There is a rapid increase in the use of biometrics to establish the identity of an individual, on the premise that certain characteristics of a person, such as their fingerprint or iris pattern, are unique to that person. Similarly, the unique characteristics of products or packaging  are being used as a means of product authentication. There are several sets of characteristics that can be captured and several are now being exploited by a variety of different methods that have been introduced to the authentication world in recent years. This article provides an overview of the current methods available.

Technologies that fit this category are generically known as product fingerprinting and they are all based on the same premise: at the microscopic, molecular or nano-level the characteristics of every printed document, package or product are unique to that item. Capturing these unique characteristics and storing them, as a digital picture or, through the use of an algorithm, as a number, provides a means of matching the item with the captured information. Therefore the item itself is providing the means of authentication, as opposed to other technologies whereby the authentication is applied or added in the form of taggants, inks, holograms and so on.

The information about these unique characteristics is printed or coded in to the product or its packaging, but it may also be stored on a central database. In the former case, with the required reader tool this becomes a self-authenticating feature, also referred to as auto-identification. This refers to the fact that the product can be authenticated without through self-referencing and without the requirement to access an external database. The feature originally captured can be captured again in the field and the resulting image or algorithm compared to that derived from the original and recorded on the pack or the product. If the original and the new codes match, the item is genuine, if they do not match it is an indication that someone has printed a random code which mimics the proper code - ie there is a high probability that the item is not from the purported manufacturer.

If the data is stored on a database, then this also becomes useable for track and trace purposes in the supply chain as the code on the pack can be read at certain transaction points and reported to the database to check that the code is genuine and the item is where it is expected to be. The codes then serve the dual purpose of tracking and authentication, combining the two key elements of combating the counterfeiting of that product.

Self-Authentication

There are several ways of capturing the surface characteristics of a material. One of the first companies to enter this particular arena of authentication was Ingenia Technologies, with LSA™ (Laser Surface Authentication - see AN Vol 11 No 9). This was developed by scientists at Imperial College London and Durham University and uses laser speckle, a phenomenon which causes tiny interference patterns in lightwaves of the same wavelength when those waves are reflected of a surface which is uneven at the nano-scale (ie practically any supposedly flat or smooth surface). The naturally-occurring and unavoidable nanometre-sized imperfections which give each surface its own unique identity reflect light from a focused laser at different angles, so the intensity pattern of that reflected light provides a record of those surface imperfections. LSA works on a variety of materials – including matt-finished plastic cards, coated paper-board packaging and paper – and produces clear results even after the materials are subjected to rough handling, including submersion in water, abrasion, scorching and even being scribbled on with thick black marker pens.

Ingenia Technologies was the spin-out company formed in 2005 to commercialise the technology. One of its first commercial partners was Bayer Technology Services, the two companies joining forces to launch ProteXXion®. This integrates the technology into production and packaging lines so that products can be automatically scanned and registered during production, and verified downstream in the supply chain thereafter in a matter of seconds using mobile readers.

Another example of surface-characteristic authentication is Atlantic Zeiser’s ProDNA system, which captures an image of the microstructure of a document substrate and converts it into a code which is stored on a database. The document can be read with a scanner to verify the code - a process which requires a telecoms connection with the database. Alternatively, the code can be converted to a 2D barcode and printed onto the item. Equipped with the correct scanner and software, the user can match the two codes without checking with the database.

An alternative to capturing the surface characteristics is to capture the molecular structure, on the same principle that no two items made from the same material will have exactly the same molecular structure. One approach to this is used by Rogue DNA Inc in the method of the same name (see AN Vol 12, No 9). This Vancouver company is focused on the document market, particularly passports and visas, where Rogue DNA detects the unique composition of each document at the structural level by measuring the light reflectance in three dimensions in a specific zone or area of the document. The combination of these reflectances is processed and digitized to become the unique signature, or metaphorical ‘DNA’, of the material, which is then stored in a database for subsequent verification of the original.

Document Biometrics

French company Neryos also concentrates on document authentication. Neryos produces document handling equipment for mailrooms and other environments where documents are handled and sorted in large volumes, but it also produces digital printing equipment which is capable of individualising each document. To help its customers provide security and authentication to such documents it has worked with another French company, Signoptics, to develop GeneSign™. Based on Signoptics’ process for imaging and capturing the surface structure of a substrate, this is another technique which exploits the fact that the surface characteristics of every item are unique. The surface is scanned during printing or production using an opto-electronic scanner and the unique surface patterns are captured and converted with an algorithm into alpha-numeric data which is then recorded to a database. Verification of the product requires a simple hand held reader.

Neryos coined the term document biometrics for the family of document identification methods it has developed. It states that its software is fully compatible with and can be integrated in to standard office applications, so that authentication can be undertaken either utilising data that has been captured on the customer’s own database, or on a database provided and hosted by Neryos.

Swiss-German company U-NICA, meanwhile, offers ScryptoTrace™, whereby an area of the surface of the document or product – typically around 5 mm sq - is scanned by standard imaging equipment (anything from a mobile phone camera to high speed cameras on production lines) and then converted to a unique digital descriptor for storage (see AN Vol 14 No 3). Authentication in the field involves taking a digital picture – with a scanner or camera phone – and transmitting this to the database for verification. A particular feature of this system is that it identifies and separates from the photo the 5 mm sq image that was originally scanned, so that the person checking the item does not need to know the exact location of that scan.

Reverse Principle: Sameness = Authentic

Innovia Security has also developed a technique for verifying products made from its films, but applies the principle in reverse. It is a division of Innovia, a leading supplier of films to the tobacco industry and joint owner of Securency, suppliers of polymer substrates for banknotes.

The biaxially-orientated polypropylene that forms the basis of these substrates is unlike those used for commercial applications due to the proprietary bubble process that the company uses to make the films and the resultant very specific film construction. The resulting characteristics are both inherent and unique, and cannot be reproduced by other film manufacturing processes. They are read by Verus™ readers but, unlike other detection systems that use the different, random features of the product or substrates as the authenticator, the base film is identical, and it is its uniformity, regardless of subsequent coating and processing, that provides the verification that the material is genuine.

Authentication not Just for Paper and Plastic

While many characterising techniques record the surface of paper or plastic document or packaging substrates, there are also techniques which examine the intrinsic characteristics of the product itself.

Seattle company Visualant, for example, has developed a technique to read and map colours from near-UV to near IR, thus creating a record of the visible spectrum of any scanned area, such as a photo or printed area. The surface on which the image is printed has its own unique characteristics that are also captured in this colour map because that surface reflects the illuminating light with a unique pattern. So even each example of a multi-printed image will generate a slightly different colour-map.
Colour pattern files can be created from any digital photograph or scan without having to reprint, recreate, recall or modify existing digital source documents. These files are, in effect, unique signatures which are matched against existing databases to detect any variation and thus detect counterfeit or forged items.

Applied DNA Sciences, best-known for its DNA-based taggants, also offers what it terms BioMaterial Genotyping, which uses the actual DNA of natural materials to authenticate the finished product from which it is made. This can be used on any finished product made from organic materials, which includes textiles, consumables and paper.

Swiss-based AlpVision offers FingerPrint™, which looks for the unique characteristics imparted to products through the tools and moulding processes used to manufacture them. It stores a digital image of the originals on a database, converting these into digital codes that enable a comparison to be made against millions of stored reference images in a matter of seconds. This technique is aimed particularly at products such as pharmaceutical tablets, some automotive components, watch cases and jewellery, which are manufactured through being moulded or pressed.

An Elegant Solution

Creating a unique code from a particular characteristic of an intrinsic component is an elegant way to be able to authenticate and identify that component later, but it does depend on the availability of a reader of the appropriate type to locate and interpret the converted information. It therefore, complements the use of overt authentication aimed at examination by human senses, it does not negate the use of overt methods.

Contacts: www.ingeniatechnology.com, www.bayertechnology.com, www.atlanticzeiser.com,, www.neryos.com, www.signoptic.com, www.u-nica.com, www.innoviafilms.com,, www.visualant.net, www.adnas.com, www.alpvision.com.