Commissioned by the Bank of Canada to help improve the detection of counterfeit currency, we designed a series of tests of performance to explore the contributions of note quality, sensory modality, training, security features and demographic variables to the accuracy of counterfeit detection with three different note types. In each test, participants (general public, and cash handlers, divided amongst commercial cash handlers and bank tellers) were presented with notes, one at a time, for up to seven seconds, and were asked to judge whether each note was genuine or counterfeit. With whole note inspection, overall accuracy was about 80%. When the security features were tested individually, the Optical Security Device (OSD) was the best feature, the hidden number was the worst, and the portrait, maple leaves, fluorescence, and microprinting were intermediate. Accuracy was higher with notes that could be seen but not touched than vice versa. Cash handlers were 74% correct with touch alone and adding touch to vision significantly improved counterfeit detection. This paper will demonstrate how performance differences between the different note types can be explained in terms of the efficacy of the individual security features incorporated into the notes.

Bank note producers are working to thwart the threat of counterfeit notes created using high resolution, digital image processing software and color output devices such as inkjet printers, color copiers, and scanners. Genuine notes must incorporate better overt and machine-readable security features that will reduce the chance of counterfeit notes being passed. Recently, Canada and the United States introduced newly designed bank notes that are intended to enable the general public to more easily distinguish genuine notes from counterfeits. The Bank of Canada (BoC) and the U.S. Department of Treasury’s Bureau of Engraving and Printing (BEP) have conducted similar market research projects to explore target audiences' perceptions and attitudes towards currency design and security features. This paper will present a comparative analysis of the two research projects, both of which were conducted using similar methodology. The results of these research studies assist in the selection of security features for future generations of bank notes.

A lot of information can be found in the media about the possibility of using micro-chips in banknotes. This mostly comes from chip manufacturers whose technology is becoming mature for this application. A lot of patents have been applied therefore but what must be noticed is that all these patents concern the processes to insert chips in banknotes and not a lot is said about the product itself and for what use. The Banque de France is a Central Bank involved in all tasks concerning banknotes from design, production, issue, recirculation and sorting, action against counterfeiting and finally destruction. These activities concern, of course, the banknotes in circulation in France (formerly the French francs notes, presently the Euro notes as Banque de France is part of the Eurosystem) and in other countries in the world. The Banque de France approach in looking to the future of chips in banknotes is at first a product approach. Banknotes are means of payment for which security of authentication is fundamental. They could carry chips to provide more security in the transactions but without altering their nature: the anonyminity and immediacy of the transactions.

The inspection of bank notes is a highly labour intensive process where traditionally every note on every sheet is inspected manually. However with the advent of more and more sophisticated security features, both visible and invisible, and the requirement of cost reduction in the printing process, it is clear that automation is required. Machines for the automatic inspection of bank notes have been on the market for the past 10 to 12 years, but recent developments in technology have enabled a new generation of detectors and machines to be developed. This paper focuses on the latest developments in both the off-line and on-line inspection of bank notes covering not only the visible spectrum but also a new range of detectors for inspection some of the more common invisible features used as covert features in today's bank notes.

Banknote security features are evolving and changing. New features are constantly being developed and slowly being incorporated into banknotes. The assumption is that these features make the notes more secure for everyone; but do they? This paper looks at some of the features incorporated in today's banknotes and how (or if) they add security to banknotes processed by low cost banknote readers. The sensing technology used in low cost note readers has changed somewhat in the last few years but the industry is still faced by the cost constraints of a very competitive market. Some of the new note features require high-resolution image capture, complex optical measurements or expensive emission/detection devices. Paper watermarks, digital watermarks, OVI, Holograms, Stokes conversion, IR and magnetic features are examined, as well as the technologies used and the relative cost/benefit developed for these note features.

Both Canada and the United States have undertaken recent studies of public knowledge and human perception related to bank notes and counterfeits. These two types of studies yield complementary results that confirm or refute accepted beliefs regarding security features and bank notes, and provide guidance in their design. However, to be useful, the results of these studies need to be evaluated and applied in the context of note design, such evaluation and incorporation of results can be used to improve how bank notes are designed for different users, such as members of the general public, cash handlers, bank tellers and law enforcement personnel. Analysis of the counterfeits used in the perception studies and comparative evaluation of results can lead to better understanding of types of counterfeiters and help identify gaps in note designs to address those types. In this paper, the results from two recent studies conducted by the Bank of Canada on public awareness of currency design features and on human perception of genuine and counterfeit notes are used to illustrate the method of analysis and application of results to bank note design. Interpretations for specific features are highlighted.

A systematic approach for comparing the effectiveness of counterfeit deterrence features in banknotes, credit cards, digital media, etc. was previously presented. That approach built a probabilistic model around the expert identification of the most efficient process by which a counterfeiter can gain sufficient information to replicate a particular feature. We have extended the scope and functionality of that approach to encompass the entire counterfeiting process from the learning phase to the production of counterfeits. The extended approach makes determining the probabilities more straightforward by representing a more detailed model of the counterfeiting process, including many probable counterfeiting scenarios rather than just representing the least costly successful scenario. It uses the counterfeiter's probability of succeeding and level of effort as metrics to perform feature comparisons. As before, these metrics are evaluated for a security feature and presented in a way that facilitates comparison with other security features similarly evaluated. Based on this representation, the cost and laboratory procedures necessary for succeeding may be recovered by a dynamic programming technique. This information may be useful in forensic profiling of potential counterfeiters.

As growing more global economic activities, both sales figures and brand protection are great concerns for international enterprises. To protect the brand, various kinds of security devices have been used. It is, however, difficult to evaluate these security devices. One of the major reasons of this difficulty is based on the fact that properties of the security devices are quite hard to be quantified. Accessing costs of the devices is one of the barriers in the evaluations when a neutral person wants to evaluate the devices. Moreover, detailed specifications of the devices are often kept secret because of the devices' basic characteristic: “security.” Several projects to establish security evaluation methods, such as CC (Common Criteria) and its derivative standard ISO/IEC 15408, are energetically proceeded, and however mainly focused on security of information and entities who address the information as their scopes. In this paper, we assume a distribution model of branded products to discuss properties of security devices. Then, we propose a simple classification method of the devices on the assumed model. In the proposed method, we classify security devices without quantifying any properties. We also discuss how to utilize the proposed classification method effectively. Users of security devices can reduce research costs by examining only preselected devices in detail after the class-selection.

Along at least twelve dimensions biometric systems might vary. We need to exploit this variety to manoeuvre biometrics into place to be able to realise its social potential. Subsequently, two perspectives on biometrics are proposed revealing that biometrics will probably be ineffective in combating identity fraud, organised crime and terrorism: (1) the value chain perspective explains the first barrier: our strong preference for large scale biometric systems for general compulsory use. These biometric systems cause successful infringements to spread unnoticed. A biometric system will only function adequately if biometrics is indispensable for solving the dominant chain problem. Multi-chain use of biometrics takes it beyond the boundaries of good manageability. (2) the identity fraud perspective exposes the second barrier: our traditional approach to identity verification. We focus on identity documents, neglecting the person and the situation involved. Moreover, western legal cultures have made identity verification procedures known, transparent, uniform and predictable. Thus, we have developed a blind spot to identity fraud. Biometrics provides good potential to better checking persons, but will probably be used to enhance identity documents. Biometrics will only pay off if it confronts the identity fraudster with less predictable verification processes and more risks of his identity fraud being spotted. Standardised large scale applications of biometrics for general compulsory use without countervailing measures will probably produce the reverse. This contribution tentatively presents a few headlines for an overall biometrics strategy that could better resist identity fraud.

There are, in general, two ways for an observer to deal with light that is incorrect in some way (e.g. which is partially out of focus). One approach is to correct the error (e.g. by using a lens to selectively bend the light). Another approach employs selective masking to block those portions of the light which are unwanted (e.g. out of focus). The principle of selective masking is used in a number of important industries. However it has not found widespread application in the field of optical security devices. This work describes the selective masking, or modulation, of digital images as a means of creating documents and transparent media containing overt or covert biometric and other images. In particular, we show how animation effects, flash-illumination features, color-shifting patches, information concealment devices, and biometric portraiture in various settings can be incorporated in transparent media like plastic packaging materials, credit cards, and plastic banknotes. We also demonstrate the application of modulated digital images to the preparation of optically variable diffractive foils which are readily customized to display biometric portraits and information. Selective masking is shown to be an important means of creating a diverse range of effects useful in authentication. Such effects can be readily and inexpensively produced without the need, for example, to fabricate lenses on materials which may not be conducive in this respect.

Bacteriorhodopsin (BR), a photochromic retinal protein, has been developed into a new materials platform for applications in anti-counterfeiting. The combination of three different properties of the material on its molecular level, a light-inducible color change, photochemical data storage and traceability of the protein due to molecular marker sequences make this protein a promising material for security applications. The crystalline structure of the biopigment combines these properties with high stability. As BR is a biological material specialized knowledge for modification, cost- effective production and suitable processing of the material is required. Photochromic BR-based inks have been developed for screen printing, pad printing and ink jet printing. These prints show a high photochromic sensitivity towards variation of illumination. For this reason it is not possible to reproduce the dynamic color by photocopying. In addition to such visual inspection the printed symbols offer the possibility for digital write-once-read-many (WORM) data storage. Photochemical recording is accomplished by a two-photon process. Recording densities in a range from 10⁶ bit/cm² to 10⁸ bit/cm² have been achieved. Data structures are stored in a polarization sensitive mode which allows an easy and efficient data encryption.

Japanese National Printing Bureau has been focused upon the development of anti-copy lines for many years. The basic concept with regard to security measure lies in the merge of art and technology. On this basis, our originally developed anti-copy lines show flexibility to various security designs. Our newest anti-copy lines comprising from the Tri-Branched and Divided Lines shows clearer latent image effect compared to that of our other developed anti-copy lines. However, the anti-copy effect of security printing lines with microstructure is deteriorating due to the emergence of digital image techniques with higher resolution. In this situation, this paper introduces a new security measure comprising from luminescence and security printing lines with microstructure. It gives rise to a latent image effect under UV light due to the characteristic microstructure while visually same density. The principle advantage is that the combination of the anti-copy and luminescent feature strongly enhances its secure effect in documents. There is no necessity of two kinds of inks and any specially designed equipment to produce security documents with microstructural lines involving luminescence.

This white paper reviews the method for making bearer printed information indistinguishable on a non-copyable substrate when a copied attempt is made on either an analog or digital electrostatic photocopier device. In 1995 we received patent number 5,704,651 for a non-copyable technology trademarked MetallicSafe. In this patent the abstract describes the usage of a reflective layer, formed on a complex pattern region and having graphic or font size shapes and type coordinating to particular patterns in the complex pattern region. The technology used in this patent has now been improved and evolved to new methods of creating a non-copyable substrate trademarked CopySafe+. CopySafe+ is formed of a metallic specular light reflector, a white camouflaged diffused light reflector, and the content information 'light absorption' layer. The synthesizing of these layers on a substrate creates dynamic camouflaged interference patterns and the phenomena of image chaos on a copy. In short, the orientation of a plurality of spectral and diffused light reflection camouflaged layers, mixed and coordinated with light absorption printed information, inhibits the copying device from reproducing the printed content.

This paper introduces a new security solution regarding security documents with secure unique information. Our newly proposed security measure enables outputting ID documents by commercially available printer. On this basis, a citizen can apply and accept his ID certificates to and from Issuing Authority via website. A unique gradational latent image emerges if a third party authenticates it under Infrared ray. The principle of this new measure lies in the complicated microstructure generated by our specially designed software. It is understood that its security feature based on secure software and wide applicability for commercially available printers show profound potentiality to construct new security system for ID documents in IT society.

An image analysis system that can differentiate between different black toners or inks non-destructively on printed text documents and images is currently under development at The London College of Printing. It is envisaged that the system will be able to find alterations in documents or images that are difficult to detect even by the most skilled expert document examiners using established forensic techniques. This paper describes the development of a nondestructive method that is intended to detect imperceptible fraudulent alterations to digital print samples. A digital image analysis system that incorporated a high-resolution low noise CCD monochrome camera with an optical system to enlarge images was used. Software that could obtain measurements of the relative optical reflectivity and sharpness characteristics of printed image areas from the raw image analysis data was developed. A single A4 sized paper sheet with a printed image that was produced using a combination of two different laser printers and an optical photocopier was illuminated using visible light. The results of subsequent image analysis measurements demonstrated it was possible to detect imperceptible alterations on the A4 sheet using this technique.

In this paper, we described a method of embedding information in hardcopies that is both digitally and optically retrievable. The method is based on the concept of conjugate screening. Two screens are applied in the halftoning process, one of the areas that corresponds to the symbol to be embedded (object), and the other one for the background. Both screens can be conceptually decomposed into a two-layer structure similar to a multicenter dot. The top layer determines the overall halftone texture, while the bottom layer, which is conjugate for background and object, carries embedded data. Compared to other similar technologies, the proposed method is simple in computation and is robust to registration errors in retrieval.

Technologies for making high-quality copies of documents are getting more available, cheaper, and more efficient. As a result, the counterfeiting business engenders huge losses, ranging to 5% to 8% of worldwide sales of brand products, and endangers the reputation and value of the brands themselves. Moreover, the growth of the Internet drives the business of counterfeited documents (fake IDs, university diplomas, checks, and so on), which can be bought easily and anonymously from hundreds of companies on the Web. The incredible progress of digital imaging equipment has put in question the very possibility of verifying the authenticity of documents: how can we discern genuine documents from seemingly “perfect” copies? This paper proposes a solution based on creating digital images with specific properties, called a Copy-detection patterns (CDP), that is printed on arbitrary documents, packages, etc. CDPs make an optimal use of an "information loss principle": every time an imae is printed or scanned, some information is lost about the original digital image. That principle applies even for the highest quality scanning, digital imaging, printing or photocopying equipment today, and will likely remain true for tomorrow. By measuring the amount of information contained in a scanned CDP, the CDP detector can take a decision on the authenticity of the document.

Traditionally, Intaglio printing is one of the key security elements for banknotes and security documents, providing high-resolution fine-line elements and the characteristic tactility easily recognized by the public. The conventional process of creating Intaglio printing-plates involves multiple production steps from the hand-engraving of the artist and the computer-aided-design of security elements to the final, print-ready metal plate. We present the results of a feasibility study regarding the direct laser engraving of Intaglio printing-plates. Results of our studies on laser optics and choice of material to achieve optimal line quality are presented. In our studies we have found a novel plate material superior to galvanic nickel regarding plate lengthening and have achieved line widths in the 10μm range. The process found, allows reintroducing true three-dimensional elements with line-depth and -profiling control independent of line-width, while decreasing lead-times in the production of security documents. We give a comparison between direct laser engraving and traditional platemaking, comparing aspects such as resolution, plate performance and production time.

Up until now, the only variable alphanumeric data which could be added to banknotes was the number, applied by means of impact typographical numbering boxes. As an additional process or an alternative to this mechanical method, a non-contact laser marking process can be used offering high quality and greater levels of flexibility. For this purpose KBA-GIORI propose an exclusive laser marking solution called NotaMark. The laser marking process NotaMark is the ideal solution for applying variable data and personalizing banknotes (or any other security documents) with a very high resolution, for extremely large production volumes. A completely integrated solution has been developed comprised of laser light sources, marking head units, and covers and extraction systems. NotaMark allows the marking of variable data by removing locally and selectively, specific printed materials leaving the substrate itself untouched. A wide range of materials has already been tested extensively. NotaMark is a new security feature which is easy to identify and difficult to counterfeit, and which complies with the standard mechanical and chemical resistance tests in the security printing industry as well as with other major soiling tests. The laser marking process opens up a whole new range of design possibilities and can be used to create a primary security feature such as numbering, or to enhance the value of existing features.

A method of providing a digital image with a unique, machine readable, code image is presented. It is called "Full Spectrum," because the method uses Fourier transform techniques to embed the code in a wide range of spatial frequencies. The changes made to the original image by the encoding process are meaningless to the observer, and, by proper choice of the embedding parameters and the resolution (reproduction size) of the marked image, they can be made totally imperceptible. Full Spectrum has some intrinsic advantages for application to printed security structures in a document authentication/-identification environment. Using its mathematical properties, the method is shown to be invariant to shifting and cropping, which enables the code image to be reconstructed from a recording of the document with arbitrary position and size. Techniques to deal with possible rotation and scaling of the recorded image with respect to the (printed) original are elaborated. Finally, a general method is developed to match the reconstructed code image to the reference image (expected code image). Experiments show that the code image can survive various graphical transfer processes, such as halftone screening, printing and digitising. An actual document containing a printed Full Spectrum structure is demonstrated, the Security ID.

We present recent commercial anti-counterfeit projects that use machine-vision principles, to either verify genuine documents or trace the origin of counterfeits. In the first case we show how the characteristic nature of a reflection hologram, as used on a credit card, can be used to verify it quickly and economically. Many counterfeit holograms can be discriminated from a genuine example by a two-step test: first, that the visible object displayed by the hologram has the correct form when viewed at a given angle, and second, that the object changes in the correct way as the viewing angle is varied. Both of these can be implemented using a machine-vision system as we describe. Another application of machine-vision techniques in an anti-counterfeit context is their use in forensic investigation. We demonstrate how the origin of compact disks can be traced using marks in the outer surface, by imaging a magnified portion of the CD surface under darkfield illumination to maximise outer surface features while suppressing reflections from the internal data surface. We show that CDs from the same pressing machine exhibit matching defect patterns under darkfield illumination. This technique can be used to trace the origin of a sample counterfeit CD.

The simultaneous engineering of diffractive structures and amterial systems enables innovative appraoches for realizing iridescent color shifts for Optically Variable Devices (OVDs) for document secrity. In a first exmaple, we dmonstrate the interplay between a color-shifting coating, whichfunctions inreflection,a nd embossed gratings,w ith effects inthe first and hgher diffraction orders. In a second exmpale, we demosntrate novel surface-releif, zero-order gratingw hich show a color shift, e.g. green to red, uponrotation by 90 degrees. In a third example, we explore the use of combination gratings to realize color-shifting and color-contrast features. These color-shifting features are integrated within OVD designs in which an observer can easily check the behavior of the feature and verify the authenticity of the document.

Color-shifts have been used in the field of optical security for many years. Through the use of birefringent polymers, 3M has pioneered highly reflective, multilayer, all-polymeric interference optical films for use as mirrors and polarizers. Polarizer and mirror multilayer films with reflectance bands covering all of the visible wavelengths have found uses in LCD displays and solar light pipes. Color-shifting polarizer (CSP) films may be made by uniaxially orienting a multilayer stack that has sharp band edges and does not cover all of the visible wavelengths. By judicious choice of polymers, the refractive indices of the two polymers have a large difference in refractive index in the stretch direction and match in the transverse direction. The resulting film has a noticeable color shift to the unaided eye, and a readily verifiable feature when viewed with both polarization states. In the pass condition, the film becomes colorless; in the block direction, the color is very saturated and noticeably shifts in hue when the viewing angle is changed. The films may have reverse printing under the CSP films, which hides during verification. The indelible marking of the film for the intended end use and the tamper resistance of labels made from these films will also be discussed.

Over the years, holograms have evolved from purely decorative images to bona fide security devices. During this evolution, highly secure technologies have been developed specifically for product and document protection. To maximize the security potential of these hologram technologies requires a holistic approach. A hologram alone is not enough. To be effective it must be part of a security program and that security program needs to inform the design and development of the actual hologram. In the most elementary case the security program can be as simple as applying a tamper evident label for a one-day event. In a complex implementation it would include multi-level technologies and corresponding verification methods. A holistic approach is accomplished with good planning and articulation of the problem to be solved, and then meeting the defined security objectives. Excellent communication among all the stakeholders in a particular project is critical to the success of the project. The results of this dialogue inform the design of the security hologram.

Iridescent Optically Variable Image Devices (IOVID) for the document security market are currently produced using thin film or diffractive interference phenomena. Special optical effects by diffractive interference depend on the alignment of a series of grooves with differet frequencies and modulations to produce Diffractive Optically Variable Image Devices (DOVIDs). These devices, more commonly know as holograms, have been exclusively restricted to foil applications. In this work, we are taking into consideration basic concepts of thin film and diffractive light interference theory together with some fundamentals of magnetic behavior of materials to create a new family of diffractive pigments. These pigments not only exhibit thin film and diffractive interference but the grooves can also be aligned along predetermined orientations in a magnetic field. This property of groove alignability opens the door to the concept of printable holograms. Different groove alignable diffractive pigments have been produced. The influence of the particle size, loading, and groove frequency has been studied. The microstructure of the groove orientable flakes has been characterized by optical and electron micrscopy, and the optical effects by goniospectrophotometry. Finally, simple DOVIDs have been produced by silkscreen printing to demonstrate the feasibility of the concept.

Optical effects in Optically Variable Devices (OVDs) are generally grouped in three different categories depending on how the effects can be verified: First-line features, second-line features, and third-line features. In this paper, we present novel examples for different classes of second-line security features designed for use in OVDs. The first class consists of features based on polarization effects. The second class consists of features which are based on special forms of very small text or images, that are invisible to the naked eye. The third class encompasses moire features that are based on engineered diffractive microstructures. These second-line security features can be checked by using simple verification devices like a polarizer, a magnifier glass, or a binary amplitude screen.

OVP security pigment, the active ingredient in OVI security ink, is an assembly of high performance microscopic filters. The market acceptance of these filters has led them to become perhaps the most widely distributed interference devices on the planet. Recently, interference devices have been developed that provide the security industry with features beyond proven overt protection. New products are being launched that unite the attributes of optical interference with those of other technologies. One approach integrates thin film interference and diffractive interference to create a host of new security devices. The combined effects are complex and often surprising. The science behind the fusion is explored and the effects demonstrated. Interference pigment technology has also been combined with the science of magnetics to create a new line of OVP security pigments. To facilitate the practical use of such pigments, novel application technology has been developed which allows for the creation of new overt effects. This paper examines pigment designs and describes the physics behind the advanced application technology. The science of layering security features has long been demonstrated effective in deterring counterfeiting. Now it is possible to provide multiple layers of security within the same device through the integration of proven technologies.

The unbroken global increase of forgery and counterfeiting of valuable documents and products steadily requires improved types of optical security devices. Hence, the "security world" is actively seeking for new features which meet high security standards, look attractively and allow easy recognition. One special smart security device created by ROLIC's technology represents a cholesteric device combined with a phase image. On tilting, such devices reveal strong color shifts which are clearly visible to the naked eye. The additional latent image is invisible under normal lighting conditions but can be revealed to human eyes by means of a simple, commercially available linear sheet polarizer. Based on our earlier work, first published in 1981, we now have developed phase change guest-host devices combined with dye-doped cholesteric material for application in new security features. ROLIC has developed sophisticated material systems of cross-linkable cholesteric liquid crystals and suitable cross-linkable dyes which allow to create outstanding cholesteric color-shifting effects not only on light absorbing dark backgrounds but also on bright or even white backgrounds preserving the circularly polarizing state. The new security devices combine unambiguously 1^st and 2^nd level inspection features and show brilliant colors on black as well as on white substrates. On tilting, the security devices exhibit remarkable color shifts while the integrated hidden images can be revealed by use of a sheet polarizer. Furthermore, due to its very thin material layers, even demanding applications, such as on banknotes can be considered.

Unison is a new class of highly counterfeit and simulation resistant micro-optic security films that provide a wide range of overt, unique, and highly visible three-dimensional and fluidic motion visual effects for currency, document, and product authentication by the general public. Unlike holograms, interference films, and diffractive OVDs, Unison incorporates micron-scale geometrical optic systems to create synthetic images that exhibit striking visual effects that are independent of illumination angle and collimation. Unison presents a pattern of visually dynamic, non-holographic, colored images that are seen against either a transparent or an opaque background. These images can be designed to either float above the surface, appear beneath the surface, or appear in the plane of the surface and to move in a counter-intuitive ortho-parallactic manner. Unison can be used as a laminate over print without obscuring it; the Unison images appear to move within, under, or over the print. Unison images can be viewed under all lighting conditions from any azimuthal angle and from a wide range of elevation angles. This new material is highly resistant to counterfeiting because it is an all-polymer multi-layer film that contains no metallized layers and its non-diffractive optical elements are based on proprietary origination, tooling, and manufacturing processes.

Three-dimensional images may be produced by a number of methods, the earliest being integral photography. The basic concept involves exposing a photographic emulsion to light scattered from an object through a fly's eye lens to produce an array of micro-images, one behind each lenslet. An observer viewing the composite image through the lenslet array sees a three-dimensional representation of the object. Over the past 5 years, 3M has applied laser technology to the creation of three-dimensional virtual images using the integral photography approach. The virtual images made by this process can be observed by a viewer with the unaided eye in either reflected or transmitted light. The images display large movement as an observer's viewing perspective changes and have a distinct on/off-viewing angle beyond which the image cannot be seen. The fidelity of the virtual images requires maintaining the registration of the substrate lenslets and the micro-images produced by the laser imaging process. This makes the images difficult to copy or modify and an ideal, cost-effective candidate for an overt security feature.

At Nanoplex Technologies, Inc. we have developed Nanobarcodes particles, which are encodeable, machine-readable, durable, sub-micron sized taggants which have application for document and product security. We will present results on the use of Nanobarcodes particles in a number of authentication and anti-counterfeiting applications. We also focus on the software component in recognition of particles imaged against varied backgrounds.

Embossing in the transparent window area of polymer banknotes, such as those seen on the Australian, New Zealand and Romanian currencies, have enormous potential for the development of novel optical security devices. The intaglio printing process can provide an efficient means for embossing of optical security structures such as micro lenses. Embossed micro lens arrays in the transparent window of a polymer banknote can be folded over a corresponding printed image array elsewhere on the note to reveal a series of moire magnified images. Analysis of samples of embossed micro lenses showed that the engraving side and impression side had a similar embossed profile. The embossed micro lens profiles were modelled using Optalix-LX commercial optical ray tracing software in order to determine the focal length of the lenses and compare with the focal length of desired embossed lenses. A fundamental understanding of how the polymer deforms during the embossing process is critical towards developing a micro lens embossing tool which can achieve the desired embossed micro lenses. This work also looks at extending the early research of the Intaglio Research Group (IRG) to better understand the embossibility of polymer substrates such as biaxially oriented polypropylene (BOPP).

This paper presents a new approach for the protection of travel documents. We propose a digital watermarking technique which requires for the verification process a low scanning resolution of at least 72 DPI. The approach is based on the wavelet decomposition and supports three key aspects: Message encoding is accomplished by iterative error correction codes satisfying a nearly optimal channel capacity. This encoding is based on specific modulation that requires for the implementation a significant lower complexity as the often applied M-array modulation. The watermark embedding is applied in the wavelet domain based on stochastic driven perceptional criteria for a good quality and invisibility. The watermarking process is considered as a communication process with side information. The approach utilizes two different watermarks, one for the channel state information estimation and one for the informative watermark which carries as a payload the hidden information.

This paper presents a new approach, called smartID, for the protection of travel documents. We introduce a specific signature format exploiting as much as possible the given modulus size for generating a digital signature with a partial message recovery feature. This specific formatted digital signature enables a very efficient representation of the authenticity information of the travel document. It is show that the complete whole content of a travel document page, i.e. the image information and the text information, can be securely stored with a RSA modulus size of up to 6144 bits in a single PDF417 2D barcode which is quite limited in its total capacity. The approach supports the Kerckhoff principle, the authenticity of the data, and the authenticity of the issuing authority that generated the data. The approach neither depends on a specific data carrier nor on the specific cryptographic public key system.

The optical characteristics of pixellated passive micro mirror arrays are derived and applied in the context of their use as reflective optically variable device (OVD) nanostructures for the protection of documents from counterfeiting. The traditional design variables of foil based diffractive OVDs are shown to be able to be mapped to a corresponding set of design parameters for reflective optical micro mirror array (OMMA) devices. The greatly increased depth characteristics of micro mirror array OVDs provides an opportunity for directly printing the OVD microstructure onto the security document in-line with the normal printing process. The micro mirror array OVD architecture therefore eliminates the need for hot stamping foil as the carrier of the OVD information, thereby reducing costs. The origination of micro mirror array devices via a palette based data format and a combination electron beam lithography and photolithography techniques is discussed via an artwork example and experimental tests. Finally the application of the technology to the design of a generic class of devices which have the interesting property of allowing for both application and customer specific OVD image encoding and data encoding at the end user stage of production is described. Because of the end user nature of the image and data encoding process these devices are particularly well suited to ID document applications and for this reason we refer this new OVD concept as biometric OVD technology.

Computer-generated holograms (CGH's) of phase modulation type have been designed and fabricated in the biological material Bacteriorhodopsin (BR). BR is a photochromic retinal protein which may be used in optical data storage and security applications. Using the permanent light-inducible refractive index change of BR, we demonstrate that both analog and digital optical data can be stored in this material in a write-once-read-many (WORM) mode. The calculation and the optimization of the phase function of the CGH's have been accomplished with iterative Fourier transform algorithm methods (IFTA) such as error reduction algorithms. In the fabrication procedure the optimized phase functions of the CGH's have been recorded in BR which was coated onto a glass substrate. A direct laser writing process employing the 532 nm line of a cw-Nd:YAG laser was used for recording the CGH as a modulation of the absorption coefficient as well as of the refractive index. The design and fabrication method of the CGHs with a pixel pitch of 20 μm and a total size of 10 mm x 10 mm are presented.

The new reflecting optical mark is created. This mark has been received by recording of a joint power spectrum (JPS) of a transformed and reference phase masks on a chalcogenide glass As₄₀S₄₀Se₂₀. In order to fabricate the reflecting optical mark, we must choose the optimum exposure of its writing. We have offered the procedure for calculation of such exposure by using the experimental dependence of diffraction efficiency as a function of a chalcogenide glass layer exposure and the analytical equation for the JPS of two phase masks containing rectangular phase elements. This procedure includes the calculation of the correlation peak relative intensity as a function of the JPS interference pattern frequency band that is read by laser beam, and calculation of the dependence "peak relative intensity versus exposure." The proposed reflecting marks allow realizing the quantitative estimation of a secured product authenticity due to producing of a correlation field and realization of the mark's identification procedure. The experimental setups based on an optical Fourier processor architecture were created for writing of reflecting optical marks and their reading and identification. The experimental examinations of dependency between a peak-to-noise ratio and exposure of a chalcogenide glass layer for the series of fabricated reflective marks were carried out. The obtained results were compared with theoretical results.

A novel fluorescent security label has been produced that could replace numerous conventional fluorescent dyes in document security. This label utilizes rare earth ions doped in a borosilicate glass matrix to produce sharp spectral fluorescence peaks with characteristic long lifetimes due to the rare earth ions. These are subsequently detected by an online detection system based on fluorescence and the long lifetimes to avoid any interference from other fluorophores present in the background. Security is further enhanced by the interaction of the rare earth ions with each other and the effect of the host on the emission spectra and therefore the number of permutations that could be produced. This creates a very secure label with various applications for the security market.

In the context of the paper there are represented the theoretical foundations and technological aspects of creation of the Optical Security Devices by Polygram technology. This technology implies the images of different types combining. There are generally discussed the Computer-Generated Rainbow Holograms (CGRHs) of 3D images. This type of holographic images is distinguished by its reliability against counterfeit, caused by the fact it requires matchless in this field precision of printing system, using extreme for the Electron Beam Lithography Equipment, which is applied for the recording, values of the stamp sizes. On the other hand CGRHs certainly distinguish from similar optical and stereographic images, so they can be easy recognized on the visual level of the verification and don’t need application of any tools. The theoretical basis of the CGRHs creation is strictly presented in this paper. The special attention is paid to the right choice of the non-linear quantization parameters. This paper is mainly concentrated on the investigation of the CGRH combining both with another CGRHs and with the other different images implying by the Polygram technology. The methods of the space restriction of the separate CGRH topology with the information loss and without it are compared. There are carried out the investigations of the influence of the additional images on visual perception of the CGRH.

An anti-counterfeiting feature, latent image, has been widely applied for banknotes and security documents. The hidden pattern of denomination by intaglio printing process can be observed by viewing the bill at certain angles of elevation. While designing the latent image, a continuous-tone cover image and a binary figurative pattern are used. The continuous tone image is halftoned by horizontal and vertical line screen, respectively. The binary figurative pattern then serves as a mask to render the corresponding area of horizontal and vertical line screen on the figurative region and background region, respectively. These procedures can be done by many available commercial softwares. However, there are various artifacts such as gaps in the junctions of horizontal and vertical screen lines, discontinuous screen lines and the white or black artifacts on the edges of the latent image. The retouching of the resulting latent image needs to be carefully and skillfully handled. In this research, we developed an automatic process to generate the artifact-free latent image inside a cover image by modified digital halftoning techniques. The methods we applied include: (1) To design new 8x8 threshold matrices in order to make a perfect joint of the horizontal and vertical screen lines. (2) To use the linear scaling adjustment to enhance the cover image not resulting discontinuous line. (3) To register the 8x8-based figurative pattern to the 8x8 threshold matrix and to avoid the visual artifacts. For latent image detection, a frequency domain treatment by FFT (Fast Fourier Transformation) and inverse-FFT is used to extract the encrypted image. This is especially useful for machine-readable applications. The results show that the developed process in this research does have the ability to automatically generate the desired latent image without any artifact. It also saves the costly retouching in the existing process. A frequency domain detection method is applied to extract latent images. The proposed techniques in this research also have great potential to proceed security printing in a digital way.

The state of the art in manufacturing security documents includes the usage of a multitude of inks and pigments. The chemical and physical stability of these materials is a crucial point for their application in long lasting security products such as banknotes. For our studies regarding the bleaching characteristics of pigments and inks we have developed a highly integrated double beam gonio-spectrometer with in-situ ageing capability. The new spectrometer is equipped with a stabilized solar simulator lamp featuring a dosimeter, which is an advanced alternative to the commonly used blue wool scale. Additionally the sample temperature can be stabilized during ageing tests by a thermostatted sample holder. The instrument is capable of performing reflection measurements using monochromatic and polychromatic excitation and further allows fluorescence, phosphorescence and polarization measurements with high resolution over a wide wavelength range. We will present first results of defined ageing tests on a variety of security pigments and the setup of the newly developed spectrometer.

Public verification features are part of a matrix of security features on banknotes which allow the authenticity of legitimate banknotes to be established. They are characterised by being overt and easy to verify -- no examination tool or equipment is required even though the devices themselves are invariably highly sophisticated. Recent developments, though, combine overt and covert elements which may reqire inspection tools. Traditionally, banknote issuers were reluctant to involve the general public in the checking of banknotes, preferring to rely on those employed to handle them, experts and machinery to authenticate the various (normally undisclosed) features. This has now changed as the ability to counterfeit has moved from those highly skilled in printing to anyone with a scanner and computer -- the incidence of counterfeiting has grown exponentially in the last decade. Three techniques for what can be categorized as public verification features have been used for banknotes for many decades and continue to provide a barrier to counterfeiting: (1) the optical effects of watermarks; (2) the appearance and tactile characteristics of cylinder mould-made paper; (3) the tactile characteristics of intaglio print. Since the 1980s the emergence of threads and optically variable features have added to the available features which can be utilized on banknotes for public verification purposes. OVDs fall broadly into the two categories of diffraction and color shift. Products which utilize the former include holograms, kinegrams and other devices originated with similar techniques and bearing a variety of proprietary names, but collectively known as diffractive optically variable image devices (DOVIDs). All share the fundamental characteristic of changing in appearance according to the viewing angle, providing an effective barrier to the increasingly common use of digital reprographic technology as a counterfeiting tool as well as a simple means for verification by the man on the street. They differ, however, in the underlying technology, their specific characteristics and their functionality, which is what this paper will examine, along with their growth and usage on the world's currencies and the current technical developments and trends which are likely to affect their role in the future.

Jura has developed different security features based on Information Carrier Digital Screening. Substance of such features is that a non-visible secondary image is encoded in a visible primary image. The encoded image will be visible only by using a decoding device. One of such developments is JURA's Invisible Personal Information (IPI) is widely used in high security documents, where personal data of the document holder are encoded in the screen of the document holder's photography and they can be decoded by using an optical decoding device. In order to make document verification fully automated, enhance security and eliminate human factors, digital version of IPI, the D-IPI was developed. A special 2D-barcode structure was designed, which contains sufficient quantity of encoded digital information and can be embedded into the photo. Other part of Digital-IPI is the reading software, that is able to retrieve the encoded information with high reliability. The reading software developed with a specific 2D structure is providing the possibility of a forensic analysis. Such analysis will discover all kind of manipulations -- globally, if the photography was simply changed and selectively, if only part of the photography was manipulated. Digital IPI is a good example how benefits of digital technology can be exploited by using optical security and how technology for optical security can be converted into digital technology. The D-IPI process is compatible with all current personalization printers and materials (polycarbonate, PVC, security papers, Teslin-foils, etc.) and can provide any document with enhanced security and tamper-resistance.

Approximately 60% of U.S. currency notes circulate abroad. As the most widely used currency in the world, U.S. notes are the most likely to be counterfeited. Since 1996, the United States has been issuing currency with new security features. These features make U.S. currency easier to recognize as genuine and more secure against advancing computer technology that could be used for counterfeiting. Currency counterfeiters are increasingly turning to digital methods, as advances in technology make digital counterfeiting of currency easier and cheaper. In 1995, for example, less than one percent of counterfeit notes detected in the U.S. were digitally produced. By 2002, that number had grown to nearly 40 percent, according to the Secret Service. Yet despite the efforts of counterfeiters, U.S. currency counterfeiting has been kept at low levels. According to current estimates, between 0.01 and 0.02 percent of notes in circulation are counterfeit, or about 1-2 notes in every 10,000 genuine notes. The strategy for maintaining the security of Federal Reserve notes is to enhance the design of U.S. currency every seven to ten years. One objective of introducing the new currency is to emphasize the number of features available to the public for authenticating bills. The most-talked-about aspect of the redesigned currency is the subtle introduction of background colors to the bills. While color itself is not a security feature, the use of color provides the opportunity to add features that could assist in deterring counterfeiting. Color will also help people to better distinguish their notes. Security features for the newly designed currency include a security thread, a watermark, and a more distinct color-shifting ink. The new $20 note was issued in fall 2003, with the $50 and $100 notes scheduled to follow 12 to 18 months later. Plans to redesign the $10 and $5 are still under consideration, but there are no plans to redesign the $2 and $1 notes. As was the case with the redesigned $20 note issued in 1998, the new design will co-circulate with the current design. As notes return to the Federal Reserve from depository institutions, the Federal Reserve will only destroy the unfit notes introduced since 1998. Designs older than the Series 1996 are destroyed when returned to the Federal Reserve regardless of condition. To ensure a smooth introduction of the new currency, a five-year international public education effort was launched in 2002 to inform the public and target audiences, including financial institutions, law enforcement, and the vending industry of the transition to the new design. The public is the first line of defense against counterfeiting. So, it's important the public has the tools to recognize the new and modified security features in the redesigned notes.