An Optimal and Hybrid Encryption-based Integer Wavelet Transform with DCT for Color Image Watermarking

Abstract

This article introduces the hybrid encryption (HE)-based CIW using combined integer wavelet transform (IWT) with discrete cosine transform (DCT), where the HE performs on watermark image to encrypt the data securely before embedding it into cover image while both IWT, and DCT are used to extract the features from cover RGB image. In addition, the grey-wolf optimization (GWO) is employed for extracting the enhanced features obtained from IWT- DCT. Then, LSB approach is employed for embedding the encrypted watermark image into the cover image, here after the proposed method is denoted as OHE-based IWT-DCT with LSB. Finally, the watermarked image is obtained using inverse transforms of IWT, and DCT with postprocessing operations. The simulations carried out on standard test images discloses the superiority of proposed OHE-based IWT-DCT with LSB approach as compared to state- of-art CIW approaches in terms of peak signal-to-noise ratio (PSNR), structural similarity (SSIM) index, mean square error (MSE), normalized cross correlation (NCC) and unified averaged changed intensity (UACI) values.