Abstract
With rapid growth of multimedia, that how to protect electronic data from attacking becomes an important issue to be considered. And digital watermarking is one scheme to hide copyright marks and information into digital media (such as audio, image and video) for copyright protection. And we need to be sure that the watermark still existed and could be recognized after extracted under compression and malicious attack.In this paper, we implement the method that integrates encryption algorithm to find the positions where watermarks are going to be embedded into. This method is based on Block DWT (discrete wavelet transform) and we embed multi-watermark into Block DWT coefficients except the low frequency bands. And in this paper, we try to use the concept of digital signature to produce our watermark. Finally, we compare the results of experiments under different attacking.