Chaotic Image Encryption Algorithm Based on Wavelet Transform

Abstract

Image encryption algorithm based on the chaotic system has the characteristics of large key space, sensitive initial value, and fast encryption speed, so it has become an important research object in the field of image encryption. To improve the ability of current chaotic image encryption algorithms to resist selective plaintext attacks and to reduce the burden of public network transmission, an image encryption algorithm based on wavelet transform and chaotic system is proposed. The wavelet transform is first applied to the image, the low-frequency sub-band image is extracted, and then the low-frequency sub-band image is scrambled using ZigZag coding. The new chaotic sequence is then cyclically shifted with the Chebychev chaotic sequence to obtain the encrypted image. The obtained encrypted images are subjected to grayscale histogram, adjacent pixel correlation, information entropy, and anti-noise detection. The obtained results are closer to the theoretical values than the values in the references, and the algorithm is proven to have a good encryption effect.