Exploiting oscillator arrays as randomness sources for cryptographic applications

This paper shows how arrays of coupled resonant oscillators can provide wildly disordered phase responses corresponding to nonsynchronized regimes. The unpredictability of their time response makes oscillator arrays attractive randomness sources for cryptographic applications. We describe a possible implementation of a random number generator (RNG) combining the proposed randomness source with a few low cost elements needed for bit stream generation. Several bit stream sequences are simulated with a numerically efficient phase-domain model able to include oscillator phase noise and parameters variability. The randomness of the generated bit streams are checked with the tests provided by the National Institute of Standards and Technology. Our results show that the statistical properties of the proposed RNG are indeed resilient to temperature-induced thermal noise variations as well as to the statistical uncertainty of oscillating frequencies and coupling strengths.