RF-DNA: Radio-Frequency Certificates of Authenticity

Abstract

A certificate of authenticity (COA) is an inexpensive physical object that has a random and unique multidimensional structure S which is hard to near-exactly replicate. An inexpensive device should be able to scan object’s physical “fingerprint,” i.e., obtain a set of features in the form of a multidimensional signal x that pseudo-uniquely represents S. For a given “fingerprint” x and without access to S, it should be computationally difficult to construct an object of fixed dimensions with a “fingerprint” y which is at a bounded proximity from x according to a standardized distance metric. We introduce objects that behave as COAs in the electromagnetic field. The objective is to complement RFIDs so that they are physically, not only digitally, unique and hard to replicate. By enabling this feature, we introduce a tag whose information about the product can be read within a relative far-field, and also whose authenticity can be reliably verified within its near-field. In order to counterfeit a tag, the adversary faces two difficulties – a computational and a manufacturing one. The computational difficulty stems from the hardness of solving linear inverse problems in the electromagnetic field. In order to create an actual tag, the adversary must also manufacture a multidimensional object with a specific three-dimensional topology, dielectric properties, and conductivity.