基于小规模量子线路和格雷码置乱的量子水印方案

Quantum Watermarking Scheme Using Small-scale Quantum Circuits and Gray-code Scrambling

为解决量子彩色图像的水印嵌入和抽取问题,提出一种采用新颖的增强量子图像描述和格雷码置乱的实现方案.对于嵌入过程,首先采用受控非门对于水印图像像素的位置和颜色同时置乱;然后将置乱后水印图像的幅度从2n?2n扩展到2n+1?2n+2,将像素颜色值由24比特(每通道8比特)改为3比特(每通道1比特);最后将扩展后水印图像的颜色值,通过模2加运算嵌入到幅度为2n+1?2n+2载体图像颜色值的最低位中.抽取过程为嵌入的逆过程.仿真结果表明,该方案在可视化质量、噪声下的鲁棒性能、水印图像置乱效果和计算复杂度4个方面优于对比方案.

To solve the problem of watermark embedding and extracting of quantum color images,a method of using novel enhanced quantum representation and Gray-code scrambling was proposed.For the embedding process of quantum watermarking,at first,the position and color of pixels in watermark image were scrambled by the controlled-not gates,and then,the scrambled watermark with2n?2n image size and24color qubits(8qubits per channel)was expanded to an image with2n+1?2n+2image size and3color qubits(1qubit per channel).Finally,the color value of the expanded watermark image was added to the lowest qubit of color value of the carrier image sized2n+1?2n+2by modulo2additions.The watermark was extracted from the watermarked image by applying operations in the reverse order.The experimental results show that the proposed method is superior to the contrast method in terms of four items:visual quality,robustness performance under noises,scrambling effect of watermark image,and computational complexity.