impact and compensation of correlated process variation on ring oscillator based puf
A Physical Unclonable Function in silicon is a die-unique challenge-response function that exploits circuit variations. A PUF has the potential to become an important security solution due to its ability to generate volatile secret keys. Before a PUF can be integrated into a system, its critical quality factors, including uniqueness, reliability and resiliency to different types of attacks, must be ensured. The uniqueness of a PUF is determined by the random inter-die process variations. However, manufacturing process variations have another component, called correlated intra-die variations. This component becomes significant in deep-submicron device technology below 90nm. In this paper, we show that the quality of a ring oscillator (RO) based PUF is affected by correlated intra-die process variation. We present experiments on 90nm FPGA devices and analyze the experimental data to quantify the effect and also propose a method to improve the quality of an RO-PUF by minimizing the effect of correlated intra-die variations.
correlated process variation ring oscillator (ro) fpga physical unclonable function (puf)