On the protection and authentication of digital image based on wavelet transformation

A wavelet based watermarking algorithm for digital image protection is proposed in this paper. Different from the traditional watermarking algorithms, in this algorithm the watermark is not embedded into the source image, but father, used to derive a secret key. The secret key is generated by mixing-up the image features and the watermark kept by the rightful owner. Signification coefficients of the image after digital wavelet transformation are adopted for feature selection. The major merit of this algorithm is that the host image will not be degraded for protection purpose and the algorithm is robust against various attacks, such as image compressing, blurring and cropping. Experimental results show the effectiveness and robustness of this algorithm.