Some Digital Image Scrambling Algorithms And Related Theoretical Research

Due to the fast updating speed of network technology,video and images have been generally disseminated.The images are widely employed in social media and how to protect the privacy information contained in them has become the focus of research.Because some of the properties inherent in digital images,such as the amount of data compared to text,are hundreds or thousands of times;Pixels in the same region show extremely high correlation;As the image contains more information,it also leads to the existence of a large number of data redundancy.These make the traditional encryption scheme is not suitable for images.We need to improve the efficiency of image scrambling,but at the same time keep the data privacy.Therefore,a new class of lightweight encryption schemes is needed.Digital image scrambling technology is one of the most important image encryption methods.Digital image scrambling technology is based on cryptography and integrates other advanced methods to encrypt the image information,so as to protect it from the attack and decoding by the enemy during the network transmission.In this paper,three digital image scrambling algorithms are designed.Simulation experiments and cryptography analysis show that these algorithms can effectively resist the existing attack means and ensure the security of image information.This paper mainly studies the following contents:1.An image encryption scheme based on double chaotic cyclic shift and Josephus problem is designed.The improved Logistic mapping and Standard mapping are used in this algorithm.In the permutation phase,the cyclic shift of pixels is improved to improve the efficiency of confusion.In the diffusion stage,Josephus problem is used to change the gray value of the pixel while the pixel is transferred.Finally,the security analysis shows the feasibility of the algorithm,and the superiority of the algorithm is proved by comparing with other advanced algorithms.2.A color image encryption scheme based on the CRT and chaotic sequence is designed.This scheme makes use of the pseudo-randomness of Logistic to improve the security of the scrambling scheme,and combines with the Chinese residual theorem to process the RGB channel of color images to improve the encryption efficiency of the scheme.Through the comparison and analysis of simulation results,the reliability and efficiency of the algorithm are verified.3.An image scrambling algorithm based on bit-plane Arnold transformation and tensor expansion is designed.The algorithm transforms image matrix into tensor for processing through bit-plane decomposition of the image.The position transformation of the segmented image is carried out by taking advantage of the Arnold transformation's fast permutation speed.Then the pixel bits are diffused according to the modulus expansion of the tensor to obtain the final encrypted image.The simulation results of gray image and color image show that the proposed algorithm is safe and feasible.