Automatic Balancing of “Arbiter” Physical Unclonable Function Paths

The features of building on the basis of programmable logic integrated circuits of “arbiter” physical unclonable functions (APUF) are considered. The problem of asymmetry of pairs of APUF paths is indicated and the negative impact of this phenomenon on their characteristics is noted. A time measuring system based on a ring oscillator scheme, which is used to analyze the time characteristics of APUF paths, is described. A method for automatic balancing of signal propagation delays through the APUF paths based on the calculation of the corrective value is proposed. The consistency of the proposed balancing technique is experimentally confirmed based on the improvement in the characteristics of the APUF after its implementation. A digital scheme of this technique is presented, which can form the basis for the development of a delay auto correction scheme through APUF paths with different levels of autonomy.