A novel third party's double watermarking scheme reject to malice attack

A novel third party's double watermarking scheme is presented in this paper. In this scheme, the third party employs the double watermark technique to embed and detect watermark, while timestamp and users' secret keys or authorization codes can be added into this process. Analysis work indicates that the new scheme confines the preconditions of malice attack employed by pirates, and guarantees the security in application protocol when compared with the traditional watermarking system. Based on the requirements for double watermark algorithm in this scheme, a new double watermark algorithm of still digital image is provided. Simulation experiments reveal that the third party's double watermark algorithm has benign robustness to reject general image operations, which benefits to provide accurate and reliable detecting results of timestamp and ownership for the scheme applied in digital image.