Abstract: A modulo map is used on wavelet domain to encrypt image in this paper，and it also uses chaos parameter sensitivity and pseudo-random to encrypt the coefficients after discrete wavelet transform which can achieve high-strength encryption and ensure the safety of digital image information.The modulo map which authors adopt can not only extend and collapse image but also save computation time greatly.The simulation result shows that the modulo map integrating chaos map executes very well on discrete wavelet domain，it has high quality of secrecy as well as short computation time，and well coherence between the restored image and the original image.

Key words: modulo map, chaos sequence, discrete wavelet transform

摘要： 将一种模运算运用于小波域来进行图像加密，同时利用混沌映射的参数敏感性和伪随机性对小波变换后的系数进行加密处理，实现图像信息的高强度加密，来确保基于网络图像信息的安全。采用的模运算不仅具有像Ａrnold等变换对图像进行拉伸和折叠的作用，而且可以在很大程度上节约计算时间。仿真实验结果表明这种模运算映射与混沌序列相结合的方法运用于小波域加密有很好的效果，加密强度高，保密性强，计算时间短，恢复图像与原图像的一致性良好。

关键词: 模运算, 混沌序列, 离散小波变换