使用密码技术对云存储数据实施机密性保护和访问控制,是当前云计算安全研究的重要内容.选择加密(selective encryption)技术根据访问控制策略产生密钥推导图来分发密钥,在保证云存储数据机密性和细粒度访问控制的前提下,具有简化文件存储加密、系统密钥量少的优势.然而,已有选择加密方案需要完全或部分地公开访问控制策略,以用于密钥推导;该信息反映了用户/文件之间的授权访问关系,泄露了用户隐私.基于现有的研究工作,提出一种访问控制策略隐藏机制,在支持加密云存储数据的细粒度访问控制和高效密钥分发的前提下,能更好地隐藏访问控制策略信息,而且在密钥获取计算速度上有明显优势.

Enforcing access controls on cloud storage by cryptography is an important topic of cloud security. Based on access control policies, selective encryption builds key derivation graphs to distribute symmetric keys among users. Selective encryption can ensure the confidentiality and fine-grained access control of cloud storage data, while simplifying data encryption procedure and reducing the total number of keys. However, the existing selective encryption solutions have to fully or at least partially disclose the access control policies. This policy information unfortunately, is usually related to the authorization relation between users and files, leading to privacy leakage. This work significantly improves the existing policy-hiding schemes (of selective encryption) with much less privacy leakage and much faster key derivation, while supporting fine-grained access control on encrypted cloud storage.

国家重点基础研究发展计划(973)(2014CB340603);国家高技术研究发展计划(863)(2013AA01A214);中国科学院战略性先导专项(XDA06010702)