基于哈希函数的小波域脆弱水印算法

针对基于分块独立的脆弱水印算法的安全性问题，提出一种利用查找表和哈希函数的小波域脆弱水印算法。该算法利用小波变换的空频特性，在LL子带用查找表的方法嵌入一个标识水印，用于检测和定位篡改；选取HL子带或LH子带的哈希值作为水印嵌入到HH子带中，用于抵抗各种伪认证攻击。实验仿真结果表明该算法既提高了基于分块的脆弱水印算法的安全性，又保持了良好的局部修改检测性能。

Fragile Watermarking Algorithm Based on Hash Function in Wavelet Domain

A novel fragile watermarking algorithm based on binary look-up-table (LUT) and Hash value in the discrete wavelet domain is proposed to overcome the security problems of block-wise independence watermarking schemes. Since the wavelet transform has space and frequency characteristic, we embed a marking watermark in the LL sub-band with the look-up-table method for the detection and localization tampering. Choose the Hash value of the HL sub-band or LH sub-band as another watermark to embed in HH sub-band for resisting the counterfeiting attacks. The experimental results demonstrate that the algorithm has both the effectiveness in resisting possible attacks and good ability of detecting local alterations.