An RGB colour image steganography scheme using overlapping block-based pixel-value differencing.

Shiv Prasad,Arup Kumar Pal

doi:10.1098/rsos.161066

Abstract

This paper presents a steganographic scheme based on the RGB colour cover image. The secret message bits are embedded into each colour pixel sequentially by the pixel-value differencing (PVD) technique. PVD basically works on two consecutive non-overlapping components; as a result, the straightforward conventional PVD technique is not applicable to embed the secret message bits into a colour pixel, since a colour pixel consists of three colour components, i.e. red, green and blue. Hence, in the proposed scheme, initially the three colour components are represented into two overlapping blocks like the combination of red and green colour components, while another one is the combination of green and blue colour components, respectively. Later, the PVD technique is employed on each block independently to embed the secret data. The two overlapping blocks are readjusted to attain the modified three colour components. The notion of overlapping blocks has improved the embedding capacity of the cover image. The scheme has been tested on a set of colour images and satisfactory results have been achieved in terms of embedding capacity and upholding the acceptable visual quality of the stego-image.

Highlights

In the digital world, one of the major and essential issues is to protect the secrecy of confidential data during their transmission over a public channel
Khodei & Faez [14] have suggested a combination of least significant bit (LSB) and pixel-value differencing (PVD) methods 3 where three consecutive pixels are considered in hiding the secret message
Swain [17] proposed another combination of LSB- and PVD-based improved image steganographic schemes where the secret message bits are hidden into 2 × 2 pixel non-overlapping blocks of a cover image

Summary

Introduction

One of the major and essential issues is to protect the secrecy of confidential data during their transmission over a public channel. Khodei & Faez [14] have suggested a combination of LSB and PVD methods 3 where three consecutive pixels are considered in hiding the secret message Their scheme has improved the embedding capacity and retained the acceptable visual quality of the stego-image. Swain [17] proposed another combination of LSB- and PVD-based improved image steganographic schemes where the secret message bits are hidden into 2 × 2 pixel non-overlapping blocks of a cover image. Namely (R,G), (G,B) and (B,R), are formed from two consecutive colour pixels and the secret message is embedded based on differences of colour component pairs They have improved the hiding capacity while maintaining acceptable visual quality of the stego-image.

Basics of pixel-value differencing

Proposed scheme

Experiment results

Conclusion