Design And Implementation Of Discrete Chaotic Maps Digital Image Encryption Algorithm

With the growing popularity of the Internet interaction,more and more information began to spread on the Internet,such as text information,image information and video information,etc.,therefore,how to ensure the Internet information is not being stolen in the process of interaction,such as leaks,tampering with became a hot topic,however,the image as an information carrier,image information security has also been concern.In this paper,three encryption algorithms are designed by studying chaos theory and cryptography.The first algorithm is using pseudo randomness,ergodicity of chaotic system such as peculiar features,this paper proposes a new image block encryption scheme based on double chaos mapping,the method is to use Chebyshev maps with Henon mapping structure pseudo random sequence generator,two-dimensional random sequence key generated flow,using the Chebyshev maps generated key stream encrypt plaintext image confusion,then the encrypted image is divided into two blocks with the same size,by Henon map key pixel values of two sub-block diffusion encryption,achieve finally encryption effect.The simulation results show that the algorithm can effectively resist differential attack,exhaustive attack and other types of attacks,and has strong sensitivity and security.The second algorithm puts forward a new kind of double chaos mapping a true color image encryption scheme,a secret key encryption system,including the external and internal keys,external key is for natural sampling noise to get true random number,internal key SHA-512 hash hash function is used to calculate plaintext image hash value,through the conversion algorithm combined the two initial value and generate chaos mapping parameters,generate the initial value and parameter of each round only used once to form a dense,Logistic-control-logistic map is used to construct a sequence generator to generate a one-time key stream and scramble the plain-text image.Secondly,the one-time key stream generated by Chebyshev mapping is used to encrypt the plaintext image by bit xor diffusion.Finally,thesimulation results show that the algorithm can resist differential attack and exhaustive attack.In order to improve the security of color images,a new chaotic map based on dynamic parameter control system was proposed.First,the initial key is obtained by hashing hash value of plain-text image,which makes it have strong plain-text correlation,and 9 new chaotic maps are substituted for repeated iteration to generate 9completely different random key flows.Secondly,to extract the color clear image of RGB color component,and the three different color component grouping of gray image segmentation,then system random calls to different key flow separately for each image block pixel position scrambling encryption,and finally,using the add avalanche effect of bitwise xor encryption mode for the second round of diffusion encryption.The result of the algorithm is that the color plaintext image is encrypted into a meaningless random noise image,and the data simulation proves that the algorithm has a strong security and can effectively resist various attack types such as exhaustive attack,differential attack and plaintext attack.