Date of Award


Document Type


Degree Name

Master of Science in Electrical Engineering


Department of Electrical and Computer Engineering

First Advisor

Barry E. Mullins, PhD


This thesis investigates the impact of using three different rekeying protocols–pair-wise, hierarchical, and Secure Lock within a wireless sensor network (WSN) under the Hubenko architecture. Using a Matlab computer simulation, the impact of the three rekeying protocols on the number of bits transmitted across the network and the amount of battery power consumed in WSN nodes during rekey operations is investigated. Baseline pair-wise rekeying performance can be improved by using either Secure Lock or hierarchical rekeying. The best choice depends on the size of the WSN and the size of the key used. Hierarchical rekeying is the best choice for networks with 500 or more nodes using a key size of 512 bits. It is also the best choice for a network of 1,000 nodes using a 256-bit key. For smaller networks with shorter key sizes, Secure Lock is the best choice. Overall, the number of bits transmitted for rekey operations can be reduced 3.32% to 75.80% and the battery power savings range from 0.03% to 39.94% compared to pair-wise keying. Based on the number of bits transmitted, the savings in battery power and the amount of memory required, hierarchical keying is clearly the best approach for network sizes of 1,000 nodes or more utilizing a key with 128 bits or more in length. For smaller network sizes, Secure Lock can be beneficial, but any savings over hierarchical keying are offset by the weaker security scheme and increased complexity of Secure Lock.

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