III. Physical One-Way Functions

Abstract How can we assign unique, tamper-resistant, and unforgeable identifiers to everyday objects at a very low cost? Physical One-Way Functions (POWFs) provide a novel approach to answering this question. POWFs can be obtained from the inherent threedimensional microstructure of a large class of physical systems known as mesoscopic systems. They are inexpensive to fabricate and prohibitively difficult to duplicate; they admit no compact mathematical representation and are intrinsically tamper-resistant. In this paper, we show how POWFs are obtained by using coherent scattering of visible laser radiation from inhomogeneous structures and experimentally demonstrate their properties. We also discuss potential attacks on POWFs and possible applications