Abstract: A lossless scheme of a binary image watermark based on wavelet transform is proposed. Because no distortions are introduced into the original image, the contradiction between the transparency and the robustness is solved. Moreover, with introducing digital signature and digital timestamp into the watermarking scheme, One can use the public keys to extract the watermark without the involvement of the owner. Experimentalresults show our algorithm is strong enough to resist common image processing and geometric distortions.

Key words: copyright protection, digital watermarking, wavelet transform, digital signature, digital timestamp