Optical nano artifact metrics using silicon random nanostructures.

Tsutomu Matsumoto,Naoya Tate,Yasuyuki Ohyagi,Morihisa Hoga,Makoto Naruse,Shumpei Nishio,Naoki Yoshida

doi:10.1038/srep32438

Abstract

Nano-artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, expensive and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension; our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostructuring technology, we experimentally fabricate clones from the genuine devices. We demonstrate that the statistical properties of the genuine and clone devices are successfully exploited, showing that the liveness-detection-type approach, which is widely deployed in biometrics, is valid in artificially-constructed solid-state nanostructures. These findings pave the way for reasonable and yet sufficiently secure novel principles for information security based on silicon random nanostructures and optical technologies.

Highlights

Artifact metrics[1], known as physical unclonable functions (PUFs)[2], use the unique physical properties of ubiquitous materials to improve the information security of devices[3]; this is increasingly important as society enters the age of the Internet of Things[4]
In [9], we proposed the concept of nano-artifact metrics and experimentally demonstrated the principle by fabricating silicon random nanostructures, which we measured using critical dimension scanning electron microscopy (CDSEM)
Resist collapse occurs during the rinsing step of lithography, and it depends on the pattern resolution, resist thickness and duration of e-beam exposure[11]

Summary

Introduction

Artifact metrics[1], known as physical unclonable functions (PUFs)[2], use the unique physical properties of ubiquitous materials to improve the information security of devices[3]; this is increasingly important as society enters the age of the Internet of Things[4]. In [9], we proposed the concept of nano-artifact metrics and experimentally demonstrated the principle by fabricating silicon random nanostructures, which we measured using critical dimension scanning electron microscopy (CDSEM). Practical optical solutions can be expected if the unique features of a three-dimensional (3D) nanostructure pattern are retrievable via conventional confocal laser microscopy and retain sufficiently secure performance, including authentication and clone resistance.

Results

Conclusion