Data Sharing in Social Networks

In the context of multi-user cooperative systems and, in particular, in social networks, personal data is uploaded to user profiles and shared with other users. These data are often jointly owned and associated with different degrees of sensitivity according to the users. Controlling access to such multi-owner data, under the authority of different users, is challenging. Traditional access control policies are not expressive enough to determine whether a data disclosure meets the privacy expectations of the different involved parties. In this work, we propose a fine-grained access control model for multi-user cooperative systems and apply it to the context of social networks. We consider compound objects and extend attribute-based access control with provenance information to specify additional access control constraints. We also present a prototype implementation and provide an experimental evaluation to demonstrate the feasibility of the proposed model.