Research On Color Image Encryption Schemes Based On Chaotic Systems

Recently,with the increasing development of Internet and information technology,digital image communication has become the common means of information communication,and at the same time digital image information has also been widely applied in every field of society.Compared with text information,digital image information has many characteristics,such as intuitive and vivid,which makes it the most widely used form in the digital information.Thus,the information security has drawn a lot attention.And images encryption is the key technology to solve this problem.Therefore,research on the image encryption has profound theoretical and practical significance.With characteristics of a large amount of data and high adjacent pixels correlation,digital image is encrypted with the traditional method of digital image algorithm,which results in poor performance in encryption speed and encryption effect and makes it impossible to guarantee the security,vulnerable to attack and crack.Because chaotic systems is extremely sensitive to system parameters and initial value,and has the basic characteristics of unstable motion orbit and ergodicity,it can cause ideal effect for digital image encryption.This paper designs and verifies in experiments of three kinds of algorithm of color image encryption based on chaotic systems,in order to improve the security of image encryption algorithm on the basis of the chaotic systems,and with the use of the second order,fourth order and six order chaotic systems,a key and a DNA sequence,which has obtained the good experimental results.The paper is as follows:In the first place,based on the second-order chaotic systems and fractional fourier transform,this paper proposes the first color image encryption algorithm.With the use of global confusion and dummy complex function,the algorithm applies fractional fourier transform to diffuse pixels points.The algorithm simulation show it can resist shear and noise interference,and enhances the security of encryption algorithm.In the second place,based on four order chaotic systems and one-time keys,the paper proposes the second color image encryption algorithm.The algorithm employs one-time keys to increase the randomness of the algorithm;it uses single-wheel diffusion to reduce the complexity of encryption algorithm;algorithm is with a large key space,high key sensitivity,and high safety.Last but not the least,based on six order chaotic systems and DNA sequence,the paper proposes the third color image encryption algorithm.The algorithm introduces DNA coding sequence,implements DNA sequence of addition,subtraction,and XOR operation effectively,and encrypts images through “confusion-diffusion”.Theoretical analysis and simulation experiments show that these three algorithms are with large key space,effective encryption,key high sensitivity,high safety,which can be widely implemented in digital image information communication with security.