关键词: 属性基加密算法（ABE）, 访问控制, 云存储, 密钥托管, 计算效率

Abstract: Attribute-based encryption (ABE) is a promising technique that provides not only data encryption but also flexible access control for cloud storage. Existing ABE schemes are mainly threatened by key escrow problem in terms of security, and are unacceptable in term of efficiency due to large bilinear pairing computation. To address these problems, an improved ABE is proposed. Owing to distributed generation of private keys, the key escrow problem is addressed. In addition, the improved ABE does not need any bilinear pairing computation. Compared with existing schemes, as a result, the computation overhead is reduced. By reduction to computational Diffie-Hellman assumption (CDH), the proposed scheme is proven to be secure against chosen ciphertext attacks in random oracle model.

Key words: attribute-based encryption (ABE), access control, cloud storage, key escrow, computational efficiency