基于属性加密的用户隐私保护云存储方案
User privacy-preserving cloud storage scheme on CP-ABE

为了保护云存储环境下用户数据的隐私，该文提出一种基于属性加密（ciphertext-policy attribute based encryption，CP-ABE）的用户隐私保护云存储（user privacy-preserving cloud storage，UPCS）方案。首先，数据所有者为不同的文件设置不同的访问权限属性；其次，可信第三方使用CP-ABE方案将访问属性嵌入到密文中，只有当用户的属性满足密文的访问属性，才能解密相应密文；最后，为减少数据所有者和用户的计算时间开销，在索引生成和文件解密阶段，将部分操作授权给分布式代理服务器。结果表明：该方案可以有效地保证用户数据和关键词的隐私以及减少数据所有者和用户的计算时间开销。
Abstract：A ciphertext-policy attribute based encryption (CP-ABE) user privacy-preserving cloud storage (UPCS) scheme was developed to protect user privacy in cloud storage environments. The data owner sets different access right attributes on different data files. The CP-ABE scheme has the trusted third-party embed the access right attributes into a ciphertext wich can be decrypted only when the user's attributes satisfy the access attributes of the ciphertext. The computational times of the data owner and users are reduced by authorizing some data owner and user operations to a distributed proxy server. Tests show that this scheme can effectively guarantee the user data and keyword privacy and reduce the data owner and user computational times.