Lossless Image Encryption Algorithms Based On Chaotic System

With the rapid development of 5G networks today,the demand for processing and transmission of digital information have become more frequent.Massive amounts of data have to be transmitted in an open network environment,which undoubtedly increases the security risks of user information.Image information is widely used in scenarios where users exchange in batches due to its intuitive and specific characteristics.In order to ensure the safe transmission of images information,the most direct and effective way is to encrypt the image information before transmission.Chaotic systems have received wide attention in the field of image encryption due to their sensitivity to initial values and good pseudo-randomness.However,some chaosbased image encryption algorithms have low sensitivity and poor security.Therefore,fused with DNA mutation and semi-tensor product theory respectively,and two chaosbased lossless image encryption algorithms are constructed in the dissertation.The specific research works are as follows:A lossless image encryption scheme based on compound chaotic system and DNA molecular mutation theory is proposed.This scheme realizes the encryption in the image blocks with three chaotic systems.With the help of the random characteristics of the chaotic sequences,the rectangular-ambulatory-plane cyclic shift operation is performed in the image block,and two chaotic blocks are allocated on each block for bidirectional random confusion to enhance the randomness of image pixels.A closedloop diffusion strategy is adopted in and between image blocks to form a self-feedback system.Subsequently,the image block is dynamically encoded into a DNA matrix,and two dynamic DNA molecular mutation methods are used to further destroy the characteristics of the matrix block.The final ciphertext image is obtained after DNA decoding.In addition,the proposed algorithm possesses a large key space and the keys are highly related with the plaintext image.Experimental results demonstrate that the suggested image encryption strategy is practicable and has strong ability against common attacks,such as noise attack and cropping attack.A lossless image encryption algorithm based on chaotic system and semi-tensor product theory is proposed.First,a matrix is constructed from the sequence obtained by iterating the Logistic-Tent chaotic map,and a semi-tensor product operation is performed on the matrix and the plaintext image to obtain a semi-ciphertext matrix.Then,the random interpolations are inserted into the semi-ciphertext matrix and the four-way diffusion process is performed on it,the implant position is calculated from the plaintext image.Finally,the image is converted into three planes of equal size through octal conversion,and the sequence generated by the two-dimensional LogisticSine-coupling is used to control the step length of Josephs scrambling to complete the confusion of each plane pixels.These planes are combined to obtain the final ciphertext image.In addition,the position selection of the chaotic sequence in this scheme is associated with the plaintext image,which not only boosts the algorithm security,but also solves the time-consuming problem of multiple iterations when building chaotic sequences.The simulation results and security analyses verify the algorithm has high security and strong robustness.