Copyright Protection is one of the many aspects of implementing a commercially successful video streaming solution. Copyright protection should be implemented using both passive schemes – such as watermarking – and active schemes – such as encryption. While some algorithms for encryption of video have been proposed, they are in the main unsuitable for implementation in a streaming video environment. In this paper I describe a set of requirements that an MPEG-1 cipher must possess in order to function in a distributed streaming server environment using existing streaming server products and technologies.