中文摘要：

为了有效地解决属性基加密中属性的撤销问题,减少解密过程中用户的计算量,提出了具有撤销和解密外包功能的属性基加密方案.新方案利用线性秘密共享技术实现了秘密的分割与重组,基于密钥加密密钥树实现了密钥的更新.在解密过程中,将部分解密运算外包给解密服务器,减少了用户的计算代价.安全性分析表明,新方案能够抵抗共谋攻击,保证数据的机密性和前向、后向安全性.仿真实验表明,新方案在密文更新和解密过程中所需时间都有很大程度降低.

英文摘要：

Aiming to tackle the attribute revocation issue and reduce the user＇s computational overheads, an attribute-based encryption scheme is proposed and it can support attribute revocation and deeryption outsoureing. In the proposed scheme, the splitting and reconstruction of secrets is realized by the linear secret sharing technique, and key update is based on the KEK（Key Encrypting Key） tree. In decryption, our scheme outsources some decryption computational tasks to a decryption service provider, which reduces the computational cost on users＇ side. Security analysis indicates that the proposed scheme can resist collusion attack, and ensure data confidentiality and forward/backward secrecy. Experimental results show that the efficiency of ciphertext update and decryption is improved in terms of time cost.