Traditional Ciphertext-Policy Attribute-Based Encryption (CP-ABE) schemes have large computational overhead in key generation,decryption and attribute revocation processes.Aiming at this problem,this paper proposes an outsourced CP-ABE scheme which supports attribute revocation.It utilizes linear secret sharing mechanism as an access structure in the process of encryption and outsources parts of the work in the process of key generation and decryption process.In addition,it achieves attribute revocation by adding a unique number into each user's key.Meanwhile,it proves the security of the proposed scheme under the Repeatable Chosen-Ciphertext Attack (RCCA).Experimental results demonstrate the efficient performance of the proposed scheme in attribute revocation and low computational overhead.%针对传统基于密文策略的属性加密方案在密钥生成、密文解密和属性撤销阶段计算开销大的问题,提出一种具有属性撤销功能的外包属性加密方案.在加密过程中使用线性秘密共享机制作为访问结构,将密钥生成和密文解密的部分计算外包,通过为每个用户的私钥设置版本号实现用户属性的撤销,同时证明方案在可重复的选择密文攻击下是安全的.实验结果表明,该方案的计算开销较低,并且能较好地实现密文策略的属性撤销功能.
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