Study On Digital Image Encryption And Information Hiding Algorithm Based On Chaos

Nowadays, with the development of Computer communication and Internet technology, multi-media information is widely used. Thus, the information security has become increasingly important, especially the copyright protection of digital products. Chaotic cryptography is considered to be an effective method to solve those problems.First, the multi-media information has a larger quantity of data and higher redundancy than the normal text data. And it will cost plenty of times and computing resources by using the traditional cryptography to encrypt the multi-media information. Second, the traditional encryption theory can only protect those encrypted digital products; thus, the copyright cannot be protected effectively. The information hiding is a technique protecting the secret information which is hided in the ordinary information from being stolen or destructed by illegals in the information transmission process. This paper is going to analyze and design a digital image encryption algorithm and a hiding information algorithm by using the chaotic system. The main research work is summarized as follows:Firstly, we are going to introduce the background of the data-encryption and the data-hiding technique, their application areas and their development in current times. Expounding the concept and characteristics of information hiding and digital watermark and putting forward the requirement of robust watermark algorithm as well. At the same time, we also introduce the chaotic system's application of its concept, characteristic in the digital image processing.Secondly, we propose a digital image encryption algorithm which is based on three-dimensional chaotic system by combining the technology of chaotic system and the three-dimension matrix. Taking advantage of the effectively combination of the DPP model and the three-dimensional chaotic system, we are going to combine the permutation and diffusion to encrypt the image. Finally, simulation results show the performance of algorithm and the advantages of three-dimensional chaotic system in digital image encryption.Finally, by focusing on the three-dimensional chaotic system, we propose a digital image robust watermarking algorithm based on discrete wavelet transformation (DWT) and discrete cosine transformation (DCT). According to the size of watermark the embedding positions are partitioned into blocks. The watermark algorithm, on the premise of keeping invisibility, strengthens its robustness. Through the experimental comparative analysis, it shows that the algorithms have practical significance.The last part of the paper summarizes and gives a simple explanation to the innovation, the inadequacy of the issues, also the need for further research.