Research on Image Encryption Algorithm Based on Wavelet Transform and Qi Hyperchaos

Abstract

In this paper, the Wavelet transform is used to decompose the image into low-frequency components, horizontal components, vertical components, and diagonal components. Then, the low-frequency components are scrambled by constructing index sequences, obtaining the scrambled image by wavelet reconstruction. The chaotic sequence generated by the logistic chaotic system is used to encrypt the scrambled image, and then multiple sequences generated by Qi hyperchaos are used for the second encryption of images. The decryption process is the inverse of encryption. The encryption scheme is simulated on MATLAB, and the security analysis is carried out by key space, key sensitivity, histogram, information entropy, pixel correlation, etc., and compared with other algorithms, it is concluded that the algorithm can be applied to images encryption.