Robust and flexible FPGA-based digital PUF

We have developed the first FPGA-based digital physical unclonable function (PUF) by leveraging the reconfigurability of an FPGA and introducing a new way of using the standard analog delay PUF. The key observation is that for any analog delay PUF, there is a subset of challenge inputs for which the PUF output is stable regardless of operation and environmental conditions. We use only such stable inputs to initialize the look-up tables (LUTs) that are configured in such a way that the digital PUF is formed. We demonstrate the effectiveness of the new security primitive using extensive simulation and experimental results. For example, we show that the new PUF is resistant against a wide spectrum of security attacks and its output stream passes all the NIST randomness tests.