Key Distribution and Route Selection in Wireless Sensor Networks

flangeeasyMobile - Wireless

Nov 21, 2013 (3 years and 11 months ago)

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Key Distribution and Route Selection
in Wireless Sensor Networks

Nathan Lewis, Noria Foukia

{
ndlewis,nfoukia
}@
infoscience.otago.ac.nz

Information Science Institute

University of Otago

Dunedin, New Zealand

Objectives


Efficiency of distribution of pair
-
wise
encryption keys


Reliability of route selection


Overview


Key Distribution


Trust


Neighbor
-
based key distribution


Route Selection


Trust and Cost


Expenditure


Avoiding Loops


Testing routes

Key Distribution


By Base Station


All keys created by the Base Station


Nodes must communicate with the Base Station
to receive pair
-
wise keys


Nodes may be many hops from the Base Station

Key Distribution


By Neighbor


Common trusted neighbor can create a key


Initial trust calculation


Communications savings

Number of transmissions/node required for all nodes to
acquire pair
-
wise keys with their immediate neighbors.

40
50
60
70
80
90
100
100
200
300
400
500
Key Distribution by Neighbors - Degree = 10
Key Distribution by BS - Degree = 10
Key Distribution by Neighbors - Degree = 15
Key Distribution by BS - Degree = 15
Route Selection


Trust and Cost


Route Trust
(TR) is the minimum of the trust
values that each node has for the next hop on the
route


Route Cost
(CR) is the sum of the costs of each
hop to the destination


TR
A→B →BS

= min(TN
A →B
, TR
B →BS
)


CR
A →B →BS

= CN
A →B

+ CR
B →BS

Route Selection


Expenditure


How much we expect to pay to use a given route


E
A

= CR
A

+ (1


TR
A
)CR
B


CR
A

is the cost to use route A


(1


TR
A
) is the probability of route A failing


CR
B

is the cost to use route B


E
B

= CR
B

+ (1


TR
B
)CR
A


Compare two routes


Calculate E
A

and E
B

and select route with smaller
Expenditure


Multiple routes (C, D, ...)

Avoiding Loops


Loss of route information messages


Inconsistent picture of the state of the neighborhood


Possibility of selecting route that causes a loop


First send route test message


If message is received at destination then route does
not contain loop


If message returns to sender then sender knows a
loop exists and can avoid using that route

Summary


Neighbor
-
based pair
-
wise key distribution
reduces communications with large numbers
of nodes


Route selection requires only local
information, has simple calculation and only
requires a single pass through the list of
available routes


Reliable method of avoiding loops

Future work


May not need to test whole route, limit
number of hops


Add a reputation mechanism


Test in environment where nodes are mobile


Test in hostile environment with hostile nodes




nfoukia@infoscience.otago.ac.nz