Abstract: In medical,military,financial systems and other scenarios where important images need to be transmitted,image compression and encryption is a feasible and effective way to transmit images safely and efficiently.Image compression and transmission can reduce the transmission overhead.Compressed images can be encrypted to make images more secure,and ordinary people can not get key information from them.After encryption,it can also resist some attacks means to ensure the security of information.Based on the compression perception theory,sparse sampling can be completed,and images can be compressed to any scale.Hyperchaotic system can guarantee the security of the system.Chaotic characteristics such as Lyapunov exponents of hyperchao-tic system are also analyzed.It is proved that the system is chaotic and safe enough.Chaotic sequences generated by hyperchaotic system are also used to construct measurement matrix.This eliminates the need to transfer a matrix with large text during transmission,but only the key.On the basis of compression theory,scrambling diffusion operation is also used,and diffusion operation related to plain text is used,which greatly improves image security and ensures data security.Experiments show that the image is compressed and encrypted well,the key space is large,the key is sensitive enough,the cipher histogram is distributed evenly,the cipher information entropy is close to the theoretical value,and the correlation between cipher images is low,which shows that it can resist many common attacks such as violent attacks and statistical attacks.At the same time,the decrypted image restored under normal compression ratio has a small visual gap with the original image,even if the compression ratio is small,most of the information content of the image can be seen,which indicates that the algorithm has a good reconstruction quality and high security.

Key words: Chaotic system, Compressed sensing, Compression encryption, Visual safety, Image security