非对称数字水印系统研究

Research on asymmetric digital watermarking system

针对传统对称水印的不足,设计并实现了一种用于版权保护的非对称图像水印系统。该系统采用三级认证结构:用户和认证机构分别拥有由私钥变换而成的不同的公钥,他们可以利用各自的公钥对数字产品进行两层检测,并且无法去除和伪造水印,只有掌握私钥的版权所有者才能进行最终的认证。实验表明:该水印的检测性能良好,同时对常规的图像处理方法具有较强的顽健性。与其它非对称水印相比,该水印系统不但抵御公开攻击的能力较强,而且可防止认证机构的欺骗行为,因而具有更高的安全性。

Aiming at the limitations of traditional symmetric watermarking, an asymmetric image watermarking system that offers three-level authentication for copyright protection was described. In the proposed system, the two watermarks could be publicly detected by users and third trusted party respectively, but they couldnot be forged and removed. The final authentication could be implemented by only data owner knowing the private key. The experimental results showed that the watermark has perfect detection performance and robustness against the common image processing techniques. Compared with recent asymmetric watermarking schemes, the proposed system provides a higher security level against malicious attacks, including attack on the public detector and fraudulent act of trusted third party.