Multiple-image encryption by using robust chaotic map in wavelet transform domain

Abstract

With the superiority of capacity space in storage and transmission, multiple-image encryption has become the new focus of information security technology. In this paper, we introduce a multiple-image encryption scheme by using robust chaotic map in wavelet domain, based on the architecture of unified permutation and separate diffusion. Firstly, the original images are decomposed using discrete wavelet transform (DWT) and the low-frequency components are reassembled as the plain image (approximate image). Then, the plain image is entirely scrambled by using Arnold cat map. Thirdly, the scrambled image is further decomposed and the resulted block images are separately employed to combine with the amplitude parameter of robust chaotic map (RCM) to generate key stream in each diffusion process. Since the keys in every diffusion process depend on the plain image and each encrypted block image contains aliased information of multiple images, it is difficult for the intruder to decipher the intercepted encrypted information. Numerical simulations are made to further demonstrate the reliability of the encryption scheme.