Digital Image Encryption Research Based on DWT and Chaos

In this paper, a digital image watermark algorithm based on discrete wavelet transform and chaos theory is referred. During the embedding of the watermarking, discrete wavelet transform is done firstly and extract low frequency part as the embedding field; then the chaotic sequence is used to encrypt the watermark and transform the encrypted part and extract the low frequency; finally, embed the low frequency part into that of the original image. It is a kind of non-blind detection as the extracting needs original image. The similar coefficient NC and peak noise to signal ration (PNSR) are used to evaluate the algorithm. The experiment results indicate that this algorithm can resist JPEG compression, noise attack, filter and so on. The effect of watermark image is very well.