Digital Image Steganography Based on Combination of DCT and DWT

Abstract

In this paper, a copyright protection scheme that combines the Discrete Wavelet Transform (DWT) and Discrete Cosine Transform (DCT) is proposed. The proposed scheme first extracts the DCT coefficients of secret image by applying DCT. After that, image features are extracted from cover image and from DCT coefficients by applying DWT on both separately. Hiding of extracted features of DCT coefficients in the features of cover image is done using two different secret keys. Experimentation has been done using eight different attacks. Experimental results demonstrate that combining the two transforms improves the performance of the steganography technique in terms of PSNR value and the performance is better as compared to that achieved using DWT transform only. The extracted image has good visual quality also.