Research And Application Of Chaotic Map In Image Encryption

With the rapid development of technology and the application of big data,5G and other emerging technologies,nowadays society is undergoing rapid changes.The commercialization of 5G in 2019 marks the official entry of China into the 5G era.In the 5G era,people are increasingly relying on network communication,enjoying the unprecedented convenience brought by 5G.However,at the same time,as all kinds of information are basically transmitted in open channels,there may be illegal behaviors that threaten the security of plaintext information,such as illegal interception and information tampering.As a major carrier of information transmission in nowadays society,image is widely used in various fields of society.Therefore,its security is worthy of attention.Among many means of protection,image encryption is one of the most basic methods.Since the image has the characteristics of high redundancy and strong correlation,the existing traditional encryption algorithm is no longer applicable to it.With the discovery of chaotic map,it has been found to have initial value sensitivity,pseudo random and other characteristics,which makes it very consistent with the image encryption requirements.Therefore,chaotic image encryption has gradually become an important research direction in the field of image encryption.With the continuous development of chaotic image encryption,many algorithms have been proposed by scholars,but there are some shortcomings.Therefore,how to improve the existing algorithm or propose better algorithms becomes a top priority.On the basis of relevant research results,this paper proposes two image encryption algorithms,and carries out MATLAB simulation and relevant security analysis.One is a dual image cross mixed encryption algorithm based on chaotic system.In the process of initial value generation of chaotic map,the algorithm introduces the hash value of plaintext image,and improves the excellence of hash value through cross mixing transformation of these two hash values,and then generates the final initial value of chaotic map.Then,two plaintext images are merged,and the merged images are forwardly diffused,scrambled and backward diffused by using chaotic sequence.The advantage of this method is that the plaintext information of each other can be introduced into the respective ciphertext images,which increases the security of the algorithm.Finally,the algorithm was simulated by MATLAB software.The simulation results show that the algorithm has a key space of 691.0995?10 and can effectively resist brute force cracking.The ciphertext information entropy is 7.9983,and the ciphertext NPCR and UACI are 99.5837 and 33.4501,respectively.The values of the above three are very close to the theoretical values,which can effectively resist statistical analysis attacks and differential attacks.Therefore,it can be known from the simulation results that the algorithm has good security and good encryption effect,and can effectively ensure the security of plaintext images.The other is image encryption algorithm based on chaotic map and dynamic DNA sequence.The algorithm first decomposes the plaintext image into bit-plane images,then generates a scrambling sequence using the one-dimensional Logistic chaotic map and the hash values of each bit-plane image,and uses scrambling sequences to scramble the bit-plane respectively.Then,the bit plane is merged,and three chaotic sequences are generated by using Chen chaotic map and the hash value of the merged image,which are respectively used to determine the dynamic encoding and decoding rules of each line of the image and the DNA logic operation rules,and finally the ciphertext image is generated.Finally,the algorithm is simulated using MATLAB software.The results show that the algorithm has a key space of 9010 and can effectively resist exhaustive attacks;the ciphertext information entropy is 7.9989,and the ciphertext NPCR and UACI are 99.6048 and 33.4451,respectively These values are very close to the theoretical values,indicating that they can effectively resist statistical analysis attacks and differential attacks.Therefore,combined with the simulation results,it shows that the algorithm has good security,can effectively encrypt the plaintext image,and makes up for the shortcomings of the existing algorithms that depart from the plaintext encryption and the single encoding and decoding rules.