移动云环境下的多授权机构属性基加密方案

针对移动云数据的访问控制进行了研究，提出一种高效的、无需CA的多授权机构密文策略属性基加密方案。通过借助外部资源，在数据加密和解密过程分别增加预加密操作和可验证外包解密操作，从而降低用户的加解密计算量，并采用双因子身份认证机制实现对用户的匿名认证。安全性分析表明，新方案基于判断性q-BDHE（decisional q-parallel Bilinear Diffie-Hellman Exponent）假设可证明是选择明文安全的，并且方案能够抵抗合谋攻击。仿真实验表明，新方案有效降低了数据加密、解密的计算开销以及对密文的通信开销。因此，新方案能够实现对移动云数据安全、高效的访问控制。

Multi-authority attribute-based encryption scheme in mobile cloud environment

Study on the data access control in mobile cloud, this paper proposed an efficient multi-authority ciphertext-policy attribute-based encryption scheme without any central authority. The main idea was to outsource a part of computing tasks to some external servers, consider to increase a pre-encryption operation and outsourcing decryption operation in the process of encryption and decryption, and use the two-factor authentication mechanism to achieve anonymous authentication. Security analysis indicates that this scheme is proven choose plaintext attack (CPA) security under the decisional q-parallel Bilinear Diffie-Hellman Exponent assumption, furthermore, it can resist collusion attack. Experimental result shows that this scheme significantly reduce the bandwidth and the computation time for both data encryption and data decryption. Therefore, this scheme could achieve security and efficiency of data access control in mobile cloud environment.