Cryptanalysis and Improvement of a Digital Watermarking Scheme Using Chaotic Map

In the recent past, a new statistically efficient digital image watermarking scheme based on chaotic map was proposed. The authors of this watermarking scheme claimed under study that their scheme is efficient, secure, and highly robust against various attacks. However, the security analysis of the scheme unveils that it has serious inherent flaws. In this article, the shortcomings of the proposed watermarking scheme and cryptanalysis are presented to demonstrate that the scheme is not secure against the proposed attacks. Specifically, with the chosen host image and chosen watermarks, we can successfully recover the watermark from received watermarked image without having any knowledge of the secret key. The simulation analysis of the proposed cryptanalysis is provided to exemplify the proposed attack and lack of security of the anticipated watermarking scheme. In addition, an improved version is proposed to enhance the security performance of the watermarking scheme against possible attacks. The improved scheme tends to hold against attacks and statistical efficiency.