ISSN 1000-1239 CN 11-1777/TP

• 信息安全 •

### 自适应安全的外包CP-ABE方案研究

1. 1(山东师范大学信息科学与工程学院 济南 250014); 2(山东省分布式计算机软件新技术重点实验室 济南 250014); 3(鲁东大学信息与电气工程学院 山东烟台 264025) (wanghao@sdnu.edu.cn)
• 出版日期: 2015-10-01
• 基金资助:
基金项目：国家自然科学基金项目(61272434,61502218)；山东省自然科学基金项目(ZR2013FQ021)；山东省优秀中青年科学家科研奖励基金项目(BS2014DX016)

### Adaptively Secure Outsourcing Ciphertext-Policy Attribute-Based Encryption

Wang Hao1,2, Zheng Zhihua1,2, Wu Lei1,2, Wang Yilei3

1. 1(School of Information Science and Engineering, Shandong Normal University, Jinan 250014);2(Shandong Provincial Key Laboratory for Novel Distributed Computer Software Technology, Jinan 250014);3(School of Information and Electrical Engineering, Ludong University, Yantai, Shandong 264025)
• Online: 2015-10-01

Abstract: Attribute-based encryption (ABE) is a type of public key encryption that allows users to encrypt and decrypt messages based on users attributes. In such a system, the decryption of a ciphertext is possible only if the set of the attributes of the user key matches the access policy of the ciphertext. Given its expressiveness, ABE is currently being considered for many network applications, especially for cloud storage and cloud computing. However, one of the main drawbacks of ABE is that the running time of encryption and decryption grows with the complexity of the access formula or the number of attributes. In practice, this makes encryption and decryption be possible bottlenecks for a lot of applications. In this work, we introduce outsourcing ABE system to mitigate this problem. In the outsourcing ABE system, users can outsource a part of the storage and computing tasks to some semi-honest servers. It is significant for mobile devices to save storage and computational resources. Then, we propose a specific outsourcing ciphertext-policy ABE (CP-ABE) scheme using the composite order bilinear groups. In our scheme, the local computation of (online) encryption and decryption can reach constant level. Finally, we prove its adaptive security in the standard model using the methodology of dual system encryption.