4. securIty In WIRELESS sensor networks Serdar SANCAK, 2003.

Keywords : Wireless Sensor Networks, Security, Sensor Wars, Spam Attacks, Unsolicited Messages, Quarantine Region, Authentication, Battery Exhaustion.

A sensor network is a collection of sheer number of sensor nodes that collaboratively work by using a multi-hop wireless communications architecture. Sensor networks have wide-range of applications especially in a battlefield because of their flexible, low cost, and self organizing features. Some feasible military applications are: monitoring friendly forces, equipment and ammunition; battle-field surveillance; reconnaissance of opposing forces and terrain; targeting; battle damage assessment; and nuclear, biological and chemical (NBC) attack detection and reconnaissance.

Security issues are of the key issues especially in wireless sensor networks often deployed beyond the enemy lines. When they are reachable, they can be collected and/or destroyed by the enemy. If they are deployed in a hazardous region or a region not accessible for a time period, anti-nodes can be deployed inside the sensor network. Anti-nodes can generate frequent dummy messages. These dummy messages may cause nodes especially close to the sink fail quicker due to energy depletion. We name these types of attacks spam attacks.

In this thesis, we explain our practical solutions for spam attacks and we also evaluate the performance of our schemes by simulation. We consider mobile anti-nodes scenarios. We also do not use encryption and continuous authentications, because sensor nodes have limited computation, power and memory. Instead we determine the regions, named quarantine regions, that may hold suspicious nodes, and the nodes in those regions relay only the authenticated packets for a time period.