A key distribution scheme for mobile underwater wireless sensor networks

Official URL: http://192.168.1.20/record=b1378237 (Table of Contents)

Wireless Sensor Networks consist of small battery-limited devices called sensor nodes. They are used for collecting data from surrounding environment and relay them via wireless communication. One of the recent application areas is underwater sensing. Communication in Underwater Wireless Sensor Networks (UWSN) is different from airborne communication. Radio frequencies cannot be used for UWSN. Instead acoustic waves, which cause extra challenges, are used in UWSN. When UWSNs are deployed in hostile environment, nodes can be captured by an adversary. In order to secure UWSNs, firstly key distribution problem must be addressed. Moreover, UWSNs are inherently mobile since the nodes may be drifted in the sea. In this thesis, we propose a key distribution model which is applied for two group mobility models, namely (i) nomadic mobility model and (ii) meandering current mobility model. Our nomadic mobility based key distribution scheme works in three dimensions. However, this scheme is suitable only for small coastal areas. On the other hand, our meandering mobility based key distribution model is a two dimensional one and spans several kilometers in the open sea. In both schemes, a hierarchical structure is used. Secure and resilient group communication is handled via well-known Blom's key distribution scheme. We analyzed the performance of the proposed schemes using simulations. Our results show that secure connectivity of both schemes is generally high. Of course, mobility causes some temporary decreases in the connectivity, but our schemes help to heal the connectivity performance in time. Moreover, our schemes show good resiliency performance such that capture of some nodes by an adversary only causes very small amount of links between uncaptured nodes to be compromised.