Research On Chaotic Image Encryption Based On One-time Pad And Region Partition

With the application of big data,cloud computing and artificial intelligence,the information security of cyberspace faces many threats,and information security technology is gradually being valued by the public.Due to the development and sharing characteristics of the network,it poses a great security risk when communicating.Among them,the image as an important carrier of information transmission,its security features and confidentiality in the transmission process are also gradually taken seriously.As a new type of cryptography,chaos is applied to image encryption because its unique characteristics such as initial condition sensitivity,pseudo-random characteristics,ergodicity and cryptography are similar.In this paper,the author designs a new image encryption algorithm structure by improving chaotic system,combining content perception and polymorphism,and proposes three chaotic image encryption algorithms with better security performance:(1)A chaotic-based image encryption algorithm that divides pictures into key information and non-key information and then encrypts them separately is proposed.Specifically,using the RSA algorithm,combined with the plaintext size information,the initial value of the improved CML system is calculated,and the initial values and control parameters of the logistics map and the Chebyshev polynomial are also calculated.Key;extract key information in the picture and extract key information,and spread and scramble different parameters for non-critical information and key information;use CML system and sorting function in scrambling step,from diffusion to scrambling The method is encrypted.The simulation results and security analysis show that the privacy encryption algorithm based on the improved chaotic system has large key space,good key sensitivity and sensitivity to plaintext images,and can resist common attack methods.(2)A new color image encryption algorithm based on polymorphism CML is proposed,which is embodied in this paper: a diffusion matrix is extended in this paper;and a new pixel replacement method is proposed,using Huffman function.Replace the gray value and make up 0 in the high position;use the idea of polymorphism to select the space-time chaotic system,make the random sequence more diversified,and normalize the sequence,aura pseudo The randomness effect is better;the simulation results and security analysis show that the image encryption algorithm based on polymorphic CML mapping has large key space,good key sensitivity and sensitivity to plaintext images,and can resist common attack methods.(3)A new one-time chaotic image encryption algorithm is proposed,which uses the hash function to carry out the idea of multiple mixing and one-time secret.Specifically,this paper combines the SHA256 and SHA512 hash algorithms to combine with each other,and combines with the chaotic sequence to calculate the initial value and the logistic map of the plaintext position information to generate the reference sequence of the image scrambling stage;The column function is irreversible,resulting in an improvement to the phenomenon that cannot be decrypted when using plaintext information,and using the hash value to calculate the initial value sequence required for the logistics map.The simulation results and security analysis show that the image encryption algorithm based on multiple hash function and one-time-one secret has large key space,good key sensitivity and sensitivity to plaintext images,and can resist common attack methods.