Implementation of 16 * 16 Quantization Table Steganography on Gray Scale Images

Steganography is defined as an art of concealed data sharing for communication that prevents the detection of hidden messages. This paper presents a steganographic method based on modification of JPEG quantization table. Modified Discrete Cosine Transform (MDCT) is implemented based on transform domain technique. The proposed work hides the secret message inside an image using Modified Discrete Cosine Transform (MDCT). In this paper, the image is divided into non-overlapping blocks of 16*16 so as to embed secret information. The secret message is hidden inside an image which forms a stego image. The stego image is a combination of secret message and the cover image. Here four grayscale images have been considered and these images have been compared on the basis of three performance parameters such as capacity, PSNR, MSE.