COLLOQUIUM
             Computer Science Department, Boston University
                                    and
          Reliable Information Systems and Cyber Security Center
                              Boston University

Speaker: Professor Cristina Nita-Rotaru
         Purdue University

Date:  Wednesday, February 22
Time:  3:00
Place: Room MCS 135, 111 Cummington Street 
       (for directions, see www.cs.bu.edu/colloquium)

Title: Towards Robust Overlay Networks: Enhancing Adaptivity Mechanisms
with Byzantine Resilience

Abstract:

Adaptive measurement-based overlay networks offer increased
performance and resilience to benign failures for end-to-end communication
by using aggressive adaptivity mechanisms. These mechanisms dynamically
optimize application-centric metrics such as latency, jitter, bandwidth,
and loss rate. However, end-systems are more vulnerable than core
routers, making overlay networks susceptible to malicious attacks coming from
untrusted outsiders, and especially from trusted (but compromised) members of the
overlay. Unlike outsider attacks, insider (or Byzantine) attacks can not be
prevented by simply deploying cryptographic authentication mechanisms.

In this talk, we present several insider attacks against adaptivity
mechanisms in overlay networks and demonstrate them against the
ESM/Narada multicast overlay system. The attacks target the overlay network
construction, maintenance, and availability and allow malicious nodes to control
significant traffic in the network,facilitating further attacks such as selective
forwarding and traffic analysis. We propose techniques to enhance the adaptivity
mechanisms with Byzantine-resilience and demonstrate their effectiveness
through real-life deployments and emulations conducted on the PlanetLab
and DETER testbeds, respectively.

Biography:

Cristina Nita-Rotaru is an Assistant Professor in the Department of
Computer Science and a member of Center for Education and Research in
Information Assurance and Security (CERIAS) at Purdue University. She
leads the Dependable and Secure Distributed Systems Laboratory.

Her research interests lie in designing distributed systems, network
protocols and applications that are dependable and secure, while
maintaining acceptable levels of performance. Her Ph.D. work, Secure
Spread, focused on providing support for secure and robust services
for group communication. Secure Spread is one of the 12 technologies
featured on a DARPA DVD summarizing the accomplishment of 6 programs
(Cyber Panel, Dynamic Coalitions, Chats, OASIS, Fault Tolerant Networks,
and IA OPX) and it was selected to participate in JWID 2004, a large
coalition experiment.

Her current research focuses on designing intrusion-tolerant
architectures for distributed services that scale to wide-area networks, 
investigating survivable services in multi-hop wireless networks and 
building robust and secure overlay networks.

Her work is funded by the Center for Education and Research in
Information Security and Assurance (CERIAS), by the Defense Advanced Research
Projects  Agency (DARPA), and by the National Science Foundation (NSF).

Cristina Nita-Rotaru holds a Ph.D. in Computer Science from Johns
Hopkins University and a M. Sc. from Politehnica University of Bucharest,
Romania.
        
More information available at http://homes.cerias.purdue.edu/~crisn/

Host: Azer Bestavros