Watermarkingwith both obliviousdetection and high robustness capabilities is still a challenging problem. The existing methods are either robust or oblivious, but it is di cult to achieve both goals simultaneously. In this paper, we tackle the above-mentioned problem. Our basic design methodology is to exploit prior knowledge available at the detector side and then use it to design a \non-blind" embedder. We prove that the proposed scheme can resist two famous denoising-based attacks, which have successfully cracked many existing watermarking schemes. False negative and false positive analyses are conducted to verify the performance of our scheme. The experimental results show that the new method is indeed powerful.