Periodic Reporting for period 1 - VALIDATE (Verifying Authenticity with Liquid crystal-Derived Anti Theft Encoding)
Okres sprawozdawczy: 2019-09-01 do 2021-06-30
The material at the heart of VALIDATE is based on the unique optical properties of Cholesteric Spherical Reflectors, or CSRs, which are spherical particles made from droplets or shells of cholesteric liquid crystal that are polymerized into a solid after the liquid crystalline self-assembly has completed. The self-assembly leads to a helical modulation of the optical properties along the radial direction within the sphere, and this is the origin of the attractive and useful optical properties: it turns each CSR into a selective retroreflector, reflecting a narrow wavelength band of light (thus with a saturated colour), with a single well-defined circular polarization, back to an observer that illuminates the CSR along the viewing direction. If the illumination is different from the viewing direction, the reflection takes place in different directions and with different colours, but with several CSRs in a plane also these reflections can be detected thanks to reflections between CSRs eventually bringing the light in the direction of the observer. This ’optical cross communication’ in addition to the basic retroreflection from each CSR in a plane creates a colorful geometric pattern that is unique to the particular arrangement of CSRs. Moreover if the illumination characteristics are changed, this pattern can change dramatically, but always in a way that is unique to the particular sample. This means that the sample does not have one optical appearance but an infinite set of appearances, which depend on how it is illuminated and observed. In the language of security research, the sample has an infinite set of ”challenge–response” combinations.
By dispersing CSRs with slight variations in their individual characteristics (apart from size variations these regard which polarisation and which colour is reflected for a particular illumination condition) in a liquid that can be turned into a solid (like a nail polish), depositing this on a target surface, and then making the resulting coating solid, we can give any object with a solid surface a unique ’fingerprint’ defined by the CSR arrangement, that for all practical purposes is uncloneable, because it is practically impossible to reproduce the exact same arrangement of CSRs a second time. Not even the original producer of the coating can make a copy, because of the unpredictable arrangement of CSRs. This, together with the inherent variability of the optical appearance through the infinite set of challenge–response functions, turns such a solidified coating of CSRs into a Physical Uncloneable Function, or PUF, which is one of the most promising concepts in ensuring secure authentication of physical items, whether for identifying an object or a person holding this object, or tracing a component through a supply chain, or ensuring that an item received by an end customer in one part of the world is indeed the original item that was sent by a producer located very far away.
In VALIDATE we have refined our materials and procedures in order to apply coatings with embedded CSRs onto objects of value, in order to give each object a unique and uncloneable artificial fingerprint that allows persons interacting with the object—whether producer, retailers, transporters or other intermediaries, or the final customer—to authenticate the object as original (and, by consequence, reject any copy they encounter as a fake) as well as tracing the object throughout the supply chain. Originally aiming to focus on the tracing of highly valuable raw gem stones from the mines where they are found to companies refining them into jewelry items, the impact of the covid-19 pandemic on this sector led us to shift gear to the tracing of sustainably produced agricultural produce. In partnership with a European-based company specializing on the import of sustainably produce palm oil, cacao and sheah butter from Ghana, we adapted our solution to be used for making tamper-proof, unique and uncloneable seals of containers for the products, which would allow customers anywhere in the world to obtain trustworthy proof of origin of the products, ensuring that they get the premium-quality product, at minimum environmental impact, that they are paying for.
The project allowed us and our computer science collaborators to improve our technology and adapt it to customer expectations and real-world usage situation to such a degree that we are now taking steps for founding a company that will commercialize the material and the authentication service associated with it. In addition to the encouraging feedback we recieved from farmers, producers and sellers of the sustainably produced agricultural products, our technology has raised strong interest across a range of sectors, and we are now tailoring our authenticaion solution for jewelry, apparel, pharmaceuticals, and many other markets where counterfeited or otherwise substandard products are threatening the business and/or the customers.