Laser Fault Injection on RO-Based PUFs Implemented on FPGA
Aghiles Douadi, Elena Ioana Vatajelu, Paolo Maistri, Jean-Max Dutertre, David Hély, Vincent Beroulle, Giorgio Di Natale · 2025
Physical Unclonable Functions (PUFs) offer an attractive alternative for cryptographic key generation by leveraging intrinsic manufacturing variations, thus eliminating the need for permanent key storage. Among them, RO-PUFs—based on ring oscillators—are widely studied due to their simplicity and efficiency. While the sensitivity of individual ROs to laser fault injection has been previously explored, this paper presents, to the best of our knowledge, the first experimental demonstration of a successful laser attack directly impacting the global output of an RO-PUF system implemented on an Artix-7 FPGA. We show that a localized laser injection can selectively alter the frequencies of targeted ROs, leading to deterministic changes in the PUF response. Our results reveal a significant physical vulnerability of RO-PUFs to this type of attack, highlighting the need to develop appropriate countermeasures.