Energy Budget Analysis for Signature Protocols on a Self-powered Wireless Sensor Node

The Internet of Things will include many resource-constrained wireless sensing devices, hungry for energy, bandwidth and compute cycles. The sheer amount of devices involved will require new solutions to handle issues such as identification and power provisioning. In this contribution, we analyze the energy needs of several public-key based authentication protocols, taking into account the energy cost of communication as well as of computation. We have built an autonomous, energy-harvesting sensor node which includes a micro-controller, RFunit, and energy harvester. We investigate the Elliptic Curve Digital Signature Algorithm (ECDSA), the Lamport-Diffie one-time hash-based signature scheme (LD-OTS) and the Winternitz one-time hash-based signature scheme (W-OTS). We demonstrate that there’s a trade-off between energy used for communication, energy used for computation, and security level. However, when we consider the energy needs for the overall system, we show that all schemes are within one order of magnitude from each another.