A Novel Technique for Simultaneous Encryption of Multiple Images Using 3D Chaotic Permutation

With the swift increase of digital data exchange and increased usage of digital images, it is important to protect the confidential image data from illegitimate access. Digital image scrambling or encryption is the solution which transforms a meaningful image into a meaningless or disordered image in order to enhance the ability to tackle attack and in turn improve the security. However inherent features of image data such as bulky nature, high redundancy and high correlation among pixels demand the need to treat an image in a different way from text data regarding confidentiality. In this paper a novel scheme is proposed to simultaneously encrypt multiple images in an image database or image folder. Images are stacked and are viewed as a 3D block of images. Permutation of image pixels/blocks across the images is done using 3D chaotic permutation and pixel substitution using three-way grid based noise induction. 2D grid structure projected on each dimension of the 3D block of images defines the scrambling nature of pixels resulting in varied distortion of information. The proposed novel model of perceiving multiple images as 3D block of images and simultaneous scrambling provides an additional level of complexity for unauthorized access. The proposed scheme is more apt for secured storage of images. The experimental results demonstrate that the proposed algorithm can effectively and simultaneously scramble the images, and the security analysis of the algorithm also reveals that the proposed scheme can survive various attacks.