Security marking, method and device for reading the security marking, security document marked with the security marking, and method and system for verifying the security document

Abstract

The present invention relates to a security marking 100, a method and device for reading and decoding the security marking 100, a security document 150 marked with the security marking 100, and a method and system for verifying and authenticating the security document 150. The security marking 100 includes a machine-readable marking 130 overlying a magnetically inductive layer 120 of a material containing magnetically oriented, reflective, platelet-like, magnetic or magnetizable pigment particles having two zones 120a and 120b of different particle orientations. Only after separately read data from the two zones 120a and 120b have been collected can the encoded data in the machine-readable marking 130 be decoded.

Description

[Technical Field]

[0001]

[0001] The present invention relates to magnetically inductive layers, methods and apparatus for reading magnetically inductive layers, and methods and systems for verifying and authenticating documents containing magnetically inductive layers, the magnetically inductive layers containing oriented magnetic or magnetizable pigment particles.

[0002]

[0002] For example, in the field of security documents, it is known in the art to use inks, compositions, coatings, or layers containing oriented magnetic or magnetizable pigment particles, in particular magnetic or magnetizable pigment particles that are also optically variable, to produce security elements in the form of magnetic induction marks. Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in U.S. Pat. Nos. 2,570,856, 3,676,273, 3,791,864, 5,630,877, and 5,364,689. Coatings or layers useful for protecting security documents, which contain oriented magnetic color-shifting pigment particles and thus produce particularly attractive optical effects, are disclosed in WO 2002 / 090002 and WO 2005 / 002866.

[0003]

[0003] Magnetic or magnetizable pigment particles in printing inks or coatings allow for the production of magnetically inductive layers, designs, and / or patterns by inducing local orientation of the magnetic or magnetizable pigment particles in the unsolidified coating through the application of a corresponding magnetic field, followed by solidification of the coating. The result is a fixed magnetically inductive layer, design, or pattern. Materials and techniques for the orientation of magnetic or magnetizable pigment particles in coating compositions are described in U.S. Pat. Nos. 2,418,479; 2,570,856; 3,791,864; DE 2006848; 3,676,273; 5,364,689; 6,103,361; EP 0406667; U.S. Pat. No. 202002232; 0 / 0160194, U.S. Patent Application Publication No. 2004 / 70062297, U.S. Patent Application Publication No. 2004 / 0009308, European Patent Application Publication No. 0710508, International Publication No. WO 2002 / 09002, International Publication No. WO 2003 / 000801, International Publication No. WO 2005 / 002866, and International Publication No. WO 2006 / 061301, which are incorporated herein by reference. In this manner, a highly counterfeit-resistant magnetic induction layer can be produced. The magnetic induction layer thus obtained produces an angular reflection profile that is substantially asymmetric with respect to the normal to the substrate to which it is applied. This is unique and distinct from conventional specular or Lambertian reflection / scattering behavior.

[0004]

[0004] Security features, for example, for security documents, can generally be categorized as "covert" security features on the one hand and "overt" security features on the other. The protection afforded by covert security features relies on the notion that such features are difficult to detect and typically require specialized equipment and knowledge for detection, whereas "overt" security features relies on the notion that they are easily detectable by unaided human senses; for example, such features may be visible and / or detectable by touch, but remain difficult to manufacture and / or replicate. Magnetic induction layers are typically used as "overt" (or Level 1) security features and should enable direct, unambiguous authentication by humans without any external devices or tools. However, the effectiveness of overt security features depends heavily on their easy recognition as security features, because most users, and especially those without prior knowledge of the security features of the document or item protected by the security features, will in fact only perform security checks based on the security features if they actually learn of their existence and nature.

[0005]

[0005] Even if the security level of a magnetic induction layer is high in terms of its resistance to copying, the average consumer may be confused as to exactly what effect should be observed for a particular overt security element in a given product. In particular, flipping holograms (low-security, low-cost security elements) that produce similar patterns or logos also produce angle-dependent reflection patterns, which may lead to misinterpretation of authenticity by untrained consumers.

[0006]

[0006] Many authentication methods using mobile (handheld) devices, such as smartphones, have emerged in recent years. Most of them rely on the imaging capabilities of smartphone cameras to extract geometric or topological information below the resolution of the human eye, as disclosed in International Publication No. 0225599, or to extract signals very close to noise, exceeding human capabilities, or to interpret subtle variations in color or shape in printed designs, as disclosed in International Publication No. 2013071960. While these methods have the advantage of extracting coded information for identification, they require high-resolution printing and / or magnification optics attached to the smartphone camera.

[0007] Other authentication methods applicable to low-resolution printed features have been developed that rely on colorimetric analysis of security features, such as those disclosed in U.S. Patent Application Publication No. 2011190920, which analyzes the color shift characteristics of optically variable patterns measured upon augmented reality-assisted azimuthal displacement of a smartphone around the pattern, based on holograms or other methods such as SICPASMART™ disclosed in WO 2015052318. These methods rely on the movement of the smartphone camera relative to the mark, which is complex to implement. Furthermore, they rely on external light illumination and are therefore highly sensitive to environmental light conditions (e.g., direct sunlight, dark environments, or highly chromatically imbalanced lighting).

[0008] Other methods for authenticating features with angular dependence of reflection intensity have been proposed, such as randomly oriented flakes as disclosed in WO 2012136902 and US 20140224879, micromirror diffractive features such as holograms or embossed 3D structures as disclosed in WO 2015193152 or US 2016378061, which capture two images based on two angular positions of the camera, which are then analyzed.

[0009]

[0009] Controlling both the smartphone camera and sample illumination to obtain reproducible measurements of security feature reflectivity remains a challenge. Smartphone cameras typically use automated exposure and focusing algorithms adapted to typical camera usage (e.g., landscape or portrait photography), but such algorithms are not adapted to imaging highly reflective markings with magnetic induction layers. Illumination of the security feature can be from indoor or outdoor ambient light, which is generally unknown and difficult to control and can prevent reliable detection of certain security features of the magnetic induction layer, such as angular reflectivity.

[0010]

[0010] Therefore, some drawbacks of currently known smartphone-based authentication technologies include the fact that they require high-resolution printing of fine structures, and / or rely on complex smartphone movements to reveal color, and / or are unreliable due to limited information available to accurately authenticate strict angle dependencies.

[0011]

[0011] It is therefore desirable to propose to the public, and possibly also to the inspectors involved, an improved, accurate and reliable technical solution that is robust to ambient light disturbances, does not rely on high-resolution printing or complex movements of a smartphone, and avoids tilt or azimuth positions or complex rotational movements that are difficult to control and unintuitive.

[0012]

[0012] In particular, there is a need for an authentication method and device that can clearly distinguish a given magnetic induction layer from other magnetic induction layers or from other obvious security features manufactured by other techniques, and from imitations based on other technologies that reproduce the topology of the security feature or logo and attempt to imitate or simulate its effect except with some degree of angular dependence of the reflected intensity.

[0013]

[0013] It is well known to grant a user access to a given service (e.g., via a website) over a communication network (e.g., the Internet or a local network) to enable the user to perform some operations (e.g., financial operations on the user's bank account). Typically, the user must "prove" his or her identity by using a cryptographic key and / or password to request access from an authority controlling the access, and only if the password and / or key are correct is full access to the service granted. However, the password or key can be stolen, or the user can also be registered (e.g., on the website or by its administrative authority) under a false identity, so the reliability of this type of access is quite low. Therefore, there is a need to improve the reliability of personal access credentials.

[0014]

[0014] On the other hand, it is well known to use a certified government-issued ID document (such as an ID card or passport) to prove the holder's identity to an administrative agent (e.g., at a check-in counter) and then access some services (or buildings). In this case, the agent manages some hard-to-counterfeit security markings presented on the holder's ID document, possibly matching the holder's facial similarity with biometric data and / or ID photo, and then, i.e., if the agent has sufficient confidence in the holder's identity, the agent allows the holder to perform some authorized operations. For example, document WO 2014 / 160582 presents a method including the following steps: generating, in a mobile device, an association between a user's government-issued ID document and a payment mode; supporting, in the mobile device, a request for payment upon presentation of the user's government-issued ID document; verifying whether the presented government-issued ID document is a valid identification of the user; and proceeding with the payment by using the payment mode in response to verifying the presented government-issued ID document. Government-issued ID documents can include printed text, magnetic media, and bar codes.

[0015]

[0015] Authentication methods applicable to security documents are also well known and are disclosed in the document US Patent Application Publication No. 2007 / 170248. The authentication method described involves capturing an image of the cardholder's face by a reader. Facial recognition software processes the image to generate a hash. The same reader is used to decode a digital watermark and / or barcode. The digital watermark (and / or barcode) contains an associated facial recognition hash. If the hashes match, the individual and the identity document are authenticated.

[0016]

[0016] The object of the present invention is to eliminate the need for preliminary identity management via an agent and enable any user to directly access online services offered by a private or public operator while providing the operator with a high degree of confidence regarding the user's true identity (and therefore true right to perform operations).

[0017]

[0017] Therefore, the object of the present invention is to provide a method for authenticating a magnetic induction layer used as an obvious security feature printed or fixed to a substrate (such as a label, product or document) using a mobile device, preferably a smartphone, in order to overcome the drawbacks of the prior art.

[0018]

[0018] A further object of the present invention is to provide a portable device, preferably a smartphone, for authenticating a magnetic induction layer applied to a substrate that is easy to control, has excellent resistance to ambient light variations, is highly resistant to counterfeiting, and is easy to distinguish from other angle-dependent reflective marks.

[0019]

[0019] It is a further object of the present invention to provide a method and system for both verifying the content of a document and authenticating said document marked with a magnetic induction layer according to the present invention.

[0020]

[0020] A further object of the present invention is to provide a corresponding non-transitory computer-readable medium containing computer code portions or instructions executable by a processor to cause a portable device equipped with a light source and an imaging device to perform the reading, decryption and authentication methods described herein. Summary of the Invention

[0021] According to one aspect, the present invention provides a method for manufacturing a semiconductor device comprising: a flat substrate (110); a magnetically inductive layer (120) of a material comprising magnetically oriented reflective platelet-shaped magnetic or magnetizable pigment particles, the magnetically inductive layer (120) being applied to a substrate (110), the magnetically inductive layer (120) comprising: a first zone (120a) in which planar surfaces of the magnetically oriented reflective platelet-shaped magnetic or magnetizable pigment particles are oriented in a first direction; and a second zone (120b) different from the first zone (120a) in which planar surfaces of the magnetically oriented reflective platelet-shaped magnetic or magnetizable pigment particles are oriented in a second direction different from the first direction, the platelet-shaped particles in the first zone (120a) having planar surfaces with an elevation angle γ1 relative to the plane of the substrate (110), and the platelet-shaped particles in the second zone (120b) having planar surfaces with an elevation angle γ2 relative to the plane of the substrate (110), the acute angles of the planar surfaces relative to the plane of the substrate (110) being in the range of about 5° to about 25°; a machine-readable marking (130) including a reference pattern (133) and a code pattern (134) representing encoded data, the machine-readable marking (130) being applied to the upper surface (121) of the magnetically inductive layer (120) or to the substrate (110) between the substrate and the back surface (122) of the magnetically inductive layer (120), respectively, a first area (134a) of the code pattern (134) being disposed in front of the first zone (120a) and a remaining second area (134b) of the code pattern (134) being disposed in front of the second zone (120b); The present invention relates to a security marking (100), including:

[0022]

[0022] In the above security marking (100), a) the pigment particles are a magnetic metal selected from the group consisting of cobalt, iron, gadolinium and nickel; Magnetic alloys of iron, chromium, manganese, cobalt, nickel or mixtures of two or more thereof; Magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more thereof; or It may comprise a mixture of two or more thereof, or b) The code pattern can be any one of a one-dimensional barcode, a stack one-dimensional barcode, a two-dimensional barcode, and a three-dimensional barcode.

[0023] The first zone 120a and the second zone 120b of the magnetically inductive layer 120 can belong to the same single material layer. Alternatively, the first zone 120a and the second zone 120b of the magnetically inductive layer 120 can belong to a first sublayer and an adjacent second sublayer, respectively, that form the magnetically inductive layer 120 ("adjacent" meaning that the first sublayer and the second sublayer can be in direct contact or spaced apart).

[0024]

[0024] In the above security marking (100), a machine-readable marking (130) may be applied to the upper surface (121) of the magnetic induction layer (120) and encoded with a dark symbol, a dark primer layer (140) may be applied to the substrate (110), and the back surface (122) of the magnetic induction layer (120) may be applied to the upper surface (141) of the dark primer layer (140).

[0025]

[0025] According to another embodiment of the security marking (100), a machine-readable marking (130) may be applied to the upper surface (121) of the magnetic induction layer (120) and encoded with a bright symbol, a dark primer layer (140), preferably a black primer, may be applied to the substrate (110), and the back surface (122) of the magnetic induction layer (120) may be applied to the upper surface (141) of the dark primer layer (140).

[0026] In the security marking (110), a machine-readable marking (130) may be applied to the substrate (110) and encoded with a dark symbol.

[0027]

[0027] According to another aspect, the present invention provides a method for reading and decoding the security marking (100) by a portable device (200) comprising a light source (201) operable to deliver illumination light, an imaging device (202), and a processor having a memory and configured to perform image processing and decoding operations, the method comprising: placing the security marking (100) within the field of view of an imaging device (202); illuminating the security marking (100) with illumination light delivered by a light source (201); capturing a first digital image of the security marking (100) with an imaging device (202) at a first viewing angle θ1 associated with a first elevation angle γ1 and storing the captured first digital image in memory; capturing a second digital image of the security marking (100) with the imaging device (202) at a second field of view angle θ2 associated with a second elevation angle γ2 and storing the captured second digital image in memory; forming a composite digital image of the code pattern (134) by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern, and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern, with a reference pattern (133) detected in the first digital image and the second digital image, through image processing by a processor, and storing the obtained composite digital image in a memory; reading and decoding the code pattern (134) from the stored composite digital image by a processor; The present invention relates to a method, including:

[0028] The present invention also provides a portable device (200) for reading and decoding the security marking (100), comprising: a light source (201) operable to deliver illumination light; an imaging device (202); a processor having a memory and configured to perform the steps of the method for reading and decoding a security marking (100) in a digital image of the security marking (100) acquired by an imaging device (202); The present invention relates to a mobile device (200) comprising:

[0029] A further aspect of the present invention is a security document (150) issued to a user by an authorized person, comprising: The present invention relates to a security document (150) including a security marking (100) according to the present invention applied to the security document (150), wherein the encoded data in the code pattern (134) of the security marking (100) includes digital ID data corresponding to a user and a digital signature of the user digital ID data, and the digital signature issued by the authorized person is obtained by signing the user digital ID data with a cryptographic key.

[0030]

[0030] Another aspect of the present invention is a method for verifying said security document (150) of a user by means of the above-mentioned mobile device (200), further comprising a communication unit operable to send and receive data over a communication network (CN) to an authorized server (S), connected to a database (DB) storing encryption keys and corresponding decryption keys, comprising: placing the security marking (100) within the field of view of an imaging device (202); illuminating a security marking (100) of a security document (150) with a light source (201); capturing a first digital image of the illuminated security marking (100) with an imaging device (202) at a first viewing angle θ1 associated with a first elevation angle γ1, and storing the captured first digital image in memory; capturing a second digital image of the illuminated security marking (100) with the imaging device (202) at a second viewing angle θ2 associated with a second elevation angle γ2 and storing the captured second digital image in memory; forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by image processing by a processor, by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern, and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern, with a reference pattern (133) detected in the first digital image and the second digital image; reading and decoding the code pattern (134) from the composite digital image, extracting user ID data and a digital signature of the user ID data from the decoded data of the code pattern (134) through image processing and decoding operations by a processor, and storing the extracted user ID data and digital signature in a memory; sending a first message (M1) containing the extracted user ID data stored in the memory and a digital signature to a server (S) via a communication unit; In the server (S), the extracted digital signature received in the first message (M1) from the mobile device (200) is decrypted with a decryption key stored in the database (DB), and the extracted user ID data received in the first message (M1) is confirmed to be consistent with the received extracted digital signature; If there is a match, returning a server message (SM) to said mobile device (200) indicating successful verification of the user identity data; The present invention relates to a method, including:

[0031] According to one variant, the method for verifying a security document (150) comprises, before the step of returning the server message (SM) to the mobile device (200), the following preliminary step: illuminating the magnetically inductive layer (120) with a light source (201) and capturing multiple digital images of the illuminated magnetically inductive layer (120) with an imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetically inductive layer (120) for each different digital image by moving the imaging device relative to the magnetically inductive layer (120) parallel to the plane of the substrate (110); calculating, by a processor, for each captured digital image, a corresponding intensity I of light reflected by the magnetic induction layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and storing the calculated intensity of the reflected light and the corresponding viewing angle to obtain a corresponding reflected light intensity curve I(θ); sending a second message (M2) comprising the obtained reflected light intensity curve I(θ) to a server (S) via a communication network (CN) by a communication unit; The server (S) compares the reflected light intensity curve I(θ) received in the second message (M2) with the reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in the database (DB). ref (θ) and determining in the server (S) whether the magnetic induction layer (120) is authentic based on the result of the comparison; If the magnetic induction layer (120) is determined to be authentic, the method may include returning a server message (SM) indicating successful verification of the user ID data to the mobile device (200) together with an indication that the security marking (120) is authentic, and sending a server authorization message (SAM) containing access data authorizing the user to access the service by the server (S) to the user's communication device via the communication network (CN). The user's communication device may be the mobile device (200) itself.

[0032] According to an alternative variant, the method for verifying a security document (150) comprises, when the server (S) sends a server message (SM) indicating successful verification of the user identity data, the following further steps: illuminating the magnetically inductive layer (120) with a light source (201) and capturing multiple digital images of the illuminated magnetically inductive layer (120) with an imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetically inductive layer (120) for each different digital image by moving the imaging device (202) relative to the magnetically inductive layer (120) parallel to the plane of the substrate (110); calculating, by a processor, for each captured digital image, a corresponding intensity I of light reflected by the magnetic induction layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and determining a corresponding reflected light intensity curve I(θ) using the calculated intensities of the reflected light and the corresponding viewing angles; The processor calculates the reflected light intensity curve I(θ) based on a reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in memory. ref (θ) and determining whether the magnetic induction layer (120) is authentic based on the result of the comparison, and if it is determined that the magnetic induction layer (120) is authentic, sending a message (M) indicating that the security marking (100) is authentic to a server (S) via a communication network (CN) by a communication unit; - if the server (S) receives a message (M) from the mobile device indicating that the security marking (100) is authentic, sending by the server (S) back to the user's communication device via the communication network (CN) a server authorization message (SAM) containing access data authorizing the user to access the service; The user's communication device may be the mobile device (200) itself.

[0033] A further aspect of the present invention is a system for verifying a security document (150) according to the present invention issued to a user by an authorized person, the system comprising: an authority server (S) connected to the database (DB) and operable to transmit and receive data via a communications network (CN); A portable device (200) according to the invention for reading and decoding a security marking (100) according to the invention applied to a security document (150), comprising: a light source (201) operable to deliver illumination light; an imaging device (202); a communication unit operable to transmit and receive data to and from a server (S) over a communication network (CN); a processor equipped with a memory and configured to perform image processing and decoding operations to perform the steps of the method of reading and decoding a security marking (100) in a digital image of said security marking captured by an imaging device (202); a mobile device (200) comprising: Equipped with The following steps of the method by which the server (S) and the mobile device (200) verify the security document (150) of the user: illuminating a security marking (100) of a security document (150) with a light source (201), wherein the security marking (100) is within the field of view of an imaging device (202); acquiring a first digital image of the illuminated security marking (100) with an imaging device (202) at a first viewing angle θ1 associated with a first elevation angle γ1, and storing the acquired first digital image in memory; acquiring a second digital image of the illuminated security marking (100) with an imager (202) at a second viewing angle θ2 associated with a second elevation angle γ2 and storing the acquired second digital image in memory; forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by image processing by a processor, with respect to a reference pattern (133) detected in the first digital image and the second digital image, by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern (134), and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern (134); reading and decoding the code pattern (134) from the composite digital image through image processing and decoding operations by the processor, extracting user ID data and a digital signature of the user ID data from the decoded data of the code pattern (134), and storing the extracted user ID data and digital signature in a memory; sending a first message (M1) containing the extracted user identity data stored in a memory and a digital signature to a server (S) via a communication unit (CN); In the server (S), the extracted digital signature received in the first message (M1) from the mobile device (200) is decrypted using the decryption key stored in the database (DB), and the extracted user ID data received in the first message (M1) is confirmed to be consistent with the received extracted digital signature; If there is a match, returning a server message (SM) to the mobile device (200) indicating successful verification of the user identity data; The system is further configured to perform the steps of:

[0034] In a first variant of the system for verifying a security document (150) according to the invention issued by an authorized person to a user, the server (S) is further adapted to transmit data to the user's communication device via the communication network (CN), The server (S) and the mobile device (200) perform the following preliminary steps before returning the server message (SM) to the mobile device: illuminating the magnetically inductive layer (120) with a light source (201) and capturing multiple digital images of the illuminated magnetically inductive layer (120) with an imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetically inductive layer (120) for each different digital image by moving the imaging device (202) relative to the magnetically inductive layer (120) parallel to the plane of the substrate (110); calculating, by a processor, for each captured digital image, a corresponding intensity I of light reflected by the magnetic induction layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and storing the calculated intensity of the reflected light and the corresponding viewing angle to obtain a corresponding reflected light intensity curve I(θ); sending a second message (M2) comprising the obtained reflected light intensity curve I(θ) to a server (S) via a communication network (CN) by a communication unit; The server (S) compares the reflected light intensity curve I(θ) received in the second message (M2) with the reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in the database (DB). ref (θ) and determining in the server (S) whether the magnetic induction layer (120) is authentic based on the result of the comparison; If the magnetic induction layer (120) is determined to be authentic, returning a server message (SM) indicating successful verification of the user identity data to the mobile device (200) with an indication that the security marking (100) is authentic, and sending by the server (S) a server authorization message (SAM) containing access data authorizing the user to access the service to the user's communication device via the communication network (CN); The device is further configured to:

[0035]

[0035] In a second variant of the above system for verifying a security document (150) according to the invention issued by an authorized person to a user, the server (S) is further adapted to transmit data to the user's communication device via the communication network (CN), The server (S) and the mobile device (200) perform the following steps: When a server message (SM) indicating successful verification of the user identity data is sent by the server (S), the following further steps are performed: illuminating the magnetically inductive layer (120) with a light source and capturing a plurality of digital images of the illuminated magnetically inductive layer (120) with an imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetically inductive layer (120) for each different digital image by moving the imaging device (202) relative to the magnetically inductive layer (120) parallel to the plane of the substrate (110); calculating, by a processor, for each captured digital image, a corresponding intensity I of light reflected by the magnetic induction layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and determining a corresponding reflected light intensity curve I(θ) using the calculated intensities of the reflected light and the corresponding viewing angles; The processor calculates the reflected light intensity curve I(θ) based on a reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in memory. ref (θ) and determining whether the magnetic induction layer (120) is authentic based on the result of the comparison, and if it is determined that the magnetic induction layer (120) is authentic, sending a message (M) indicating that the security marking (100) is authentic to a server (S) via a communication network (CN) by a communication unit; - if the server (S) receives a message (M) from the mobile device (200) indicating that the security marking (100) is authentic, sending by the server (S) via the communication network (CN) to the user's communication device a server authorization message (SAM) containing access data authorizing the user to access the service; The device is further configured to:

[0036]

[0036] The present invention will be more fully described below with reference to the accompanying drawings, in which like reference numerals represent like elements throughout the various views and in which prominent aspects and features of the invention are illustrated, but in no way limited to, the drawings. [Brief explanation of the drawings]

[0037] [Figure 1] 1 is a schematic representation of a platelet-like pigment particle, with Cartesian axes (X, Y, Z) attached to the (substantially flat) faces of the particle. [Figure 2A]FIG. 1 is a schematic diagram of a magnetically inductive layer (120) according to one embodiment of the present invention, comprising two zones (120a, 120b) in which magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles have different orientations relative to the plane of the back surface (122) of the magnetically inductive layer (120), i.e., a first zone (120a) having reflective platelet-like pigment particles with a first elevation angle γ1, and a second area (120b) having reflective platelet-like pigment particles with a second elevation angle γ2. [Figure 2B] 1 shows a schematic cross-section of a magnetically inductive layer (120) comprising magnetically oriented platelet-like magnetic or magnetizable pigment particles in a single layer of material applied onto a flat substrate (110). The magnetically inductive layer (120) comprises two distinct zones (120a, 120b) in the single layer (120) in which the reflective pigment particles have different elevation angles γ1 and γ2. [Figure 2C] 1 shows a schematic cross-section of a magnetically inductive layer (120) according to one embodiment of the present invention, comprising magnetically oriented, platelet-shaped magnetic or magnetizable pigment particles in two layers on a flat substrate (110). The magnetically inductive layer (120) comprises two zones: a first zone (120a) is a first layer of material comprising magnetically oriented, reflective, platelet-shaped magnetic or magnetizable pigment particles having a first elevation angle γ1; and a second zone (120b) is a second layer of material comprising magnetically oriented, reflective, platelet-shaped magnetic or magnetizable pigment particles having a second elevation angle γ2, the first and second layers having abutting edges. [Figure 3] 1 shows a schematic exploded perspective view of a security marking (100) according to one embodiment of the present invention, comprising a flat substrate (110), a magnetically inductive layer (120) having an upper surface (121) and a lower surface (122) and two zones (120a) and (120b) of differently oriented, reflective, platelet-like, magnetic or magnetizable pigment particles, and a machine-readable marking (130) having an upper surface (131) and a lower surface (132), the machine-readable marking (130) partially overlapping the magnetically inductive layer (120). [Figure 4A]1 shows a schematic cross-section of a security marking (100) including a flat substrate (110), a magnetically inductive layer (120) having two zones applied to the substrate, and a machine-readable marking (130) printed on the top surface (121) of the magnetically inductive layer, the machine-readable marking (130) partially overlapping the magnetically inductive layer (120). [Figure 4B] 1 shows a schematic cross-section of a security marking (100) including a flat substrate (110), a dark primer (140) having an upper surface (141) and a lower surface (142), a magnetically inductive layer (120) having two zones applied to the substrate, and a machine-readable marking (130), wherein the dark primer has its lower surface (142) applied to the upper surface of the substrate (110), the lower surface (122) of the magnetically inductive layer (120) is applied to the upper surface (141) of the dark primer, and the machine-readable marking (130) partially overlaps the magnetically inductive layer (120). [Figure 4C] 1 shows a schematic cross-section of a security marking (100) including a flat substrate (110), a magnetic induction layer (120), and a machine-readable marking (130), wherein the machine-readable marking (130) is printed on the top surface of the substrate (110), the back surface (122) of the magnetic induction layer (120) is applied to the top surface (131) of the machine-readable marking (130), and the machine-readable marking (130) partially overlaps the magnetic induction layer (120). [Figure 5A] 1 shows a top view of an example of a machine-readable code (130) (shown in FIG. 3) in the form of a small QR Code® having a reference pattern (133) for locating a code pattern (134) during a decoding operation, a first area on a first zone (120a) of the magnetic induction layer, and a second area on a second zone (120b) of the magnetic induction layer. [Figure 5B] 1 shows a top view of an example of a machine-readable code (130) (shown in FIG. 3) in the form of a large QR code having a reference pattern (133) for locating a code pattern (134) during a decoding operation, a first area on a first zone (120a) of the magnetic induction layer, and a second area on a second zone (120b) of the magnetic induction layer. [Figure 5C]1 shows a top view of an example of a machine-readable code (130) (shown in FIG. 2) in the form of a data matrix having an L-shaped reference pattern (133) for positioning the code pattern (134) during a decoding operation, a first area (134a) on a first zone (120a) of the magnetic induction layer, and a second area (134b) on a second zone (120b) of the magnetic induction layer. [Figure 6A] A portable device (200) is shown taking an image of a security marking (100) including a magnetic induction layer (120) having two distinct zones (120a) and (120b) at one of two different viewing angles θ1, with illumination of the first zone (120a) and the second zone (120b) shown as (210a) and (210b), respectively, and reflected light from the first zone and the second zone shown as (220a) and (220b), respectively. [Figure 6B] A portable device (200) is shown taking an image of a security marking (100) including a magnetic induction layer (120) having two distinct zones (120a) and (120b) at one of two different viewing angles θ2, with illumination of the first zone (120a) and the second zone (120b) shown as (210a) and (210b), respectively, and reflected light from the first zone and the second zone shown as (220a) and (220b), respectively. [Figure 7] 5B is a schematic flow chart illustrating a process (700) for extracting decoded data from the machine-readable marking (130) of FIG. 5A. [Figure 8A] 8 shows a pose estimation flowchart for one of two methods (800a) for reading and decoding a security marking (100) according to the present invention using an imaging device in a mobile device. [Figure 8B] 8 shows a pose estimation flowchart for one of two methods (800b) for reading and decoding a security marking (100) according to the present invention using an imaging device in a mobile device. [Figure 9]An example of a security document (150) according to the present invention is shown, namely a user's ID card issued by an authorized person. [Figure 10] 10 illustrates a method for verifying the security document of FIG. 9 according to the present invention. [Figure 11] FIG. 10 shows a system for verifying security documents according to the method shown in FIG. [Figure 12A] A process is shown for producing a magnetically inductive layer (120) on a substrate (110), said layer (120) comprising biaxially oriented reflective platelet-like magnetic or magnetizable pigment particles. [Figure 12B] A process is shown for producing a magnetically inductive layer (120) on a substrate (110), said layer (120) comprising biaxially oriented reflective platelet-like magnetic or magnetizable pigment particles. [Figure 13] A process is shown for producing a magnetically inductive layer (120) on a substrate (110), said layer (120) comprising uniaxially oriented, reflective platelet-like magnetic or magnetizable pigment particles. [Figure 14A] 12-13 show photographic images of a security marking (100) on which a magnetically inductive layer (120) is obtained by using the method and device shown in FIGS. [Figure 14B] 12-13 show photographic images of a security marking (100) on which a magnetically inductive layer (120) is obtained by using the method and device shown in FIGS. [Figure 14C] 12-13 show photographic images of a security marking (100) on which a magnetically inductive layer (120) is obtained by using the method and device shown in FIGS. [Figure 14D] 12-13 show photographic images of a security marking (100) on which a magnetically inductive layer (120) is obtained by using the method and device shown in FIGS. Detailed Description

[0038] The following definitions shall be used to interpret the meaning of the terms discussed in this specification and recited in the claims.

[0039] As used herein, the term "at least one" is meant to define one or more than one, for example, one or two or three.

[0040]

[0039] As used herein, the term "about" means that the amount or value in question may be the specified particular value or some other value in its vicinity. Generally, the term "about" referring to a particular value is intended to indicate a range of within ±5% of the value. As an example, the phrase "about 100" indicates a range of 100 ±5, i.e., a range of 95 to 105. Generally, when the term "about" is used, it can be expected that similar results or effects of the present invention can be obtained within a range of ±5% of the indicated value.

[0041] As used herein, the term "and / or" means that either all or only one of the elements of the group may be present. For example, "A and / or B" shall mean "A only, or B only, or both A and B." In the case of "A only," the term also includes the possibility that B is absent, i.e., "A only is present and B is absent."

[0042]

[0041] As used herein, the terms "comprising" and "containing" are intended to be non-exclusive and open-ended. Thus, for example, a mixture comprising / containing compound A may contain other compounds in addition to A. However, the terms "comprising" and "containing" also include, as specific embodiments thereof, the more restrictive meanings of "consisting essentially of" and "consisting of", so that, for example, a "mixture comprising A, B and optionally C" may consist (essentially) of A and B, or (essentially) of A, B and C.

[0043] The security markings (100) described herein preferably comprise a flat substrate (110) selected from the group consisting of paper or other fibrous materials (including woven and nonwoven fibrous materials), such as cellulose, paper-containing materials, glass, metal, ceramic, plastics and polymers, metallized plastics or polymers, composite materials, and mixtures or combinations of two or more thereof. Typical paper, paper-like, or other fibrous materials are made from a variety of fibers, including, but not limited to, abaca, cotton, linen, wood pulp, and blends thereof. However, according to different embodiments, the substrate (110) may be based on plastics and polymers, metallized plastics or polymers, composite materials, and mixtures or combinations of two or more thereof. Suitable examples of plastics and polymers include polyolefins, such as polyethylene (PE) and polypropylene (PP), including biaxially oriented polypropylene (BOPP), polyamides, polyesters, such as poly(ethylene terephthalate) (PET), poly(1,4-butylene terephthalate) (PBT), poly(ethylene 2,6-naphthoate) (PEN), and polyvinyl chloride (PVC). Spunbond olefin fibers, such as those sold under the trademark Tyvek®, can also be used as the substrate. Typical examples of metallized plastics or polymers include the aforementioned plastic or polymer materials having metals continuously or discontinuously disposed on the surface. Typical examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), alloys thereof, and combinations of two or more of the aforementioned metals. Metallization of the aforementioned plastic or polymer materials can be performed by an electrodeposition process, a high-vacuum coating process, or a sputtering process. Typical examples of composite materials include, but are not limited to, multi-layer structures or laminates of paper and at least one plastic or polymer material such as those mentioned above, and plastic and / or polymer fibers incorporated into paper-like or fibrous materials such as those mentioned above.Of course, the substrate may contain additional additives known to those skilled in the art, such as fillers, sizing agents, brighteners, processing aids, reinforcing or wet strength agents, and the like.

[0044]

[0043] According to one embodiment of the present invention, for example as shown in Figure 2, a security marking (100) includes a magnetically inductive layer (120) made from a material containing a plurality of magnetically oriented, reflective, platelet-like, magnetic or magnetizable pigment particles as described above, the pigment particles being fixed or frozen (fixed / frozen) in a predetermined position and orientation within the material. In contrast to needle-shaped pigment particles, which can be thought of as one-dimensional particles, platelet-shaped pigment particles are quasi-two-dimensional particles due to the large aspect ratio of their dimensions, as shown in Figure 1. Platelet-shaped pigment particles can be thought of as two-dimensional structures, with dimensions along axes X and Y substantially greater than the dimension along axis Z (i.e., thickness). Platelet-shaped pigment particles are also referred to in the art as flat particles or flat flakes.

[0045] Oriented, reflective platelet-shaped magnetic or magnetizable pigment particles have anisotropic reflectivity due to their planar shape. As used herein, the term "anisotropic reflectivity" means that the proportion of incident radiation from a first angle that is reflected by a particle in a particular (viewing) direction (second angle) is a function of the particle's orientation, i.e., a change in the particle's orientation relative to the first angle can lead to a different magnitude of reflection in the viewing direction. The reflective platelet-shaped magnetic or magnetizable pigment particles described herein preferably have anisotropic reflectivity with respect to incident electromagnetic radiation over some portion or the entire wavelength range of about 400 to about 1000 nm (i.e., visible to NIR wavelengths), more preferably about 400 to about 700 nm (i.e., the visible range), such that a change in particle orientation results in a change in the particle's reflection in a particular direction. Thus, even if the intrinsic reflectivity per unit surface area (e.g., per μm²) is uniform over the entire surface of a platelet-like particle, the particle's visible area depends on the direction from which it is viewed, and thus, due to its shape, the particle's reflectivity is anisotropic. As known by those skilled in the art, the reflective platelet-like magnetic or magnetizable pigment particles described herein differ from conventional pigments in that, while said conventional pigment particles exhibit the same color and reflectivity regardless of particle orientation, the magnetic or magnetizable pigment particles described herein exhibit either reflectivity or color, or both, that depend on the particle orientation within the layer material. The platelet-like pigment particles, initially randomly distributed within a material layer, are oriented within the layer by the application of a strong (uniform) magnetic field and then fixed / frozen in place by subsequent solidification of the layer material. The platelet-like pigment particles are then preferably oriented with their flat surfaces in the (uniaxial) direction of the applied magnetic field according to a statistical distribution with a sharp peak (e.g., a Gaussian distribution). The pigment particles are therefore statistically oriented, with their flat faces having corresponding angles of elevation relative to the plane of the layer. The angle between two planes is by definition the angle between vectors perpendicular to the respective planes, and is also the angle between two straight lines in the respective panes perpendicular to the line at the intersection of the two planes.Here, straight lines along the flat surfaces of the oriented pigment particles are aligned (substantially according to a statistical distribution) with the orientation direction of the pigment particles. The full width at half maximum (FWHM) of this statistical distribution makes it possible to estimate the corresponding standard deviation of the orientation of the flat surfaces relative to the direction of the magnetic field lines. Therefore, the normal direction to the surfaces of (uniaxially) oriented platelet-like pigment particles may actually have a tilt angle around the uniaxial orientation direction that is less than 30°. To achieve a better relative orientation of the surfaces of the various pigment particles (i.e., to reduce the tilt angle and therefore a better relative parallelism of the surfaces), a second magnetic field is applied (before solidification) in which the magnetic field lines are oriented in a second direction (e.g., along the Y-axis shown in FIG. 1 ). This biaxial orientation of the surfaces of the pigment particles significantly reduces the aforementioned standard deviation, and the surfaces of the pigment particles are (statistically) parallel to each other while still oriented in a defined direction corresponding to the elevation angle. In a preferred embodiment of the present invention, a biaxial magnetic induction layer is used, in which the surfaces of the pigment particles in each zone of the magnetic induction layer are biaxially oriented.

[0046] Suitable examples of platelet-shaped magnetic or magnetizable pigment particles include, but are not limited to, pigment particles comprising a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe), and nickel (Ni); a magnetic alloy of iron, manganese, cobalt, nickel, or a mixture of two or more thereof; a magnetic oxide of chromium, manganese, cobalt, iron, nickel, or a mixture of two or more thereof; or a mixture of two or more thereof. The term "magnetic" with respect to metals, alloys, and oxides refers to ferromagnetic or ferrimagnetic metals, alloys, and oxides. The magnetic oxides of chromium, manganese, cobalt, iron, nickel, or a mixture of two or more thereof may be pure oxides or mixed oxides. Examples of magnetic oxides include, but are not limited to, iron oxides such as hematite (Fe2O3), magnetite (Fe3O4), chromium dioxide (CrO2), magnetic ferrite (MFe2O4), magnetic spinel (MR2O4), magnetic hexaferrite (MFe12O19), magnetic orthoferrite (RFeO3), and magnetic garnet M3R2(AO4)3, where M represents a divalent metal, R represents a trivalent metal, and A represents a tetravalent metal.

[0047]

[0046] Other examples of platelet-shaped magnetic or magnetizable pigment particles include, but are not limited to, pigment particles comprising a magnetic layer M made from one or more of a magnetic metal such as cobalt (Co), iron (Fe), or nickel (Ni), and a magnetic alloy of iron, cobalt, or nickel, and the magnetic or magnetizable pigment particles may be a multilayer structure comprising one or more additional layers. Preferably, the one or more additional layers are a layer A independently made from one or more selected from the group consisting of metal fluorides such as magnesium fluoride (MgF), silicon oxide (SiO), silicon dioxide (SiO), titanium oxide (TiO), and aluminum oxide (AlO), more preferably silicon dioxide (SiO); or a layer B independently made from one or more selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (AI), chromium (Cr), and nickel (Ni), even more preferably aluminum (AI); or a combination of one or more layers A such as those described above with one or more layers B such as those described above. Typical examples of platelet-shaped magnetic or magnetizable pigment particles having the above-mentioned multilayer structure include, but are not limited to, A / M multilayer structure, A / M / A multilayer structure, A / M / B multilayer structure, A / B / M / A multilayer structure, A / B / M / B multilayer structure, A / B / M / B / A multilayer structure, B / M multilayer structure, B / M / B multilayer structure, B / A / M / A multilayer structure, B / A / M / B multilayer structure, B / A / M / B / A multilayer structure, where Layer A, Magnetic Layer M and Layer B are selected from those described above.

[0048] According to one embodiment, at least a portion of the preferred platelet-shaped magnetic or magnetizable particles are constituted by platelet-shaped optically variable magnetic or magnetizable pigment particles. Optically variable pigment refers to a pigment that exhibits a change in illuminance or a combination of a change in illuminance and a change in color. According to one embodiment, at least a portion of the platelet-shaped magnetic or magnetizable particles are constituted by particles that exhibit a metallic color, more preferably a silver or gold color.

[0049]

[0048] The platelet-shaped magnetic or magnetizable pigment particles are preferably selected from the group consisting of magnetic thin film interference pigment particles, magnetic cholesteric liquid crystal pigment particles, interference coated pigment particles containing magnetic material, and mixtures of two or more thereof.

[0050]

[0049] Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in U.S. Pat. No. 4,838,648, WO 2002 / 073250, EP 0686675, WO 2003 / 000801, U.S. Pat. No. 6,838,166, WO 2007 / 131833, EP 2402401, WO 2019 / 103937, WO 2020 / 006286, and the references cited therein. Preferably, the magnetic thin film interference pigment particles include pigment particles having a five-layer Fabry-Perot multilayer structure, and / or pigment particles having a six-layer Fabry-Perot multilayer structure, and / or pigment particles having a seven-layer Fabry-Perot multilayer structure, and / or pigment particles having a multilayer structure including one or more multilayer Fabry-Perot structures.

[0051]

[0050] A preferred five-layer Fabry-Perot multilayer structure consists of a multilayer structure of absorber / dielectric / reflector / dielectric / absorber, where the reflector and / or absorber are also magnetic layers, and the reflector and / or absorber are preferably magnetic layers containing nickel, iron and / or cobalt, and / or magnetic alloys containing nickel, iron and / or cobalt, and / or magnetic oxides containing nickel (Ni), iron (Fe) and / or cobalt (Co).

[0052] A preferred six-layer Fabry-Perot multilayer structure consists of an absorber / dielectric / reflector / magnetic / dielectric / absorber multilayer structure.

[0053] A preferred seven-layer Fabry-Perot multilayer structure comprises an absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure as disclosed in US Pat. No. 4,838,648.

[0054]

[0053] Preferred pigment particles having a multilayer structure including one or more Fabry-Perot structures are described in WO 2019 / 103937, which consist of a combination of at least two Fabry-Perot structures, each of which independently comprises a reflector layer, a dielectric layer, and an absorber layer, and each of the reflector and / or absorber layers may independently comprise one or more magnetic materials, and / or a magnetic layer is sandwiched between the two structures. WO 2020 / 006 / 286 and EP 3587500 disclose further preferred pigment particles having a multilayer structure.

[0055]

[0054] The reflector layer described herein is selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective materials and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (pd), rhodium (Ph), niobium (Nb), chromium (Cr), nickel (Ni), and alloys thereof, even more preferably independently made from one or more selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni), and alloys thereof, and even more preferably aluminum (Al). Preferably, the dielectric layer is selected from the group consisting of metal fluorides such as magnesium fluoride (MgF), aluminum fluoride (AlF), cerium fluoride (CeF), lanthanum fluoride (LaF), sodium aluminum fluoride (e.g., NaAlF), neodymium fluoride (NdF), samarium fluoride (SmF), barium fluoride (BaF), calcium fluoride (CaF), lithium fluoride (LiF), and metal oxides such as silicon oxide (SiO), silicon dioxide (SiO), titanium oxide (TiO), aluminum oxide (AlO), more preferably one or more selected from the group consisting of magnesium fluoride (MgF) and silicon dioxide (SiO), even more preferably magnesium fluoride (MgF). Preferably, the absorber layers are independently made from one or more selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium (V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), metal oxides thereof, metal sulfides thereof, metal carbides thereof, and metal alloys thereof, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), metal oxides thereof, and metal alloys thereof, even more preferably selected from the group consisting of chromium (Cr), nickel (Ni), and metal alloys thereof.The magnetic layer preferably comprises nickel (Ni), iron (Fe) and / or cobalt (Co), and / or a magnetic alloy comprising nickel (Ni), iron (Fe) and / or cobalt (Co), and / or a magnetic oxide comprising nickel (Ni), iron (Fe) and / or cobalt (Co).

[0056]

[0055] When magnetic thin film interference pigment particles comprising a seven-layer Fabry-Perot structure are preferred, it is particularly preferred that the magnetic thin film interference pigment particles comprise a seven-layer Fabry-Perot absorber / dielectric / reflector / magnetic / reflector / dielectric / absorber multilayer structure consisting of a multilayer structure of Cr / MgF2 / Al / Ni / Al / MgF2 / Cr.

[0057] The magnetic thin film interference pigment particles described herein are believed to be safe for human health and the environment, and may be multilayer pigment particles based on, for example, a 5-layer Fabry-Perot multilayer structure, a 6-layer Fabry-Perot multilayer structure, and a 7-layer Fabry-Perot multilayer structure, the pigment particles comprising one or more magnetic layers comprising a magnetic alloy having a substantially nickel-free composition comprising, by weight, about 40% to about 90% iron, about 10% to about 50% chromium, and about 0% to about 30% aluminum. Typical examples of multilayer pigment particles believed to be safe for human health and the environment can be found in EP 2 402 401 A1, the contents of which are incorporated herein by reference in their entirety.

[0058] Suitable magnetic cholesteric liquid crystal pigment particles exhibiting optically variable properties include, but are not limited to, magnetic single-layer cholesteric liquid crystal pigment particles and magnetic multi-layer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed, for example, in WO 2006 / 063926, U.S. Pat. No. 6,582,781, and U.S. Pat. No. 6,531,221. WO 2006 / 063926 discloses a monolayer and pigment particles obtained therefrom having high brightness and color-changing properties as well as specific properties such as magnetizability. The disclosed monolayer and pigment particles obtained therefrom by milling the monolayer comprise a three-dimensionally crosslinked cholesteric liquid crystal mixture and magnetic nanoparticles. US Patent Nos. 6,582,781 and 6,410,130 disclose platelet-shaped cholesteric multilayer pigment particles having the sequence A1 / B / A2, where A1 and A2 may be the same or different and each comprise at least one cholesteric layer, and B is an intermediate layer that absorbs all or part of the light transmitted by layers A1 and A2 and imparts magnetic properties to said intermediate layer. US Patent No. 6,531,221 discloses platelet-shaped cholesteric multilayer pigment particles having the sequence A / B and optionally C, where A and C are absorbing layers containing pigment particles that impart magnetic properties, and B is a cholesteric layer.

[0059]

[0058] Suitable interference-coated pigment particles containing one or more magnetic materials include, but are not limited to, a structure consisting of a substrate selected from the group consisting of a core coated with one or more layers, wherein at least one of the core or the one or more layers is magnetic. For example, suitable interference-coated pigment particles include a core formed from a magnetic material such as those described above, coated with one or more layers formed from one or more metal oxides, or have a structure consisting of a core formed from synthetic or natural mica, layered silicates (e.g., talc, kaolin, and sericite), glass (e.g., borosilicate), silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), graphite, and mixtures of two or more thereof. Additionally, one or more additional layers, such as color layers, may be present.

[0060]

[0059] The platelet-shaped magnetic or magnetisable pigment particles described herein preferably have a size d50 (as measured by direct optical particle size distribution) of between about 2 μm and about 50 μm.

[0061]

[0060] The platelet-shaped magnetic or magnetizable pigment particles described in this specification may be surface treated to protect them from any deterioration that may occur in the coating compositions and coating layers and / or to facilitate their incorporation into said coating compositions and coating layers, typically with the use of corrosion inhibitors and / or wetting agents.

[0062]

[0061] The magnetic induction layer (120) described herein is prepared by a process comprising the steps of: a) applying a coating composition comprising the reflective platelet-shaped magnetic or magnetizable pigment particles described herein; b) orienting at least a portion of the reflective platelet-shaped magnetic or magnetizable pigment particles by exposing the coating composition to a magnetic field of a magnetic field generating device; and c) solidifying the coating composition to fix the reflective platelet-shaped magnetic or magnetizable pigment particles in their adopted position and orientation.

[0063] The coating compositions described herein preferably comprise the reflective platelet-shaped magnetic or magnetizable pigment particles described herein dispersed in a binder material, the reflective platelet-shaped magnetic or magnetizable pigment particles being present in an amount of from about 2 wt % to about 40 wt %, more preferably from about 4 wt % to about 30 wt %, wherein the weight percent is based on the total weight of the coating composition including the binder material, the reflective platelet-shaped magnetic or magnetizable pigment particles, and other optional components of the coating composition. The coating compositions described herein may further comprise one or more coloring components selected from the group consisting of organic pigment particles, inorganic pigment particles, and organic dyes, and / or one or more additives. Additives include, but are not limited to, compounds and materials used to adjust the physical, rheological, and chemical parameters of the coating composition, such as viscosity (e.g., solvents, thickeners, and surfactants), firmness (e.g., anti-settling agents, fillers, and plasticizers), foaming properties (e.g., antifoaming agents), lubrication properties (waxes, oils), UV stability (light stabilizers), adhesion properties, antistatic properties, storage stability (polymerization inhibitors), etc. The additives described herein, including so-called nanomaterials, in which at least one of the additive's dimensions is within the 1-1000 nm range, may be present in the coating composition in amounts and forms known in the art.

[0064] The applying step a) described in the previous paragraph is preferably carried out by a printing process selected from the group consisting of screen printing, rotogravure printing, and flexography. These processes are well known to those skilled in the art and are described, for example, in Printing Technology, J.M.A. Dams and P.A. Dolin, Delmar Thomson Learning, 5th Edition, pp. 293, 332, and 352. While a coating composition comprising the reflective platelet-like magnetic or magnetizable pigment particles described herein is still wet or soft enough to allow the pigment particles therein to move and rotate (i.e., while the coating composition is in a first state), the coating composition is subjected to a magnetic field to achieve particle orientation. The step of magnetically orienting the reflective platelet-like magnetic or magnetizable pigment particles comprises exposing the applied coating composition, while it is "wet" (i.e., still liquid but not too viscous), to a predetermined magnetic field generated by a magnetic field generating device, thereby orienting the reflective platelet-like magnetic or magnetizable pigment particles along the field lines of the magnetic field, for example to form an orientation pattern. Subsequent to, partially simultaneous with, or simultaneous with application of the coating composition, the reflective platelet-like magnetic or magnetizable pigment particles are oriented by use of an external magnetic field to orient the particles according to a desired orientation pattern. The orientation pattern so obtained can be any pattern except a random orientation and except a pattern in which the magnetic axes of the reflective platelet-like magnetic or magnetizable pigment particles are oriented parallel or perpendicular to the layer (120).

[0065] The process for producing the magnetically inductive layer (120) described herein includes, partially simultaneously with or subsequent to step b), step c) of converting the coating composition to a second state by solidifying the coating composition to fix the partially reflective platelet-like magnetic or magnetizable pigment particles in their adopted positions and orientations in a desired pattern to form the magnetically inductive layer. This fixation forms a solid coating or layer. The term "solidifying" refers to a process that includes drying or solidifying, reacting, curing, crosslinking, or polymerizing the binder components, including an optional crosslinking agent, an optional polymerization initiator, and optionally additional additives, in the applied coating composition in such a manner that an essentially solid material that adheres to the surface is formed. As described herein, the solidifying step c) can be carried out by using various means or processes depending on the materials contained in the coating composition, including the reflective platelet-like magnetic or magnetizable pigment particles. The solidifying step generally can be any step that increases the viscosity of the coating composition to form a substantially solid material that adheres to the support surface. The solidifying step may involve a physical process based on evaporation of volatile components such as solvents and / or water evaporation (i.e., physical drying). Herein, hot air, infrared radiation, or a combination of hot air and infrared radiation may be used. Alternatively, the solidifying process may involve a chemical reaction, such as curing, polymerization, or crosslinking, of the binder and optional initiator and / or crosslinking compounds contained in the coating composition. Such a chemical reaction may be initiated by heat or IR radiation as outlined above for the physical solidifying process, but preferably involves initiation of a chemical reaction by irradiation mechanisms, including, but not limited to, ultraviolet-visible light radiation curing (hereinafter referred to as UV-Vis curing) and electron beam radiation curing (E-beam curing), oxidative polymerization (oxidative reticulation generally caused by the cooperative action of oxygen with one or more catalysts, preferably selected from the group consisting of cobalt-containing catalysts, vanadium-containing catalysts, zirconium-containing catalysts, bismuth-containing catalysts, and manganese-containing catalysts), crosslinking reactions, or any combination thereof.Radiation curing is particularly preferred, with UV-Vis light radiation curing being even more preferred, because these techniques advantageously lead to a very rapid curing process, thus dramatically reducing the production time of any document containing the magnetically inductive layer described herein. Furthermore, radiation curing has the advantage that it results in a nearly simultaneous increase in the viscosity of the coating composition after exposure to curing radiation, thereby minimizing any further particle movement. As a result, any loss of information after the magnetic orientation step is essentially avoided. Particularly preferred is radiation curing by photopolymerization under the influence of actinic light having wavelength components in the UV-Vis electromagnetic spectrum. Equipment for UV-visible curing can include, as actinic radiation sources, continuous or pulsed lasers (e.g., GaN), powerful light-emitting diode (LED) lamps, or arc discharge lamps such as medium-pressure mercury arc (MPMA) or metal vapor arc lamps.

[0066]

[0065] When a primer (140), preferably a dark primer and more preferably a black primer, is present between the substrate (110) and the magnetically inductive layer (120), a step of applying and solidifying the primer composition is carried out before preparing the magnetically inductive layer (120). The primer compositions described herein can be applied by a wide variety of coating processes, preferably selected from the group consisting of an inkjet printing process, an offset printing process, a flexographic printing process, a gravure printing process, a screen printing process, a pad printing process, and a roller coating process.

[0067]

[0066] The magnetic induction layer (120) described in this specification comprises (at least) two zones (see Figure 2A), namely, a first zone (120a) comprising magnetically oriented, reflective, platelet-shaped magnetic or magnetizable pigment particles whose flat surfaces are oriented in a first direction and have a first elevation angle γ1 relative to the substrate (110) corresponding to the angle between the flat surfaces and the plane of the substrate (110), and a second zone (120b) different from the first zone (120a) comprising magnetically oriented, reflective, platelet-shaped magnetic or magnetizable pigment particles whose flat surfaces are oriented in a second direction different from the first direction and have a second elevation angle γ2 relative to the substrate (110) corresponding to the angle between the flat surfaces and the plane of the substrate (110). To obtain definitions of the elevation angles in the two zones of the magnetic induction layer that correspond to a common counterclockwise rotation direction corresponding to some defined right-hand orthogonal triad (e.g., x and y lie in the plane and the z-axis is oriented outward) defined in the reference plane of the substrate (top surface), the elevation angle γ1 of the flat surface of the pigment particle in the first zone is the angle of forward rotation about the line L1 (from the reference plane to the flat surface) of the intersection of the flat surface and the reference plane, considered counterclockwise, between the plane of the substrate and the plane of the surface, while the elevation angle γ2 of the flat surface of the pigment particle in the second zone is the angle of forward rotation about the corresponding line L2, still considered counterclockwise, but now obtained by rotating the line L2 of the intersection of the flat surface and the reference plane in the reference plane to align it with line L1. This method of defining the elevation angles in the two different particle orientation zones facilitates clear comparison of the elevation angles and orientation directions. In each zone of the magnetically inductive layer (120), the acute angle of the flat surface relative to the plane of the substrate (110) is preferably within a range of about 5° to about 25°, consistent with experimental testing conducted in accordance with the present invention. Furthermore, as a result of said experimental testing, in order to obtain acceptable contrast between the two zones when the illuminated security marking (100) is viewed at two viewing angles corresponding to the best light reflection from the first and second zones, respectively, the two different orientation directions of the flat surfaces in the two zones (120a) and (120b) are preferably at an angle of at least 30°.In the example shown in Figure 2, where the faces of the pigment particles in each zone (120a, 120b) are approximately parallel to each other (i.e., the normals to the faces in each zone are approximately parallel, see Figure 2A), the first elevation angle γ1, when measured in the counterclockwise direction as defined above, has a value in the range of about 5° to about 25° (5° < γ1 < 25°), preferably about 5° to about 20° (5° < γ1 < 20°), and the second elevation angle γ2, when measured in the counterclockwise direction as defined above, has a value in the range of about 155° to about 175° (155° < γ2 < 175°), more preferably about 160° to about 175° (160° < γ2 < 175°). Therefore, the acute angle formed by the faces of the pigment particles in the second zone (120b) of the magnetic induction layer (120), i.e., the angle complementary to the elevation angle γ2, is in the range of about 5° (assuming 180°-175°=5°) to about 25° (assuming 180°-155°=25°).

[0068] In the embodiment shown in Figure 2B, the magnetically inductive layer (120) comprises magnetically oriented platelet-like magnetic or magnetizable pigment particles in a single layer of material applied to the flat substrate (110). In the embodiment shown in Figure 2C, the magnetically inductive layer (120) comprises two distinct sub-layers forming two zones (120a) and (120b), respectively, the first and second sub-layers being adjacent, i.e., having abutting edges forming a common boundary. According to another embodiment (not shown in Figure 2C), the two distinct sub-layers forming the two zones (120a) and (120b), respectively, are spaced apart from each other.

[0069]

[0068] Instead of using a magnetic induction layer containing magnetically oriented, reflective, platelet-like magnetic or magnetizable pigment particles having the elevation angles described herein, diffractive, reflective, or refractive microstructures may be used, such as layers containing diffraction gratings and microlens or micromirror structures, the structures including micromirrors whose facets have the specific elevation angles described herein.

[0070]

[0069] According to the present invention, as shown in Figures 3 to 5, a machine-readable marking (130) in the form of a two-dimensional barcode including a reference pattern (133) and a code pattern (134) representing encoded data is applied either to the upper surface (121) of the magnetically inductive layer (120) or to the substrate (110) between the substrate (110) and the back surface (122) of the magnetically inductive layer (120), with a first area (134a) of the code pattern (134) located in front of the first zone (120a) and a remaining second area (134b) of the code pattern (134) located in front of the second zone (120b). When reading and decoding the machine-readable marking (130), the reference pattern (133) is used to accurately position the code pattern (134) during image processing operations. Figure 5B shows an embodiment with a QR code and its unique reference pattern (133) in the form of three squares. 5C shows an embodiment with a Data Matrix code having an L-shaped reference pattern (133). Other machine-readable code formats (e.g., dot matrix) can be used with the present invention with their reference patterns. It is also possible to use machine-readable markings in which the reference pattern is marked separately from the code pattern in an area outside the magnetically inductive layer (however, it must still be within the field of view of the reader while reading the machine-readable marking).

[0071]

[0070] The machine-readable markings (130) described herein may be produced by any suitable means, including printing processes (particularly inkjet printing), etching and ablation methods (particularly laser etching or laser burning), embossing methods, etc.

[0072] 3 is an exploded perspective view of a security marking (100) according to one embodiment of the present invention, comprising a flat substrate (110), a magnetically inductive layer (120) having an upper surface (121) and a lower surface (122) and two zones (120a) and (120b) of differently oriented, reflective, platelet-like magnetic or magnetizable pigment particles, and a machine-readable marking (130) in the form of a QR code having an upper surface (131) and a lower surface (132) and partially overlapping the magnetically inductive layer (120). Here, the machine-readable marking (130) is applied to the upper surface of the magnetically inductive layer (120) applied to the substrate (110). A first area (134a) of the code pattern (134) is disposed in front of the first zone (120a), and a second area (134b) of the code pattern (134) is disposed in front of the second zone (120b). The advantage of the present invention is that, in order to obtain sufficient coded data from the code pattern, it is necessary to take two different images of the machine-readable marking (130) at two different viewing angles, which respectively correspond to the elevation angles and orientations of the pigment particles in the two zones (120a) and (120b). In fact, when imaged under a single viewing angle, due to the difference in light reflectivity of the two zones (120a) and (120b) of the magnetically inductive layer (120), only a portion of the imaged code pattern can be reliably detected, i.e., the portion of the code pattern that is in front of the zone of the magnetically inductive layer that provides the best contrast (if the viewing angle is at the right angle corresponding to the elevation angle of the faces of the pigment particles in said zone, the elevation angle of the faces of the pigment particles sets the viewing angle at which the specular reflection of light from the faces is maximum for a given position of the light source). Therefore, it is not possible to obtain the required contrast for detection of encoded data for both areas 134a and 134b of code pattern 134 simultaneously from a single viewing angle.To reliably detect the complete encoded data, it is necessary to first acquire two images of the machine-readable marking (130) at two different viewing angles adapted to the respective elevation angles of the planes of the pigment particles in the first zone (120a) and the second zone (120b) of the magnetic induction layer (120), to obtain in each image only the corresponding parts of the code pattern (130) that can be reliably detected, and then reconstruct an image of the complete code pattern from these two acquired images in order to reassemble the two detected parts of the code pattern. Reconstruction requires the use of the imaged reference pattern (133) to obtain common reference position elements in the two images, accurately reassemble the two detected parts, and reconstruct a decodable image of the complete code pattern (130). If such reconstruction is possible, it implicitly means that the imaging operation was performed according to the very specific structure of the security marking and therefore that the security marking (100) is most likely genuine, which is a further advantage of the present invention.

[0073]

[0072] Figures 4A-4C show various embodiments of a security marking 100 according to the present invention. In the example of Figure 4A, which shows a cross section of the security marking 100, a magnetically inductive layer 120 is applied to a substrate 110, and a machine-readable marking 130 is applied to an upper surface 121 of the magnetically inductive (single) layer 120, with the machine-readable marking 130 partially overlapping the magnetically inductive layer 120.

[0074]

[0073] In the example of Figure 4B showing a cross section of the security marking (100), a dark primer (140) (preferably a black primer) is disposed between the substrate (110) and the magnetic induction layer (120), i.e., the dark primer (140) has its back surface (142) applied to the top surface of the substrate (110), the back surface (122) of the magnetic induction layer (120) is applied to the top surface (141) of the dark primer, and the machine-readable marking (130), which may be encoded with either a light or dark symbol, partially overlaps the magnetic induction layer (120).

[0075]

[0074] In the example of Figure 4C showing a cross section of security marking (100), machine-readable marking (130) is applied to the top surface of substrate (110) and is preferably encoded with a dark symbol, and the back surface (122) of magnetic induction layer (120) is applied to the top surface (113) of machine-readable marking (130), with machine-readable marking (130) partially overlapping magnetic induction layer (120).

[0076]

[0075] As explained above, reading and decoding the two-zone magnetic induction layer (120) requires taking (at least) two images of the security marking (100). According to the present invention, a method for reading and decoding the security marking (100) uses a portable device (200) (e.g., a smartphone) equipped with a light source (201) preferably delivering illumination light in the visible or NIR spectrum (i.e., wavelengths between 400 nm and 1000 nm), an imaging device (202) (e.g., a smartphone camera) for taking digital images, and a processor (not shown) equipped with a memory (not shown) and configured for image processing and decoding operations, as shown in Figure 6, and includes the following steps: (i) illuminating a security marking (100) located within the field of view of an imaging device (202) with illumination light delivered by a light source (201), for example, an LED ("light emitting diode") flash of a smartphone, adjacent to the imaging device (the camera of the smartphone); (ii) capturing a first digital image of the security marking (100) with the imaging device (202) at a first viewing angle θ1 associated with a first elevation angle γ1 of the pigment particles in the first zone (120a) of the magnetic induction layer (120) and storing the captured first digital image in memory. In the smartphone example above, with the imaging device very close to the (quasi-point) light source, the viewing angle θ1 at which the intensity of light reflected by the surfaces of the pigment particles in the first zone (120a) is greatest corresponds to a position of the imaging device in a direction substantially perpendicular to the surfaces of the pigment particles in the first zone (120a). Due to this viewing angle θ1, the part of the code pattern (134) that is applied to the second zone (120b) of the magnetic induction layer (120) does not reflect enough light (θ1 is not adapted to the elevation angle γ2), so that only the part of the code pattern (134) that is applied to the first zone (120a) of the magnetic induction layer (120) can be reliably read (with good contrast) in the first digital image. (iii) capturing a second digital image of the security marking (100) with the imaging device (202) at a second viewing angle θ2 associated with a second elevation angle γ2 of the pigment particles in the second zone (120b) of the magnetic induction layer (120) and storing the captured second digital image in memory. In the above example of a smartphone where the imaging device is very close to the light source, the viewing angle θ2 at which the intensity of light reflected by the surfaces of the pigment particles in the second zone (120b) is greatest corresponds to a position of the imaging device in a direction substantially perpendicular to the surfaces of the pigment particles in the second zone (120b). Due to this viewing angle θ2, the part of the code pattern (134) applied to the first zone (120a) of the magnetic induction layer (120) does not reflect enough light (θ2 is not adapted to the elevation angle γ1), so that only the part of the code pattern (134) applied to the second zone (120b) of the magnetic induction layer (120) can be reliably read (with good contrast) in the second digital image. (iv) forming a composite digital image (i.e., a reconstructed digital image) of the code pattern (134) from the stored first digital image and the stored second digital image by image processing using a processor, by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern, and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern, with respect to the reference pattern (133) (detected in the first digital image and the second digital image), and storing the obtained composite digital image in memory. Here, the first part of the code pattern (134) is the part of the code pattern in the first area (134a) applied to the upper surface (121) of the first zone (120a) of the magnetic induction layer (120), and the second part of the code pattern (134) is the part of the code pattern in the second area (134b) applied to the upper surface (121) of the second zone (120b) of the magnetic induction layer (120). (v) Reading and decoding the code pattern (134) by a processor from the stored composite digital image, i.e., from a reconstructed digital image of the complete code pattern in which the two areas of the code pattern can be detected and decoded simultaneously and reliably.

[0077] As explained above, the only way to reliably detect and decode the machine-readable marking 130 is to take two images of the first area 134a and the second area 134b of the code pattern 134 at two viewing angles that are adapted to the specific orientation of the magnetically oriented, reflective, platelet-like magnetic or magnetizable pigment particles in the first zone 120a and the second zone 120b of the magnetically inductive layer 120, respectively. Being able to decode the machine-readable marking 130 implies that the two-zone structure of the magnetically inductive layer 120 has been confirmed by viewing angles that correspond to the correct elevation angle (i.e., the correct orientation) of the planes of the pigment particles in the two zones 120a and 120b. Therefore, being able to decode the machine-readable marking 130 constitutes a first stage of authentication of the security marking 100.

[0078] According to the present invention, a further level of authentication of the security marking (100) can be achieved by taking deeper advantage of the very material properties of the security marking (100), by moving the imaging device (202) of the mobile device (200) over (parallel to) the security marking (100) while observing different viewing angles θ i By taking a number of digital images of the security marking, where i=1,...,N, and from the acquired digital images, for each zone of the magnetic induction layer, a corresponding "curve" I(θ) of the intensity I of light reflected from said zone at said various viewing angles upon illumination of the security marking by a light source (201) is determined. i) (i=1,...,N). Each curve I(θ) allows for a more detailed analysis of the reflectivity (since intensity is a function of reflectivity) of the magnetically oriented, reflective, platelet-like magnetic or magnetizable pigment particles in the corresponding zone of the magnetically inductive layer (120). In particular, the fact that the precise shape of the reflectivity curve R(θ)~I(θ) (R(θ) is the average reflectivity) is characteristic of the nature and orientation of the pigment particles and the inductive layer material for the relevant zone, and that it exhibits a characteristically shaped peak around a viewing angle value associated with an elevation angle value of the pigment particles in that zone, allows for the use of a reference reflectivity curve R(θ)~I(θ) (known to the authority issuing the security marking) to determine whether the shapes of the two curves reasonably match based on curve similarity criteria. ref (θ)~I ref(θ). For example, the curves can be compared using a degree of correlation. Another method is to perform linear regression to estimate the linear relationship between the measured curve and a reference curve and evaluate how closely the slope and the fit match. Each curve I(θ) is preferably derived from the measured average intensity I of reflected light from the corresponding zone. This provides a strong verification of the authenticity of the material structure of the security marking, and therefore of the encoded data within the machine-readable marking of the security marking. Another advantage of the present invention, which also contributes to the authentication of the security marking, is the manner in which an imaging device is moved over the security marking to appropriately capture multiple digital images of the machine-readable marking according to the relative arrangement of the pigment particles within the various zones of the magnetic induction layer. For example, if the magnetic induction layer is as shown in FIG. 2 , due to the orientation directions of the pigment particles in the first zone (120a) and the second zone (120b), both of which are contained in a plane perpendicular to the plane of the substrate (110), a relative translational movement of the imaging device (202) and the security marking (100) (along a direction contained in said perpendicular plane) is required to acquire multiple digital images to obtain the reflectance curve I(θ). However, due to different designs of the two (or more) zones of the orientation of the pigment particles in the magnetic induction layer (e.g., due to orientation directions at angles less than or greater than 180°), the relative movement corresponds to a rotational movement. The reflectance curve I(θ) is preferably obtained from the measured average intensity I. However, other metrics can be used to authenticate the security marking. Further embodiments can include authentication algorithms based on classifiers or neural network-based machine learning that can distinguish authentic intensity profiles (or other measured or extracted features, such as variance profiles or image entropy) from inauthentic ones.

[0079]

[0078] As an example of an equivalent method for authenticating a security marking, instead of measuring the intensity (or even the average intensity) of light reflected by the magnetic induction layer for a reflectance curve, the intensity is measured at various viewing angles θ i Machine learning can be applied to the above-mentioned multiple digital images of the security marking taken at (i=1,...,N). Such a method includes three steps: feature extraction, model training and selection, and prediction. For the feature extraction step, the imager returns a sequence of RGB images I(θ), where θ min ≦θ≦θ max If necessary, only the region of interest (RoI) around the security marking may be preserved by cropping the image. These images can be linearized and converted to grayscale (as described in R.C. Gonzalez, T.E. Woods, "Digital Image Processing", 4th ed., Pearsons, 2017). However, separate processing of the color channels is also possible.

[0080]

[0079] For each image, one or more metric functions f(θ) are calculated. A thorough description of image metrics applied to images can be found in R.C. Gonzales and T.E. Woods, op. cit. The metric can be calculated either directly on the image intensity or on a transform such as the Discrete Fourier Transform (DFT) or Discrete Wavelet Transform (DWT). Useful metrics that can be used include the mean, standard deviation and entropy. Depending on the metric used, it may be necessary to scale the metric by the mean intensity of the reference neighboring RoIs (this operation makes it possible to compensate for variable exposure times of the imaging device and any variations in the illumination of the mark). In order for all measurements to have the same scale, the metric must be evaluated on a uniform sampling grid of angles. These angles must be symmetric about the normal to the sample. We call this uniform grid θ = [θ...θN ], where N is the number of angles (e.g., N=21). In practice, scanning at uniformly spaced angles is not always possible, and metric interpolation may be necessary. At the end of the scanning procedure, the feature vector x T =[f(θ1)f(θ1)...f(θ N )]=[x1x1...x N To account for the variability of different security markings, we further perform M scans on different security markings to obtain a dataset X of size N × M. T =[x1...x M ] is constructed.

[0081] Regarding the model training and selection steps, general machine learning techniques for classification and detection are described in C.M. Bishop, "Pattern Recognition and Machine Learning," Springer, 2009. Here, the authentication problem boils down to distinguishing true feature vectors from fakes or attacks. However, the true feature vectors are known and available, while the other feature vectors are either unknown or rare. Therefore, directly training a two-class classifier is infeasible. As described in O. Mazhelis, "One-Class Classifiers: A Review and Analysis of Suitability in the Context of Mobile-Masquerader Detection," South African Computer Journal, Vol. 36, pp. 29-48, 2006, authentication can be shown to be equivalent to one-class classification. In this scenario, classifier models rely only on true feature vectors to learn their parameters and decision boundaries. Among these, deep learning models such as support vector data description (SVDD), v-support vector classification (v-SVC), Gaussian mixture models (GMM), and autoencoders are of practical interest. The choice of model is determined by its performance during training and is also constrained by its complexity: for equivalent performance, simpler models are preferred.

[0082]

[0081] Before training the model, the dataset X is pre-processed as shown in the figure below, and the following steps are performed: Sample cleanup: defective samples such as saturated samples or samples missing features are discarded. - Sample normalization, where feature vectors are normalized to unit energy. -Feature standardization. Feature average μ(θ d ) and feature standard deviation σ(θ d ) is estimated and removed feature by feature. - Sample detrending: A low-order polynomial trend of constant degree P is estimated at each sample and removed. - Feature reduction. Correlations between features are removed and the dimensionality of the problem is reduced. Here, for example, the reduction can be from N=21 to K=3-5. Optimization problems with lower dimensions converge faster and allow easier testing. This step creates a vector subspace V=[v1...v] of size NxK. K This is achieved by principal component analysis (PCA), which generates a K × N feature set (see C.M. Bishop, "Pattern Recognition and Machine Learning," Springer, 2009). After PCA, we project the dataset X onto a subspace V, resulting in a reduced feature set X of size K × N. ’T =[x'1...x' N ] is obtained. This dataset is used to train the parameters Θ of a candidate one-class classification model. Finally, the best candidate is kept for prediction.

[0083] Regarding the prediction step, this step performs the following operations on the dataset: data cleanup, sample normalization, feature standardization, trend removal, subspace projection, and model decision function calculation. Finally, after feature reduction by subspace projection, the decision function of the classifier is calculated using the learned parameters (see also I. GoodFellow, Y. Bengio, A. Courville, "Deep Learning", MIT Press, 2016).

[0084] In one example of an embodiment of the above method based on the reflectivity curve I(θ), for an example of a machine-readable marking (130) as a QR code (see FIGS. 3 and 5A), the overlap of the magnetic induction layer (120) and the machine-readable marking (130) is selected to maintain detection of the code reference pattern (133) and the clock (in this way the code pattern (134) can be positioned at any viewing angle without necessarily being decoded). QR codes are a well-known standardized symbology, graphically structured to allow three basic operations to be performed from features or graphic elements obtained from an image of the QR code: 1) Placement of the code using a specific graphic design (fiducial pattern (133)) that is robustly and accurately detectable by appropriate image processing algorithms. 2) Extraction of sampling grid and module size from consecutive alternating dark and light modules (clock visible in Figure 5A) arranged along one or more lines in two orthogonal directions. 3) Data, encoding mode and error correction areas are included in the QR code in another area (to the right edge) of Figure 5A. Data is encoded as light and dark modules in specific areas of the symbol according to a specific encoding algorithm. The machine-readable marking (130) of the security marking (100) is a light source (201) for delivering illumination light; an imaging device (202) (camera) that takes a digital image of the security marking (100); It is read and decoded by a portable device (200) having a memory and a processor configured to perform the steps of the method on a digital image of the security marking (100) taken by an imaging device (202).

[0085]

[0084] As shown in Figure 7, the decoding method (700) acquires (701) a first sequence of digital images of the security marking (100) at various viewing angles of the imaging device (202) relative to the security marking (100), which are close to a first viewing angle θ1 (associated with the elevation angle γ1 of the pigment particles in the first zone (120a) of the magnetically inductive layer). The pose of the imaging device relative to the machine-readable marking (130) is estimated (702) using the acquired digital image sequence in a manner described below (in this context, the combination of position and orientation is referred to as the pose of an object in computer vision). The pose of the imaging device is checked against various acceptance criteria, for example, to ensure that the digital images from the sequence are sufficiently sharp (703), for example, by checking Weber contrast, Michelson contrast, and RMS contrast. If the considered digital image is not acceptable (703, "N" or "No"), the next digital image in the sequence is considered (701). If a pose passes the acceptance criteria, the digital image corresponding to that pose is further processed (703, "Y" or "Yes"). The digital image is then corrected for perspective distortion and resampled using a predetermined resolution (704). Using the pose information of the imaging device and a priori knowledge of the location of the magnetic induction layer (120) in the security marking design, a mask can be formed (705) to retain only those portions of the digital image where the first zone of the magnetic induction layer is present.

[0086] The same process is repeated (706-710) by the imaging device (202) at various viewing angles close to the second viewing angle θ2, which is the viewing angle associated with the elevation angle γ2 of the pigment particles in the second zone (120b) of the magnetically inductive layer (120).

[0087]

[0086] The digital image obtained in step (704) and subsequently masked in step (705) and the digital image obtained in step (709) and subsequently masked in (710) are combined in step (711) to form a resulting composite digital image. The composite digital image obtained in step (711) is then decoded (including error correction) by a decoder in step (712) to extract the data content of the code pattern (134). The combining of the two digital images in step (711) can be achieved by known digital image processing algorithms, which stitch the two digital images and adjust the contrast and intensity throughout the machine-readable marking. Another possibility is to perform the following operations on two digital images A and B of the security marking (100), taken at viewing angles close to θ1 and θ2, respectively, as described above: locating a "partial" code pattern from image A (corresponding to a first portion of the code pattern (134)), where a sampling grid is constructed using standard code detection techniques; forming a binary representation B1 of a partial code pattern of image A; locating a "partial" code pattern from image B (corresponding to a second portion of the code pattern (134)), where a sampling grid is constructed using standard code detection techniques; forming a binary representation B2 of the partial code pattern of image B; combining the obtained binary representations B1 and B2 of the code patterns of images A and B by applying a truth table to all corresponding modules of the binary representations (i.e. a "black" module in B1 and a black module in B2 result in a black module of the combined binary representation CB, a "white" module in B1 and a "white" module in B2 result in a white module in CB, and a black (or white) module in B1 and a white (or black) module in B2 result in a white module in CB); applying standard code error correction algorithms to the resulting combined binary representation CB of the (complete) code pattern to compensate for possible errors that may be present, resulting in an error-free composite digital image of the code pattern (134); The purpose is to do the following.

[0088] Pose estimation of the image capture device (202) can be performed using several known methods, two of which are shown schematically in Figures 8A and 8B, respectively.

[0089] One possible method of pose estimation is as follows (see FIG. 8A). Machine-readable markings (130) are applied to a flat surface, and the acquired digital image sequence (801) is sent (802) to a commercially available plane extraction library (e.g., Vuforia, ARCore, or ARKit), which returns (803) an estimated pose of the imaging device relative to the plane of the applied machine-readable markings.

[0090] Another possible method of pose estimation is as follows (see FIG. 8B) (if a reference pattern is not suitable for pose estimation, a reference mark, eg, a CCTag, can be added to the security marking). The acquired digital image (804) is processed (by conventional image processing) to extract graphic design information (i.e., the location of the reference pattern) (805), detect the reference pattern (133) by using known pattern matching or detectors specific to the type of marking (here, a QR code), e.g., CCTag, ARTag, ARToolKit tag, etc. (806), and perform pose estimation using the detected location of the reference pattern (807), for example, by using the SolvePnP program from the OpenCV library (see, e.g., the article by V. Lepetit et al., "An accurate o(n) solution to the pnp problem," International Journal of Computer Vision, 81(2), pp. 155-166, 2009). However, many other pose estimation methods are known to those skilled in the art.

[0091]

[0090] Other types of machine-readable markings can be used to implement the invention, for example a Data Matrix (see Figure 5C) whose reference pattern is in the form of an L-shape.

[0092]

[0091] Figure 9 shows an example of a security document (150) according to the present invention, here an ID card for user John Doe, bearing printed ID data (151) showing the user's name, address, and date of birth. This security document has been issued to the user by an authorized person, who has applied a security marking (100) to the document. The code pattern (134) of the machine-readable marking (130) of the security marking (100) contains the user's encoded digital ID data (here corresponding to the printed ID data) and a digital signature of these digital ID data. The digital signature is issued by the authorized person and is obtained by an encryption key (stored in the authorized person's database together with a corresponding decryption key). The security marking (100) corresponds to that shown in Figure 5C (i.e., a two-dimensional GS1 Data Matrix barcode). Depending on the data storage capacity of the machine-readable marking, additional ID data (e.g., the user's biometric data, or possibly a photo of the user) can be encoded in the code pattern (130).

[0093]

[0092] Figure 10 is a flow chart of a method for verifying by a controller the security document shown in Figure 9. This method for verifying a security document (150) by a controller having a portable device (200) as shown in Figure 6, further equipped with a communication unit operable to send and receive data through a communication network (CN) to an authorized server (S) connected to a database (DB) (see also Figure 11) in which the encryption key K used to digitally sign the encoded data in the code pattern (134) is stored together with the corresponding decryption key K', comprises the following steps (see also Figure 6): Positioning (1000) a security marking (100) on a security document (150) within the field of view of an imaging device (202) of a mobile device (200) (by a controller); Illuminating (1001) a security marking (100) of a security document (150) by a light source (201) of a portable device (200); acquiring (1002) a first digital image of the illuminated magnetically inductive layer (120) with an imaging device (202) at a first viewing angle θ1 associated with a first elevation angle γ1 of magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles in a first zone (120a) of the magnetically inductive layer (120), and storing the acquired first digital image in a memory; acquiring (1003) a second digital image of the illuminated magnetically inductive layer (120) by an imaging device (202) at a second viewing angle θ2 associated with a second elevation angle γ2 of the magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles in a second zone (120b) of the magnetically inductive layer (120), and storing the acquired second digital image in memory; a step (1004) of forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by image processing by a processor, by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern (134), and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern (134), with a reference pattern (133) (here, an L-shaped data matrix) detected in the first digital image and the second digital image; A step (1005) of reading and decoding a code pattern (134) from the obtained composite digital image, extracting user ID data UID and a digital signature UIDS of the user ID data from the decoded data of the code pattern through image processing and decoding operations by a processor, and storing the extracted user ID data UID and digital signature UIDS in a memory; - sending (1006) a first message (M1) containing the extracted user identity data UID and the digital signature UIDS stored in the memory to the server (S) via the communication unit; In the server (S), the extracted digital signature UIDS received in the first message (M1) from the mobile device (200) is decrypted with the decryption key K' stored in the database (DB), and a step (1007) is performed to confirm whether the extracted user ID data UID received in the first message (M1) matches the decrypted extracted digital signature UIDS; If there is a match, returning (1008) a server message (SM) to the mobile device (200) indicating successful verification of the user identity data; If the extracted user identity data UID received in the first message (M1) does not match the decrypted extracted digital signature UIDS, returning a server alert message (SALM) to the mobile device (200) indicating that verification of the user identity data has failed (1009); Includes: If a Server Alert Message (SALM) is received by the mobile device (200), the controller using the mobile device may be notified that the security document is not authentic and may take necessary action regarding the user who created the counterfeit security document, for example.

[0094]

[0093] A system configured to perform the above-described operations allowing a controller to verify a user's security document (as shown in Figure 9) is shown schematically in Figure 11. The figure shows a server (S) of the authority that issued the security document (150) to the user, connected to a database (DB) in which the encryption key K and its corresponding decryption key K' are stored. The controller's mobile device (200) is a smartphone. Here, the smartphone's screen displays a server message (SM) indicating successful verification of the security document (e.g., the information OK is displayed).

[0095]

[0094] The above method for verifying a user's security document according to the invention, and the corresponding system implementing the operations necessary to perform said verification, may have several variants involving detailed authentication of security markings, especially when the verification method is used to grant a user access to some online service (e.g. banking transactions, online registration, online payment, etc.).

[0096]

[0095] In one embodiment of the first variant of the verification method, a user is considered who has his / her smartphone suitably programmed (for example by having downloaded suitable applications for image processing and decoding operations to be executed on the smartphone) so as to also function as a mobile device (200) according to the invention as shown in Figure 6. The smartphone is equipped with a communication unit operable to send and receive data over a communication network (CN) to a server (S) of the authority who has issued the user an ID card corresponding to the security document (150) shown in Figure 9. The server (S) is connected to a database (DB) which stores the encryption key K used to digitally sign the coded data in the code pattern (134) of the machine-readable marking (130) of the security marking (100) applied to the ID card, together with the corresponding decryption key K'. The following steps are carried out: A step (1200) of placing (by a user) a security marking (100) on a security document (150) within the field of view of an imaging device (202) of a smartphone (200); a step (1201) of illuminating (1201) a security marking (100) of a security document (150) by a light source (201) of a smartphone (200), the illumination being due to a user activating a flash on the smartphone; acquiring (1202) a first digital image of the illuminated magnetically inductive layer (120) with an imaging device (202) at a first viewing angle θ1 associated with a first elevation angle γ1 of magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles in a first zone (120a) of the magnetically inductive layer (120), and storing the acquired first digital image in a memory of the smartphone; acquiring (by a user) a second digital image of the illuminated magnetically inductive layer (120) with an imaging device (202) at a second viewing angle θ2 associated with a second elevation angle γ2 of the magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles in a second zone (120b) of the magnetically inductive layer (120), and storing (1203) the acquired second digital image in a memory of the smartphone; forming (1204) a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by image processing by the smartphone processor, by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern (134), and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern (134), with respect to a reference pattern (133) (an L-shaped data matrix) detected in the first digital image and the second digital image; A step (1205) of reading and decoding a code pattern (134) from the obtained composite digital image, extracting user ID data UID and a digital signature UIDS of the user ID data from the decoded data of the code pattern through image processing and decoding operations by a processor of the smartphone, and storing the extracted user ID data UID and digital signature UIDS in a memory of the smartphone; a step (1206) of sending a first message (M1) containing the extracted user identity data UID and the digital signature UIDS stored in the memory to the server (S) via the communication unit of the smartphone (200); In the server (S), a step (1207) is performed in which the extracted digital signature UIDS received in the first message (M1) from the smartphone (200) is decrypted using a decryption key K' stored in the database, and the extracted user ID data UID received in the first message (M1) is confirmed to be consistent with the decrypted extracted digital signature UIDS; Step (1208) of illuminating the magnetic induction layer (120) with a light source (201) and capturing multiple digital images, e.g., 10 images, of the illuminated magnetic induction layer (120) with an imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetic induction layer (120) for each different digital image by moving the imaging device (202) relative to the magnetic induction layer (120) parallel to the plane of the substrate (110) (this movement, here, translation, of the smartphone imaging device is performed by a user); calculating (1209) for each acquired digital image, by a processor of the smartphone, a corresponding average intensity I of light reflected by the magnetic induction layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and storing (in the smartphone memory) the calculated average intensity of the reflected light and the corresponding viewing angle to obtain a corresponding reflected light intensity curve I(θ); a step (1210) of transmitting a second message (M2) including the obtained reflected light intensity curve I(θ) to a server (S) via a communication network (CN) by a communication unit of the smartphone (200); The server (S) compares the reflected light intensity curve I(θ) received in the second message (M2) with the reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in the database (DB). ref (θ) and comparing the step (1211); In the server (S), a step (1212) of determining whether the magnetic induction layer (120) is authentic based on the result of the comparison; If the magnetic induction layer (120) is determined to be authentic, a step (1213) of returning a server message (SM') indicating successful verification of the user ID data to the smartphone (200) together with an indication that the security marking (100) is authentic, and sending a server authorization message (SAM) containing access data (e.g., a password for online registration) authorizing the user to access online services by the server (S) to the user's smartphone (200) via the communication network (CN); If the extracted user ID data UID received in the first message (M1) does not match the decrypted extracted digital signature UIDS, or if the magnetic induction layer (120) is determined to be counterfeit, returning a server alert message (SALM) to the smartphone (200) indicating that verification of the user ID data has failed (1214); is executed.

[0097]

[0096] Reflectance curve I(θ) and I ref In an embodiment of the second variant of the verification method, in which (θ) is compared by a mobile device (200), we again consider a user carrying his smartphone, suitably programmed to also function as a mobile device (200) according to the invention, as shown in Figure 6. The smartphone is equipped with a communication unit operable to send and receive data over a communication network (CN) to a server (S) of the authority that has issued the user an ID card corresponding to the security document (150) shown in Figure 9. The server (S) is connected to a database (DB) that stores the encryption key K used to digitally sign the coded data in the code pattern (134) of the machine-readable marking (130) of the security marking (100) applied to the ID card, together with the corresponding decryption key K'. The following steps are carried out: A step (1300) of placing (by a user) a security marking (100) on an ID card (150) within the field of view of an imaging device (202) of a smartphone (200); a step (1301) of illuminating (1301) a security marking (100) of a security document (150) by a light source (201) of a smartphone (200), the illumination being due to a user activating a flash on the smartphone; acquiring (1302) a first digital image of the illuminated magnetic induction layer (120) with an imaging device (202) of the smartphone (200) (by imaging by a user) at a first viewing angle θ1 associated with a first elevation angle γ1 of magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles in a first zone (120a) of the magnetic induction layer (120), and storing the acquired first digital image in a memory of the smartphone; acquiring (1303) a second digital image of the illuminated magnetically inductive layer (120) by the imaging device (202) at a second viewing angle θ2 associated with a second elevation angle γ2 of the magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles in a second zone (120b) of the magnetically inductive layer (120), and storing the acquired second digital image in the memory of the smartphone (200); forming (1304) a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by image processing by the smartphone processor, by aligning a first portion of the code pattern (134) detected in the first digital image, which corresponds to a first area (134a) of the code pattern (134), and a second portion of the code pattern (134) detected in the second digital image, which corresponds to a second area (134b) of the code pattern (134), with respect to a reference pattern (133) (an L-shaped data matrix) detected in the first digital image and the second digital image; A step (1305) of reading and decoding the code pattern (134) from the obtained composite digital image, extracting user ID data UID and a digital signature UIDS of the user ID data from the decoded data of the code pattern through image processing and decoding operations by a processor of the smartphone (200), and storing the extracted user ID data UID and digital signature UIDS in a memory of the smartphone; a step (1306) of sending a first message (M1) containing the extracted user identity data UID and the digital signature UIDS stored in the memory to the server (S) via the communication unit of the smartphone (200); In the server (S), a step (1307) is performed in which the extracted digital signature UIDS received in the first message (M1) from the smartphone (200) is decrypted using a decryption key K' stored in the database (DB), and the extracted user ID data UID received in the first message (M1) is confirmed to be consistent with the decrypted extracted digital signature UIDS; If there is a match, returning (1308) a server message (SM) to the smartphone (200) indicating successful verification of the user ID data; a step (1309) of illuminating (by the user) the magnetic induction layer (120) of the machine-readable marking (130) on the ID card (150) with a light source (201) and capturing multiple digital images of the illuminated magnetic induction layer (120) with an imaging device (202) of the smartphone (200), where the imaging device (202) is at a corresponding different viewing angle θ with respect to the magnetic induction layer (120) by moving the imaging device (202) relative to the magnetic induction layer (120) parallel to the plane of the substrate (wherein the user translates the imaging device parallel to the security marking) for each different digital image; calculating (1310) for each acquired digital image, by a processor, a corresponding average intensity I of light reflected by the magnetic induction layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and determining a corresponding reflected light intensity curve I(θ) using the calculated average intensity of the reflected light and the corresponding viewing angle; The processor of the smartphone (200) calculates the reflected light intensity curve I(θ) based on a reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in the smartphone's memory. ref (θ) and comparing the step (1311); A step (1312) in which a processor of the smartphone (200) determines whether the magnetic induction layer (120) is authentic based on the result of the comparison, and if the magnetic induction layer (120) is determined to be authentic, a message (M) indicating that the security marking (100) is authentic is sent to a server (S) via a communication network (CN) by a communication unit of the smartphone; a step (1313) of the server (S) returning a server authorization message (SAM) containing access data authorizing the user to access the online service to the user's smartphone (200) via the communication network (CN) when the server (S) receives a message (M) from the smartphone (200) indicating that the security marking (100) is authentic; is executed.

[0098] Security marking examples Examples E1 to E4 were carried out by using a UV-Vis curable screen printing ink of the formulation shown in Table 1 and the first and second magnetic assemblies described below.

[0099] [Table 1]

[0100] Magnetic field generating device for biaxial alignment (Fig. 12A-Fig. 12B)

[0099] The pigment particles were biaxially oriented using a magnetic assembly, which included nine rod-shaped dipole magnets (M1 to M9).

[0101] Each of the nine rod-shaped dipole magnets (M1-M9) had the following dimensions: 100 mm (L1) x 10 mm (L2) x 10 mm (L3). The magnetic field generator was embedded in a non-magnetic holder (not shown) made of polyoxymethylene (POM) with the following dimensions: 250 mm x 150 mm x 12 mm. The nine rod-shaped dipole magnets (M1-M9) were made of NdFeB N40.

[0102]

[0101] Nine bar-shaped dipole magnets (M1 to M9) were arranged in a row at a distance (d1) of approximately 10 mm from each other, with the top surfaces of the nine bar-shaped dipole magnets (M1 to M9) flush with each other. The magnetic axis of each of the nine bar-shaped dipole magnets (M1 to M9) was approximately parallel to the thickness (L3) of the magnet, and the magnetic orientations of two adjacent magnets (M1 to M9) were in opposite directions (alternating magnetization). The magnetic field was approximately uniform, and the magnetic field lines were approximately coplanar in area A.

[0103] Magnetic field generation for uniaxial alignment (Figure 13)

[0102] The pigment particles were uniaxially oriented using a magnetic field generator, which was equipped with two rod-shaped dipole magnets (M1, M2) and two pole pieces (P1, P2).

[0104]

[0103] Each of the two rod-shaped dipole magnets (M1, M2) had the following dimensions: 40 mm (L1) x 40 mm (L2) x 10 mm (L3). The two rod-shaped dipole magnets (M1, M2) were made from NdFeB N42.

[0105]

[0104] The two bar-shaped dipole magnets (M1, M2) were placed at a distance (d1) of approximately 40 mm from each other. The magnetic axis of each of the two bar-shaped dipole magnets (M1, M2) was approximately parallel to the length (L1) of the magnet, and the magnetic orientations of the two bar-shaped dipole magnets (M1, M2) were oriented in the same direction. Each of the two pole pieces (P1, P2) had the following dimensions: 60 mm (L4) x 40 mm (L5) x 3 mm (L6). The two pole pieces (P1, P2) were made of iron (ARMCO®).

[0106]

[0105] Two rod-shaped dipole magnets (M1, M2) and two pole pieces (P1, P2) were arranged to form a rectangular parallelepiped with a rectangular parallelepiped cavity in the center, which constituted an area A, in which the magnetic field was approximately uniform and the magnetic field lines were approximately parallel to each other, so that the distance (d2) between the two pole pieces (P1, P2) was approximately 40 mm, i.e., the distance (d2) between the two pole pieces (P1, P2) was the length (L1) of the two rod-shaped dipole magnets (M1, M2). As shown in Figure 13, the magnetic field was approximately uniform in the area A.

[0107] E1 (Figure 2, Figures 12A to 12B, Figure 14A)

[0106] The UV-Vis curable screen printing ink of Table 1 was applied to a piece of black coated paper (45 mm x 60 mm) (110) to form a first coating layer (30 mm x 19 mm) (120a), the application step being carried out with a laboratory screen printing apparatus using a 90T screen to form a layer having a thickness of approximately 20 μm.

[0108]

[0107] While the coating layer (120a) was still wet and not yet at least partially cured, the substrate (110) was placed on the center of a support plate (300 mm x 40 mm x 1 mm) made of high-density polyethylene (HDPE). The support plate supporting the substrate (110) was moved at a speed of about 10 cm / sec alongside the magnetic field generator (as shown in Figure 12A) at a distance (d5) of about 20 mm between the surface of the magnetic field generator facing the substrate (110) and the nearest edge of the first coating layer (120a), and the height between the nearest edge of the first coating layer (120a) and the bottom surface of the magnetic field generator was half the length ( 1 The support plate supporting the substrate (110) was moved concomitantly while forming an angle α formed by the first coating layer (120a) and a tangent to the magnetic field lines of the magnetic field in the uniform magnetic field area A of the magnetic field generating device, and the angle α had a value of about 20°, allowing the particles to be oriented at an elevation angle γ1 of about 20°.

[0109] The first coating layer (120a) is at least partially cured to form a first zone (120a), said curing being carried out by a curing unit (UV LED lamp (Phoseon FireFly 395 nm, 4 W / cm)) positioned above the substrate path at a distance (d4) of about 15 mm from the center of the length (L1) of the rod-shaped dipole magnets (M1-M9). 2 )) near the space between the eighth and ninth dipole magnets (M8 and M9) and also near the ninth rod dipole magnet (M9) at a distance (d3) of about 10 mm.

[0110] The UV-Vis curable screen printing inks of Table 1 were applied to a piece of black coated paper (110) using the same laboratory 90T screen printing apparatus to form a second coating layer (30 mm x 19 mm) (120b) adjacent (along a 19 mm edge) to the first zone (120a). The resulting combined coating layers (120a and 120b) had a total surface of 30 mm x 38 mm.

[0111]

[0110] While the second coating layer (120b) was still wet and not yet at least partially cured, the substrate (110) was placed on the center of a support plate (300 mm x 40 mm x 1 mm) made of high-density polyethylene (HDPE). The support plate supporting the substrate (110) was moved at a speed of about 10 cm / sec alongside the same magnetic field generator (as shown in Figures 12A-12B) at the same distance (d5) of about 20 mm between the surface of the magnetic field generator facing the substrate (110) and the nearest edge of the second coating layer (120b), and the height between the nearest edge of the second coating layer (120b) and the bottom surface of the magnetic field generator was half the length (d5) of the rod-shaped dipole magnets (M1-M9). 1 The support plate supporting the substrate (110) was moved concomitantly while forming an angle α formed by the coating layer (120b) and a tangent to the magnetic field lines of the magnetic field in the uniform magnetic field area A of the magnetic field generating device, and the angle α had a value of about 160°, thereby enabling the particles to be oriented at an elevation angle γ2 of about 160°.

[0112] The second coating layer (120b) is at least partially cured to form a second zone (120b), said curing being carried out by a curing unit (UV LED lamp (Phoseon FireFly 395 nm, 4 W / cm)) positioned above the substrate path at a distance (d4) of about 15 mm from the center of the length (L1) of the rod-shaped dipole magnets (M1-M9). 2)) near the space between the eighth and ninth dipole magnets (M8 and M9) and near the ninth rod-shaped dipole magnet (M9) at a distance (d3) of about 10 mm to form a second zone (120b), thereby providing a magnetic induction layer (120).

[0113] A QR code (25 mm x 25 mm) was printed on the magnetic induction image (120) by inkjet printing using a Konica Minolta printhead (KM1024i) with black ink (Sicurajet SUV Black, manufactured by Siegwerk) so that the QR code was positioned in the center of the layer (120). The inkjet-printed QR code was then illuminated with a mercury lamp (500 mJ / cm 2 ) and at least partially cured.

[0114]

[0113] The resulting sample of Example E1 is shown in Figure 14A (left: +22° viewing angle θ1; right: -22° viewing angle θ2).

[0115] E2 (Figure 2C, Figure 13, Figure 14B)

[0114] The UV-Vis curable screen printing ink of Table 1 was applied to a piece of black coated paper (45 mm x 60 mm) (110) to form a first coating layer (30 mm x 19 mm) (120a), the application step being carried out with a laboratory screen printing apparatus using a 90T screen to form a layer having a thickness of approximately 20 μm.

[0116] While the first coating layer (120a) was still wet and not yet at least partially cured, the substrate (110) was placed on the center of a support plate (300 mm x 40 mm x 1 mm) made of high-density polyethylene (HDPE). The support plate supporting the substrate (110) was positioned in the center of the magnetic assembly cavity, as shown in Figure 13, with an angle α formed by the first coating layer (120a) and a line tangent to the magnetic field lines of the magnetic field in the uniform area A of the magnetic field generator having a value of approximately 8°, thereby allowing the particles to be oriented at an elevation angle γ1 of approximately 8°.

[0117] After about 1 second, the first coating layer (120a) is at least partially cured to form a first zone (120a), and the curing is performed using a curing unit (UV LED lamp (Phoseon FireFly 395 nm, 4 W / cm)) as shown in FIG. 2 )) was carried out.

[0118] The UV-Vis curable screen printing inks of Table 1 were applied to a piece of black coated paper (110) using the same laboratory 90T screen printing apparatus to form a second coating layer (30 mm x 19 mm) (120b) adjacent (along a 19 mm edge) to the first zone (120a). The resulting combined coating layers (120a and 120b) had a total surface of 30 mm x 38 mm.

[0119] While the second coating layer (120b) was still wet and not yet at least partially cured, the substrate (110) was placed on the center of a support plate (300 mm × 40 mm × 1 mm) made of high-density polyethylene (HDPE). The support plate supporting the substrate (110) and the second coating layer (120b) were placed in the center of the magnetic assembly cavity, as shown in Figure 13, with angle α formed by the second coating layer (120b) and a line tangent to the magnetic field lines of the magnetic field in the uniform area A of the magnetic field generator having a value of approximately 172°, thereby allowing the particles to be oriented at an elevation angle γ2 of approximately 172°.

[0120] After about 1 second, the second coating layer (120b) is at least partially cured to form a second zone (120b), said curing being performed by a curing unit (UV LED lamp (Phoseon FireFly 395 nm, 4 W / cm 2 )) to obtain a magnetic induction layer (120).

[0121] A QR code (25 mm x 25 mm) was printed on the magnetic induction layer (120) by inkjet printing using a Konica Minolta printhead (KM1024i) with black ink (Sicurajet SUV Black, manufactured by Siegwerk) so that the QR code was positioned in the center of the layer (120). The inkjet-printed QR code was then illuminated with a mercury lamp (500 mJ / cm 2 ) and at least partially cured.

[0122]

[0121] The resulting sample of Example E2 is shown in Figure 14B (left: +10° viewing angle θ1; right: -10° viewing angle θ2).

[0123] E3 and E4 (Fig. 2C, Fig. 12A to Fig. 12B, Fig. 13, Fig. 14C to Fig. 14D)

[0122] A 10 mm x 10 mm piece of the substrate (110) obtained in Example E1 or Example E2, bearing a magnetic induction layer (120) (10 mm x 5 mm) alone, was applied to and glued to a piece of white coated paper (50 mm x 50 mm).

[0124] A QR code (25 mm x 25 mm) was printed on the magnetically inductive layer (120) by inkjet printing using a Konica Minolta printhead (KM1024i) with black ink (Sicurajet SUV Black, manufactured by Siegwerk) so that the quiet zone of the QR code was positioned on the layer (120) as shown in Figures 14C and 14D. The inkjet-printed QR code was then illuminated by a mercury lamp (500 mJ / cm 2 ) and at least partially cured.

[0125] The resulting sample for Example E3 is shown in Figure 14C (left: +22° viewing angle θ1; right: -22° viewing angle θ2). The resulting sample for Example E4 is shown in Figure 14D (left: +10° viewing angle θ1; right: -10° viewing angle θ2).

[0126]

[0125] The subject matter disclosed above should be considered as illustrative and not restrictive, and serves to provide a better understanding of the invention defined by the independent claims.

Claims

1. a flat substrate (110); A magnetically inductive layer (120) of material comprising magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles, said magnetically inductive layer being applied to said substrate (110), said magnetically inductive layer comprising: a first zone (120a) in which planar surfaces of said magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles are oriented in a first direction; and a second zone (120b) distinct from said first zone (120a) in which planar surfaces of said magnetically oriented reflective platelet-like magnetic or magnetizable pigment particles are oriented in a second direction distinct from said first direction, said platelet-like particles in said first zone (120a) being oriented at an elevation angle γ with respect to the plane of said substrate (110). １ and the platelet-like particles in the second zone (120b) have a flat surface having an elevation angle γ with respect to the plane of the substrate (110). ２ a magnetically inductive layer (120) having a planar surface having a respective acute angle of said planar surface relative to said plane of said substrate, said elevation angle γ 1 or said elevation angle γ 2 being in the range of about 5° to about 25°; a machine-readable marking (130) including a reference pattern (133) and a code pattern (134) representing encoded data, the machine-readable marking (130) being applied to the upper surface (121) of the magnetic induction layer (120) or to the substrate (110) between the substrate and a back surface (122) of the magnetic induction layer (120), respectively, a first area (134a) of the code pattern (134) being disposed in front of the first zone (120a) and a remaining second area (134b) of the code pattern (134) being disposed in front of the second zone (120b); A security marking (100) comprising:

2. a) the pigment particles are a magnetic metal selected from the group consisting of cobalt, iron, gadolinium, and nickel; magnetic alloys of iron, chromium, manganese, cobalt, nickel, or mixtures of two or more thereof; magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more thereof; or or a mixture of two or more thereof; b) the code pattern is any one of a one-dimensional barcode, a stack one-dimensional barcode, a two-dimensional barcode, and a three-dimensional barcode; 2. The security marking of claim 1.

3. 3. The security marking of claim 1, wherein the first zone (120a) and the second zone (120b) of the magnetically inductive layer (120) belong to the same single material layer.

4. 3. The security marking of claim 1, wherein the first zone (120a) and the second zone (120b) of the magnetic induction layer (120) belong to a first sub-layer and an adjacent second sub-layer forming the magnetic induction layer (120), respectively.

5. 5. The security marking of claim 1, wherein the machine-readable marking (130) is applied to the top surface (121) of the magnetic induction layer (120) and is encoded with a dark symbol, a dark primer layer (140) is applied to the substrate (110), and the back surface (122) of the magnetic induction layer (120) is applied to the top surface (141) of the dark primer layer (140).

6. 5. The security marking of claim 1, wherein the machine-readable marking (130) is applied to the top surface (121) of the magnetic induction layer (120) and is encoded with a bright symbol, a dark primer layer (140), preferably a black primer, is applied to the substrate (110), and the back surface (122) of the magnetic induction layer (120) is applied to the top surface (141) of the dark primer layer (140).

7. The security marking of any one of claims 1 to 4, wherein the machine-readable marking (130) is applied to the substrate (110) and is encoded with a dark symbol.

8. 10. A method for reading and decoding a security marking (100) according to any one of claims 1 to 7 by a mobile device (200) comprising a light source (201) operable to deliver illumination light, an imaging device (202), and a processor comprising a memory and configured to perform image processing and decoding operations, the method comprising: placing the security marking (100) within the field of view of the imaging device (202); illuminating the security marking (100) with illumination light delivered by the light source (201); The first elevation angle γ １ A first viewing angle θ associated with １ capturing a first digital image of the security marking (100) with the imaging device (202) and storing the captured first digital image in the memory; The second elevation angle γ ２ A second viewing angle θ associated with ２ capturing a second digital image of the security marking (100) with the imaging device and storing the captured second digital image in the memory; forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by aligning a first portion of the code pattern (134) corresponding to a first area (134a) of the code pattern detected in the first digital image and a second portion of the code pattern (134) corresponding to the second area (134b) of the code pattern detected in the second digital image with the reference pattern (133) detected in the first digital image and the second digital image, and storing the obtained composite digital image in the memory; reading and decoding said code pattern (134) from said stored composite digital image by said processor; A method comprising:

9. A portable device (200) for reading and decoding a security marking (100) according to any one of claims 1 to 7, comprising: a light source (201) operable to deliver illumination light; An imaging device (202); a processor having memory; and comprising the steps of: illuminating the security marking (100) with illumination light delivered by the light source (201); First elevation angle γ １ A first viewing angle θ associated with １ capturing a first digital image of the security marking (100) with the imaging device (202) and storing the captured first digital image in the memory; Second elevation angle γ ２ A second viewing angle θ associated with ２ capturing a second digital image of the security marking (100) with the imaging device and storing the captured second digital image in the memory; forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by aligning a first portion of the code pattern (134) corresponding to a first area (134a) of the code pattern detected in the first digital image and a second portion of the code pattern (134) corresponding to a second area (134b) of the code pattern detected in the second digital image with the reference pattern (133) detected in the first digital image and the second digital image, and storing the obtained composite digital image in the memory; reading and decoding said code pattern (134) from said stored composite digital image by said processor; A mobile device configured to:

10. A security document (150) issued to a user by an authorized person, 8. The security marking (100) according to claim 1, applied to the security document (150), wherein the encoded data in the code pattern (134) of the security marking (100) includes digital ID data corresponding to the user and a digital signature of the digital ID data corresponding to the user, and the digital signature issued by the authorized person is obtained by signing the digital ID data corresponding to the user with a cryptographic key. A security document comprising:

11. 11. A method for verifying a user's security document (150) according to claim 10 by a mobile device (200) according to claim 9, further comprising a communication unit operable to send and receive data over a communication network (CN) to an authorized server (S) connected to a database (DB) storing encryption keys and corresponding decryption keys, the method comprising: placing the security marking (100) within the field of view of the imaging device (202); illuminating the security marking (100) of the security document (150) with a light source (201); First elevation angle γ １ A first viewing angle θ associated with １ capturing a first digital image of the illuminated security marking (100) with the imaging device (202) and storing the captured first digital image in the memory; Second elevation angle γ ２ A second viewing angle θ associated with ２ capturing a second digital image of the illuminated security marking (100) by the imaging device (202) and storing the captured second digital image in the memory; forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by aligning a first portion of the code pattern (134) corresponding to a first area (134a) of the code pattern detected in the first digital image and a second portion of the code pattern (134) corresponding to a second area (134b) of the code pattern detected in the second digital image with a reference pattern (133) detected in the first digital image and the second digital image; reading and decoding the code pattern (134) from the composite digital image, extracting user ID data and a digital signature of the user ID data from the decoded data of the code pattern through image processing and decoding operations by the processor, and storing the extracted user ID data and the digital signature in the memory; sending a first message (M1) containing the extracted user ID data stored in said memory and said digital signature to said server (S) via said communication unit; In the server (S), the extracted digital signature received in the first message (M1) from the mobile device (200) is decrypted using the decryption key stored in the database (DB), and the extracted user ID data received in the first message (M1) is confirmed to match the received extracted digital signature; If there is a match, returning a Server Message (SM) to said mobile device (200) indicating successful verification of said user ID data; A method comprising:

12. Before the step of sending a server message back to the mobile device (200), the following preliminary steps are carried out: illuminating the magnetic induction layer (120) with the light source (201) and acquiring a plurality of digital images of the illuminated magnetic induction layer (120) with the imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetic induction layer (120) for each different digital image by moving the imaging device (202) relative to the magnetic induction layer (120) parallel to the plane of the substrate (110); calculating, with the processor, for each captured digital image, a corresponding intensity I of light reflected by the magnetically inductive layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and storing the calculated intensity of the reflected light and the corresponding viewing angle to obtain a corresponding reflected light intensity curve I(θ); sending a second message (M2) containing the obtained reflected light intensity curve I(θ) to the server (S) via the communication network (CN) by the communication unit; The server (S) compares the reflected light intensity curve I(θ) received in the second message (M2) with a reference reflected light intensity curve I(θ) for the magnetic induction layer (120) stored in the database (DB). ｒｅｆ (θ) and determining in the server (S) whether the magnetic induction layer (120) is authentic based on the result of the comparison; if the magnetic induction layer (120) is determined to be authentic, returning the server message (SM) indicating successful verification of the user identity data to the mobile device (200) with an indication that the security marking (100) is authentic, and sending by the server (S) to the user's communication device via the communication network (CN) a server authorization message (SAM) containing access data authorizing the user to access a service; The method of claim 11 , comprising:

13. When a server message (SM) indicating successful verification of said user identity data is sent by said server (S), the following further steps are performed: illuminating the magnetic induction layer (120) with the light source (201) and acquiring a plurality of digital images of the illuminated magnetic induction layer (120) with the imaging device (202), the imaging device (202) being at a corresponding different viewing angle θ with respect to the magnetic induction layer (120) for each different digital image by moving the imaging device (202) relative to the magnetic induction layer (120) parallel to the plane of the substrate (110); calculating, by the processor, for each captured digital image, a corresponding intensity I of light reflected by the magnetically inductive layer (120) and collected by the imaging device (202) at a corresponding viewing angle θ, and determining a corresponding reflected light intensity curve I(θ) using the calculated intensities of the reflected light and the corresponding viewing angles; The processor compares the reflected light intensity curve I(θ) with a reference reflected light intensity curve I(θ) for the magnetically inductive layer (120) stored in the memory. ｒｅｆ (θ) and determining whether the magnetic induction layer (120) is authentic based on the result of the comparison, and if the magnetic induction layer (120) is determined to be authentic, sending a message (M) indicating that the security marking (100) is authentic to the server (S) via the communication unit through the communication network (CN); - if the server (S) receives a message (M) from the mobile device (200) indicating that the security marking (100) is authentic, sending by the server (S) to the user's communication device via the communication network (CN) a server authorization message (SAM) containing access data authorizing the user to access a service; The method of claim 11 , comprising:

14. 11. A system for verifying a security document (150) issued to a user by an authorized person according to claim 10, comprising: a server (S) of said authority connected to a database (DB) storing encryption keys and corresponding decryption keys and operable to send and receive data via a communications network (CN); A mobile device (200) according to claim 9 for reading and decoding a security marking (100) according to any one of claims 1 to 7 applied to said security document (150); wherein the mobile device (200) a light source (201) operable to deliver illumination light; An imaging device (202); a communication unit operable to send and receive data to said server (S) through said communication network (CN); a processor equipped with a memory and configured to perform image processing and decoding operations, said processor comprising the following steps: illuminating the security marking (100) with illumination light delivered by the light source (201); A first digital image of the security marking (100) is imaged at the first elevation angle γ １ A first viewing angle θ associated with １ and storing the acquired first digital image in the memory; A second digital image of the security marking (100) is imaged at the second elevation angle γ ２ A second viewing angle θ associated with ２ and storing the acquired second digital image in the memory; forming a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by image processing by the processor, with respect to a reference pattern (133) detected in the first digital image and the second digital image, a first portion of the code pattern (134) corresponding to a first area (134a) of the code pattern detected in the first digital image and a second portion of the code pattern (134) corresponding to a second area (134b) of the code pattern detected in the second digital image, and storing the obtained composite digital image in the memory; reading and decoding said code pattern (134) from said stored composite digital image by said processor; configured to run The system comprises the following steps: extracting user ID data and a digital signature of the user ID data from the decoded data of the code pattern through image processing and decoding operations by the processor, and storing the extracted user ID data and digital signature in the memory; sending a first message (M1) containing the extracted user ID data stored in said memory and said digital signature to said server (S) via said communication unit; In the server (S), the extracted digital signature received in the first message (M1) from the mobile device (200) is decrypted using the decryption key stored in the database (DB), and the extracted user ID data received in the first message (M1) is confirmed to match the received extracted digital signature; If there is a match, returning a Server Message (SM) to said mobile device (200) indicating successful verification of said user ID data; The system is further configured to run.

15. The server (S) is further configured to transmit data to the user's communication device via the communication network (CN), 15. The system of claim 14, wherein the server (S) and the mobile device (200) are further configured to perform the steps of the method of claim 12 or 13, verifying the security document (150) of the user.

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