DCT domain watermarking scheme using Chinese Remainder Theorem for image authentication

In this paper, we propose a novel Chinese Remainder Theorem (CRT) based watermarking scheme that works in the Discrete Cosine Transform (DCT) domain. We first reviewed a Singular Value Decomposition (SVD) based watermarking scheme followed by an existing CRT based watermarking scheme that works in the spatial domain and their shortcomings are highlighted. The proposed CRT based scheme is more resistant to different types of attacks, particularly to JPEG compression; in addition, it improves the security feature of the watermarking scheme. Experimental results have shown that the proposed scheme makes the watermark perceptually invisible and has better robustness to common image manipulation techniques such as JPEG compression, brightening and sharpening effects compared to the spatial domain based CRT scheme; in addition, its computational complexity is much lower than the SVD-based scheme.