Chain-of-trust for microcontrollers using SRAM PUFs: The linux case study

Many security challenges have emerged from what is defined as Internet of Things (IoT), due to the inherent permanent connection of devices involved in networks. Furthermore, IoT devices are often deployed in unattended working environment and, hence, they are prone to physical attacks. Attackers take advantages of such weaknesses to clone devices, tamper the software installed on them and extract cryptographic keys. In this paper, we propose a technique to exploit Static Random Access Memory based Phisical Unclonable Functions to have available a chain-oftrust on a microcontroller device. We prove its effectiveness in terms of reliability and required overhead by introducing a case study based on the STM32F7 device running the Linux operating system.