关键词: 数字水印, 几何攻击, 尺度不变特征变换（SIFT）, 参数估计, 零水印

Abstract: In order to achieve the copyright protection of digital image，a universal watermarked image geometric correction and zero-watermarking method is proposed.Firstly，test image rotation and scaling parameters can be estimated by the difference between the stable and the farther SIFT feature point’s coordinates of it and those of the original image.After revising，the test image translation can be corrected by the change of one stable SIFT feature point’s coordinates of it and those of the original image.Then，According to the zero watermark characteristic，the zero-watermarking is constructed by performing the XOR operation on the pixel of watermark with another pixel randomly extracted from the original image.Theoretical analysis and experimental results show that the watermarked image geometric correction algorithm can effectively recover watermark synchronization，so that the watermark can be correctly detected.The zero-watermarking method has a better security performance，and compared with the same class zero watermarking algorithm based on DWT，it has a stronger ability of resisting shear，geometric distortions，image process and signal process attacks.

Key words: digital watermarking, geometric attacks, Scale Invariant Feature Transform（SIFT）, estimate affine factors, zero-watermarking