【作者】 许力；

【导师】 何大可；

【作者基本信息】 西南交通大学 ， 计算机应用技术， 2008， 硕士

【摘要】 随着计算机网络的迅速发展,通过因特网传输的数字产品非常容易受到非法拷贝和窜改。数字水印技术的诞生正是为了解决这个问题。而公钥数字图像水印是数字水印技术的一个分支,具有极大的应用前景,是当前研究的一个热点。本文首先分析了数字水印技术与传统加密技术的关系,总结了水印技术的优势领域和加密技术可应用到水印中的相关技术,同时,总结了水印系统的分类、鲁棒性水印的特性、水印的攻击方法。然后,本文总结了非对称数字水印(公钥数字水印)系统的当前研究方法,指出其中的不足。同时,提出了一种混合水印的方案,通过使用嵌入的公钥和私钥水印实现对称和非对称的水印提取。非对称水印允许任何人使用公钥提取公钥水印来验证一些信息。假如公钥水印被破坏,版权人可以使用对称水印提取秘密信息来证明他的版权。同时,为了解决公钥水印健壮性不高的问题,混合水印算法采用Hash函数、纠错码、小波域的临界可见误差门限等多种手段,增强了水印的鲁棒性;为了抵御解释攻击,混合水印算法引入了时间戳服务,并将混合水印算法拓展到彩色图像领域。借助Stirmark和Matlab等多种软件工具,仿真实现水印的嵌入、提取以及各种类型的攻击。使用随机选取的格式、大小相同的图像组,测试混合水印算法的虚检率。仿真实验将证实我们提出的这种方案的有效性。通过研究本水印系统的设计目标,以及实验结果,可以得出结论:在设定的工作范围下,水印系统可以基本完成目标。更多还原

【Abstract】 With the development of network technology, the digital products transmitted though the internet is easier to be modified or copied by attackers without authorization by the actual owner. The digital watermarking technology was presented to resolve this problem several years ago. Asymmetric digital watermarking technology is one of the investigation hotspots in the digital watermarking field.Firstly, this paper analyzes the relationship between the digital watermarking technology and the traditional encrypting technology, and then summarizes the advantages of the digital watermarking technology and the encrypting technology which can be used in our hybrid-watermarking scheme. Secondly, a hybrid-watermarking scheme is proposed that enables both asymmetric and symmetric watermark extraction by embedding public and private watermarks. Using the asymmetric extraction, anyone with the public-watermark key can extract the public watermark to verify some information. If the public watermark is destroyed by some attack, the symmetric watermark extraction allows the actual seller to extract the hidden private watermark to prove his ownership claim. Finally, it makes full use of the Hash function, error correcting code, HVS in the algorithm to strengthen the robust of the watermarking. It also uses the digital time stamp service to resist the IBM attack and expands to multicolor image area.Watermarking serial is implanted into the original image and detected by using the special tools, such as Stirmark and Matlab. We present experimental results to show the effectiveness of our proposed scheme.We can conclude that this hybrid-watermarking scheme can achieve our design goal because of the research and experiments’ results as former concerned.更多还原