Multiple layer encryption and steganography via multi-channel ghost imaging

Abstract

Multiple layers of information security are introduced based on computational ghost imaging (CGI). We show, in the first step, that it is possible to design a very reliable image encryption scheme using 3D computational ghost imaging with two single-pixel detectors sending their data through two channels. It is then shown that further level of security can be achieved by merging data carrying channels into one and using a coded order for their placement in the sequence of bucket data carried by the single channel. Through the Normalized Root Mean Square scale, we show that the second security level is a one step forward. Yet another layer of security is introduced through hiding the actual grayscale image (or even a color image) inside another image (object) before the ghost imaging process such that the hidden image cannot be recognized by the naked eye. We then successfully retrieve the hidden image from a CGI-reconstructed image despite the presence of noise while such noises make steganography impossible by conventional methods. We show that CGI-based steganography is intrinsically robust to attacks involving manipulation of the image matrix and pixels. As for the cryptography attacks, it is shown that the proposed scheme increases the security and robustness such that an attacker needs more than 96 percent of the coded order to recover the hidden image. Storing a gray scale image in a ghost image and retrieving different intensities for the hidden image is unprecedented and could be of interest to the information security community. We also present performance, robustness and attack analyses and show that our layered configuration for information encryption based on CGI successfully passes these checks.