A lot of digital watermarking techniques have been proposed to resolve the issues of copyright protection. However, almost proposed watermarking methods keep the watermarking algorithm private to ensure the embedded watermark secret. If the watermarking technique needs to be widespread applied to realistic multimedia environment, the algorithm used by watermarking techniques should be public. In this paper, a novel watermarking scheme which can be public is presented. The proposed watermarking technique is developed based on the following criterions: (1) the watermarking algorithm is open; (2) the embedded watermark can be extracted and embedded by the people who own the secret key. The watermarking scheme employs the advance encryption standard (AES) and the Reed-Solomon code, to make the watermarking algorithm public. Simulation shows that the proposed algorithm can be very robust to resolve the ownership of the digital image.