Research On Digital Image Encryption Based On Chaotic System

In the information age,computer technology with the rapid development needs are high-speed development,information has become the pronoun of current era,information is a kind of resources,are bringing convenience for people's life.People to express information,such as image information and video information,text information and voice information,and the contemporary mainstream information carrier,image,will naturally become widely accepted modern life as well as the important way to express information;Mainly because of image information can give a person intuitive,image,vivid characteristics of information is closely related to us,so how to ensure the security of digital image has become a focus of concern,in today's modern,image encryption is more and more play an important role;It is the image encryption to protect important scheme of image information,so the image password system has value and practical significance。Based on chaos theory and characteristics,the thesis first analyzes the performance of digital image encryption algorithms based on scrambling or diffusion-only algorithms.Then,based on the theory of this thesis,a new digital image encryption scheme is designed.The main work of this paper includes the following two aspects.1.digital image encryption scheme based on bit-plane decompositionFor the digital image encryption schemes mentioned in the literature,there are 2 shortages in this scheme: 1)Arnold transforms with four different parameters are used to perform the scrambling operation on bit planes,and this transform operation is a point-level transform operation.,And with periodicity;In other words,as long as the number of Arnold cycles,or reverse the same number of times,the ciphertext image can be restored to the original image,and then the ciphertext image deciphered;2)With the same key,two small differences The difference between the two ciphertexts obtained by the plaintext encryption is very small.In this paper,a new bit-plane-based digital image encryption algorithm is proposed to improve the security of the algorithm.The security of the algorithm is verified by various security parameters of image encryption.2.Digital encoding scheme for DNA encodingThere are some deficiencies in some DNA encoding encryption algorithms,such as: 1)There is a single DNA encoding scheme,but only pay attention to improving the dimension and complexity of the chaotic system,and there is no further improvement in the encryption structure;2)The existence of a single chaotic system,while some The inherent characteristics of chaotic systems,such as: low key parameters,periodicity,etc.,result in low security of the image cryptosystem;3)given the same key,can not restore the ciphertext generated by the encryption system with the decryption system;4)a single DNA The encoding method can select the specific plaintext attack and the logic of the logic relationship between the functions.This kind of method may not need to use the key to crack the encryption system to obtain the original plaintext image.In view of the above-mentioned defects,this paper proposes a better digital image encryption algorithm based on DNA coding scheme with better security performance,and validates the security of the algorithm through various types of image encryption security performance parameters.