An asymmetric watermarking system with many embedding watermarks corresponding to one detection watermark

In this letter, we propose a new asymmetric watermarking system which can accommodate many embedding watermarks but needs only one reference watermark for detection. Such a system is useful in averting attacks that seek to estimate the embedding watermark. In the proposed system, the phase of the reference watermark is shifted randomly (clockwise or counterclockwise) in the discrete Fourier transform domain to make embedding watermarks. They are correlated with one another and have the same correlation with the reference one. We also address how to select the design parameters.