混沌系统盲水印模型

A Blind Watermark Model Based on Compound Chaotic System

为了解决目前水印加密系统中存在的单一混沌加密算法安全性能差,而高维混沌加密又公式复杂、计算量大的问题,提出了一种复合混沌加密算法。算法首先将彩色载体图像由RGB空间转换到YCbCr空间,通过在图像的Y分量上实施3级小波分解后,提取小波变换的低频分量作为水印的嵌入区域;然后利用Cat映射、Logistic映射和扰动作为复合混沌发生器,用以将水印图像加密,再将加密后的水印图像嵌入到小波变换的低频区域;在水印检测过程中利用已知的密钥对水印进行重构。实验结果证明,设计实现的加密和水印嵌入算法具有计算量小,可以抵抗JPEG压缩、噪声、滤波等攻击,具有良好的数字水印特性。

In order to increase the security of chaos-based encryptiun algorithnl while not aft＇coting the performance, a kind of encryption algorithm based on Cut）it maps and Logistic maps with the combination of the chaos is put forward. During the embedding of the watermark, cnh）r images are converted from RGB space to YCbCr space, discrete wavelet transform is done to the Y frequency, and the low frequency part is extracted as the embedding field. Then, the watermark is encrypted by using the compound chaotic sequence and is embed into the low frequency part of the carrier image. In the watermark deteclion process, the known key was used to reconstruct the watermark. The experimental results show that this watermark technique, in which the encrypting and embedding algorithms have less computational capacity, can resist JPEG compression, noise attack, filter and so on and has good performance.