中文摘要：

云存储是未来信息存储的一种理想方式，它提供方便易用的外包存储空间，以缓解爆炸增长的信息对存储空间的海量需求，然而，数据的存储存在着安全与隐私泄露等问题，致使云存储服务的推广与普及存在困难。针对用户各数据的安全需求，本文提出了一高效的线性同态加密方案（LHES），其安全性基于多项式环上差错学习（R-LWE）问题的困难性。分析表明，该方案的效率比基于格上差错学习（LWE）问题的加密方案有很大的提高，并且在随机预言机模型下是选择明文攻击不可识别的。

英文摘要：

Cloud storage is an ideal storage form in future, in order to deal with the enormous demands from volatile information, cloud storage provides convenient epibolic storage space. However, many problems such as security, privary leaking,etc. are still exist. This make the permeation of cloud storage more difficulty.Aiming at the users' security request, this paper proposes an efficient linear homomorphic encryption scheme, whose security is based on the difficulty of R-LWE. The efficiency analyses and simulation results indicate that the scheme is much more efficient than previous lattice-based cryptosystems, and it is secure against CPA in random oracle model.