PUF-based software protection for low-end embedded devices

Abstract

In recent years, low-end embedded devices have been used increasingly in various scenarios, ranging from consumer electronics to industrial equipment. However, this evolution made embedded devices profitable targets for software piracy and software manipulation. Aggravating this situation, low-end embedded devices typically lack secure hardware to effectively protect against such attacks. In this work, we present a novel software protection scheme, which is particularly suited for already deployed low-end embedded devices without secure hardware. Our approach combines techniques based on self-checksumming code with Physically Unclonable Functions (PUFs) to establish a hardwareassisted software protection. In this way, we can tie the execution of a software instance to a specific device and protect its program code against manipulations.We show that our software protection scheme offers a high level of security against static adversaries and demonstrate that dynamic adversaries require considerable resources to perform a successful attack. To explore the feasibility of our solution, we implemented the protection scheme on an ARM-based low-end commodity microcontroller. A further performance evaluation shows that the implemented solution exhibits a fair overhead of ten percent.