EP3414102A1

EP3414102A1 - Verification of an article provided with a security element

Info

Publication number: EP3414102A1
Application number: EP17703024.4A
Authority: EP
Inventors: Georg Depta; Tilo FRITZHANNS; Christian Fuhse
Original assignee: Giesecke and Devrient Currency Technology GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2016-02-09
Filing date: 2017-02-01
Publication date: 2018-12-19
Also published as: DE102016001465A1; US20210074109A1; CN108602374A; WO2017137153A1; MX2018009669A; CN108602374B

Abstract

The invention relates to a method for verifying an article (10) provided with a security element, in which the security element is produced in a multistep process with variations of register and in a test zone (12) contains an individual characteristic feature of the security element in the form of a superposition of at least two areas (14-B, 16-B), which are created during the production of the security element in different production steps with variations of register, wherein in the method the test zone (12) of the security element is optically captured with a camera (30), the area components of the superposed and non-superposed area regions (14-B, B-16) are determined and used to form a test value for the individual characteristic feature of the security element, the test value formed is compared with a reference test value and, on the basis of the result of the comparison, a verification result is produced for the article provided with the security element. The invention also relates to an associated computer program product, a verification system for the implementation of the method, a security element and a testing device for such a verification system and an article provided with such a security element.

Description

Verification of an item provided with a security element

The invention relates to the verification of an object provided with a security element, and relates in particular to a verification method together with associated computer program product, a verification system for carrying out the method, a security element or a checking device for such a verification system and an object provided with such a security element.

Data carriers, such as valuables or identity documents, but also other valuables, such as branded goods, are often provided with security elements for the purpose of security, which permit verification of the authenticity of the data carrier and at the same time serve as protection against unauthorized reproduction.

For reliable authentication of such security elements often expensive inspection devices are used, for example, in cash deposit machines or banknote processing machines in commercial banks. In many cases, however, such complex devices are not available, for example, in an examination of a security element "in the field" or in a security element used to secure an extended or bulky object that can not be readily brought together with the object in a test device , In this case, a hundred percent authenticity check is often not necessary, but it is sufficient to be able to recognize or exclude a readjustment or transfer of the security element to another object with high probability.

Based on this, the object of the invention is to provide methods and associated devices with which a element provided with safety element can be verified easily and yet with high reliability. In particular, verification using a smartphone as a test device should also be possible in the field. To this end, the invention contains a method for verifying an object provided with a security element, in which the security element is produced in a multi-step process with register fluctuations and contains in a test field an individual characteristic feature of the security element in the form of an overlay of at least two areas the production of the security element are produced in different production steps with register fluctuations, wherein the method

the test field of the security element is optically detected with a camera,

the surface portions of the superimposed and / or non-superposed surface areas are determined and from this a test value for the individual characteristic feature of the security element is formed,

the test value formed is compared with a reference test value, and

On the basis of the comparison result, a verification result is produced for the object provided with the security element.

The reference check value is advantageously formed during or after the production of the security element or during or after the article has been provided with the security element by determining the surface portions of the superimposed and / or non-superimposed surface regions and from this the reference check value is formed. The reference check value can be stored together with an individual identification of the security element and / or the object in a database and queried for comparison with the test value formed from the database.

Alternatively or additionally, the reference check value, in particular in encrypted or coded form, can be present on the security element or on the object provided with the security element and read in for comparison with the formed check value. A reference test value applied to the security element or article is advantageously applied using pressure-free methods, for example in the form of a laser marking, by means of ink-jet or toner-based methods. In this case, it is also possible to dispense with storing the reference check value in a database, so that an expensive database with short access times and a very large dataset can be dispensed with.

The code containing the reference check value may be proprietary to this method or may be based on standard methods such as Data Matrix or other 2D codes, with the data contained in the code advantageously encrypted and / or signed. Standard methods can be used for encryption and decryption, asymmetric methods with public and private keys are advantageous, and proprietary derivations of these methods can be used as long as the required security standards are met.

In addition, prior to the comparison of the test value and the reference test value, further tests may be performed to confirm the use of printing methods from the security print, thus excluding copies based on always pixelated scans. It will be advantageous exploited the typically quite high resolution of smartphone cameras. In addition, a simple plausibility check can check whether the same test field has already been read in unusual time or space. Made field checks can not only be recorded for this purpose and so foci with many counterfeits can be determined. When using banknotes, a central bank is also able to monitor the circulation behavior of its notes and derive planning data from it, which helps to avoid unnecessarily high or too small volumes in printing and thus in stockpiling.

In an advantageous embodiment, the test field of the security element with a smartphone camera is optically detected and the determination of the area ratio and the formation of the test value by running on the smartphone software program, hereinafter also called App.

In order to have a large number of register fluctuation combinations, the verification method is advantageously performed on a test field containing a superimposition of three, four or more surface areas generated during production of the security element in different manufacturing steps with register variations.

The verification method is advantageously carried out on a test field whose surface areas are generated at least partially by printing processes, in particular offset printing, indirect high-pressure, gravure gravure, screen printing, letterpress printing, stamp printing or flexographic printing. The verification method is likewise advantageously carried out on a test field whose surface areas are at least partially applied to the application by means of applications, in particular applied film elements, or by elements or windows. plications are formed. Further advantageously, the verification method is carried out on a test field whose surface areas are at least partially formed by surface laser cuts, watermarks, laser markings or inkjet labels or toner-based methods. For printing inks, glazing colors are an advantage, but opaque colors can also be used. The printing inks can have the same hue or different hues, so that in the superimposed surface areas mixed colors. With regard to the achievable resolution, background pressure (indirect

High pressure) the finest line on banknote substrates typically positive 30 μιη, negative 50 μιη, usually 40 μιη or 80 μιη wide; is in offset printing the finest line on banknote substrates typically positive 25 μπι, negative 35 μιη, usually 30 μιη or 50 μιη wide; In engraving gravure (intaglio) the finest line on banknote substrates is positive 15 μπι, negative 10 μπι, usually 50 μιη or 30 μητ. wide; is in screen printing the finest line positive 250 μπ, negative 500 μπι, usually 400 μιη or 900 μιη wide; and is in the stamp printing (imprinting at Zif f erung) the finest line usual 700 μπι wide. With pressure-free methods, a variation of the distances of printing elements in the test field can already be generated in a single pass and thereby additional information is introduced into the test field. For example, the spacing of printing or marking elements generated in a manufacturing step may be varied and the local distribution of the elements stored together with an individual identifier, such as a serial number, in a database.

The verification method is preferably carried out on a test field whose surface areas each consist of a plurality of small pressure elements. ments, in particular in the form of characters or graphic elements. In particular, the small pressure elements have a maximum extension of 3 mm or less, preferably 2 mm or less. In order to enable a particularly reliable test value determination, the test field can have a plurality of partial regions in which the relative positions of the respective pressure elements are shifted from one another. In this case, a partial test value can first be formed for each partial area and then the partial test values can be combined to form a total test value, for example by summing, multiplying, dividing or correlating, or by a combination with other evaluation methods such as pattern recognition. The subdivision into subregions can be carried out, for example, in the form of fields, rows or columns. With particular advantage, the verification process is performed on a security element that is integrated into the article. For example, the security element may be part of a banknote or another value document. In this case, the test field is advantageously smaller than the object and, for example, expediently occupies at most half the area of the value document in the case of a document of value. The test field is further advantageously arranged close to a serial number, identification number or other code of the security element or object to be detected in order to easily detect both with the camera. The invention also includes a verification system for carrying out the method of the type described above, with

a security element provided article, wherein the security element is manufactured in a multi-step process with register fluctuations and in a test field an individual Characteristic feature of the security element in the form of a superposition of at least two surface areas, which are generated in the production of the security element in different manufacturing steps with register fluctuations, and

- a verification device for the verification of the article, with

a camera for the optical detection of the test field of the security element,

an evaluation unit for determining the surface portions of the superimposed and / or non-superposed surface areas and for forming a check value for the individual characteristic of the security element thereof, and means for comparing the formed check value with a reference check value and for generating a Verifikationsresultats based on the comparison result.

The test apparatus advantageously contains means for detecting a coded reference test value, for decoding the detected reference test value and for comparing the test value formed with the decoded reference test value.

The superimposed surface areas, in particular the size of the printing elements of the surface areas can be adapted to the requirements, for example, the resolution of the test apparatus. In an advantageous development, it is further provided that

the verification system comprises a database in which a reference check value is stored together with an individual identification of the security element and / or the item for the security elements, and in that the test apparatus includes means for querying the reference test value or the comparison result of test value and reference test value from the database based on the individual identification of the security element and / or the object.

The test apparatus can be in particular a bank note processing machine or a smartphone.

The invention also includes a security element for a verification system of the type described above, which is manufactured in a multi-step process with register fluctuations and contains in a test field an individual characteristic feature of the security element in the form of an overlay of at least two surface areas, which in the production of the security element are produced in different production steps with register fluctuations, as well as the use of such a security element for verification of an article provided with the security element. The invention further includes an article, in particular value document, security paper, identity card or branded article with such a security element.

The invention further includes a verification device for a verification system of the type described above

a camera for the optical detection of the test field of the security element,

- An evaluation unit for determining the surface areas of the superimposed and non-superimposed surface areas and for forming a test value for the individual characteristic of the security element thereof, and Means for comparing the formed check value with a reference check value and for generating a verification result based on the comparison result.

Finally, the invention also includes a computer program product comprising machine-readable program instructions for a control unit of a data-processing device, in particular a smartphone, which cause it to carry out a method of the type described above.

In further variants of the invention, individual codes or markings of the security element can be used, which are integrated into the design of the test field. On the one hand, these can serve to recognize the individual security element or the object and to identify it for a database query, and can also ensure that each individual security element remains distinguishable even with a coarser scan.

The individualization can consist in particular of characters, graphic elements, bar codes or 2D codes or the like and can either be recognizable as such or integrated into the design. Codes preferably have a redundancy of the useful contents or error correction elements. Preferably, the individualization is part of the data that gives the above test value.

For example, a digit can overlay the test field and thus contribute to the test value. Since, for example, banknotes or other documents of value do not resemble each other's serial numbers, this contribution is always individual. If only a part of the number is superimposed, it offers itself on the basis of the usual numerical schemes, the back, from note to note to use changing characters of a digit to achieve a good distinction between the sheets; the front characters, on the other hand, to achieve a good distinction between the individual benefits within an arc. The test value can either be calculated purely according to the above-mentioned methods or supplemented by an OCR reading of the numbering. For example, it is possible to use the letterpress printing standard in banknote printing, but also printing-free methods such as laser marking or inkjet methods. As a further example, color, color components or metallization of film elements can be removed or a color impression can be produced with a laser marking. Accordingly, prints in the test field can be individually modified by changing color fields by removing the color, by removing the absorbing color components, or by removing metalizations from film elements; but it can also be added by blackening of the substrate or color change another color impression. If a laser-absorbing ink is used for at least some of the prints, mixed forms of removal and addition may also occur.

In a particularly advantageous embodiment of a laser marking, the laser is only used to individually remove or lighten color for each security element. While this may be visible in the test field recognizable to the user, it may also extend over a larger area of the object provided with the security element. These markings are expediently in areas produced with different steps and have for each banknote an individual position whose coordinates or relative position to each other also represent a test value. In addition, a film Application included, so demetallized by the laser about areas.

In the case of a banknote, this check value can be assigned to the banknote identified by the serial number, and an encrypted code can be applied to the banknote from the serial number, check value and, if applicable, signature of the issuing agency, in particular once again using a printing-formless method, for example the same laser marking unit. In the latter case, the code with its relative position may also belong to the test value. All data may be advantageous, but need not be stored in a database for later tracking of the note.

The test value can be determined in the field and simultaneously read from the code with a public key and compared. For this method, the register fluctuations during printing and in the field need not be measured, since the position of the markings alone is of importance. Even a database query is not essential, but still beneficial. In customization, ink-jet printers can be used primarily to print individual graphic elements or codes. In most cases, you can only add color, if necessary bleached by solvents or other substance combinations, but also color. For example, the security element or check box may also contain links to consumer information, such as provided by QR (Quick Response) codes, or data matrix codes. Such codes may or may not be integrated into the design of the test field but may or may not contribute to the test value. For the evaluation of an optically recorded test field, the image captured by the smartphone camera can first be preprocessed in a manner known per se, for example by transformations in spatial or frequency space, for example by Fourier transformation or wavelet analysis, by projections, interpolations, for example between different rasters, resolutions or coordinate systems, scaling, rotations, filtering, both isotropic and anisotropic, morphological methods, segmentation and methods of feature extraction, pattern recognition, entropy measurement, or averaging.

In order to improve the results, a one-time calibration of the used camera of the tester in field may be required, for example by a white balance or the recording of a test pattern. The evaluation can be facilitated by registration marks, which can also result from distinctive points of the design, and thus improve the alignment and / or scaling of the image in the preprocessing. Even codes can advantageously serve as registration marks. The evaluation can be facilitated and improved in the field and possibly also in the production by the recording of several images, possibly from different angles and distances (hereinafter referred to as video mode). In this case, security features in the test field can also be verified, which offer different impressions depending on the viewing angle.

Codes used within the scope of the invention may be visually recognizable as such and thus encourage use or may be integrated in the design of the test field and possibly even hidden. While If codes are advantageously two-dimensional, the identifiable codes are advantageously Id codes, such as bar codes EAN, 2 / 5i, UPC, Codel28, and 2d codes stacked ld codes, such as PDF417. such as QR codes or data matrix or mixed forms.

In the present case, 2d codes in particular offer themselves, since the readout is advantageously carried out with cameras, ie 2d sensors. But there are also applications with bar code readers into consideration. The presentation must follow not known standards, but can also be proprietary. For example, it can be achieved that the content can only be read by a specific app on a smartphone.

The content of the code or codes on a security element may include a unique signature of the issuing office. The content may contain real or pseudo-random data. The content may also contain hashed test data for later comparison. For an application with mobile devices, in particular a smartphone, the use of asymmetric encryption methods is advantageous. Since, as in biometrics, the actual measured quantities are analogue in nature, similar procedures are recommended for the storage in the production and the verification in the field: For example, a "fuzzy vault" can be used. For this purpose, additional error correction data (auxiliary data) can be stored on the security element or object or stored in a database, which ensures sufficient redundancy. The error correction and the elements to be read are advantageously closely matched. But it can also be standard biometric methods with a once read template and the definition of maximum permissible deviations in the measurement in the field.

Furthermore, the so-called biometric template protection can be used, in which instead of the test data protected reference data are stored, which allow a comparison, but no retroactive accounting on the original data. Again, a fuzzy vault can be used. Often, the fault tolerance can also be achieved by quantizing the analog input values.

For example, to compare similar data and determine the degree of correspondence, the method of "context triggered piecemeal hashes (CTPH)", also known as "fuzzy hashing", can be exploited. Statistical methods such as "Principal Component Analysis (PCA)" can also be used or contribute to the storage and evaluation. Furthermore, the code can contain not only the optionally encrypted and signed check value, but also the possible range of variation. The fluctuation can also be included in an extra code. The fluctuation can also be encrypted and / or signed. During verification, the fluctuation range can then be measured, even with a different resolution, and compared with the specified value. Thus, it can be determined whether the test result is within a precision determined both in the first test and in the field. Depending on the resolution of the camera of the tester so increases the security of the verification. Simultaneous verification of a signature further increases security.

The security element or test field can be combined with other security features, in particular with identifiable only with aids. safety features, as long as they do not affect the evaluation of the useful information lying in the visible range of light or even contribute to this information. In this way, the test field can help to use the limited area, for example, on banknotes for other security elements, and / or it may indicate the actual function of the test field in the test with the help of additional devices.

For example, a fluorescent pressure over the test field in the form of a smartphone or in the form of a QR code may indicate that information is available for smartphones when the note is held at about a cash register under a UV lamp. An IR cut can also be provided in the test field, for example, without impairing its function. Effect colors can change their register variation to the others

On the one hand, printing methods contribute to the information in the test field, on the other hand, for example, by color-shift effects allow the testing without tools. If a code is checked from several directions, the color-tilting effect can also be checked with the smartphone. This can be done, for example, by using the above-described video mode when recording the test field.

Even paints, threads or foils with hard or soft magnetic pigments or vapor depositions can contribute to machine readability without disturbing the principle of the test field. The same applies to colors that show piezo, photo or thermochromic effects, which can also be electrically excited. The test described the test field can be combined in the field with other methods that allow verification of the authenticity of the bill. These include, for example, an examination of the printing methods used, an examination of security features such as holograms or effect colors on angle-dependent correct image or color data, an examination of the interaction of printing ink and substrate in high-resolution images; a plausibility check with respect to the query times and locations of the same serial number, or a check for the presence of the serial number in a database of banknotes in circulation. Such supplementary procedures can easily preclude forgery of impressions in advance.

In addition to smartphones, stationary devices at bank note processing plants, stationary devices at points of sale and machines that collect banknotes, especially at commercial banks, as well as mobile devices, especially for checking the test areas for law enforcement, are used as testing devices. Authorities, outlets, or offices and other authorities. Further exemplary embodiments and advantages of the invention are explained below with reference to the figures, in the representation of which a representation in terms of scale and proportions has been dispensed with in order to increase the clarity. Show it:

1 shows a schematic representation of a banknote with a security element in the form of a test field printed on the banknote, 2 is a detail view of the test field of Fig. 1,

Fig. 3 is a schematic representation of the verification of

Banknote of FIG. 1 involved components,

FIG. 4 shows a test field consisting of a plurality of partial regions with pressure elements displaced relative to one another, FIG. 5 shows a test field integrated in the graphic design of a banknote, and FIG

Fig. 6 shows a design in which a test field is present in a separate security element which is applied to a cash deposit to be hedged.

The invention will now be explained first using the example of the verification of a banknote with the aid of a smartphone. 1 shows a schematic representation of a banknote 10 with a security element in the form of a test field 12 printed on the banknote 10. The test field 12 shown in detail in FIG. 2 is part of the banknote 10 and was used in the production of the banknote 10 together with the other printing elements on the

Banknote substrate generated. In other configurations, however, the test field can also be present on a separate security element, for example a transfer element, which is applied to a banknote or another article to be protected.

For checking the authenticity, the banknote 10 with the test field 12 in the manner described below can simply be optically with a smartphone camera be verified and verified using a test app installed on the smartphone.

The banknote 10 and the test field 12 are generated in a multi-step method with register fluctuations. For example, on the bank note 10 in the screen printing process the value 14 A, in the engraving gravure printing a portrait 16-A and in the book printing a serial number 18 was applied. Simultaneously with the value 14- A, a first checkerboard pattern 14-B (narrow hatched in FIG. 2) was screen-printed in the test field 12, as shown in more detail in the detailed illustration of the test field 12 in FIG. In a separate printing step, a second checkerboard pattern 16-B (hatched in FIG. 2) in stitch gravure printing was produced simultaneously with the portrait 16-A in the test field 12. Due to the generation of the elements 14- A / 14-B or 16-A / 16-B i in each separate operations with different manufacturing processes inevitable Passerschwankungen occur, resulting in an offset of the two checkerboard pattern 14-B, 16-B in Run test field 12.

The present inventors have now recognized that these inevitable registry variations of the various manufacturing processes may serve as a kind of fingerprint for identifying a particular security item or bill.

For estimation, it can be assumed, for example, that the production steps involved in the generation of the test field 12 each have register fluctuations of ± 1 mm in mutually orthogonal directions (hereinafter referred to as x and y direction). The maximum permitted variation is, for example, ± 1.5 mm. A typical smartphone camera with a nominal 6 megapixels has a resolution of 2848 x 2136 pixels. If a surface is recorded with such a camera, which contains at least the test field 12 and the serial number 18, for example, with a recording surface of 120 mm x 90 mm, the result is a dot density of about 600 dpi or a resolution of 42 μπι. Thus, in two production steps, 2000 μιη / 0 μιη = 50 distinguishable positions in each direction, ie a total of 50 ² = 2,500 different combinations of register fluctuations. If three manufacturing steps are mapped in the test field 12, there are already 6,250,000 possibilities. If a surface area exists, for example, in a security thread whose insertion position in the transverse direction can fluctuate by ± 3 mm, the number of possibilities can be multiplied again by 6000 μm / 40 μm = 150. With a security thread with a well-recognizable subject you can also use the position in the longitudinal direction and thus further increase the number of possible combinations.

Referring to FIG. 2, the register variations of the manufacturing steps of screen printing (elements 14A, 14B) and engraving gravure (elements 16A, 16B) result in an offset of the two checkerboard patterns 14B, 16B, which can be quantified, for example, via the surface portions of the superimposed and non-superimposed surface regions 20, 22, 24, 26. As can be seen in FIG. 2, due to the offset of the two checkerboard patterns 14-B, 16-B, first surface regions 20, in which only the printing ink of the screen printing step 14-B is present, arise second surface regions 22, in which only the printing inks of the stitch Gravure step 16-B, third surface areas 24, i overlay the ink of the screen printing step and the ink of the engraved gravure step and fourth areas 26 in which neither of the two inks is present. The relative surface portions of the surface areas 20 to 26 depend on the concrete in the production of the banknote 10 Therefore, a test value can be derived from them, which represents a banknote 10 individual and characteristic size. As can be seen from the above estimation, the number of possible register fluctuation combinations in the current resolution of smartphone cameras in two production steps is generally still too low to be able to clearly identify a banknote. Nevertheless, the number of possibilities is already so great that despite the simple check with a smartphone with a positive verification with high probability on a real banknote can be closed. If a larger number of production steps are included, the number of register fluctuation combinations can also be sufficient for a clear identification of a banknote.

The test value derived from the relative surface portions can be detected for the first time during or immediately after the production of the banknote 10, for example in the quality control of the banknotes, and stored together with the serial number 18 of the banknote 10 as reference check value in a database 34 (FIG. 3). In the database 34, the serial number 18 is then linked to a specific relative area proportion of the surface areas 20-26 in the check field 12 of the banknote 10. As explained above, the assignment does not necessarily have to be unique for meaningful verification.

For verification, the banknote 10 is then photographed (as shown in FIG. 3) by a user with the camera of his smartphone 30 (reference numeral 32) and thus optically detects the test field 12 and the serial number 18. One on the smartphone 30 running test app can on the one hand over an OCR module read the serier ummer 18 of the banknote 10 and on the other hand via an image processing module determine the surface portions 20-26 in the test field 12 and form the check value for banknote 10. The test app then builds a connection 36 from the smartphone 30 to the database 34 and transmits the serial number 18 and the test value formed. In the database 34, the transmitted test value is compared with the reference test value stored there for the serial number 18 and the comparison result is transmitted back to the test app via the connection 36. This displays the result of the authenticity check, for example, in the display 38 and can also give an audible feedback on the successful or failed verification for reinforcement. In one variant, the database can also transmit the stored reference test value to the test app and the comparison of the test value formed with the reference test value can be made in the test app itself.

Alternatively or additionally, the reference check value can also be provided encrypted on the banknote 10 itself after its first detection, for example in the form of a barcode 28 arranged next to the checkbox 12. For verification, the banknote 10 can then be photographed by a user with the camera of his smartphone 30 and thus the test field 12 are optically detected together with the barcode 28. The test app executed on the smartphone 30 then determines the surface portions 20-26 in the test field 12 via the image processing module, forms the check value for banknote 10 therefrom, reads the bar code 28 and decrypts the reference check value encoded with it. The determined test value is compared with the decrypted Referenzprüfwert and displayed the result of the authenticity check in the display 38 and possibly also issued acoustically. In FIG. 2, the overlaying of only two surface areas is shown for the sake of simplicity, however, it is understood that in practice it is also possible to superimpose three, four or more surface areas and, because of the greater number of possible combinations, also makes sense. Accordingly, there are more than the combination possibilities for the area overlaps mentioned in FIG.

For the determination of the test value, the image acquired by the camera of the smartphone is first preprocessed advantageously in the manner described above. Then, for example, a histogram formation can take place in which the pixel frequencies of different colors or gray levels are determined. Furthermore, threshold values can be formed in different gradations or different color channels and the resulting pixel numbers can again be determined, similar to a histogram. Other statistical methods of image processing can also be used which, for example, correlate different fields via correlations. As shown in FIG. 4, a test field 40 can also consist of a plurality of partial regions 42, 44, 46, wherein the relative positions of the pressure elements 48-R, 48-G, 48-B of the individual printing passages in the different partial regions are shifted from one another In order to allow a particularly good evaluation of the surface portions of the superimposed and non-superimposed surface areas. For example, it may be difficult to determine the relative area proportions exactly when the register fluctuation of two surface areas of a banknote is close to zero, since then there are hardly any non-overlapping cache areas. As a remedy, the pressure elements 48-R, 48-G, 48-B are arranged offset in one or more subregions so that they do not completely cover each other with perfect register. This is illustrated in Fig. 4 by the example of printing elements representing the three primary color pixels 48-R, 48-G, 48-B of an RGB print. In each of the subregions 42, 44, 46, the three primary color pixels 48-R, 48-G, 48-B are arranged in a different relative position to each other so that the register variations of the three color channels in each sub-region 42, 44, 46 are different affect the superimposed and non-superimposed area proportions of the printing elements, thus making the determination of the individual characteristic test value for the test field 40 more reliable. For example, a partial test value can be formed for each subarea 42, 44, 46 and the subtest values can be combined by adding or multiplying them together to form a total test value.

A test field need not be present as a separate field on the document, it may also be integrated into the graphical design of the document, as illustrated by the test field 50 of FIG. 5. In the exemplary embodiment shown, a banknote 10 contains in a partial area a graphic 52 in the form of a gravure-applied tree with differently colored apples, namely with green apples 56 produced in simultaneous printing and with red apples 58 produced in stamp printing. The test field 50 contains a green apple 56, a red apple 58 and a part 54 of the leaf structure of the tree. Since all three printing elements were produced in different printing steps with different production methods, they have individual characteristic register fluctuations which can be detected in the test field 50 in the manner described above with the aid of a smartphone camera 30 and compared with a reference test value. The user must not be aware of the presence or location of the test field 50 in the graphic design 52. It suffices if the user acquires the entire banknote or at least the design 52 with his smartphone camera 30 since the test app knows the position of the test field 50 and its properties to be tested. If the recording quality is insufficient or the test field 50 is not completely recorded, the test app can generate an error message and ask for a new recording, possibly with a reference to the area to be recorded. FIG. 6 shows a further embodiment in which a test field of the type described above is present in a separate security element 60 which is applied to an object to be protected, such as a cash box 62. In the exemplary embodiment, the cash box 62 shown in FIG. 6 is filled, closed and the cover gap 64 is sealed with the security element 60. Then, the test field of the security element 60 is photographed with the camera of a smartphone 30 (reference numeral 32), for example, and a test value for the security element 60 is determined by an app in the manner described above. Furthermore, an identification number 66 of the cashbox 62 is either entered or also recorded with the camera. The app then establishes a connection 36 to a database 34 and transmits the identification number 66 and the formed test value for the security element 60 used for the security. The transmitted verification value is then stored in the database 34 as the reference verification value for the identification number 66 and thus the security element 60 linked to the cash box 62 to be secured.

After the transport of the cash box 62, the recipient may first check whether the security element 60 is intact and then verify that the security element 60 is actually added to the identification number 66 of the cash box. sette 62 belongs. For this purpose, he only has to photograph the test field of the security element 60 with the camera of his smartphone and enter the identification number 66 of the cash box 62 or also photograph it. The app then forms the check value for the security element 60, optionally determines the identification number 66 via an OCR module, then establishes a connection to the database 34 and transmits the identification number 66 and the test value formed. In the database 34, the transmitted check value is compared with the reference check value stored there to the cookie number 66 and the comparison result is transmitted back to the smartphone app, which notifies the recipient of the success or failure of the verification.

LIST OF REFERENCE NUMBERS

10 banknote

12 test field

14-A value

14-B first checkerboard pattern

16-A portrait

16-B second checkerboard pattern

18 serial number

20, 22, 24, 26 surface areas

28 barcode

30 smartphone

32 photographic capture

34 database

36 connection

40 test field

42, 44, 46 subareas

48-R, 48-G, 48-B printing elements

50 test field

52 graphic

54 Part of the leaf structure

56 green apples

58 red apples

60 security element

62 cashbox

64 cover gap

66 identification number

Claims

Patent claims

1. A method for verifying an article provided with a security element, in which the security element is produced in a multi-step process with register fluctuations and contains in a test field an individual characteristic feature of the security element in the form of an overlay of at least two surface areas used in the production of the security element Security elements are produced in different manufacturing steps with register fluctuations, wherein the method

the test field of the security element is optically detected with a camera,

the surface portions of the superimposed and / or non-superimposed surface areas are determined and from this a test value for the individual characteristic feature of the security element is formed,

the test value formed is compared with a reference test value, and

- Based on the comparison result, a Verifikationsresultat for the provided with the security element object is created.

2. The method according to claim 1, characterized in that the Referenzprüfwert is formed during or after the preparation of the security element or during or after the provision of the object with the security element by the surface portions of the superimposed and / or non-superimposed surface areas are determined and from the Reference check value is formed.

3. The method of claim 1 or 2, characterized in that the Referenzprüfwert stored together with an individual identification of the security element and / or the subject in a database and is queried for comparison with the test value formed from the database.

4. The method according to at least one of claims 1 to 3, characterized in that the reference check value is present in particular in encrypted or coded form on the security element or on the object provided with the security element and is read in for comparison with the test value formed.

5. The method according to at least one of claims 1 to 4, characterized in that the test field of the security element with a smartphone camera is optically erfst and the determination of the area ratio and the formation of the test value is performed by running on the smartphone software program.

6. The method according to claim 1, wherein the verification method is carried out on a test field which contains a superimposition of three, four or more surface areas which generates in the production of the security element in different production steps with register fluctuations are.

7. The method according to at least one of claims 1 to 6, characterized in that the verification process is carried out on a test field, the surface areas are generated at least partially by printing process, in particular offset printing, engraving gravure, screen printing, letterpress, stamp printing or flexographic printing.

8. The method according to at least one of claims 1 to 7, characterized in that the verification method is carried out on a test field, the surface areas at least partially by applications NEN, in particular applied foil elements, or by elements or windows are formed on the applications.

9. The method according to at least one of claims 1 to 8, characterized in that the verification method is carried out on a test field whose surface areas are at least partially formed by surface laser cuts, watermarks, laser markings, ink-jet labels or toner-based methods ,

10. The method according to at least one of claims 1 to 9, character- ized in that the verification process is carried out on a test field whose surface areas each consist of a plurality of small printing elements, in particular in the form of characters or graphic elements.

11. The method according to claim 10, characterized in that the

Test field has several sub-areas in which the relative positions of the respective pressure elements are shifted from each other.

12. The method according to at least one of claims 1 to 11, characterized in that the verification method is carried out on a security element which is integrated into the article.

13. Verification system for carrying out the method according to one of claims 1 to 12, with an article provided with a security element, wherein the security element is manufactured in a multi-step process with register fluctuations and contains in a test field an individual characteristic feature of the security element in the form of an overlay of at least two surface areas, which generates during production of the security element in different production steps with register fluctuations , and a verifier for verifying the article

a camera for the optical detection of the test field of the security element,

an evaluation unit for determining the surface portions of the superimposed and non-superposed surface areas and for forming a test value for the individual characteristic feature of the security element thereof, and

Means for comparing the generated check value with a reference check value and for generating a verification result based on the comparison result.

14. Verification system according to claim 13, characterized in that the test apparatus comprises means for detecting a coded reference test value, for decoding the detected reference reference value and for comparing the formed test value with the decoded reference test value.

15. Verification system according to claim 13 or 14, characterized in that

the verification system comprises a database in which a reference check value for each of the security elements together with a individual identification of the security element and / or the object are stored, and that

the test device means for interrogating the reference test value or the comparison result of the test value and the reference test value from the database on the basis of the individual marking of the

Contains security elements and / or the item.

16. Verification system according to at least one of claims 13 to 15, characterized in that the test device is a banknote processing machine or a smartphone.

17. A security element for a verification system according to one of claims 13 to 16, which is manufactured in a multi-step method with register fluctuations and contains in a test field an individual characteristic feature of the security element in the form of an overlay of at least two surface areas, which in the production of the security element are produced in different manufacturing steps with register fluctuations.

18. An article, in particular value document, security paper, identity card or branded article with a security element according to claim 17.

19. Testing device for a verification system according to one of claims 13 to 16, with

a camera for the optical detection of the test field of the security element,

an evaluation unit for determining the surface portions of the superimposed and non-superposed surface areas and for forming a Check value for the individual characteristic feature of the security element thereof, and

Means for comparing the formed check value with a reference check value and for generating a verification result based on the comparison result.

A computer program product having machine-readable program instructions for a control unit of a data-processing device, in particular a smartphone, which cause it to carry out a method according to one of claims 1 to 12.