Speaker: Prateek Mittal, UIUC Title: Trustworthy Communications Using Social Networks Day: Thursday, March 1, 2012 Time: 4:30 pm Room: B205, E-Quad

Abstract: Internet systems and applications are shifting towards a participatory paradigm, where users contribute content and resources. Popular examples include reputation systems such as Yelp, peer-to-peer networks, Web 2.0 applications like Wikipedia, and online forums such as Slashdot. These applications, however, struggle with the concepts of identity and trust, as it is easy to create a large number of pseudonyms (called Sybils) that join the system and disrupt its functionality. In this talk, I will outline two mechanisms for defending against the Sybil attack. A common theme in these mechanisms is the use of social network trust relationships to validate user identities. Such an approach forces the adversary to infiltrate users’ trusted social circles, presenting a significant barrier for attack.

First, I will present SybilInfer, an algorithm for labeling nodes in a social network as honest users or Sybils controlled by an adversary. SybilInfer uses a combination of Bayesian inference and Monte-Carlo techniques to perform a global analysis of the entire social graph to isolate attackers. Second, I will present X-Vine, a mechanism that enables users in a social network to efficiently communicate with each other, while resisting Sybil attacks. X-Vine is scalable, preserves the privacy of users’ social network contacts, and provides a basis for pseudonymous communication. Finally, I will conclude by highlighting the potential for leveraging social networks in the design of trustworthy communication systems that improve user security and privacy.

Bio: Prateek Mittal is a Ph.D. Candidate in Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign. His research in security and privacy focuses on computer networks and distributed systems, with an emphasis on social networks and Internet protocols. He is also interested in applications of network modeling and analysis techniques to interdisciplinary settings, especially cancer genomics. He received the M.E. Van Valkenburg graduate research award for outstanding doctoral research, the Rambus Computer Engineering fellowship, and the ACM CCS 2008 outstanding paper award. He earned his M.S. in Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign and a B.Tech. in Computer Science and Engineering at the Indian Institute of Technology, Guwahati.

Host: Ruby Lee