Paper 2007/482

TinyPBC: Pairings for Authenticated Identity-Based Non-Interactive Key Distribution in Sensor Networks

Leonardo B. Oliveira and Michael Scott and Julio López and Ricardo Dahab

Abstract

Key distribution in Wireless Sensor Networks (WSNs) is challenging. Symmetric cryptosystems can perform it efficiently, but they often do not provide a perfect trade-off between resilience and storage. Further, even though conventional public key and elliptic curve cryptosystem are computationally feasible on sensor nodes, protocols based on them are not. They require exchange and storage of large keys and certificates, which is expensive. Using Pairing-based Cryptography (PBC) protocols, conversely, parties can agree on keys without any interaction. In this work, we (i) show how security in WSNs can be bootstrapped using an authenticated identity-based non-interactive protocol and (ii) present TinyPBC, to our knowledge, the most efficient implementation of PBC primitives for an 8-bit processor. TinyPBC is an open source code able to compute pairings as well as binary multiplication in about 5.5s and 4019.46$\mu$s, respectively, on the ATmega128L 7.3828-MHz/4KB SRAM/128KB ROM processor -- the MICA2 and MICAZ node processor.