Visually Secure Image Encryption Algorithm Based On Chaotic System And Compressed Sensing

In recent years,with the rapid development of computers and the Internet,the information transmission is becoming more and more convenient.Multimedia information has been spread and used more and more on the Internet platform.Among them,as a main information carrier,digital images,which is intuitive and vivid,is widely used on the network,but security incidents such as information leakage frequently occur when information is transmitted in a completely open environment.The most effective way to protect image information security is to encrypt the image.However,the current image encryption methods are to encrypt the plain image into a cipher image similar to noise or texture,which is easy to attract the attention of hackers and then be attacked with emphasis in the process of transmission or storage.Therefore,how to design a visually secure image encryption algorithm,that is,the obtained cipher image is not disorderly,and visually meaningful,which can guarantee the data security and visual security of information at the same time has become a research hotspot and has high research value.Chaotic system,which has good performances of internal randomness,sensitivity to initial values and parameters,ergodicity and so on,is widely used in image encryption.In the case of limited transmission bandwidth and storage space,it is often necessary to compress and then transfer and store the image.Compressed sensing can compress and encrypt images at the same time,which starts to be used in the field of image encryption.Based on chaotic system and compressed sensing,this paper proposes three visually secure image encryption algorithms.The main work is as follows:(1)A visually secure image encryption algorithm based on compressed sensing and three-dimensional cat map is proposed.First,the plain image P is converted into sparse coefficients by using a two-dimensional discrete wavelet transform(2-D DWT),and using the measurement matrix generated by the three-dimensional cat map to encrypt the scrambled matrix into a cipher image F.Then,the cipher image F is embedded in the carrier image R according to the method of embedding the least significant bit(LSB),and finally the visually secure cipher image E is obtained.The algorithm can simultaneously achieve image data security and image appearance security,and the cipher image and the plain image are equal in size,and additional transmission bandwidth and storage space are not required.Both the simulation results and performance analysis have proved the good encryption performance of the proposed encryption scheme.(2)A visually secure multi-pair color image encryption algorithm based on two-dimensional compressed sensing(2-D CS)is proposed.First,the R,G,and B color components of the two color plain images are dispersed by using 2-D DWT,then the two-dimensional compression measurement,scrambling,and quantization operations are performed on the sparse coefficient matrix.Then,DWT operation is performed on the carrier image to obtain high frequency bands LH and HL,and the quantized matrix is randomly embedded in the high frequency band,and finally a visually secure ciphertext image is obtained.The key parameters related to the plain are embedded in the carrier image and transmitted to the receiver along with the cipher image.In the case of large-scale image encryption,not only the two images are simultaneously encrypted,but also the transmission bandwidth and storage space are saved.Simulation results verify the effectiveness and security of the encryption algorithm.(3)A visually secure color image encryption algorithm based on compression-scrambling-diffusion multi-embedded scheme is proposed.First,the R,G,and B color components of the color plain image are dispersed,and then the two-dimensional compression measurement,scrambling,quantization,and diffusion operations are performed on the sparse matrix to obtain a diffusion matrix.Then,an integer wavelet transform(IWT)is used to obtain a high frequency band for the color or grayscale carrier image,and the diffused matrix is randomly embedded in the high frequency band,and finally a visually safe color or grayscale ciphertext image is obtained,and the size of the cipher image is less than or equal to the plain image,and additional transmission bandwidth and storage space are not required.In the diffusion operation,the matrix generated by the Logistic chaotic system is processed by the threshold processing method of the local binary mode(LBP)algorithm to obtain the key matrix for diffusion,which improves the randomness of the algorithm.The experimental results verify the effectiveness and security of the algorithm.