Improve symmetry of arbiter in APUF

Arbiter-based physical unclonable function (APUF) is a classical kind of physical unclonable function (PUF). In APUF-based device authentication, the fairness of traditional APUF is insufficient due to setup time of arbiter. To solve this problem, in this paper we design an arbiter and conduct Monte Carlo simulations to test the performance of the new arbiter. In addition, we present some new evaluation metrics to evaluate the new arbiter quantitatively. Finally, we certify that the new arbiter can work continuously with both one stage racing paths and eight stages racing paths. The new arbiter has good performance in correct rate, stability and fairness. Particularly, it mitigates the setup time problem by reducing the Asymmetry.