基于地址码的脆弱数字水印技术

提出了一种适用于数字产品的认证、内容篡改证明和完整性证明的脆弱数字水印算法．用置乱后的水印生成地址码，根据地址码在载体图像的DCT域块上找到对应的参考位置，并根据一个混沌随机序列改变该参考位置邻域的系数值、由于把水印从单个bit转换成了一组bit来形成一个参考点的地址，这样有效地减少了修改载体图像DCT系数的个数，从而提高了含水印图像的不可见性．实验结果表明，所提出的水印方案对篡改证明的有效性和敏感性．

A Fragile Watermark Technique Based on Address Code

A new fragile watermarking scheme was presented, which is capable of authentication, tamper-proofing and integrity verification of digital products. It uses permuted watermark to generate address codes, then finds the corresponding position in DCT domain blocks of host image and changes the coefficient value of the neighboring pixels according to a chaotic pseudo-random sequence. This method succeeds in the transformation of the watermark information from individual pixel to a group of pixels that forms relative address, hence greatly reduces the number of changed coefficients and obtains a high peak signal-to-noise ratio (PSNR) as expected. The proposed scheme is blind because the original image is not required during the watermark extraction process. The simulation results show the effectiveness and sensitivity of this technique.