Key distribution schemes for resource constrained devices in wireless sensor networks

Wireless sensor networks based on highly resource-constrained devices require symmetric cryptography in order to make them secure. Integral to this is the exchange of unique symmetric keys between two devices. In this dissertation, we propose three novel decentralized key distribution schemes that guarantee the confidentiality of a key exchange even if an attacker has compromised some of the devices in the network. Our first key distribution scheme – the basic key distribution scheme – guarantees the confidentiality of any new established key in case there are only eavesdropping attacker and no device failures present. Our second scheme – the fault-tolerant key distribution scheme – extends the basic scheme so that also more powerful attackers and device failures can be handled. Our third proposed key distribution scheme – the extended key distribution scheme – is also based on the basic scheme but further optimized in terms of memory consumption and network traffic. A central objective of all key distribution scheme designs was to minimize resource consumption on the individual devices. We evaluate the resource requirements of our schemes in terms of attacker resilience, memory requirements, and network traffic both through theoretical analysis and through simulations.