For our work on Social Networks, click here
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
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
- 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.
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
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
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
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.
- Efficient data location on unstructured peer to peer
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.
(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.
QualNet Network Simulator