CollAC: Collaborative access control

Recent years have seen an increasing number of collaborative systems and platforms available online. As the importance of online collaboration grows, so does the need to protect the information used in these systems. In collaborative environments different users may be related to the information in different capacities. This means that traditional access control mechanisms are usually not suitable for collaborative environments as they assume that a single entity is in control of information. Moreover, when different entities can concurrently specify policies for the same resources, the decision making process is not transparent to the users who expect their policies to be enforced by the system. In this paper, we introduce a novel access control framework for collaborative systems. The framework is based on a notion of control which goes beyond the notion of ownership by accounting for the relation of a user with an object. We also make access control decisions transparent by showing where and why collaborative decisions deviate from the policies of single users.