A novel gray scale image encryption scheme based on pixels’ swapping operations

Abstract

Design principles for image encryption schemes abound in the literature. Among these schemes, few were built upon the philosophy of swapping of the pixels in the given input image. Swapping is a very straightforward and a naive approach for image scrambling. We believe that fuller potential of swapping has not been realized yet. In this work, a novel image encryption scheme is being presented through the swapping of pixel values of the given gray scale input image. The 5D multi-wing hyperchaotic system rendering five key streams of random numbers have been used in the proposed cipher. After the gray scale image is input, its pixels are swapped randomly. The random numbers given through the first two key streams jointly determine the address of the first pixel to be swapped with the second pixel whose address is determined by the random numbers given through the third and fourth key streams. In this way, the pixels of the given image are swapped abundantly. The selection of both the pixels for swapping is purely arbitrary and random in character having no restriction of linearity and sequentiality as was done by other schemes previously. To create the diffusion effects, an XOR operation is carried out between this scrambled image and the key image formed through the fifth stream of random numbers given by the chaotic system. SHA-384 hash codes have been used in the proposed scheme to embed the plaintext sensitivity. The simulation and the extensive security analyses carried out at the end expressly portray the good security effects and the potential for the real world application of the reported scheme.