GPIO PUF For IoT Devices

As the number of IoT devices start to explode, establishing the irrefutable device identity is at the root of trust. Physically Unclonable Functions (PUFs) are emerging as a significant alternative to the conventional methods to establish the hardware root of trust. The existing research in PUFs has focused on the design of custom circuits for deriving signatures. These signatures are used as security primitive. We design a novel GPIO PUF from GPIOs of COTS microcontrollers. Further, we demonstrate our method with low-cost off-the-shelf Arduino boards and characterize the repeatability and uniqueness of the PUF. Our experimental evaluation proves the robustness of GPIO PUF. We achieved 100% accuracy for the identification of 12 devices on the 12000 measurements collected over the duration of one month. Our evaluation has shown that the GPIO PUF is a promising alternative for generating strong identification which could be used as a primitive for several applications. We further discuss ways to enhance the uniqueness for a larger set of smart devices.