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Multi-Layer Key Establishment for Large Scale Sensor Networks

Research on key establishment for Distributed Sensor Networks (DSNs) focuses on lightweight protocols that are feasible for the sensor nodes, which by default have restricted capabilities. Although the most efficient protocols for key establishment are based on symmetric key encryption, these protocols are unable to provide adequate security against attacks, such as node impersonation and fake generation attacks. For this reason, several hybrid key establishment protocols have been developed, making limited use of public key cryptography, and more particularly of Elliptic Curve Cryptography. However, although these protocols seem to be efficient for sensor nodes, they reduce performance, especially in large-scale networks. In this paper, we propose a multi-layer key establishment protocol for DSNs, which combines hybrid and symmetric key establishment techniques. The performance analysis shows a reasonable decrease in performance, due to the optimized use of expensive public-key cryptographic operations.