Secure and Robust Image Steganography Using a Reference Image as Key
Giridhar Maji1, Sharmistha Mandal2

1Giridhar Maji, Department of Electrical Engineering, Asansol Polytechnic, Asansol (West Bengal), India.
2Sharmistha Mandal, Department of Computer Science and Technology, Kanyapur Polytechnic, Asansol (West Bengal), India.

Manuscript received on 01 May 2019 | Revised Manuscript received on 15 May 2019 | Manuscript published on 30 May 2019 | PP: 2828-2837 | Volume-8 Issue-7, May 2019 | Retrieval Number: G5939058719/19©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: A new steganography scheme using a reference image is proposed with two variants. In the first kind, secret text bits are directly embedded into the cover image after encryption using a reference image. In the second variant secret text is written/printed on a white canvas and then that image containing the secret text is converted into binary (BW) image. Any image could be used as a cover image. A special reference image will act as an encryption key and it is assumed that the used reference image is known to sender and receiver apriori. For a grayscale reference image, any k LSB bit planes could be used to encode the secret binary image bits before embedding them into k LSBs of the cover image. When k=1, the dimension of the secret image becomes the same as that of the reference image and cover image. With k=2, secret binary image size could be doubled or two secret images could be hidden using two LSB bit planes of the reference image and embedding them into two LSB bits of each cover image pixel. Any reversible mechanism could be used for encoding. Here XOR operation will be used for experiments. Two distinct advantages of this generic scheme are (i) It is far more secure than other image steganography techniques as adversary may know the encoding formulae , may collect the stego image but could not get information about the reference image used and which and how many bit planes are used for encoding as there could be millions of images and many combinations of bit planes that could have been employed; (ii) As the secret text is printed and then converted into an image, it overcomes one of the main limitations of LSB image steganography, i.e. robustness to random noise. Even with corrupted Stego image, the extracted binary image becomes corrupted too but most of the secret are still readable. This scheme has lower capacity than the capacity that would have been achieved by directly embedding the secret text binary as in the first variant, but this could be overcome by using k>=2 as k=2 doubles the capacity. This whole scheme is generic and any digital media could be used as reference or cover. Experimental results demonstrate the robustness of the second variant against random noise, and standard image quality metrics such as MSE, PSNR, SSIM are evaluated and compared between the two variants.
Keyword: Text in Image, LSB Steganography, Image Inside Image, Reference Image As Key, Secure and Robust Data Hiding.
Scope of the Article: Image Security