中文摘要：

为了满足信息多级安全性要求,提出了一种基于单向函数的等级加密方案,并结合小波变换,实现了一种基于哈希链的图像ROI多级访问控制方案。用户根据权限不同,在访问时得到不同敏感度的明文信息。经实验分析,该方案密钥管理简单,加密数据量少,在数据库中只需存放一份含密图像,有效减少了存储所需空间。

英文摘要：

In order to meet the multi-level security needs of information,a hierarchical encryption scheme based on one-way function is proposed.And a multi-level access control scheme of image ROI based on Hash chains which combined with DWT of images is accomplished.When users access the images,they can obtain different sensitive information according to their different privileges.The results of the experiment show that the key management of this scheme is simple and the encrypted quantity is relatively low.Only one single copy of the encrypted image is stored in the database,the storage space is greatly reduced.