基于公钥的可逆数字水印

摘要

为了提高可逆数字水印的安全性和透明性,增加嵌入容量,提出了一种基于公钥的可逆数字水印.该方法首先对载体图像直方图中峰值点与左右两侧的零值点之间的像素点进行移位,然后提取载体图像的特征值,将该特征值与经过混沌系统加密的数字水印进行异或处理后,采用公钥将其嵌入到处理后的载体图像内.图像的验证过程是嵌入过程的逆过程,验证完成后,根据峰值点及其与零值点之间的关系将移位的像素点复原,即可完全复原原始图像.采用公钥系统和混沌系统充分保证了系统的安全性,峰值点与其两侧的零值点之间的像素移位既保证了能够嵌入更多的信息和较高的峰值信噪比,又保证了所有的像素点都能被认证.通过对大量的图像进行仿真分析,结果显示该方法具有较高的安全性,与同类方法相比,能够嵌入更多的信息量,同时具有更高的透明性.%A reversible digital watermarking based on public key system was proposed to improve the security, transparency and embedding capacity. This technique shifted the pixels between the peak and zero in the histogram, extracted the characteristics of the original image, used the Boolean exclusive OR operator between the characteristics value and the watermark image processed with chaotic system, and finally embedded the value into the image with the public key. Verification process was the inverse process of the embedding. After the verification, the shifted pixels were recovered depending on the relationships of the peak and zero in the histogram, and the image was recovered. The public key system and chaotic system guarantee the system security. The shift between the peak and zero pixels ensured more embedded information, higher peak signal- to-noise ration, and authentication of all the pixels. The process was simulated with lots of images. The results show that the method is safer than others, can embed more information, and has more transparency.