Methods for countering attacks on image watermarking schemes: Overview

Image watermarking is an effective and promising technology. Robust watermarks that are resistant to various attacks allow authors and owners of digital images to protect their rights to digital content, control its distribution and confirm its authenticity. Most of the modern algorithms for robust image watermarking aim to achieve resistance to a large number of different attacks. However, some authors develop algorithms designed to counter targeted attacks. The study of such schemes allows developers of watermarking algorithms to evaluate special means of counteracting various attacks, and then use them to create new robust schemes, both targeted and universal ones. In this paper, we present an overview of robust image watermarking schemes in terms of countering targeted attacks. We review the state-of-the-art in the field of attacking robust watermarks and propose a four -level classification of attacks that includes different levels of attack implementation, including an attacker's intent, characteristics of actions, the main target and an attack type. The proposed classification considers a watermark as an object of attack and summarizes various characteristics of attacks in a hierarchical manner. We analyze the means of countering common attacks such as image processing attacks, geometric attacks, print -scan and screen capture attacks, collusion attacks, and ambiguity attacks. Based on the results of our review, we highlight the most common methods of countering attacks and formulate promising areas of research in the field of methods for improving security of embedding schemes.