A Ridgelet Based Symmetric Multiple Image Encryption in Wavelet Domain Using Chaotic Key Image

Abstract

In this paper, a novel symmetric multiple image encryption algorithm is proposed. The scheme exploits the features of discrete wavelet transform, finite ridgelet transform and chaotic maps in a way to achieve completely distorted and meaningless single encrypted image which secretly contains the information of the original images. The four original images are first transformed in wavelet domain followed by the finite ridgelet transformations of their HH bands to get two combined transformed matrices. This on pixel values rotation using chaotic key image, mixing and then their shuffling using random sequences results into a final encrypted image. The piece-wise linear chaotic map and 2D gingerbreadman chaotic map are utilized to generate the chaotic key image and shuffling sequences, respectively. The encrypted image is highly distorted and meaningless for a casual observer. The mean square error between the pairs of decrypted and original images is less than 0.004. Moreover, the experimental results and simulation analyses show that the scheme has the advantage of low correlation factor, high key sensitivity and large key space.KeywordsMultiple image encryptiondiscrete wavelet transformfinite ridgelet transformpiecewise linear chaotic mapgingerbreadman chaotic map