中文摘要：

利用混沌系统的初值敏感性，参数敏感性和类随机性等特点．首先提出一种称之为“混沌变换”的图像置乱算法。并在此基础上，设计了一种基于小波与混沌变换的图像加密算法。该算法的处理过程：图像预处理；对原始图像进行小波变换，得到四幅小波分解子图；用混沌变换对四幅子图进行图像置乱；小波逆变换。实验结果表明解密图像与原始图像一致性良好，同时本算法具有很高的安全性。

英文摘要：

Because of the features of initial value sensitivity, parameter sensitivity and random sensitivity, a novel image position scrambhng method, which is called chaos transform, is firstly presented. And a practical image encryption algorithm based on wavelet transform and chaos transform is put forward. Four steps are included in our algorithm. Firstly, to preprocess the original image by chaotic system. Secondly, to decompose the preprocessing image by wavelet transform and to get four sub-images. Thirdly, to scramble the four sub-images by chaos transform on same keys. Finally, the encrypted image is obtained by inverse wavelet transform of the scrambling coefficients. Experiment result shows that the encrypted image and the original image have good identity. And our algorithm has good safety.