This paper considers the security requirements of hypertext and hypermedia systems. The emphasis is on the mechanism used to determine which subjects should be allowed to access which information. Many of the concerns are already being addressed by current secure database research-especially secure object-oriented database research. However, the particular structure of hypertext and hypermedia system allows one to study the particular requirements of such systems. This paper considers the types

more »

... of links that may be used in such systems and proposes a heuristic based on link types to simplify labelling entities to be protected. Such a heuristic is important since a typical hypertext system may contain extremely many nodes and links. The heuristic will help to reduce the burden of assigning labels to nodes and decrease the amount of time before the system can be used.