2,997 research outputs found
Time-Varying Graphs and Dynamic Networks
The past few years have seen intensive research efforts carried out in some
apparently unrelated areas of dynamic systems -- delay-tolerant networks,
opportunistic-mobility networks, social networks -- obtaining closely related
insights. Indeed, the concepts discovered in these investigations can be viewed
as parts of the same conceptual universe; and the formal models proposed so far
to express some specific concepts are components of a larger formal description
of this universe. The main contribution of this paper is to integrate the vast
collection of concepts, formalisms, and results found in the literature into a
unified framework, which we call TVG (for time-varying graphs). Using this
framework, it is possible to express directly in the same formalism not only
the concepts common to all those different areas, but also those specific to
each. Based on this definitional work, employing both existing results and
original observations, we present a hierarchical classification of TVGs; each
class corresponds to a significant property examined in the distributed
computing literature. We then examine how TVGs can be used to study the
evolution of network properties, and propose different techniques, depending on
whether the indicators for these properties are a-temporal (as in the majority
of existing studies) or temporal. Finally, we briefly discuss the introduction
of randomness in TVGs.Comment: A short version appeared in ADHOC-NOW'11. This version is to be
published in Internation Journal of Parallel, Emergent and Distributed
System
Blindspot: Indistinguishable Anonymous Communications
Communication anonymity is a key requirement for individuals under targeted
surveillance. Practical anonymous communications also require
indistinguishability - an adversary should be unable to distinguish between
anonymised and non-anonymised traffic for a given user. We propose Blindspot, a
design for high-latency anonymous communications that offers
indistinguishability and unobservability under a (qualified) global active
adversary. Blindspot creates anonymous routes between sender-receiver pairs by
subliminally encoding messages within the pre-existing communication behaviour
of users within a social network. Specifically, the organic image sharing
behaviour of users. Thus channel bandwidth depends on the intensity of image
sharing behaviour of users along a route. A major challenge we successfully
overcome is that routing must be accomplished in the face of significant
restrictions - channel bandwidth is stochastic. We show that conventional
social network routing strategies do not work. To solve this problem, we
propose a novel routing algorithm. We evaluate Blindspot using a real-world
dataset. We find that it delivers reasonable results for applications requiring
low-volume unobservable communication.Comment: 13 Page
The Quest for a Killer App for Opportunistic and Delay Tolerant Networks (Invited Paper)
Delay Tolerant Networking (DTN) has attracted a lot of attention from the research community in recent years. Much work have been done regarding network architectures and algorithms for routing and forwarding in such networks. At the same time as many show enthusiasm for this exciting new research area there are also many sceptics, who question the usefulness of research in this area. In the past, we have seen other research areas become over-hyped and later die out as there was no killer app for them that made them useful in real scenarios. Real deployments of DTN systems have so far mostly been limited to a few niche scenarios, where they have been done as proof-of-concept field tests in research projects. In this paper, we embark upon a quest to find out what characterizes a potential killer applications for DTNs.
Are there applications and situations where DTNs provide
services that could not be achieved otherwise, or have potential to do it in a better way than other techniques? Further, we highlight some of the main challenges that needs to be solved to realize these applications and make DTNs a part of the mainstream network landscape
Toward Anonymity in Delay Tolerant Networks: Threshold Pivot Scheme
Proceedings of the Military Communications Conference (MILCOM 2010), San Jose, CA, October 2010.Delay Tolerant Networks (DTNs) remove traditional assumptions of end-to-end connectivity, extending network communication to intermittently connected mobile, ad-hoc, and vehicular environments. This work considers anonymity as a vital security primitive for viable military and civilian DTNs. DTNs present new and unique anonymity challenges since we must protect physical location information as mobile nodes with limited topology knowledge naturally mix. We develop a novel Threshold Pivot Scheme (TPS) for DTNs to address these challenges and provide resistance to traffic analysis, source anonymity, and sender-receiver unlinkability. Reply techniques adapted from mix-nets allow for anonymous DTN communication, while secret sharing provides a configurable level of anonymity that enables a balance between security and efficiency. We evaluate TPS via simulation on real-world DTN scenarios to understand its feasibility, performance, and overhead while comparing the provided anonymity against an analytically optimal model
Message anonymity on predictable opportunistic networks
A Predictable Opportunistic Network (POppNet) is a network where end-to-end connectivity is not guaranteed, and node communication happens in an opportunistic manner, but the behavior of the network can be predicted in advance. The predictability of such networks can be exploited to simplify some mechanisms of more generic OppNets where there is no prior knowledge on the network behavior. In this paper, we propose some solutions to provide anonymity for messages on POppNets by using simple onion routing, and thus to increase the privacy of the nodes in communication
- …