A true random number generator based on a Chua and RO-PUF: design, implementation and statistical analysis

Physical unclonable function (PUF) and true random number generator structures are important components used for security in cryptographic systems. Random numbers can be generated for cryptography by using these two components together. In particular, it is desirable that these numbers be unpredictable, non-reproducible and have good statistical properties. This study presents the design of a ring oscillator (RO)-based PUF in a field programmable gate array. Random numbers-obtained from a Chua circuit that exhibits chaotic behavior in 3D and continuous time-were applied to the RO-based PUF challenge inputs. Normalization operations were performed to convert the values in floating number format-obtained by sampling the Chua circuit-into the binary number system. Because modular arithmetic was used in the normalization process, it was simple and fast to obtain the generated numbers to be applied to the challenge inputs. NIST, autocorrelation and scale index tests were used to reveal the usability of the random numbers obtained by the RO-PUF for key generation. The results showed that the statistical properties of the numbers obtained were good and could be used in cryptography.