Glossary

A multistep process consisting of creating a lenticular image from at least two existing images, and combining it with a lenticular lens. This process can be used to create various frames of animation (for a motion effect), offsetting the various layers at different increments (for a 3D effect), or simply to show a set of alternate images which may appear to transform into each other.

A relief printing process by which many copies are produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. Letterpress printing remained the primary means of printing and distributing information until the 20th century, when offset printing was developed, which largely supplanted the role of letterpress in printing books and newspapers.

A commonly used means of grading security features created by the European Central Bank and adopted for use across the banknote industry. Level 1 refers to features that can be verified by the public, untrained examiners or specialist examiners with the naked eye. Level 2 refers to semicovert features that require some form of reading device or tool to be authenticated. They are typically deployed for use by retailers, cashiers and inspectors but are also detected by sensors in machines (the ECB defines Level 2a, 2b and 2c). Level 3 refers to covert features, generally rare chemicals or compounds that can only be identified by sensors in high speed processing machine verification used in cash centres. Level 4 authentication uses forensic examination to verify banknotes and is used solely by central banks/police.

A semiconductor device that emits light when an electric current flows through it.

Manipulating the width, length and height of line structures to create image and text effects. Using a higher resolution for the output results in effects not possible with commercially available software.

Chemicals that have properties between those of conventional liquids and solid crystals. Orientation of the crystal-like structure of the chemicals results in optically variable effects. Cholesteric liquid crystals have two refractive indices, a property known as birefringence (the ability to rotate the polarisation of incoming light and reflect circularly polarised light either clockwise or anticlockwise). Liquid crystal technology is used for security features that are validated with a polarisng filter.

A collective term for the effects of colour change or other visible characteristics under different sources of illumination.

An umbrella term for solving problems for which development of algorithms by human programmers would be cost-prohibitive, and instead the problems are solved by helping machines ‘discover’ their ‘own’ algorithms, without needing to be explicitly told what to do by any human-developed algorithms. While artificial intelligence encompasses the idea of a machine that can mimic human intelligence, machine learning does not. Machine learning aims to teach a machine how to perform a specific task and provide accurate results by identifying patterns.

A security feature requiring an instrument to verify its presence or data content.

Passports, visas and other travel documents that follow specifications set out in Document 9303 of the International Civil Aviation Organisation (ICAO) to facilitate automatic border management.

The MRZ in a machine-readable travel document contains personally identifiable information in the form of a sequence of alphanumeric characters and the symbol ‘<' spaced over two or three lines. The sequence of characters can be read by document readers to help automate inspection of travel documents.

The ability of a computer to see. The technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry.

An ink containing ferromagnetic components that have a specific reaction to the external magnetic field. Text or symbols applied by this ink can be identified by special magnetic sensors or visualised by magneto-optic converters. The ink can be applied on security threads and fibres,and used for printing images, serial numbers and barcodes.

Thin strip of magnetic material attached to a plastic card and encoded to record and store data.

An analytical technique to quantify known materials and identify unknown compounds within a sample and elucidate the structure and chemical properties of different molecules.

A shipping unit of tobacco products – usually comprising 25 or 50 cartons.

A 2D barcode (eg. datamatrix, QR code, dotcode), typically square-shaped, capable of representing more data per unit area than a linear barcode.

Traditionally, a coin-shaped artistic piece with no face value, made for religious, honorary and other commemorative purposes.

One million pixels. The term is used not only for the number of pixels in an image but also to express the number of image sensor elements of digital cameras or the number of display elements of digital displays.

Printing ink containing metallic components that provide a metallic finish to the applied substrate.

The coating of films or surfaces with a very thin layer of metal using a metal deposition technique. Metallisation is what gives holograms their silver or similar metallic appearance.

A pair of similarly shaded inks, the colour and contrast of which appear virtually identical in normal light, but which have different spectral responses so that, when viewed in another light (such as infrared), one ink displays different effects or colours to the other. In the case of IR pairs, one ink absorbs IR and the other reflects it, and only the IR-reflecting part can be seen through a filter.

Thin 2D metamaterial layers that allow or inhibit the propagation of electromagnetic waves in desired directions.

An integrated circuit embedded into a recessed area on the surface of, for example, an ID card or passport to store and process personal data. A secure document containing a contact microchip must be inserted into a card reader so that the chip can make contact with electrical terminals and allow information to be read.

An integrated circuit embedded under the surface of, for example, an ID card or passport to store and process personal data. The microchip is connected to an aerial (electromagnetic loop antenna) which allows communication with a card reader via electromagnetic waves (RFID). To supply the microchip with energy and to start communication, the card must be in close proximity to the reader.

Small lenses, typically only a few microns in size.

Tiny microscopic mirrors created using origination techniques similar to those used for diffractive OVDs (optically variable devices). Micromirrors reflect light in a specific manner defined by the size and orientation of the mirrors.

A unit of measurement commonly used in authentication when referring to the thickness or gauge of physical substrates and features. One micron is equal to one millionth (10-6) of a metre.

Optical systems that are between a few micrometres (millionths of a metre) and one millimetre in size, including small lenses or arrays of lenses.

Lines, symbols, designs, images or numbers that are printed at dimensions barely perceptible to the unaided human eye but visible at magnifications of between x5 and x10 by (say) a jeweller’s loupe. Microprinting on banknotes usually combines positive and negative characters.

The very small scale structure of a prepared surface of a material as revealed by a microscope above 25× magnification. Diffractive microstructures comprise microprotrusions or microgrooves, or a combination thereof, which are capable of diffracting lightwaves.

The process by which new cryptoassets enter into circulation and new transactions are confirmed by a blockchain network. Mining is performed using sophisticated hardware that solves a complex computational maths problem. When a problem is solved, the miner is awarded the next block of cryptoassets and the process recommences with a trickier problem. Computers verify transactions on the blockchain ledger in exchange for a reward based in cryptocurrency.

An industrial facility manufacturing coins.

An alternative to mining, the process by which assets are written to a blockchain, where the writer of the asset is a pre-determined trusted entity. In certain use cases, such as an ecosystem of banks, minting is preferred due to performance and power consumption requirements.

A letter or symbol, indicating a mint of origin.

A fibrous composition of the substrate used for banknotes, containing fibres of cotton and other materials such as linen or polyester. The purpose of using mixed fibres is to improve the mechanical properties of the paper, such as scratch or crinkle resistance.

A digital driving license held within, and presented from a mobile device.

A digital identity held within, and presented from a mobile device.

A mobile payments system based on accounts held by a mobile operator and accessible from subscribers’ mobile phones.

An app for storing financial information and other documents such as credit cards, bank information, and even driving licences.

Large-scale interference patterns produced when a partially opaque ruled pattern with transparent gaps is overlaid on another similar pattern. For the moiré interference pattern to appear, the two patterns must not be completely identical, but rather displaced, rotated, or have slightly different pitch.

Broad categories that measure the money supply in an economy. In the US, labels are attributed to standardised monetary aggregates: M0 – physical paper and coin currency in circulation plus bank reserves held by the central bank; M1 – all of M0 plus traveller’s cheques and demand deposits; M2 – all of M1 plus money market shares and savings deposits.

Monetary law is the legislative and regulatory framework that provides the legal foundations for the use of monetary value in society, the economy and the legal system.

From the Latin word ‘moneta’, money is any item that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular region, country or socio-economic context. Its onset dates back to the origins of humanity and its physical representation took on very varied forms until the appearance of metal coins. The banknote, a typical representation of money, appeared in the 17th century, and has since experienced great development and growth. Currently, electronic systems allow payments without the need to deliver physical money (banknotes or coins). Money is considered to have three basic functions: unit of account, medium of exchange and store of value.

The illegal process of making large amounts of money generated by a criminal activity, such as drug trafficking or terrorist funding, appear to have come from a legitimate source. The money from the criminal activity is considered dirty, and the process ‘launders’ it to make it look clean

A coin, token or medal whose obverse design is not matched with its reverse.

A diffractive image in which different, usually unrelated images appear at different viewing angles. The most usual, and easiest to make, are images that flip from one to another as a DOVID is tilted from side to side. The most difficult is an image that changes as the DOVID is rotated.

A multistep account login process that requires users to enter more information than just a password. For example, along with the password, users might be asked to enter a code sent to their email, answer a secret question, or scan a fingerprint.

Captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, including light from frequencies beyond the visible light range (ie. infrared and ultraviolet). Multispectral imaging can allow extraction of additional information the human eye fails to capture with its visible receptors for red, green and blue. 

A unit of measurement commonly used in authentication when referring to the thickness or gauge of physical substrates and features. One nanometre is equal to one billionth (10-9) of a metre.