Digital Image Steganography using Nine-Pixel Differencing and Modified LSB Substitution

Gandharba Swain

doi:10.17485/ijst/2014/v7i9.27

Abstract

To provide higher embedding capacity without sacrificing the imperceptibility, a novel steganographic technique based on nine-pixel differencing with modified Least Significant Bit (LSB) substitution is proposed. The image is divided into 3×3 non-overlapping blocks. In each block the average difference value is calculated. Based on this value the block is classified to fall into one of the four levels such as, lower, lower-middle, higher-middle, and higher. If a block belongs to lower level then 2-bit LSB substitution is used in it. Similarly, for lower-middle, higher-middle, and higher level blocks 3, 4, and 5 bit LSB substitution is used. After LSB substitution the pixel values are readjusted to minimize distortion such that these modified values do not disturb the embedded bits. The experimental results reveal that the stego-images are imperceptible and hiding capacity is higher. Keywords: Modified LSB Substitution, Nine-Pixel Differencing, Pixel Value Differencing, Steganography

Highlights

Steganography is an art of invisible communication, wherein the secret message is sent through a cover medium like image, audio, and video[1]
Wu and Tsai[17] proposed Pixel Value Differencing (PVD) steganography with an idea that more number of bits can be embedded in edge areas compared to smooth areas of the image
Being inspired by Wu et al.[25] and Liao et al.[27] schemes and to achieve higher capacity and higher security, a steganographic tehnique with nine-pixel differencing and modified Least Significant Bit (LSB) substitution has been proposed in this paper

Summary

Introduction

Steganography is an art of invisible communication, wherein the secret message is sent through a cover medium like image, audio, and video[1]. Wu and Tsai[17] proposed Pixel Value Differencing (PVD) steganography with an idea that more number of bits can be embedded in edge areas compared to smooth areas of the image. This scheme is based on the substitution. Wu et al.[25] proposed a technique with 2-pixel blocks using PVD and 3-bit LSB substitution to achieve high embedding capacity and more security. Being inspired by Wu et al.[25] and Liao et al.[27] schemes and to achieve higher capacity and higher security, a steganographic tehnique with nine-pixel differencing and modified LSB substitution has been proposed in this paper.

Nine-Pixel Differencing and Modified LSB Substitution Technique

Results and Discussion

Conclusion