An Improved Methodology for Data Hiding In Images Using Haar Transformed, LSB Replacement Method and Modified PVDMF 1

Abstract

Steganography is a technique of concealing secret text or image within another image.In this paper, abetterand efficient steganography methodfor hiding imagesand/or text into a color image is proposed. The proposed techniqueis based on two irreversible methods of spatial domain Least Significant Bit (LSB) and Pixel Value Differencing and Modulus Function (PVDMF 1) and one Haar Wavelet Transformation of the frequency domain. The proposed method works in four stages: at the first stage, Haar Wavelet Transformation is applied on the input image and transformed Haar coefficients are obtained. At the second stage, Haar coefficients and secret image are converted into binary form, before applying the LSB replacement method on the green channel by replacing the first two Most Significant Bits (MSB) of the input image withthe last two LSB bits of the secret image. Inthe third stage, modified PVDMF 1 is applied on intermediate stego imagesafter hiding the image by dividing the image into two non-overlapping consecutive pixels of pixels for hiding text. Inthe fourth stage, Inverse Haar Wavelet Transformation is applied to get the stego image. The proposed method offers high hiding capabilitywith goodvisual quality. The visual quality of the stego image is measured by using three widely used objective quality assessment matrices PSNR, RMSE,and SSIM. Furthermore, Regular/Singular (RS) analysis is applied on stego imagesto check theirresistanceagainst RS attack. The hiding capacity and quality assessment results are compared with some existing methods. It is evidentfrom the comparison that the proposed processis superior in termsof visual quality and hiding capacity.