关键词: 属性基加密, 安全访问, 服务外包数据, 密文策略属性基加密（CP-ABE）算法, 可追踪

Abstract:

To solve the problem of information leakage and tracking difficulty of outsourced data in cloud storage environment, an improved CP-ABE-based security access control scheme is proposed. The solution is based on the dual-pair theory and secret sharing mechanism. The third-party trusted agency generates a proxy encryption key for the user according to the access policy specified by the data owner, provides user registration based on the personal attribute information submitted by the user, and distributes the key pair. The access tree constructs an access policy to implement the matching of the user attributes. When the leakage of the user key leads to information loss, the identity of the user can be traced according to the tracking list. The analysis shows that the scheme can be proved to be secure under the assumption of DBDH, and it achieves resistance against collusion attacks and man-in-the-middle attacks. Compared with other schemes, the scheme of this paper is optimized in terms of encryption and decryption time, private key length and ciphertext length, thereby reducing storage overhead and computational cost.

Key words: attribute-based encryption, secure access, service outsourcing data, Ciphertext-Policy Attribute-Based Encryption（CP-ABE） algorithm, trackable