Round Up of New Authenticating Technologies

The importance of technology in protecting products, people and services against malicious attack has never been greater, as this cross-section of innovations shows.

Photoluminescent Effects

Tapematic has announced the grant of US Patent (US10889885B2) and European Patent (EP3441232A1) pertaining to a ‘Photoluminescent Method for Surface Decoration of Articles’.

The patent represents ‘an exclusive, innovative, decoration method, which allows parts to have a unique photoluminescent effect, allowing anti-counterfeiting properties’. During the day, light parts have a metallic effect, while in the dark, parts are completely photoluminescent or show a photoluminescent image, logo, pattern, and/or variable data.

This process can be produced automatically inline by installing the Tapematic IDM II module with the PST Line II – which is an in-line modular system for applying a stable varnish and metal coating to different substrate materials.

The company’s plan is to offer licence agreements for the US and EU patents, together with the equipment and technology for producing this unique decorative anti-counterfeit feature.

Luminescent Gels

Scientists from Trinity College, Dublin have taken inspiration from nature to create luminescent, self-healing gels with potential applications for protecting banknotes from counterfeiting.

The scientists have been able to introduce guanosine (a molecule that plays many important metabolic roles in our body cells) into these gels, as well as add other molecules that can do exciting things from a materials perspective. One such addition to these gels is that of lanthanide ions, which possess unique properties including luminescence, magnetism, and the ability to speed up specific reactions.

Guanosine gels exhibit chirality (left-handed helicity in this case), and the scientists focused on transferring that characteristic to the lanthanide elements of the gels once those ions had been added.

Although that may seem like just one more simple step in the chemical recipe, it is a leap that opens doors to a multitude of new applications as it means these gels can accurately signal varying intensities of whatever they are designed to sense.

The study was published in a recent edition of the Cell Press journal Chem.

Thorfinnur Gunnlaugsson, Professor of Chemistry at Trinity’s School of Chemistry said: ‘the material presented in this Chem article, gives rise to the chiral- based emission upon irradiation of visible light. This means that using a technique called circular polarised luminescence (CPL), we can observe either the ‘right or the left-handed’ (eg. the polarised) emission from the material.

‘The CPL technique is an important means of developing ‘responsive’ counterfeiting inks for use in printing of banknotes, labels, etc. Hence, the opportunities here are vast for future developments, and we are excited to be part of this important finding, which was only made possible with the coming together of leading research groups with strong expertise.’ 

Gold Nanoparticle PUFs

The work described in a paper titled ‘Physically unclonable functions taggant for universal steganographic prints’, recently published in Scientific Reports, generates a physically unclonable functions (PUF) taggant in an aqueous-soluble ink, based on surface-enhanced Raman scattering of discrete self-assemblies of gold (Au) nanoparticles. Using this stealth ‘nanobeacon’, the researchers detected a fingerprint-type Raman spectroscopy signal that was clearly identified, even on a business card with a pigment mask printed on it.

Accordingly, the research group claims to have overcome the reverse engineering problem that is otherwise inherent to analogous anti-counterfeiting techniques. One can readily tailor the ink to various information needs and application requirements. The stealth nanobeacon printing will be particularly useful for steganography (the practice of concealing a message within another message or a physical object) and provide a sensitive fingerprint for anti-counterfeiting.

For secure identification, PUFs with a specific challenge-response that is dependent on the fingerprint properties of the device are becoming indispensable. PUFs, combined with chemical methods that are compatible with well-established nanotechnology, are an active area of research and are increasingly being applied as various taggants to soft materials, such as printed devices and organic semiconductors.

For anti-counterfeit measures, these PUF taggants are identified by analytical methods based on the properties of the taggants instead of specific challenge-responses of the devices.

More PUFs

Another potential anti-counterfeit technique that uses PUFs is based markers created by chemical procedures in a stochastic mechanism. The unpredictability created by the non-deterministic technique assures that replicating the PUF key is close to impossible whenever the PUF sequence is digitised and saved.

The technique suggested in a study recently published in the journal ‘ACS Applied Materials & Interfaces’, entitled ‘Nanocatalyst-Enabled Physically Unclonable Functions as Smart Anticounterfeiting Tags with AI-Aided Smartphone Authentication’, aims to deliver an anti-counterfeit method via a rapid (1 minute), reversible, and equipment-free colorimetry reading facilitated by nanoscale catalysts, which would be usable at any juncture of the supply network, even the end user.

Owing to the creation of a dependable AI method for quick and reliable visual marker authentication, on the basis of deep learning and computer vision approaches, this nanotechnology-facilitated system may be readily encoded and then authorised via a smartphone.

In this study, the team demonstrated the possibility of merging chemistry, nanotechnology, and artificial intelligence to build novel cross-discipline techniques aimed at addressing critical sustainability and security challenges.

A sophisticated reversible PUF marker was presented, that combined the achievement of distinct patterning with substantial encryption capabilities, with a visual colorimetry reading perceptible by the human eye and analysable using a smartphone.

The approach adopted by the team provided ease in authenticating (ie. equipment-free visual reading) as well as cutting-edge encryption capabilities, by using the catalytic characteristics of nanoparticles. The suggested technique may be improved by creating various stochastic patterns and platforms, resulting in even greater security levels.

The ability to achieve repeated verification cycles in ambient settings, owing to the rapid ON/OFF colour emergence/fading system evoked by the nanoscale platinum catalysts, opens up fresh avenues for in-situ analyses of potential counterfeits of high-quality goods throughout the entire supply network, from quality control after production to individual evaluation by the end user.