Research On Image Encryption And Compressed Sensing Technology Based On The Characteristics Of Chaotic Cryptography

With the continuous improvement of people's requirements for the security and effectiveness of information transmission,it is urgent to improve the amount of information transmission and the efficiency of information transmission on the basis of existing hardware conditions,and to improve the security of encryption algorithm as much as possible.As a common information carrier,image has the characteristics of strong correlation and high redundancy.However,the traditional encryption method is not suitable for image encryption,so we need to find a new encryption algorithm,and make it both security and computing speed requirements.Compressed Sensing as a technology which can carry out data sampling and compression at a rate far lower than Nyquist,has been widely concerned.Through this technology,the transmission efficiency of information can be effectively improved.However,the security of using traditional compressed sensing framework to encrypt information is not strong,and the initial value sensitivity,ergodic property and pseudo-randomness of chaos theory are consistent with the requirements of cryptography.Therefore,since chaos theory was used as image encryption in the last century,the technology of using chaos to encrypt image has been rapidly developed.Combined with chaotic system,this dissertation aims to design an image encryption algorithm with high efficiency and high security by using the compressed sensing framework,so as to solve the problems of weak security in the traditional compressed sensing framework and low computational efficiency in the general image encryption algorithm.At the same time,a flexible digital logic circuit is used in this study,which can provide a certain theoretical basis for the hardware implementation of encryption algorithm.The main research contents of this thesis are as follows:(1)In this dissertation,a parallel transmission encryption and decryption scheme is designed.The purpose of this scheme is to effectively improve the calculation rate of compressed sensing algorithm.Through Matlab simulation,it is verified whether the algorithm can realize the process of image encryption and decryption,and the required time of this algorithm is compared with other non-parallel encryption algorithms.(2)On the basis of parallel algorithm,this dissertation proposes a parallel compressed sensing image encryption algorithm based on chaotic signal.In the key part of the algorithm,this paper designs a sequence signal generator based on logic circuit,which adjusts the chaotic system by using the binary signal generated by it.Experiments were carried out to verify the security and transmission speed of the proposed algorithm,and the reconstruction effect of the proposed algorithm was analyzed.(3)Based on the above algorithm,the image polluted by noise is studied.An algorithm is designed to encrypt,decrypt and denoise noisy images.At the same time,this dissertation also makes an in-depth analysis of the encryption and decryption of mixed images,and designs an algorithm that can realize the encryption and decryption of mixed images and image separation.Matlab is used to complete the feasibility verification of the above encryption scheme,and the reliability of encryption security and decryption is analyzed.