支持带权属性撤销的密文策略属性基加密方案

针对目前大部分密文策略属性基加密（CP-ABE）方案都不支持属性的多状态表示，加密、解密阶段计算开销庞大的问题，提出一种支持带权属性撤销的CP-ABE方案（CPABEWAR）。一方面，通过引入带权属性的概念，增强了属性的表达能力；另一方面，为了降低计算开销，在保证数据安全的情况下将部分计算过程外包给云服务提供商（CSP）。分析结果表明，所提方案基于判定双线性DH （DBDH）假设是选择明文安全的（CPS）。所提方案以增加少量存储空间为代价简化了访问树结构，提高了系统效率和访问控制的灵活性，适合计算能力受限的云用户。

Ciphertext policy attribute-based encryption scheme with weighted attribute revocation

Most of the existing Ciphertext-Policy Attribute-Based Encryption (CP-ABE) schemes cannot support multi-state representation of attributes, and the computation overhead of encryption and decryption phase is huge. In order to solve the problems, a CP-ABE scheme with Weighted Attribute Revocation (CPABEWAR) was proposed. On the one hand, the expression ability of attribute was improved by introducing the concept of weighted attribute. On the other hand, in order to reduce the computation cost, part calculation tasks were outsourced to Cloud Service Provider (CSP) under the premise of ensuring data securer. The analysis results show that, the proposed CPABEWAR is proved to be Chosen Plaintext Secure (CPS) under the Decisional Bilinear Diffie-Hellman (DBDH) assumption. The proposed scheme simplifies the access tree structure at the cost of a small amount of storage space and improves system efficiency and flexibility of access control, which is suitable for cloud users with limited computing power.