中文摘要：

基于数字图像加密设计的两个基本原则是置乱和扩散,一般的算法针对于图像分别单独进行置乱和扩散,而本文提出一种两者相结合同步实现加密的算法.先利用一维Ulam-von Neuman映射来控制二维Logistic映射产生两个混沌序列;再将产生的序列作用于原图像,对图像按照某种扫描方式,在每一个像素点上,每完成一次置乱,紧接着进行一次扩散,直到整个图像加密完成.仿真实验表明,与单独置乱扩散的图像加密算法比较,该算法有很大的密钥空间、很高的安全性、很快的加密速度和很强的鲁棒性.

英文摘要：

Digital image encryption is mainly based on two basic principles：permutation and diffusion,which are used separately for an image.But a new algorithm was proposed in this paper that combines them together to achieve synchronous encryption.First,a two-dimensional logistic chaotic map,which was controlled by onedimensional Ulam-von Neuman map,was used to generate two chaotic sequences.Second,the above-mentioned sequences were utilized in the original image.According to a selected image scanning method,a permutation and then a diffusion operation in each pixel time were completed until the entire image encryption was accomplished. Compared with the existing algorithms using permutation and diffusion separately,the simulation results showed that the proposed algorithm has a larger secret-key space,higher security,faster encryption speed and stronger robustness.