隐藏访问模式的高效安全云存储方案

围绕当前云存储环境中用户数据机密性和隐私泄露问题，提出一个隐藏访问模式的高效安全云存储方案.该方案首先将文件分为固定大小的数据块，利用伪随机函数和抗碰撞哈希函数将数据块编码、加密，并将密态数据块上传至云服务器的伪随机集合超集内，构建安全云存储结构;同时，设计两轮用户访问策略，在隐藏访问模式的同时降低了存储代价和访问交互次数，实现文件的动态高效更新.安全分析表明，选择适当的安全参数，方案满足L₁L₂-动态自适应安全性.实验结果表明，本方案在保证数据机密性的同时，更适用于实际的云存储环境.

An Efficient and Secure Cloud Storage Scheme with Hidden Access Patterns

Aiming at the problems of data confidentiality and user’s privacy leakage in cloud， this paper proposes an efficient and secure cloud storage scheme with hidden access patterns. Firstly， the files are divided into data blocks with fixed sizes， and encrypted by pseudo-random functions and collision-resistant Hash functions. Then， in order to construct the secure cloud storage structure， the blocks are uploaded into pseudo-random collection superset in the cloud server. Meanwhile， a two-round access strategy that hides the access patterns， reduces the storage cost and access interaction is designed. Security analysis shows that the proposed scheme achieves L₁L₂-dynamic adaptive security. Experimental results show that the proposed scheme can not only protect data confidentiality， but also be more suitable for the actual cloud storage.