Digital works such as images, audio and video present security concerns due to their portability and error free reproducibility. Thus, digital work producers are not being properly compensated for copyrighted works that are illegally copied and distributed on the Internet. One solution that has been proposed to solve some of these problems is digital watermarking. Researchers have proposed many different watermarking methods, but for any of these methods to be commercially applicable, they must be secure in the sense of being resilient to all known watermarking attacks. Therefore, the exploration and examination of watermarking attacks must be exhaustive. This paper adds to the knowledge base of known watermarking attacks on digital video. Specifically a type of collusion attack based on the replacement attack strategy is applied and tested against two digital video watermarking schemes. The effectiveness of this attack is measured by evaluating the fidelity of the attacked video as well as the ability of the attack to remove the watermark. This attack will provide yet another quality standard for measuring the effectiveness of watermarking schemes. This standard must be met if watermarking is to be a commercially viable option.</p
