Theoretical framework for physical unclonable functions, including quantum readout.

We propose a theoretical framework to quantitatively describe Physical Unclonable Functions (PUFs), including extensions to quantum protocols, so-called Quantum Readout PUFs (QR-PUFs). (QR-) PUFs are physical systems with challenge-response behavior intended to be hard to clone or simulate. Their use has been proposed in several cryptographic protocols, with particular emphasis on authentication. Here, we provide theoretical assumptions and definitions behind the intuitive ideas of (QR-) PUFs. This allows to quantitatively characterize the security of such devices in cryptographic protocols. First, by generalizing previous ideas, we design a general authentication scheme, which is applicable to different physical implementations of both classical PUFs and (QR-) PUFs. Then, we define the robustness and the unclonability, which allows us to derive security thresholds for (QR-) PUF authentication and paves the way to develop further new authentication protocols.