High capacity steganography protected using shamir’s threshold scheme and permutation framework

Abstract

This paper presents a framework that conceal large volume of secret information using distributed file system that permit implantation of decomposed secret images across multiple-cover images. The strong security is imposed utilizing Shamir’s threshold scheme and permutation generator framework. Three layers of security is being applied to protect the secret information, in first, secret image is decomposed into equal size of smaller sub-images and generate a framework of permutations from an integer for distributing and reassembling the circulated broken secret sub images among the intended participants. At the time of embedding purpose of permutation generator is to arrange the sub-images in unknown order for outsider. During the discloser stage only inverse of permutation can rearrange the distributed sub-images to reassemble into original image by authorized contributors. In second, Shamir’s threshold scheme is designed for authentication of shared associated stego-cover images before starting the extraction process. This process provides an extremely secured construction of shared secret information. In third, image is divided in 2x2 blocks of pixels and traverses it in zig-zag manner; the pixel value difference is computed for all Red, Green, and Blue (RGB) components between non-overlapping pixels of selected diagonal path with in targeted block. Secret bits are concealed inside RGB color pixels of cover image by utilizing proposed novel pixel-value differencing (PVD) scheme, furthermore varying embedding capacity may be obtained by controlling the selection of number of 2x2 block. Exploratory result displays that the proposed approach provides productive algorithms in term multilayer unbreakable security and higher payload of embedded information.