How to Manage Keys and Reconfiguration in WSNs Exploiting SRAM Based PUFs

A wide spectrum of security challenges were arose by Wireless Sensor Network (WSN) architectures and common security techniques used in traditional networks are impractical. In particular, being the sensor nodes often deployed in unattended areas, physical attacks are possible and have to be taken into account during the architecture design. Whenever an attacker enters in possession of a node, he/she can jeopardize the network by extracting cryptographic keys used for secure communication. Moreover, an attacker can also try to brute force the keys, hence they should be fully random and hard to guess. In this paper, we propose a novel solution based on generating keys from unique physical characteristics of a node integrated circuit without requiring additional hardware compared to common WSN node architectures. To this aim, we exploit the Static Random Access Memory based Physically Unclonable Functions and we show their applicability to the WSN by implementing a working prototype based on the STM32F4 microcontroller.