Controlable User Access on Multimedia Data in the World Wide Web

This paper describes a possible way of controlling access to image data via the World Wide Web. It describes how images are encrypted using a novel technique and delivered from a server. When exchanging data, a protocol ensures that requests are always tied to a registered user and that all critical data are transferred in encrypted form. User actions are permitted and logged by the server. Activities such as storing and printing are possible only after obtaining permission from the server. If illicit copies are obtained somehow despite this, an additional watermarking system permits identification of the distributor of the illicit copy. The system was implemented as a Netscape plug--in.