ContSteg: Contourlet-Based Steganography Method

A category of techniques for secret data communication called steganography hides data in multimedia mediums. It involves embedding secret data into a cover-medium by means of small perceptible and statistical degradation. In this paper, a new adaptive steganography method based on contourlet transform is presented that provides large embedding capacity. We called the proposed method ContSteg. In contourlet decomposition of an image, edges are represented by the coefficients with large magnitudes. In ContSteg, these coefficients are considered for data embedding because human eyes are less sensitive in edgy and non-smooth regions of images. For embedding the secret data, contourlet subbands are divided into 4×4 blocks. Each bit of secret data is hidden by exchanging the value of two coefficients in a block of contourlet coefficients. According to the experimental results, the proposed method is capable of providing a larger embedding capacity without causing noticeable distortions of stego-images in comparison with a similar wavelet-based steganography approach. The result of examining the proposed method with two of the most powerful steganalysis algorithms show that we could successfully embed data in cover-images with the average embedding capacity of 0.05 bits per pixel.