Trustworthy Peer-to-Peer Networks:

Peer-to-peer systems are rapidly maturing from being narrowly associated with copyright violations, to a technology that offers tremendous potential to deploy new services over the Internet. In many ways, peer-to-peer systems are beginning to herald a paradigm shift in this decade, in much the same way as HTTP in the 1990's. In this project, we are studying challenges in designing peer-to-peer systems in a safe, secure and robust manner, and considering new issues to Internet management due to the proliferation of peer-to-peer systems.

We are investigating the design of P2P systems so they may be robust to attacks exploiting them to launch DDoS attacks on the Internet. We are designing and evaluating defenses for robust P2P system design, and identifying key principles that must guide the design of membership management algorithms.

Publications

• DDoS Attacks by Subverting Membership Management in P2P Systems, Xin Sun, Ruben Torres and Sanjay Rao, Workshop on Secure Network Protocols (NPSec 2007), Beijing, China, October 2007. [PDF]

• Preventing DDoS Attacks with P2P Systems through Robust Membership Management, Xin Sun, Ruben Torres and Sanjay Rao. Technical Report TR-ECE-07-13, Purdue University, February 2007.

• Preventing DDoS Attacks with P2P Systems, Xin Sun, Ruben Torres and Sanjay Rao. Presented as POSTER in The 8th Annual CERIAS Information Security Symposium. March 20-21, 2007. [PDF]

Related Efforts Highlighting the Problem

See observations by several academic researchers, industry and the press highlighting the importance of the problem:

• Exploiting Overnet, by Keith Ross's group at Polytechnic University, NY.
• Exploiting Gnutella, by Elias Athanasopoulos et al. at FORTH, Greece.
• Exploiting BitTorrent, by Athina Markopoulou's group at UC Irvine, CA.
• Report on P2P DDoS attacks, by Prolexic Technologies
• In the Press, NewScientist

Students

• Xin Sun
• Ruben Torres

We seek to design algorithms to monitor traffic of peer-to-peer systems, and detect deviant traffic behavior. The motivation is two fold: (i) Normal behavior in peer-to-peer applications exhibit characteristics similar to an Internet worm (high failure ratio, many-to-many download profile and common substrings among many packets). This is a common cause for false positives; (ii) Software bugs, design limitations, and DDoS reflector attacks exploiting peer-to-peer systems, may lead to undesirable traffic patterns.

To address these issues, we are currently: (i) Characterizing traffic of peer-to-peer systems with regard to metrics used in anomaly detection based on data collected from operational peer-to-peer systems, and analyzing system behavior under scale and churn; and (ii) Studying the implication for traffic characteristics for detection algorithms.

Publications

• Inferring Undesirable Behavior from P2P Traffic Analysis, Ruben Torres, Mohammad Hajjat, Sanjay Rao, Maurizio Munafo and Marco Mellia, to appear in ACM SIGMETRICS, Seattle, WA, June 2009. [PDF]

Students

• Ruben Torres
• Mohammad Hajjat

Most prior work on the use of key management algorithms to enable confidentiality of video delivery has been conducted in the context of IP Multicast. We consider the unique challenges and opportunities of integrating key management algorithms in an overlay multicast system. We conducted a systematic and extensive performance evaluation of strategies for key dissemination in the context of an operational overlay broadcasting system on the Planetlab testbed using real traces of join/leave dynamics. We found that leveraging TCP in each hop of the overlay dissemination structure can significantly simplify reliable key dissemination. We also found that using two specialized dissemination structures, one for data and one for keys, potentially achieves low overhead for key dissemination without sacrificing application performance.

Publications

• Enabling Confidentiality of Data Delivery in an Overlay Broadcasting System, Ruben Torres, Xin Sun, Aaron Walters, Cristina Nita-Rotaru and Sanjay Rao, to be published in Proceedings of IEEE Infocom, Anchorage, AK, May 2007. [PDF]

• Enabling Confidentiality of Data Delivery in an Overlay Broadcasting System, Ruben Torres, Xin Sun, Aaron Walters, Cristina Nita-Rotaru, and Sanjay Rao. Presented as POSTER in The 7th Annual CERIAS Information Security Symposium. March 2006. [PDF]

Students

• Ruben Torres
• Xin Sun

Faculty

• Cristina Nita Rotaru

• Dependable and Secure Distributed Systems Laboratory (DS2)

This project is funded by the NSF CyberTrust Program, Principal Investigators: Cristina Nita-Rotaru (Computer Science, Purdue University) and Sanjay Rao (Electrical and Computer Engineering, Purdue University).

The sub-project on Detecting Anomalous Traffic in Peer-to-Peer Networks receives additional support from Cisco Systems.