Collaborative privacy management in P2P online social networks

Online Social Networks (OSNs) have become widely popular in recent years. In spite of users´ interest to join OSNs, sharing vast amounts of personal information and resources in these networks might result in privacy issues for them. In the centralized OSNs, access control policies defined by users are enforced by OSN providers. Moreover, as these shared resources are stored by providers, they can access them. To avoid such problems, various architectures for decentralized OSNs are proposed. But the proposed architectures for P2P OSNs yet do not support any mechanism for collaborative privacy management on the shared content. By increasing the amount of resources such as photos which is shared by friends or family members, privacy of a user in these networks does not depend on the resources shared by him anymore. In this case, users should be able to collaborate in control of the accessibility of all the resources belong to them. In this paper, using secret sharing scheme, we propose a collaborative access control model which all the users tagged in a content are able to define the privacy policy for it. Based on the various parameters such as sensitivity scores and privacy policies defined by each controller, an aggregated policy is assigned to a shared resource. To the best of our knowledge this is the first time such a collaborative privacy management model has been proposed for P2P based OSNs. Additionally, to demonstrate the applicability of the proposed model a prototype is implemented.