DCT Domain Encryption in LSB Steganography

Abstract

This paper on 'COLOR IMAGE STEGANOGRAPHY IN DCT DOMAIN' portrays a new arena in steganography in color images in frequency domain or more precisely that in Discrete Cosine Transform (DCT) domain. In this paper the authors have proposed the exploration of a deft method for image-secret data-steg pass based sampling along with encryption and embedding in frequency domain with a variable bit retrieval function where the secret data becomes more secure by hiding with the steg password, so that without knowing the steg password one cannot get the secret data explored. The strong adhesion amongst the color images, secret data and steg password, varied with a pixel dependant embedding in DCT domain yields a highly protected and reliable substitution. A group of 8×8 quantized DCT Coefficient (QDC) is selected as our secret data carrier for the color image. The variable bit operation is applied to the proper QDCs to embed a byte of secret data, where the variable bit operation is dependent on the pixel value. Assiduous statistical analysis has been done and provided to emphasize the strong security of the algorithm to the various steganalysis methods. This will also help to reveal its huge carrier capacity and stego image quality.