Key distribution is an important issue in
wireless sensor network
Wireless sensor networks (WSNs) refer to networks of spatially dispersed and dedicated sensors that monitor and record the physical conditions of the environment and forward the collected data to a central location. WSNs can measure environmental c ...
(WSN) desig
WSNs are networks of small, battery-powered, memory-constraint devices named
sensor node
A sensor node, also known as a mote (chiefly in North America), is a node in a sensor network that is capable of performing some processing, gathering sensory information and communicating with other connected nodes in the network. A mote is a no ...
s, which have the capability of
wireless communication
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
over a restricted area. Due to memory and power constraints, they need to be well arranged to build a fully functional network.
Key distribution schemes
Key predistribution is the method of distribution of keys onto nodes before deployment. Therefore, the nodes build up the network using their secret keys after deployment, that is, when they reach their target position.
Key predistribution schemes are various methods that have been developed by academicians for a better maintenance of PEA management in WSNs. Basically a key predistribution scheme has 3 phases:
# Key distribution
# Shared key discovery
# Path-key establishment
During these phases, secret keys are generated, placed in
sensor node
A sensor node, also known as a mote (chiefly in North America), is a node in a sensor network that is capable of performing some processing, gathering sensory information and communicating with other connected nodes in the network. A mote is a no ...
s, and each
sensor node
A sensor node, also known as a mote (chiefly in North America), is a node in a sensor network that is capable of performing some processing, gathering sensory information and communicating with other connected nodes in the network. A mote is a no ...
searches the area in its communication range to find another node to communicate. A secure link is established when two nodes discover one or more common keys (this differs in each scheme), and communication is done on that link between those two nodes. Afterwards, paths are established connecting these links, to create a connected graph. The result is a
wireless communication
Wireless communication (or just wireless, when the context allows) is the transfer of information between two or more points without the use of an electrical conductor, optical fiber or other continuous guided medium for the transfer. The most ...
network functioning in its own way, according to the key predistribution scheme used in creation.
There are a number of aspects of WSNs on which key predistribution schemes are competing to achieve a better result. The most critical ones are: local and global connectivity, and resiliency.
Local connectivity means the probability that any two sensor nodes have a common key with which they can establish a secure link to communicate.
Global connectivity is the fraction of nodes that are in the largest connected graph over the number of all nodes.
Resiliency is the number of links that cannot be compromised when a number of nodes(therefore keys in them) are compromised. So it is basically the quality of resistance against the attempts to hack the network. Apart from these, two other critical issues in WSN design are computational cost and hardware cost. Computational cost is the amount of computation done during these phases. Hardware cost is generally the cost of the memory and battery in each node.
Keys may be generated randomly and then the nodes determine mutual connectivity. A structured approach based on matrices that establishes keys in a pair-wise fashion is due to Rolf Blom. Many variations to
Blom's scheme Blom's scheme is a symmetric threshold key exchange protocol in cryptography. The scheme was proposed by the Swedish cryptographer Rolf Blom in a series of articles in the early 1980s.
A trusted party gives each participant a secret key and a publ ...
exist. Thus the scheme of Du et al. combines Blom's key pre-distribution scheme with the random key pre-distribution method with it, providing better resiliency.
[Du, W. et al., A Pairwise Key Pre-distribution Scheme for Wireless Sensor Networks. ACM Transactions on Information and System Security, Vol. 8, No. 2, May 2005, Pages 228–258 http://www.cis.syr.edu/~wedu/Research/paper/ccs10_sensor.pdf]
See also
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Wireless sensor networks
Wireless sensor networks (WSNs) refer to networks of spatially dispersed and dedicated sensors that monitor and record the physical conditions of the environment and forward the collected data to a central location. WSNs can measure environmental c ...
*
Key distribution In symmetric key cryptography, both parties must possess a secret key which they must exchange prior to using any encryption. Distribution of secret keys has been problematic until recently, because it involved face-to-face meeting, use of a trust ...
*
Blom's scheme Blom's scheme is a symmetric threshold key exchange protocol in cryptography. The scheme was proposed by the Swedish cryptographer Rolf Blom in a series of articles in the early 1980s.
A trusted party gives each participant a secret key and a publ ...
References
External links
List of publications for Key Management in WSN
{{Wireless Sensor Network
Key management