Digital Image Encryption Based On Wavelet And Chaos Theory To Study

With the development of digital technology, computer science, communication and network, image data transformation services are widely launched and applied. Meanwhile, there are new challenges in image information industry, such as torts, pirate, juggle and spread abroad. So image encryption is concerned by many people. But the traditional information security technology and encryption theory can't solve the problem of digital product copyright protection. In this case, digital watermarking is an effective way to solve these problems and has become key study in this field.In this paper, I expound the digital watermarking technology development, status and expectation first; and I studied the basic concepts, theories and main knowledge of the digital watermarking technology, wavelet analyze and chaos theory, then the research aspect of this dissertation has been proposed.Base on the reserch above, 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 embedded 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.In order to test the effect of this algorithm,I have done a lot of experiments. The correlation coefficient NC and peak noise to signal ration PNSR are used to evaluate the algorithm.. Experimental results show that the proposed algorithm keeps thequality of the image well and is robust enough to JPEG compression, noise,filtering,image scaling and cropping etc.