Arbiter PUF with 4 × 4 switch blocks

A Physical Unclonable Function (PUF) is a physical entity realized in a physical device, e.g. an integrated circuit (IC), that generates responses to given input stimuli, called challenges. Due to manufacturing process variation, every transistor or wire in a physical device has slightly different characteristics. These differences lead to measurable differences in responses of two PUF instances to the same challenge, making it possible to use the PUF as a unique device ``fingerprint''.

An Arbiter PUF (APUF) is a type of delay-based PUFs. The conventional n-stage APUF with 2 × 2 switch blocks generates 1-bit responses to n-bit challenges by letting two symmetrically designed paths to compete. An APUF with 4 × 4 switch blocks generates responses by letting four symmetrically designed paths to compete. The arbiter at the end of the switch block's chain determines in which of 4! = 24 possible orders the four racing paths arrive to its inputs. So, an n-stage 4 × 4 APUF induces a function of type {0,1,...,23}n → {0,1,...,23}.

The source code of programs simulating the behavior of an APUF with 4 × 4 switch blocks is availible in two formats: 24-valued challenges or one-hot encoded challenges.


E. Dubrova, M. Brisfors, B. Degen"A Model of Arbiter PUF with 4 × 4 Switch Blocks", Proceedings of IEEE International Symposium of Multiple-Valued Logic (ISMVL'2020), May 20-22, 2020, Miyazaki, Japan, submitted.


Elena Dubrova
School of Electrical Engineering and Computer Science
Royal Institute of Technology (KTH)
Stockholm, Sweden