Robust Digital Image Watermarking using Symmetric and Asymmetric Cryptography

Abstract

As the popularity of digital media is growing, and world is becoming smaller, due to internet and easy access of information, the copyright protection of intellectual properties have become a necessity for prevention of illegal copying and content integrity verification. So, to achieve these requirements, digital watermarking methods have been studied and implemented. Text, images, audios, videos etc. can be used as digital watermarks. Here, in this study, images have been taken as watermark. The different models of watermarking used are related with embedding and extracting image watermark from cover images in transform domain. For this, a varying technique of discrete wavelet transform (DWT) and combination of DWT with advanced encryption standard (AES), asymmetric key algorithm (RSA) and singular value decomposition (SVD) have been implemented for the security and robustness of the embedded watermark. The encrypted watermarked image has gone through many attacks, namely, noise attacks, rotation, crop, mean and median attack. Then the robustness of the extracted watermark has been evaluated by means of image quality criteria MSE, PSNR and NCC. In this thesis work, evaluation of different watermarking methods in transform domain has been carried out.