, so that we can a