Master Thesis Defense: Merve Şahin
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Merve Şahin
Computer Science and Engineering, M.Sc. Thesis, 2013 

Thesis Jury
Assoc. Prof. Albert Levi (Thesis Supervisor), Assoc. Prof. Yücel Saygın, Assoc. Prof.  Cem Güneri, Assoc. Prof. Selim Balcısoy, Asst. Prof. Hakan Erdoğan.

Date &Time: August,13th,2013 – 14:00

Place: FENS L067

Keywords: Mobile Wireless Sensor Networks, Security, Keyring Update, Connectivity


Wireless Sensor Networks (WSNs) are composed of small, battery-powered devices called sensor nodes. Sensor nodes have sensing, processing and communication capabilities to monitor the environment and gather data. WSNs have various application areas ranging from military surveillance to forest fire detection. Security is an important issue for Wireless Sensor Networks because sensor nodes are deployed in hostile and unattended areas. Nodes are vulnerable to physical capture attacks and the attackers can easily eavesdrop on network communications.

To provide security to WSNs, many key predistribution schemes have been proposed. However, most of these schemes consider the static WSNs and they perform poorly when they are applied to Mobile Wireless Sensor Networks (MWSNs). In this thesis, we propose Dynamic Keyring Update (DKRU) mechanism for MWSNs. The aim of DKRU mechanism is to enable sensor nodes to update their keyrings periodically during movement, by observing the frequent keys in their neighbors. Our mechanism can be used together with different key predistribution schemes and it helps to increase the performance of them.

For performance evaluation reasons, we used our mechanism together with an existing random key predistribution scheme and a location-based key predistribution scheme. For each of these key predistribution schemes, we analyzed our mechanism using two different mobility models. Our results show that DKRU mechanism increases the local and global connectivity when it is applied to MWSNs. Moreover, our mechanism does not cause significant degradation in network resiliency and communication overhead.