Co-utile disclosure of private data in social networks

Social Networks (SNs) have become the mainstream web service by which users publish and share information. However, since much of that information is personal and sensitive, disclosing it in an uncontrolled way entails serious privacy risks. Paradoxically, most SNs assume that their users are willing to disclose sensitive data to others (even strangers) with little to no control. In this paper, we formalize the utility that rational users derive from participating in SNs, and argue that the current information exchange model is hardly sustainable from a rational viewpoint; actually, it goes against the interests of privacy-aware users. To tackle this issue, we propose several co-utile protocols for exchanging (sensitive) information among SN users. An interaction is said to be co-utile if the best way for a participant to increase her own utility is to help other participants increase theirs; hence, co-utile information exchange is self-enforcing and mutually beneficial for rational users. In this way, we ensure the sustainability of SNs in the long term, especially SNs with a sensitive scope (e.g., healthcare).