[Colloq] PhD Thesis Defense - Bishal Thapa - Tuesday, Jan. 18th, 2011

[Rachel Kalweit]

The College of Computer and Information Science presents:

PhD Thesis Defense by:
Bishal Thapa

Date: January 18th, 2011
Time: 11:00am
Location: 166 West Village H

Title: Robust Wireless Communication in Adversarial Settings

Abstract:
Robust wireless communication is critical to the functioning of military,
civilian and commercial systems. In this thesis, we explore the security of
existing wireless communication systems in the presence of adversaries who are
trying to interfere with ongoing communication. By broadcasting RF signals over
an open medium, wireless networks make themselves vulnerable to jamming attacks.
Furthermore, the growing demand for ubiquitous wireless technology has led to
increasingly complex medium-access and resource-sharing mechanisms. This
creates security bottlenecks for the whole system since an adversary can now
focus all of its jamming on these control mechanisms in-turn enabling smart
energy-efficient Denial of Service (DoS) attacks. In our work, we show that, with
the help of readily available, low-cost, fully configurable software-defined radio
platform, an adversary can deploy highly efficient DoS attacks by targeting these
bottlenecks. We investigate their impact and devise energy-and-computationally
efficient, resiliency mechanisms.

In the past, robust communication relied on the existence of pre-shared secret
information used by legitimate clients to access the control messages sent by the server
on specific communication channels. Here, we consider a scenario where the adversary
knows this information. Adversaries can be compromised users or ``traitors'' who are
trying to deny the control channel communication. This leads to very efficient attacks,
since jamming control channel communication results in the disruption of the longterm
communication. In response, we first present several adversary-resilient control-information
sharing mechanisms that allow users to receive medium-access information in the presence of
adversaries, without requiring any hardware modifications. Then, we propose a method-based
on Spread Spectrum (SS) - which, with hardware support, allows longterm communication
without the need to pre-share secrets. This method significantly degrades the effects and
efficiency of smart jamming attacks. We analyze the efficiency of proposed solution and
evaluate their resilience under various jamming regimes, using a USRP/GNURadio/GPU-aided
network platform. Finally, we study the resilience of the longterm IEEE802.11 communication
against jamming attacks. We specifically look at attacks that exploit the vulnerabilities
within the IEEE802.11 MAC protocols and rate-adaptation algorithms, and devise jamming-resilient
mechanisms to address the identified weaknesses. We evaluate these mechanisms using analysis,
simulation, and where applicable, real-world experiments with carefully designed system prototypes.


Committee:
Guevara Noubir (Advisor)
Agnes Chan
Rajmohan Rajaraman
Radha Poovendran (Univ. of Washington)