Currency security and forensics: a survey

By its definition, the word currency refers to an agreed medium for exchange, a nation’s currency is the formal medium enforced by the elected governing entity. Throughout history, issuers have faced one common threat: counterfeiting. Despite technological advancements, overcoming counterfeit production remains a distant future. Scientific determination of authenticity requires a deep understanding of the raw materials and manufacturing processes involved. This survey serves as a synthesis of the current literature to understand the technology and the mechanics involved in currency manufacture and security, whilst identifying gaps in the current literature. Ultimately, a robust currency is desire

Arduino-controlled Reflectance Transformation Imaging to the study of cultural heritage objects

Fundacao para a Ciencia e a Tecnologia, Portugal (Grant Nos. UIDB/04349/2020 and UID/FIS/04559/2019)- Private funds. V.C. acknowledges the support from UID/Multi/04349/2019. J.C. acknowledges NOVA.ID.FCT.This article examines the development of a low-cost and portable set-up controlled by an Arduino board to perform Reflectance Transformation Imaging technique, from the information derived from 45 digital photographs of an object acquired using a stationary camera. The set-up consists of 45 high-intensity light emitting diodes (LEDs) distributed over a hemispherical dome of 70 cm in diameter and a digital camera on the top of the dome. The LEDs are controlled by an Arduino board, and the user can individually control the LEDs state (ON or OFF) and duration of illumination. An old manuscript written with iron-gall ink and a set of 1 Euro coins mint in 2002 were photographed with the set-up. The interactive re-lighting and the mathematical enhancement of the object's surface revealed corrosion, loss of material, scratches and other details, which were not perceived in standard images. These unique features, which can be extracted using edge detection processing, have immediate application in different fields such as cultural heritage or forensic studies, where they can be used as fingerprints to identify unique objects, allowing also recognizing the use of tools to alter the surface of coins to increase the price in the market.publishersversionpublishe

Applications of Artificial Intelligence to Cryptography

This paper considers some recent advances in the field of Cryptography using Artificial Intelligence (AI). It specifically considers the applications of Machine Learning (ML) and Evolutionary Computing (EC) to analyze and encrypt data. A short overview is given on Artificial Neural Networks (ANNs) and the principles of Deep Learning using Deep ANNs. In this context, the paper considers: (i) the implementation of EC and ANNs for generating unique and unclonable ciphers; (ii) ML strategies for detecting the genuine randomness (or otherwise) of finite binary strings for applications in Cryptanalysis. The aim of the paper is to provide an overview on how AI can be applied for encrypting data and undertaking cryptanalysis of such data and other data types in order to assess the cryptographic strength of an encryption algorithm, e.g. to detect patterns of intercepted data streams that are signatures of encrypted data. This includes some of the authors’ prior contributions to the field which is referenced throughout. Applications are presented which include the authentication of high-value documents such as bank notes with a smartphone. This involves using the antenna of a smartphone to read (in the near field) a flexible radio frequency tag that couples to an integrated circuit with a non-programmable coprocessor. The coprocessor retains ultra-strong encrypted information generated using EC that can be decrypted on-line, thereby validating the authenticity of the document through the Internet of Things with a smartphone. The application of optical authentication methods using a smartphone and optical ciphers is also briefly explored

Self-Organization of Bioinspired Fibrous Surfaces

Nature uses fibrous surfaces for a wide range of functions such as sensing, adhesion, structural color, and self-cleaning. However, little is known about how fiber properties enable them to self-organize into diverse and complex functional forms. Using polymeric micro/nanofiber arrays with tunable properties as model systems, we demonstrate how the combination of mechanical and surface properties can be harnessed to transform an array of anchored nanofibers into a variety of complex, hierarchically organized dynamic functional surfaces. We show that the delicate balance between fiber elasticity and surface adhesion plays a critical role in determining the shape, chirality, and hierarchy of the assembled structures. We further report a strategy for controlling the long-range order of fiber assemblies by manipulating the shape and movement of the liquid-vapor interface. Our study provides fundamental understanding of the pattern formation by self-organization of bioinspired fibrous surfaces. Moreover, our new strategies offer a foundation for designing a vast assortment of functional surfaces with adhesive, optical, water-repellent, capture and release, and many more capabilities with the structural and dynamic sophistication of their biological counterparts.Engineering and Applied Science

Digital watermarking and novel security devices

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Thin Film-Based Optically Variable Security Devices : From Passive to Active

La contrefaçon coûte des milliards de dollars à l’économie mondiale chaque année. Mis à part ces pertes financières, la contrefaçon constitue également une grande menace pour la sécurité du public, entre autre à travers l’existence de faux passeports (terrorisme), de produits pharmaceutiques d’origines incertaines (risques pour la santé) et même de pièces d’avion contrefaites (fiabilité). Les dispositifs de sécurité optiques jouent ainsi un rôle crucial dans la lutte contre la contrefaçon. Les dispositifs optiques tels que ceux basés sur l’interférence de la lumière, introduits dans les années 1980, ont depuis longtemps démontré leur efficacité ; efficacité qui est le résultat de la facilité avec laquelle peut être observé leur changement de couleur angulaire ainsi que le coût relativement élevé de l’´equipement nécessaire à leur production. Malheureusement, de nos jours, en raison de l’apparition de produits de consommation iridescents, tel le papier d’emballage à base de polymères coextrudés, les dispositifs basés sur l’interférence devront être mis à jour. Le but de la présente thèse est donc de démontrer que, grâce à l’utilisation du métaméerisme et de matériaux électrochromiques, de nouveaux types de dispositifs de sécurité actifs présentant des caractéristiques intéressantes peuvent être créés ; en effet, la plupart des dispositifs actuels sont de nature passive. Il est également important d’ajouter que, bien que ces dispositifs soient plus complexes à fabriquer et donc difficiles à contrefaire, ceux-ci restent simples à authentifier. Je d´emontre tout d’abord, que l’ajout du métamérisme dans la conception de filtres interférentiels permet de générer des dispositifs possédant de nouvelles fonctionnalités. Plusieurs structures diff´erentes, qui peuvent être utilisées soit en transmission ou en réflexion, sont ainsi conçues, fabriquées, et évaluées. La première structure qui est présentée est basée sur la combinaison de deux filtres interférentiels métamériques. Possédant des spectres de transmission très différents, ces deux filtres possèdent également différents parcours colorimétriques en fonction de l’angle d’observation, ce qui, par conséquent, rend possible la création d’un effet d’image cachée. En dépit de leurs propriétés intéressantes, ces dispositifs métamériques sont révélés comme étant très sensibles aux changements d’illuminants et d’observateurs; i.e. que le pairage de couleur est perdu dans la plupart des conditions d’observation. Ces problèmes sont résolus par l’implémentation d’une structure plus simple bas´ee sur la juxtaposition d’un filtre interférentiel et d’un matériau coloré non-iridescent. Dans ce cas particulier, en concevant un filtre reproduisant fidèlement le spectre du matériau non-iridescent, la sensibilité du dispositif aux changements de sources de lumière et d’observateurs est minimisée. Puisque seulement le filtre interférentiel change de couleur en fonction de l’angle d’observation, un effet d’image cachée est encore une fois possible. La présence d’un effet d’image cachée ainsi----------Abstract Counterfeiting costs the world economy billions of dollars every year. Aside from financial losses, counterfeiting also poses a great threat to the public’s safety, for example through the existence of counterfeit passports (terrorism), pharmaceutical products (health hazards) and even airplane parts (safety issues). Optical security devices (OSDs) have therefore played a critical role in the fight against counterfeiting. OSDs, such as those based on interference introduced in the 1980s, have clearly proven their efficiency; this high efficiency being the result of the facility with which the color shift can be observed as a function of the observation angle as well as the relatively high cost of the production equipment. On the other hand, nowadays, due to the appearance of iridescent consumer products such as coextruded polymer “wrapping paper”, interference-based devices will need to be “upgraded”. It is the aim of the present thesis to show that through the use of metamerism and electrochromic materials, new types of active security devices with interesting features can be created; indeed, most present-day devices are passive in nature. It is also important to add, that although these devices are more complex to fabricate and therefore difficult to counterfeit, they do remain simple to authenticate for the man on the street. I first demonstrate that the addition of metamerism in the design of interference filters can result in innovative features. Different structures which can be used in transmission and/or in reflection are designed, fabricated, and evaluated. The first structures which are presented here are based on a combination of two different metameric interference filters. Possessing widely different transmission spectra, these filters also offer different angular color shifts and, as a result, offer an opportunity of creating hidden image effects. Despite their interesting properties, such metameric devices are shown to be highly illuminant and observer sensitive; that is the color match is lost under most observation conditions. These issues are solved by a simpler structure based on the juxtaposition of an interference filter and a non-iridescent colored material. In this case, by closely matching the transmission or reflection spectra of both elements, the sensitivity of the device to changes in light sources and observers is minimized. Since only the interference filter will change color as a function of the observation angle, a hidden image effect is yet again possible. The presence of the hidden image, as well as of the non-iridescent material, which serves as a color reference, facilitates the user’s authentication process as well as automated detection by using a laser at a specific angle. Throughout this study, I present the design approach, analyze the filters’ sensitivity to deposition errors, and evaluate the performance of prototype devices prepared by dual ion beam sputtering

Digital Techniques for Documenting and Preserving Cultural Heritage

In this unique collection the authors present a wide range of interdisciplinary methods to study, document, and conserve material cultural heritage. The methods used serve as exemplars of best practice with a wide variety of cultural heritage objects having been recorded, examined, and visualised. The objects range in date, scale, materials, and state of preservation and so pose different research questions and challenges for digitization, conservation, and ontological representation of knowledge. Heritage science and specialist digital technologies are presented in a way approachable to non-scientists, while a separate technical section provides details of methods and techniques, alongside examples of notable applications of spatial and spectral documentation of material cultural heritage, with selected literature and identification of future research. This book is an outcome of interdisciplinary research and debates conducted by the participants of the COST Action TD1201, Colour and Space in Cultural Heritage, 2012–16 and is an Open Access publication available under a CC BY-NC-ND licence.https://scholarworks.wmich.edu/mip_arc_cdh/1000/thumbnail.jp

Fundamental Studies into the Chemical and Physical Properties of Latent Fingermarks

This thesis describes physical and chemical investigations performed on latent fingermarks deposited on non-porous surfaces in order to provide the necessary fundamental underpinnings for future fingermark research. Variation of the physical properties over time was investigated using a novel imaging mode of atomic force microscopy. Spatial distribution of fingermark components was investigated using high-resolution vibrational microspectroscopy techniques. Time-course transformation of squalene in fingermarks stored under different storage conditions was examined using liquid chromatography-high-resolution mass spectrometry