Privacy in Social Networks

Friday, 14 September 2012 - Roland Yap


Title: Privacy in Social Networks
Speaker: Roland Yap, National University of Singapore

Date: Friday, September 14, 2012
Time: 11:30
Room: 2BC60, Torre Archimede

The popularity and size of online social networks means the social graph contains valuable data about relationships. Such graph data may be sensitive. Thus, there is a need to protect the data from privacy leaks. Some social networks are essentially public, e.g. Facebook, where much of the information about the users is available in public profiles except for a certain number of private profiles which are closed. From the perspective of the operator of the social network, public information and crawlability are needed to support the basic utility and services on top of the social network. But from the users perspective, they may want to maintain privacy. We propose policies where the owner of the social network can tradeoff between these two conflicting goals. We also show that much of the link information of private users can be leaked under certain policies. We experiment with real world social network graphs and show that the owner of the graph can employ policies which can meet particular tradeoffs under different crawlers.
Another class of social networks are mostly private, e.g. LinkedIn, information about the links of a node is only available to friends. In the link privacy attack, it turns out that by bribing or compromising a small number of nodes (users) in the social network graph, it is possible to obtain complete link information for a much larger fraction of other non-bribed nodes in the graph. This can constitute a significant privacy breach. We explain why the link privacy attack is effective. We present several strategies including a privacy control to users
can reduce the effect of the attack.

Roland Yap is an associate professor in the School of Computing of the National University of Singapore. He obtained his Ph.D. in Computer Science from Monash University, Australia. He is known for his work in Constraint Logic Programming (CLP), in particular, the CLP(R) system which is one of the earliest CLP systems with arithmetic constraints. His current research interests are in the areas of constraints, distributed systems, programming languages, security and social networks.