Image Compression And Encryption Algorithms Based On Chaotic System And Compressive Sensing

The Internet of Everything is becoming a symbol of the development of informatization.As an important information carrier,digital image plays an influential role in message transmission.Images may be stolen by illegal users during the process of storage or transmission,thereby resulting in information contained in images being leaked.Meanwhile,digital images contain a larger amount of data than traditional text information,which places high demands on storage resources and transmission bandwidth.Therefore,it has received significant attention to reduce the amount of data of an image and ensure its security during the process of storage or transmission.Two image compression and encryption algorithms are designed based on compressive sensing and chaotic systems.The main research work is as follows:An image compression and encryption scheme based on secure Hash algorithm and chaotic system is proposed.Pixels of the original image are first rearranged with the Arnold transform to reduce the block effect during image compression.Then the resulting image is encrypted and compressed simultaneously by compressive sensing to decrease the amount of data.The bitwise XOR operation and the pixel coordinate scrambling method controlled by the chaotic system are respectively employed to change the values and the positions of image pixels,which makes the pixels randomly and evenly distributed.In addition,to further improve the security of the scheme,the statistical information of the original image is utilized as the input of SHA-256 to obtain a 256-bit binary sequence,and the initial values of the chaotic systems are calculated with the sequence.The experiment results verify that the scheme is secure and effective and can resist common attacks,including statistical analysis attacks and noise attacks.An optical image compression and encryption algorithm is designed combining DNA sequence operation with RSA algorithm.The Walsh-Hadamard transform and a chaos-based measurement matrix are adopted to measure the original image,which is theoretically similar to the sampling process of the single pixel camera.To reduce the correlation between adjacent pixels,the pixels are rearranged by a pixel scrambling method based on chaotic system.Besides,DNA sequence operations are performed on the scrambled image to change the pixel values of the image and acquire the final encryption image.Moreover,three initial input values and the pixel values of the original image are used to produce the keys of the proposed algorithm,which helps to flexibly control the generation of the keys.Various performance analyses of the proposed algorithm are carried out and it is demonstrated that the optical image compression and encryption algorithm is effective and has high security.