A Novel Security Key Generation Method for SRAM PUF Based on Fourier Analysis

Most of the current security key generation schemes for static random access memory physical unclonable function (SRAM PUF) are based on a fuzzy extractor. However, it is difficult to deploy the fuzzy extractor in resource-constrained systems since the implementation of error correcting codes is complicated and requires huge processing resources. To this end, we propose a novel security key generation method for SRAM PUF based on a Fourier analysis. The SRAM PUF Boolean function is introduced to describe the power-up behavior of an SRAM device, which is followed by its Fourier spectrums. By exploring spectrums of the SRAM device, it is observed that the sign-bits of Fourier coefficients at certain generalized frequency points are randomly distributed and noise resistant. As such, the generalized frequency points as well as the sign-bits are suggested for security key generation in conjunction with a sign-bit encoding algorithm. The proposed method is well compared with the conventional fuzzy extractor. It is highlighted that error correcting code will not be involved in the whole lifecycle. Consequently, the method is suitable for the resource-constrained system applications. The proposed method is performed through couple of real measurements on two different platforms. The experimental results show that 8-kB SRAM cells have sufficient entropy for 128-bit security key generation.