Arbiter Physical Unclonable Functions with Asymmetric Pairs of Paths

Abstract

The methods of constructing physical unclonable functions (PUF), which are the basis of physical cryptography, are analyzed. The broad applicability of the Arbiter PUF, based on the analysis of the delays of the signal transmitted along two paths, is noted. It is shown that the randomness of the delays is explained by technological variations in the manufacturing process of PUF and their dependence on the use of homogeneous repeating elements that ensure the symmetry of the paths. As an alternative to the existing solutions, the article proposes a new approach for constructing an Arbiter PUF based on asymmetric paths. The sources of randomness as logical element delays are investigated. Their diversity and distinctive characteristics are shown depending on the number of inputs to which an active signal is supplied and the values at other inputs. A technique for balancing a set of pairs of paths of Arbiter PUF is proposed, which lays in regulating the duration of the impulse test signal depending on four types of path asymmetry. New structures of Arbiter PUF with asymmetric pairs of paths are proposed. Experimental studies confirm the possibility of using various sources of randomness in the form of signal delays.