Date of Award
dht, freenet, p2p, peer-to-peer, restricted route, security
In many networks, such as mobile ad-hoc networks and friend-to-friend
overlay networks, direct communication between nodes is
limited to specific neighbors. Friend-to-friend ``darknet'' networks
have been shown to commonly have a
small-world topology; while short paths exist between any pair of
nodes in small-world networks, it is non-trivial to determine such
paths with a distributed algorithm. Recently, Clarke and Sandberg
proposed the first decentralized routing algorithm that achieves
efficient routing in such small-world networks.
Herein this thesis we discuss the first independent security
analysis of Clarke and Sandberg's routing algorithm. We show that a
relatively weak participating adversary can render the overlay
ineffective without being detected, resulting in significant data
loss due to the resulting load imbalance. We have measured the
impact of the attack in a testbed of 800 and 400 total nodes using
minor modifications to Clarke and Sandberg's implementation of their
routing algorithm in Freenet. Our experiments show that the attack
is highly effective, allowing a small number of malicious nodes to
cause rapid loss of data on the entire network.
We also discuss various proposed countermeasures designed to detect,
thwart or limit the attack. We found that the ``darknet'' topology
limits the ability of effective countermeasures. The problem of
fixing the topology proved so intractable due to inherent network
characteristics that the idea of using a darknet for Freenet has
been all but abandoned following the public release of this work.
Our hope is that the presented analysis acts as a step towards
effective analysis and design of secure distributed routing
algorithms for restricted-route topologies.
Evans, Nathan S., "Routing in the Dark: Pitch Black" (2009). Electronic Theses and Dissertations. 186.
Recieved from ProQuest
Nathan S. Evans