Optimizing cryptographic threshold schemes for the use in wireless sensor networks: Position paper

A huge number of small, computationally restricted sensor nodes can be connected wirelessly to form a sensor network. Such networks can be used to monitor large areas and communicate a multitude of measurements (like temperature, humidity, radiation, and so on) to a remote base station. Since this communication happens over the air interface, the transmitted messages are susceptible to forgery, manipulation and eavesdropping. Conventional cryptographic countermeasures against these kind of attacks cannot be readily applied in the context of sensor networks, due to the limited resources of the individual nodes. Since single nodes can be very easily captured and examined, symmetric schemes with the secret key present in every (or at least a subset of) node(s) pose quite a risk in this setting. In this work, we examine the applicability of threshold cryptographic techniques, especially the Gennaro-Rabin-Rabin multiparty multiplication protocol, for sensor networks by employing several optimizations to the different steps of this algorithm, building on previous results we obtained. We are able to improve the running time up to a factor of 6 compared to an unoptimized version for a bitlength of 1,024 Bit and 33 players.