Analysis of Random Number Generators Based on FibonacciGalois Ring Oscillators This paper presents the analysis of random number generators(RNGs) based on regular sampling of irregular waveform method where the irregular signal is obtained from the oscillations of combined Fibonacci and Galois ring oscillators. As the proposed random number generator is made up of logic gates only, it is implemented on a FPGA (fieldprogrammable gate array). The regular waveform generated by the digital clock manager of the FPGA is used for sampling the irregular signal and the resulting bit stream is uploaded to a computer where it is subjected to standard statistical test. The polynomials defining the Fibonacci and Galois ring oscillators are varied to assess the relationship between the polynomial and the randomness of the output bit stream. It is demonstrated that for both polynomial functions, by combining enough number of oscillator structures, the output bit streams from each RNG satisfy standard statistical tests without post processing. To the best of our knowledge, this paper presents the first comparative study on the impact of polynomials on random number generators based on Fibonacci and Galois ring oscillators.

A Robust Random Number Generator Based on Chaotic Ring Oscillators A robust chaosbased random number generator (RNG) system is newly proposed. Output bitstreams generated from this new RNG system is tested on NIST80022 test suite. Proposed RNG circuit fulfill all fifteen randomness tests of NIST80022 without undergoing any postprocessing implementations except for the X OR operation. While classical ring oscillator based RNG systems needs at least 25 rings, each of them containing 13 inverters, and 25 D flipflops to pass all the tests, newly designed RNG system pass all the tests successfully with 10 chaotic new subcells containing 20 ring oscillators with 13 inverters and each subcell includes two resistors, a capacitor and two diodes. These are enough for the new system to generate sufficient randomness without any D flipflops. Experimental results are demonstrated and comparisons are made among the new design, classical ring oscillator based RNGs and another chaotic ring oscillator based RNG. Noise analysis of the new RNG is also performed to show that the system has a nondeterministic entropy source which secures the system against possible synchronization attacks.