Research On Image Encryption Algorithm Based On Chaotic Mapping

Since the 21st century,the rapid development of the Internet has ushered in a new era of global economy,culture,military,education and other fields.In the new era people can easily realize the transmission of image information,however,these digital images may involve personal privacy or confidential information,once leaked,may cause incalculable consequences.The most common way to protect the security of image information is image encryption.Since chaos theory was first applied to the encryption system,many researchers of image encryption algorithms have proposed many algorithms with high security and practical application value.The main research content of this paper is to improve the existing chaotic mapping and design two image encryption algorithm by combining with DNA computation with high memory density and high parallelism:(1)In this paper,aiming at the shortcomings of the classical one-dimensional Logistic mapping,a two-dimensional Logistic mapping of real-time changed based on the y parameter controls the x parameter is proposed.In this algorithm,firstly,we use Arnold algorithm to scramble the image.Then use the improved two-dimensional Logistic chaotic map to generate random sequence {x},and take k1～k2 bits after the decimal point as the chaotic sequence for diffusion operation.After that,perform xor operation on the scrambled image to achieve diffusion.Finally,the ciphertext image is obtained.We have carried out simulation experiments on the encryption scheme,and analyzed its performance from many aspects.All the results show that the algorithm has good security performance and is competitive with other algorithms.(2)This paper presents an algorithm for color image encryption at the bit-level based on DNA computation and double chaotic system.In this algorithm,firstly,we extract the gray image of R,G and B components of the color plaintext image,and then use Arnold algorithm to scramble them respectively.The number of iterations is determined by their respective pixel averages.Then,the improved Lorenz chaotic map and Rossler hyperchaotic map are used to form a double chaotic system and generate three sets of chaotic sequences.After that,the scrambled images and chaotic sequences are transformed into DNA sequences according to 8 DNA coding rules,and then perform addition,subtraction,or xor operations on them respectively to achieve image diffusion.Finally,the three groups of diffused images were restored to pixel level and merged to obtain the final color ciphertext image.We also carried out simulation experiments on the proposed encryption scheme and tested its performance in detail.Experimental results show that the algorithm has good security,can resist all kinds of attacks effectively and has certain competitiveness and practicability.