441 research outputs found
A Key Predistribution Scheme for Sensor Networks Using Deployment Knowledge
To achieve security in wireless sensor networks, it is important to be able to encrypt messages sent among sensor nodes.
Keys for encryption purposes must be agreed upon by communicating nodes. Due to resource constraints, achieving such key
agreement in wireless sensor networks is nontrivial. Many key agreement schemes used in general networks, such as Diffie-Hellman
and public-key-based schemes, are not suitable for wireless sensor networks. Predistribution of secret keys for all pairs of nodes is not
viable due to the large amount of memory used when the network size is large. Recently, a random key predistribution scheme and its
improvements have been proposed. A common assumption made by these random key predistribution schemes is that no deployment
knowledge is available. Noticing that, in many practical scenarios, certain deployment knowledge may be available a priori, we propose
a novel random key predistribution scheme that exploits deployment knowledge and avoids unnecessary key assignments. We show
that the performance (including connectivity, memory usage, and network resilience against node capture) of sensor networks can be
substantially improved with the use of our proposed scheme. The scheme and its detailed performance evaluation are presented in this
paper
A Graph Theoretic Approach for Optimizing Key Pre-distribution in Wireless SensorNetworks
Finding an optimal key assignment (subject to given constraints) for a key
predistribution scheme in wireless sensor networks is a difficult task. Hence,
most of the practical schemes are based on probabilistic key assignment, which
leads to sub-optimal schemes requiring key storage linear in the total number
of nodes. A graph theoretic framework is introduced to study the fundamental
tradeoffs between key storage, average key path length (directly related to the
battery consumption) and resilience (to compromised nodes) of key
predistribution schemes for wireless sensor networks. Based on the proposed
framework, a lower bound on key storage is derived for a given average key path
length. An upper bound on the compromising probability is also given. This
framework also leads to the design of key assignment schemes with a storage
complexity of the same order as the lower bound
Secure Connectivity Through Key Predistribution Under Jamming Attacks In Ad Hoc and Sensor Networks
Wireless ad hoc and sensor networks have received attention from research communities over the last several years. The ability to operate without a fixed infrastructure is suitable for a wide range of applications which in many cases require protection from security attacks. One of the first steps to provide security is to distribute cryptographic keys among nodes for bootstrapping security. The unique characteristics of ad hoc networks create a challenge in distributing keys among limited resource devices. In this dissertation we study the impact on secure connectivity achieved through key pre-distribution, of jamming attacks which form one of the easiest but efficient means for disruption of network connectivity. In response to jamming, networks can undertake different coping strategies (e.g., using power adaptation, spatial retreats, and directional antennas). Such coping techniques have impact in terms of the changing the initial secure connectivity created by secure links through key predistribution. The objective is to explore how whether predistribution techniques are robust enough for ad hoc/sensor networks that employ various techniques to cope with jamming attacks by taking into account challenges that arise with key predistribution when strategies for coping with jamming attacks are employed. In the first part of this dissertation we propose a hybrid key predistribution scheme that supports ad hoc/sensor networks that use mobility to cope with jamming attacks. In the presence of jamming attacks, this hybrid scheme provides high key connectivity while reducing the number of isolated nodes (after coping with jamming using spatial retreats). The hybrid scheme is a combination of random key predistribution and deployment-based key predistribution schemes that have complementary useful features for secure connectivity. In the second part we study performance of these key predistribution schemes under other jamming coping techniques namely power adaptation and directional antennas. We show that the combination of the hybrid key predistribution and coping techniques can help networks in maintaining secure connectivity even under jamming attacks
On Topological Properties of Wireless Sensor Networks under the q-Composite Key Predistribution Scheme with On/Off Channels
The q-composite key predistribution scheme [1] is used prevalently for secure
communications in large-scale wireless sensor networks (WSNs). Prior work
[2]-[4] explores topological properties of WSNs employing the q-composite
scheme for q = 1 with unreliable communication links modeled as independent
on/off channels. In this paper, we investigate topological properties related
to the node degree in WSNs operating under the q-composite scheme and the
on/off channel model. Our results apply to general q and are stronger than
those reported for the node degree in prior work even for the case of q being
1. Specifically, we show that the number of nodes with certain degree
asymptotically converges in distribution to a Poisson random variable, present
the asymptotic probability distribution for the minimum degree of the network,
and establish the asymptotically exact probability for the property that the
minimum degree is at least an arbitrary value. Numerical experiments confirm
the validity of our analytical findings.Comment: Best Student Paper Finalist in IEEE International Symposium on
Information Theory (ISIT) 201
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