True Random Number Generator Based on Ring Oscillator PUFs

Random number generator is an important building block for many cryptographic primitives and protocols. Random numbers are used to initialize key bits, nonces and initialization vectors and seed pseudo-random number generators. Physical Unclonable Functions (PUFs) are a popular security primitive in cryptographic systems used for authentication, secure key storage and so on. PUFs have nature properties of unpredictability and uniqueness which is very suitable to be served as a source of randomness. In this paper we propose a new design of a true random number generator based on ring oscillator PUFs. It utilizes a self-feedback mechanism between the response and challenge of PUFs and some simple operations, mainly addition, rotation and xor, on the output of PUFs to generate truly random bits. Our design is very simple and easy to be implemented while achieving good randomness. Experiment results verified the good quality of bits generated by our design.