Non Embedding Steganography using Average Technique in Transform domain

Abstract

In this paper we propose Non Embedding Steganography using Average Technique in Transform domain (NESATT). The Lifting Wavelet Transform (LWT) is applied on both cover image and payload image. The Diagonal band (CD) of cover image and Approximation band (PA) of payload are segmented into N × N blocks. The PA band of payload is divided by CD to generate resultant matrix based on Non Embedding Threshold Value (NETV) fixed by key. The average value of resultant matrix is calculated and used to divide PA to generate modified CD. The average value of each blocks are scale downed by key and embedded into corresponding block of Horizontal band (CH) of cover image. The inverse LWT is applied on stego object to derive stego image 1. The Peak Signal to Noise Ratio (PSNR) is computed between cover image and stego image 1 for different NETV values till maximum PSNR is obtained and the corresponding stego image is considered as final stego image. The capacity and PSNR values are high in the case of proposed algorithm compared to existing algorithms since non embedding technique is used in transform domain.