Subscriber access provided by Karolinska Institutet, University Library
Applications of Polymer, Composite, and Coating Materials
Versatile and Validated Optical Authentication System based on Physical Unclonable Functions Riikka Arppe-Tabbara, Mohammad Tabbara, and Thomas Just Sørensen ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b17403 • Publication Date (Web): 16 Jan 2019 Downloaded from http://pubs.acs.org on January 24, 2019
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
ACS Applied Materials & Interfaces
Versatile and Validated Optical Authentication System based on Physical Unclonable Functions Riikka Arppe-Tabbara,* Mohammad Tabbara and Thomas Just Sørensen* Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København Ø, Denmark.
[email protected] KEYWORDS: physical unclonable functions, lanthanide luminescence, luminescent tags, optical authentication, anticounterfeiting system, anti-counterfeiting tags, anti-counterfeiting ink ABSTRACT: Counterfeit consumer products, electronic components, and medicines generate heavy economic losses, pose a massive security risk, and endanger human lives on a daily basis. Combatting counterfeits requires incorporation of uncopiable or unclonable features in each and every product. By exploiting the inherent randomness of stochastic processes an optical authentication system based on physical unclonable functions (PUFs) was developed. The system relies on placing unique tags—PUF-tags—on the individual products. The tags can be created using commercial printing and coating technologies using several combinations of carrier materials and taggant materials. The authentication system was found to be independent of how contrast was generated, and examples of PUF-tags based on scattering, absorption and luminescence were made. A version of the authentication using the combination of scattering based PUF tags and a smartphone-based reader was validated on a sample size of 9,720 unique codes. With zero false positives in 29,154 matches, an encoding capacity of 2.5·10 120, and a low cost of manufacture we conclude that the scattering based authentication system has the potential to solve the problem of counterfeit products.
INTRODUCTION The circulation of counterfeit products poses major societal challenges. Faked consumer goods and luxury products generate billion dollar economic losses,1-3 while fake medical devices and counterfeit medicine are a real threat to well-being, particularly in developing countries.4-9 The problem has accelerated with the globalization of trade and the shift in consumer habits. Consumers no longer have strong ties to the point of sale, and the point of sale does not have a full knowledge of product history. Counterfeits can easily enter the marketplace unnoticed to the consumer or the point of sale. To stop this from happening the manufacturer often implements anticounterfeiting features,10 that are often themselves subject to being counterfeited.11 A physical unclonable function—a PUF—is a unique physical manifestation that, at sufficient complexity, becomes impossible to replicate.11-20 Inherently, a PUF must be the result of a random or stochastic process.11, 13, 21-23 A perfect example is throwing a handful of sand on a surface. Each throw generates a unique pattern of sand, and the number of particles makes the chance of two identical patterns occurring essentially zero. We have developed a PUF-based optical authentication system based around this very principle. In anti-counterfeiting, the established technologies all use tags that are the result of a deterministic process.11, 24-30 Note that even DNA tags are readily read and copied if a suitable incentive is present.24, 31 While fingerprint-like or PUF tags are emerging,10, 32-34 the dominating anti-counterfeiting technologies all rely on restricted access to secure ink or secure printing technology.10-11 This makes the anti-counterfeiting measures susceptible to counterfeiting. The optical authentication system presented here is different in nature as each tag is
truly unique and can never be replicated—not even by the manufacturer, let alone the counterfeiters.
Figure 1. The concept of authentication using unique identifiers (top): as each product is marked with a unique tamperproof PUFtag all products can always be validated and the provenance ensured. The operation mechanism (bottom) of the optical authentication system presented here.
The problem we set out to solve is illustrated in Figure 1. Recently, we described a PUF-concept using luminescent lanthanide ions trapped in zeolites read using a sophisticated fluorescence microscope.34-35 Here, we show that the PUFconcept is viable even when using scattering or absorbing microparticles read by a smartphone fitted with a macro lens. Thus, the provenance of any product can be validated when the manufacturer puts a tamper proof PUF-tag on the products, see Figure 1. The PUF-tag is unique to the individual product
ACS Paragon Plus Environment
ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
and the end-user can always validate that the product is genuine. As all products are fitted with a unique PUF-tag that is registered when the product leaves the production line, validation at any point up to end-user is possible. This also ensures that each product can be uniquely identified throughout the supply chain. As the PUF can be combined with any form of barcode—here a QR code—the anti-counterfeiting measure is readily paired with existing serialization. The optical authentication system relies on a database of digital identities that is a full representation of each PUF-tag. Each validation is performed by the trusted authority against the digital identity, no data reduction occurs between end user and the trusted authority, and at no point is the registered digital identity shared with the end user. In this paper we show that PUF-tags can be created from a variety of materials using the most common printing technologies. We validate the anti-counterfeiting system using ~10.000 unique tags and find that the optical authentication system in this form gives rise to zero false positives, and has an encoding capacity of 2.5·10120. This limit is the number of different PUF-tags that can be differentiated by the system, not the number of possible patterns created on the PUF sticker.
METHODS AND MATERIALS All chemicals were used as received. Inks. A base ink was made by creating a suspension of microparticles in 1 % (w/v) poly(vinyl alcohol) (PVA, SigmaAldrich) with a molecular weight of 13000-23000. The microparticles are listed in Table 1 and they included titanium(IV) oxide powder (rutile,
