This paper discusses attacks on copyright marking systems, focusing on the vulnerabilities of various schemes used to embed hidden information in digital media. The authors analyze different marking techniques, such as fingerprints and watermarks, and present several attacks that can remove or alter the embedded information. They also examine the robustness requirements for such systems, particularly in the context of audio and video. The paper highlights the challenges in designing secure and reliable marking schemes, as many existing systems are vulnerable to attacks that can remove or distort the hidden information without affecting the perceptual quality of the media. The authors describe various attacks, including the jitter attack, which can disrupt the timing of embedded information, and the mosaic attack, which can split an image into smaller parts to avoid detection. They also discuss the echo hiding technique, which is more resistant to certain types of attacks. The paper concludes that the development of robust marking systems is an ongoing challenge, and that practical solutions must balance the trade-offs between bandwidth and robustness. The authors emphasize the importance of considering both technical and legal aspects in the design of copyright protection systems.This paper discusses attacks on copyright marking systems, focusing on the vulnerabilities of various schemes used to embed hidden information in digital media. The authors analyze different marking techniques, such as fingerprints and watermarks, and present several attacks that can remove or alter the embedded information. They also examine the robustness requirements for such systems, particularly in the context of audio and video. The paper highlights the challenges in designing secure and reliable marking schemes, as many existing systems are vulnerable to attacks that can remove or distort the hidden information without affecting the perceptual quality of the media. The authors describe various attacks, including the jitter attack, which can disrupt the timing of embedded information, and the mosaic attack, which can split an image into smaller parts to avoid detection. They also discuss the echo hiding technique, which is more resistant to certain types of attacks. The paper concludes that the development of robust marking systems is an ongoing challenge, and that practical solutions must balance the trade-offs between bandwidth and robustness. The authors emphasize the importance of considering both technical and legal aspects in the design of copyright protection systems.