中文摘要：

针对图像信息的一些内在特征，像大数据容量和高冗余性等，结合混沌系统与小波变换，提出了一种数字图像的加密算法。首先利用小波变换的Mallat算法对原始图像进行数据压缩，减少其数据容量；再选用类随机性较强的Logistic映射混沌系统对压缩图像进行空间置乱和像素值替代加密，最后对加密算法从密钥空间、统计分析、密钥敏感性分析、抗破损攻击分析等角度进行安全性测试。仿真实验表明，此算法既能实现图像数据的有效压缩，提高图像的传输速度,又能增强加密的安全性。

英文摘要：

In view of some intrinsic features of images, such as bulk data capacity and high redundancy, an encryption algorithm of digital image was put forward by combining chaotic system with wavelet transform. The original image was compressed with wavelet transform firstly in order to reduce image data capacity, then was permutated on the pixel position and the pixet value with stronger Logistic map. Finally, security analysis of the encryption algorithm was discussed, including key space analysis, statistical analysis, key sensitivity test, and anti-damaged attack. Simulation results show that the cncryption algorithm can not only compress digital image data efficiently to speed up image transmission, but also enhance the security of the encryption.