Image Steganography using Non Embedding and Average Technique in Transform Domain

The steganography is an art and science of hiding information into a given media to ensurethe security of information over the communication channel. In this paper we propose a Image Steganography using Average Technique in Transform Domain (ISATT). The Lifting Wavelet Transform (LWT) is applied on both cover image and payload. The Diagonal band (CD) of cover image and Approximation band (PA) of payload are segmented into N x N blocks. The N x N matrix of PA is divided by N x N matrix of CD to generate resultant matrix based on Non Embedding Threshold Value (NETV) fixed by key. The average value of N x N resultant matrix is calculated and used to divide PA to generate modified CD. The average value of each N x N block are scale downed by key and embedded into corresponding N x N block of horizontal band (CH) of cover image. The inverse LWT is applied on stego object to derive stego image1. The Peak Signal to Noise Ratio (PSNR) is computed between cover image and stego image1 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 propos ed algorithm compared to existing algorithms since non embedding and average technique is used in transform domain.