Access control in groupware systems - A user-centered approach

Access control system for collaborative environments tend to be rather comp lex. This leads to difficulties in the presentation and manipulation of acc ess policies at the user-interface level. This problem becomes even more im portant due to the high dynamics of collaborative work settings. This paper presents a user-centered approach, the central concept of which are access statements. These statements are based on the results of a field study and represent permissions or denials for arbitrary scopes, encompassing - amon g other factors - users, documents, roles and time-intervals. We describe h ow this approach has been implemented within a commercial groupware system and the results of an evaluation using the thinking aloud method.