ISSN 1000-1239 CN 11-1777/TP

计算机研究与发展 ›› 2014, Vol. 51 ›› Issue (12): 2614-2622.doi: 10.7544/issn1000-1239.2014.20131178

• 信息安全 • 上一篇    下一篇

云环境下多用户文件共享方案

王中华,韩臻,刘吉强   

  1. (北京交通大学计算机与信息技术学院 北京 100044) (09112059@bjtu.edu.cn)
  • 出版日期: 2014-12-01
  • 基金资助: 
    基金项目:高等学校博士学科点专项科研基金项目(20120009110007);2012年铁道部科技研究开发计划基金项目(2012X010-B);教育部创新团队发展计划基金项目(IRT201206)

File Sharing Scheme for Multi-User in Cloud Environment

Wang Zhonghua, Han Zhen, Liu Jiqiang   

  1. (School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044)
  • Online: 2014-12-01

摘要: 随着云存储技术的迅猛发展,越来越多的用户利用云存储服务将本地文件存储转移到云端实现与多个用户的文件共享.针对云环境下多个用户共享同一文件时存在不同访问权限的问题,提出了一种高效的云环境下多用户文件共享方案.新方案基于Elgamal加密系统和代理重加密技术,实现了文件拥有者只需对共享文件加密一次就能够使共享用户访问不同内容的目标.和现有方案相比,新方案的优势体现在:在保证密文生成存储空间不变的同时,文件拥有者对共享文件加密的计算量只与文件块数的指数加密运算呈线性增长关系;共享用户解密文件时只需线性次数的指数解密运算就可以访问各自不同的文件内容.分析表明,新方案更加适合云计算环境的特点,即云服务提供商可以为瘦客户端用户提供无穷的计算和存储能力.

关键词: 云计算, 安全云存储, 多用户, 文件共享, 代理重加密

Abstract: With the rapid development of cloud storage, more and more people prefer to transfer personal files and data from local to cloud and share them with each other by cloud storage service. Nevertheless, each user has different access privileges on account of different identities, roles, etc. Given the different access privileges among the multi-user sharing the same file in cloud environment, an efficient file sharing scheme for multi-user is presented. Based on Elgamal cryptographic system and proxy re-encryption, multi-user access to different contents of the same file encrypted once by file owner is achieved in the proposed scheme. Compared with previous proposals, the scheme has the following advantages: the computation of the shared file encrypted by file owner is only proportional to the exponentiations of the amount of file blocks, regardless of bilinear pairings. Besides, users access to different contents of the same file by exponentiations with linear times regardless of bilinear pairings. Furthermore, ciphertext space for storage has no increments. Further analysis shows that our scheme adapts to the characteristics of cloud computing, which means cloud service providers provide fast computation and huge storage for thin clients.

Key words: cloud computing, secure cloud storage, multi-user, file sharing, proxy re-encryption

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