Network Security and Anonymous Communication

• Reputation Systems (Gayatri Swamynathan, Ben Zhao, with Prof. Kevin Almeroth)
  We are working on developing an alternative and complementary approach to traditional global reputations. Proactive reputations allow nodes to take the initiative in accurately testing the reliability of unknown nodes. For more info, see our AEPP 2005, IPTPS 2006, CCPE 2007 papers. We also proposed mechanisms to improve reliability of reputation systems, and looked at how social links can affect trust in distributed systems (specifically for auction systems), see our papers at SRDS 2008 and SIGCOMM WOSN 2008, respectively on the publications page.

• Reliable and Attack-resistant Anonymous Communication: Cashmere and Bluemoon (Krishna Puttaswamy, Alessandra Sala, Christo Wilson, Ben Zhao, with L. Zhuang, F. Zhou at UC Berkeley, and Ant Rowstron at Microsoft Research)
  Cashmere is a MIX-based anonymous routing protocol implemented on structured overlays. It uses the flexibility inherent in structured overlays to provide resistance against relay failures, and provides path life-times 4-5 orders of magnitude greater than typical MIX approaches. For more info, see our paper in NSDI 2005 on the publications page. We also developed a new protocol called Bluemoon that is highly resistant to the powerful Predecessor Attack. The Bluemoon work will appear in an upcoming ICNP 2008 paper. An offshoot project studying the use of social networks to improve anonymity will appear in a paper at the NPSec 2008 secure network protocol workshop.

• A Measurement Study of P2P User Collusion Behavior (Ben Zhao with folks from Microsoft Research and Peking University)
  We mine centralized logs from the Maze P2P file-sharing system to detect a number of distinctive peer-collusion patterns, and measure their impact on the system as a whole. We also apply the EigenTrust reputation system to our trace, and evaluate its effectiveness in identifying colluding/misbehaving users. For more info, see our paper in ICDCS 2007 on the publications page.

• Identity / Namespace Protection (Lakshmi Ganesh, Krishna Puttaswamy, Ben Zhao)
  Malicious peers in a structured overlay can easily hijack Key-Based Routing (KBR) requests, and take over responsibility for the requested data or key. Attacks can be performed using a single node, or advanced collusion attacks can be launched following Sybil or Eclipse attacks. Our work focuses on probabilistic detection of identity attacks. For more info, see our paper in NPSec 2005 on the publications page.

Wireless Routing

• Multi-channel Routing (Ashwin Sampath, Ben Zhao with Prof. Heather Zheng)

• Table Attenuation Routing Protocol (Shaomei Wu, Ben Zhao, with Bob Gilbert and Kerby Johnson, with Prof. Heather Zheng)
  On-demand routing protocols incur relatively high control overheads when the number of flows is high or in the presence of frequent failures. The TARP project examines a low-overhead alternative that uses proactive table-based distance vector routing with Bloom Filters to compress routing table entries. For more info, see our paper in MobiShare 2006 on the publications page.

• IDLP (Integrated Data Location Protocol) (Ashwin Sampath, with Irfan Sheriff, Prashanth Kumar, Ben Zhao, with Prof. Elizabeth Belding-Royer)
  Efficient data location in wireless networks is a difficult challenge. Deploying application-level mechanisms on wireless systems incurs extremely high routing overhead. IDLP is a data location protocol that integrates object location with routing info in AODV. For more info, see our paper in COMSWARE 2007 on the publications page.

Distributed Applications and Measurement Studies

• Video-on-demand Systems (Ben Zhao with H. Yu, D. Zheng and W. Zheng from Tsinghua University)
  China Telecom has deployed a large video-on-demand system for wide-use in China. We studied the complete logs from several major cities to characterize large-scale user behavior from a number of different perspectives. The results are published in our paper in EuroSys 2006 (see the publications page).

• Video-on-demand Over Cable Systems (Matthew Allen, Ben Zhao, Rich Wolski)
  A follow-up study using data from the EuroSys 2006 paper. We look at how effectively current cable systems can use deployed Digital Video Recorders (DVRs) to as a distributed P2P cache for video-on-demand. We examine different caching algorithms and predict the amount of traffic offloaded from central servers to the distributed P2P caches. The results are published in our paper in ICDCS 2007 (see the publications page).

• Maze (Ben Zhao with folks from Microsoft Research Asia and Peking University)
  Maze is a Napster-style file-sharing system with wide-spread deployment in China. The current user-base includes more than 200,000 users sharing over 140 millions files. Because Maze is developed by an academic team at PKU, and has a centralized architecture, we have access to 100% of all transaction logs. For more info, see our paper at WORLDS 2004 on the publication page. Other papers followed at IPTPS 2005 and IPTPS 2006.

Peer-to-Peer Protocols

• Efficient data location on unstructured peer to peer networks (Krishna Puttaswamy, Alessandra Sala, Ben Zhao)
  We examine different techniques to improve search recall of rare objects on unstructured peer-to-peer overlays. We use efficient variants of multi-hop index replication to improve data recall by an order of magnitude while minimizing search message overhead. For more info, check out our paper at INFOCOM 2008 on the publications page.

• Chimera (Rama Alebouyeh, Krishna Puttaswamy, Matthew Allen, Ben Zhao)
  Chimera is a light-weight prefix-based routing structured peer-to-peer overlay network similar to Pastry and Tapestry. The Chimera protocol focuses on minimal resource utilization and memory footprint with maximum routing throughput.

• Low-Energy Peer-to-Peer (Ben Zhao w/ Selim Gurun and Priya Nagpurkar)
  We studied the impact of the peer-to-peer communication model on wireless communication devices and energy output. The always-on messaging model drained power significantly from wireless PDAs, and prevented the use of traditional sleeping mechanisms for power savings. For more info, look for our paper in ACM Mobishare 2006 on the publications page.

• Z-Ring (Shaomei Wu, Ben Zhao, with collaborators from Microsoft Research Asia)
  Z-Ring is a prefix-based routing protocol for extremely large overlay networks (billions and above), that uses group membership protocols to drastically reduce neighbor maintenance overhead. For more info, look for our paper in ICNP 2005 on the publications page.

 

 

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