DEMO: Inherent PUFs and secure PRNGs on commercial off-the-shelf microcontrollers
Anthony Van Herrewege, André Schaller, Stefan Katzenbeisser, Ingrid M.R. Verbauwhede · 2013
Research on Physically Unclonable Functions (PUFs) has become very popular in recent years. However, all PUFs researched so far require either ASICs, FPGAs or a microcontroller with external components. Our research focuses on identifying PUFs in commercial off-the-shelf devices, e.g. microcontrollers. We show that PUFs exist in several off-theshelf products, which can be used for security applications. We present measurement results on the PUF behavior of five of the most popular microcontrollers today: ARM Cortex A,ARM Cortex-M,Atmel AVR, Microchip PIC16 and Texas Instruments MSP430. Based on these measurements, we can calculate whether these chips can be considered for applications requiring strong cryptography. As a result of these findings, we present a secure bootloader for the ARM Cortex-A9 platform based on a PUF inherent to the device, requiring no external components. Furthermore, instead of discarding the randomness in PUF responses, we utilize this to create strong seeds for pseudo-random number generators (PRNGs). The existence of a secure RNG is at the heart of virtually every cryptographic protocol, yet very often overlooked. We present the implementation of a strongly seeded PRNG for the ARM Cortex-M family, again requiring no external components.