Image Scrambling Algorithm Based On Chaotic Mapping

The popularization and breakthroughs of multimedia technology bring about the problem of multimedia information security.As one of the important means of fast and efficient digital multimedia encryption to ensure information security,digital image scrambling has been paid more and more attention by researchers both at home and abroad,and many new methods and ideas are produced.In this dissertation,we take the digital image as the research object,and discuss the new method and new technology of image scrambling based on chaotic sequence and related theories.(1)The basic knowledge of digital image scrambling and chaos theory is discussed and analyzed.The definition,classification and widely-used algorithms of digital image scrambling are discussed.On the other hand,the chaotic sequence and related theories are deeply analyzed.Especially several chaotic mapping methods,such as Logistic mapping,are discussed and the chaotic sequence is briefly summarized.Finally,some recent progress and achievements of image scrambling technology are summarized.(2)Aiming at the mode of image scrambling based on image pixel position transformation,a color image scrambling algorithm based on Logistic chaotic sequence is proposed.The algorithm first generates a Logistic chaotic sequence based on a non-periodic transformation according to the specific key.Then,the sequence is transform to two-dimension matrix to obtain the new location of the pixels of the three color components of the color image.Finally,the three component matrices of the color images are scrambled according to the corresponding position of the chaotic 2D sequence.When scrambling is restored,the corresponding chaotic sequence is generated according to the same key,and the location information is generated in terms of the inverse process of scrambling,so as to restore the original image.Experimental results show that the performance of scrambling images is better,and the visual effect is much better than the existing image scrambling methods.(3)A color image scrambling algorithm based on Lorenz chaotic sequence is proposed.The algorithm first generates a Lorenz chaotic sequence of a non-periodic transformation based on a specific key,and then makes a two-dimensional image of the chaotic sequence of the three color components of the color image.Finally,the three component matrix of the color image is scrambled according to the corresponding position of the chaotic sequence.When scrambling is restored,the corresponding chaotic sequence is generated according to different keys,and the location information is generated according to the inverse process of scrambling,so as to restore the original image.The experimental results show that the scrambling image has better visual effect,which is significantly better than the existing image scrambling methods.