Abstract: This article sums up the image of the encryption algorithm and produce.24-Bitmap image encryption is implemented
in DWT domain，the data sequences used for encryption are created from Lorenz chaotic system.The article performs a
detailed comparison of the effect scrambling DWT coefficients at different scales for encryption，as well as the systematic analysis of the experimental result，finally points out a question using of wavelet coefficients for encryption，and also provides another method for the image encryption.

摘要： 在总结了图像的加密方法基础上，结合Lorenz 混沌映射，在离散小波变换域，对24 位位图进行了加密，并详细比较了不同尺度下的小波系数置乱对加密效果的影响，系统分析了实验结果，指出使用小波系数进行图像加密存在的问题，为工程应用中的图像加密提供了一种选择。