RU2684498C2 - Method of certification and authentication of protected documents based on measurement result of deviations of relative position in different processes involved in making such security documents - Google Patents

Abstract

FIELD: physics.SUBSTANCE: invention relates to means of certifying and authenticating security documents. Disclosed are methods of certifying a secure document, comprising steps of selecting a set of unique characteristics obtained as a result of deviations of the manufacturing process and consumables, obtaining a digital image of the protected document and obtaining data on the relative position between features selected from different manufacturing processes, degree of coincidence, generating a message by measuring the degree of matching of features selected from the document and the identification data of the document, generating the hashed message, which is a message, obtained after encoding by unidirectional cryptographic hash function, encrypting hashed message using cryptographic system with a public key for obtaining a digital certificate using a private key and storing a digital certificate in an external database.EFFECT: technical result consists in improvement of authentication reliability.14 cl, 6 dwg

Description

FIELD OF TECHNOLOGY

[0001] This application generally relates to the certification and authentication process of secure documents. In particular, this application relates to the use of security features and unique characteristics already existing in security documents for certification and authentication of documents of this type. In particular, this application relates to the certification and authentication of banknotes, checks or security documents of any other kind by using natural deviations during the technological process, which occurs when printing processes, security features and other characteristics are included in the document.

BACKGROUND

[0002] Due to the significant development of existing technologies for graphic reproduction, which have become generally available on the market, it is becoming commonplace for high-quality fakes of security documents such as checks, banknotes, etc. Thus, of particular importance is the method of certification and authentication of protected documents using methods that can withstand the technical development of graphic equipment and which use publicly available devices, such as scanning devices or digital cameras.

[0003] In addition, organized crime has found a way to use these professional technologies to manufacture large volumes of high-quality fakes; this fact undermines public confidence in the issuing institution and its ability to provide reliable tools for detecting fakes.

[0004] Well-known authentication methods aimed at authenticating using devices or automatic equipment are based on processes and systems that require equipment with specific characteristics to verify the authenticity of one of the security features of a document, the complexity being due to the high cost of the equipment or the need to use special material. Examples are the incorporation of magnetic materials, ultraviolet (UV) fluorescent inks that absorb infrared pigments, dynamic optical response systems, in particular phosphorescence attenuation, magnetic strips and holograms that are included in security documents. Unfortunately, attackers also use methods that are becoming more complex, and with the help of modern ease of access to information and means of reproduction, almost any security feature that manufacturers have included in documents using materials and equipment available on the market can be imitated. Counterfeiting documents may include system-based counterfeiting using laser or inkjet printers (photocopy counterfeit) and counterfeiting using processes and materials similar to the original (process counterfeiting). In the case of photocopy fakes, central banks have special features that printers cannot imitate: for example, watermarks, magnetic threads, transparent windows, engraved reliefs with tactile features, holograms and optically variable features, as well as ink that varies with the viewing angle. In the case of falsification through a process, authenticity is difficult to determine by simply examining an untrained user. In addition, for the above specific case of counterfeiting money, this has a strong impact on the finances of the country. In fact, efforts to counter such forgeries are aimed at materials and inks to be used in the manufacture of new security documents, in an attempt to anticipate which high-risk products will become available on the market within the expected life of the document to eliminate them. In general, the standard approach requires predicting a narrowing of the gap between available technologies on the market and technologies intended for secure documents due to inevitable technological progress.

[0005] In the case of currencies such as US dollars and euros, which are used in many countries, the risk of counterfeiting increases, as this opens up new opportunities for attackers from these countries, including state-sponsored criminal organizations.

[0006] Thus, it is necessary that the authenticity of the security document be based not only on the fact that genuine materials and processes are complex but not impossible to tamper with, but also on mathematically proven security such as a digital certificate.

[0007] On the other hand, in the case of banknotes that are widely used for everyday transactions, it is necessary to provide the ability to immediately determine their authenticity. As an example, if a person does not find a fake during a transaction, this will result in a loss, because he will receive a document that has no value, will receive delivery of a valuable product, and in some cases will provide a cash change when the value of the goods is less than the value of the fake. Thus, there is a need for quick authentication of secure documents, such as checks and banknotes, to prevent such fake documents from entering the national economy, which affects the country's population, and to maintain trust in issuing institutions.

[0008] Judicial checks very accurately determine whether a document is genuine or not, however one document is processed for a very long time, which usually requires expensive and specialized equipment. On the other hand, computers and portable devices with a continuous increase in the quality of received images and computing capabilities are becoming more popular and more affordable from a financial point of view for people and corporations. Thus, it is desirable to authenticate protected documents by using currently available technology for digital imaging in devices such as smartphones or scanning devices connected to computers that can analyze data to verify the authenticity of the protected document, in particular banknotes.

[0009] In the field of verification technology for protected documents, it was also found that a balance should be found between conflicting tasks such as “acceptance” and “rejection”, and acceptance with a positive result is the ability to correctly authenticate - identify and accept - all genuine protected documents independently from their condition, and deviation with a positive result is the ability to correctly recognize and reject all non-authentic protected documents. However, there is the possibility of acceptance with a negative result, in which an authentic document is accepted as genuine, and the possibility of rejection with a negative result in which the authentic document is considered a fake and rejected. The authentication process must have a high level of accuracy with respect to these definitions, which avoids accepting with a negative result and rejecting with a negative result.

[0010] US Patent Application No. 2004/0268130 discloses a system and method for product authentication, which includes the steps of selecting a product feature and converting the feature to digital data to provide an identification code for the product. The encryption system is used to encrypt the identification code using a secret private key from an asymmetric encryption key pair and is associated with the issuing party. The encrypted code is presented on the designation that complements the product. During the next phase at the authentication location, digital data related to the feature is determined directly from the product, and the code is decrypted using the public key from a pair received from a third party in accordance with the rules of the public key management infrastructure. According to the system and method described in US Patent Application No. 2004/0268130, the characteristic is the result of chemical manipulation of the product or incorporation of unique characteristics in or onto said product. It is also required that the encrypted code is available on a designation that complements the product; however, this code is encrypted without the use of a hash function. This drawback will allow the counterfeiter to obtain the source data specifying the uniqueness of the product and begin to create modifications to approximate the source data. When using the hash function, the counterfeiter will not have any information on how to modify the product for authentication. In addition, it is not clear whether the selected characteristics will be able to withstand natural damage from the use of products.

[0011] Advanced Track and Trace (ATT) has developed a method for certifying printing plates and their associated printed banknotes. This company uses strong cryptographic methods. However, this approach has a major drawback: the fact that the number of codes is limited by the plates designed for the manufacture of banknotes using the ATT process; due to cryptographic protection, only series that were printed using the same plate can be reproduced. In addition, due to the complexity of the sample to be printed, a microscope or some magnifying device, as well as improved quality control, are required to minimize deviations in batches of secure banknotes.

[0012] As you can see, there is a need for a method for certification of secure documents, as well as a reliable and fast document authentication process. In addition, with a continuous increase in the pace of development of information technology, this method increases the protection and confidence in a physically protected document using the equivalent of a digital certificate with the understanding that in both cases it is necessary to evaluate the validity of the document. In particular, in this case, due to the fact that a physical document and a digital certificate are uniquely related to each other, a banknote without a valid digital certificate will not be of any value even if the document is authentic.

SUMMARY OF THE INVENTION

[0013] In embodiments of the present invention, there is provided a system for certifying any other type of banknote, check or security document. Embodiments include digital certification of documents involving these deviations, which imply the uniqueness of each site. This is possible due to the natural possibility of deviation of industrial technological processes, as well as information that changes in a predictable and manageable way, such as: serial numbers, serial symbol, etc.

[0014] In some embodiments, the document certification process consists of a hashed message, which, even when decrypted, is only useful for verifying the authenticity of a document and which will not disclose information about the characteristics of the original document that may be useful in the forgery process.

[0015] In another embodiment, a process for authenticating banknotes, checks or security documents of any other type is provided.

[0016] In another embodiment, an automatic authentication method is provided.

[0017] In another embodiment, a method for positively identifying forged security documents with a low false-negative and false-positive authentication coefficient is provided.

[0018] Another implementation option is to classify fakes by their quality and degree of sophistication.

[0019] In some embodiments, data for individualizing each security document is obtained from a set of characteristics resulting from deviations in the degree of coincidence of features added at various stages of the manufacturing process. These characteristics relate to the features and even uniqueness of each protected document.

[0020] Creating different messages for each protected document using the previously mentioned set of characteristics and data related to the identity of the document.

[0021] In addition, in some embodiments, a method for certification and authentication of any security document based on the above message is proposed, which requires a deviation in the degree of coincidence resulting from at least two technological processes and comprising the steps according to which:

[0022] select a set of unique characteristics obtained as a result of deviations in the manufacturing process and consumables,

[0023] receive a digital image of the security document and receive the specified data,

[0024] form a message by measuring the difference in the degree of coincidence of features from the document and data related to the identification data of the document,

[0025] form a hashed message, which is a message received after encoding the original message using a unidirectional cryptographic hash function,

[0026] the hashed message is encrypted using a public key cryptographic system to obtain a digital certificate using the private key and

[0027] store the digital certificate in an external database and / or apply it to a secure document or print a digital certificate on it.

[0028] According to other embodiments, an authentication method is provided, according to which:

[0029] provide a secure document to be authenticated,

[0030] verify that the security document uses genuine security source materials and manufacturing techniques through well-known image analysis techniques or a conventional authentication method of a different kind,

[0031] form the corresponding message by measuring the difference in the degree of coincidence between the features from the document and the data related to the identification data of the document,

[0032] using a hash function to obtain a hashed message for authentication,

[0033] receive a certified hashed message; in some embodiments, a certified hashed message is obtained from a digital certificate applied to or printed on a security document, the digital certificate being decrypted using a public key to play the compared hashed message; in some embodiments, a certified hashed message is obtained from the database by accessing the database,

[0034] authenticate the specified document by comparing the certified hashed message and the hashed message for authentication, while if the certified hashed message and the hashed message for authentication are consistent, the specified document is considered authentic, and if the certified hashed message and the hashed message for authentication do not agree the specified document is considered a fake.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In FIG. Figure 1 shows the general certification process.

[0036] In FIG. 2 shows a security document containing images and symbols from various processes.

[0037] In FIG. 3 shows an example of a security document containing various images from various processes and depicting reference points and relative points.

[0038] In FIG. 4 shows an example of a function M _D for mathematically processing data to receive a message.

[0039] FIG. 5 shows an example authentication process of a secure document.

[0040] FIG. 6 shows an authentication algorithm for a secure document.

SUMMARY OF THE INVENTION

[0041] The certification process and the authentication process are based on deviations that occur during the steps of the security document manufacturing process, in particular when these steps interact.

[0042] Some embodiments relate to a system for certification and authentication of security documents.

[0043] Some embodiments also relate to a method of certification and authentication of the original document, in which the unique characteristics of each document are identified, encoded and, as an additional option, inserted directly into a secure document, or stored in an external database. This method and the proposed system prevents the falsification of security documents.

[0044] Embodiments of the present invention will become more fully understood from the detailed description given herein below and the accompanying drawings, which are for illustrative purposes only, and thus do not limit the present invention, and in which:

[0045] In the present disclosure, the following terms have the following meanings.

[0046] Certification - A formal procedure by which an accredited or authorized person or agency evaluates (and certifies in writing by issuing a certificate) the attributes, characteristics, quality, qualifications or status of people or devices, goods or services, procedures or processes, events, or situations in accordance with established requirements or standards.

[0047] Authentication is the act of verifying the truth of an attribute of a single piece of data (a given value) or subject. Authentication is the process of determining whether someone or something is actually who or what it claims to be.

[0048] Security printing process - special printing processes that commercially available processes cannot easily simulate; for example, processes used to print banknotes.

[0049] Security features - refer to security features present in a security document. It is understood that such characteristics are difficult to simulate using commercially available products, which is the case with security paper, security ink, watermarks, magnetic threads, transparent windows, tactile signs, foil, overlays, holograms, etc.

[0050] Protected documents - are a document that declares in writing some guarantee (of each of the Guarantors) and was produced using security printing processes and may also include security features.

[0051] Unique characteristics - characteristics obtained as a result of natural deviations in the degree of coincidence of features added at various stages of the manufacturing process. These characteristics relate to the features and even uniqueness of each security document produced. The characteristics can be acoustic, electrical or magnetic signals and can be measured in part of the electromagnetic spectrum. These include print errors or print rejections: random ink spots, blank lines, color, etc.

[0052] Degree of coincidence - refers to the relative position, alignment, or non-alignment of features of a security document introduced by various manufacturing processes. During the production of a security document, the relative position of various images or characters, or security features obtained by various processes, changes from document to document, which makes the document unique and inimitable due to such deviations.

[0053] Metric function - The metric over a set X is a function (called a distance function or simply distance),

d: X × X → R, where R is a set of real numbers). For all x, y, z in X, this function must satisfy the following conditions:

1.d (x, y) ≥0

2. d (x, y) = 0, if and only if x = y

3.d (x, y) = d (y, x)

4.d (x, z) ≤d (x, y) + d (y, z).

[0054] A generalized metric function - A generalized metric over a set X is similar to a metric function, but in some way not strictly following its axioms (for example, only axioms 1 and 3 can be satisfied).

[0055] Document Identification Data is data that acts as an identifier for a single document. They can be words, numbers, letters, symbols, or any combination thereof. An identifier is a name that identifies (that is, indicates identity) either a unique document or a set of documents. The term identification (ID) means an identifier (that is, an identification option). In the case of banknotes, it contains a serial number.

[0056] A message is a sequence of results from applying certain metrics, generalized metrics, or other functions to points in a preselected subset of unique characteristics (degree of coincidence for a protected document) and the document’s own identification data.

[0057] A hashed message is an encoded message by means of a unidirectional cryptographic hash function.

[0058] Digital certificate is an encrypted hashed message stored during the certification process (encrypted using the private key).

[0059] The term "unique characteristics" is used for all those natural deviations of a document that arise during the manufacturing process and which can be measured; in particular, those provided through a security printing process for producing a security document. An example of a unique characteristic is the degree of match.

[0060] According to embodiments of the present invention, security features are those parts or components that are present in a security document in order to enable various users of the document to easily authenticate the document by controlling the manufacturing process, distribution, and commercialization, while preventing an unauthorized person from receiving the security feature and tampering with it or subject.

[0061] According to embodiments of the present invention, the unique characteristics are those natural deviations that are measurable during the manufacturing process.

[0062] Also disclosed is a method for digitally certifying a security document through data obtained from unique characteristics, in particular a degree of agreement.

[0063] In one embodiment, a method is provided for digitally certifying security documents using security features and unique characteristics that are already present in said document.

[0064] In particular, the document will be digitized, which can be done through a scanning device or digital photograph using various sources and types of lighting, as well as any other measurement of the physical, chemical or physico-chemical properties of the document, from which unique characteristics can be obtained . In particular, the degree of coincidence can be measured using visible light and a device for digitizing the image of a document.

[0065] According to embodiments of the present invention, by “image capture” it is to be understood that the scanning and digitizing equipment measures features such as:

[0066] the properties of reflection, transmission, absorption, radiation at any wavelength of the electromagnetic spectrum or in combination with either stationary lighting or in a flickering state,

- magnetic and / or electrical properties, for example, electromagnetic digital fingerprints of materials constituting a security document;

- acoustic properties; paper when subjected to pressure cycles with a specific amplitude creates specific measurable levels of interference;

[0067] properties in response to mechanical and / or chemical and / or electrical effects on paper or security features.

[0068] The features to be measured are strictly dependent on the nature of the manufacturing process used during the production of the security document, as well as the operating conditions that will accompany the document.

[0069] A message is generated using some features, as well as a mathematical relationship between them. According to embodiments of the present invention, a metric function is used, which is a function of the distance between two points.

[0070] A message is generated using those signs that cannot be worsened, or whose worsening is known and / or predictable:

- multiple zones of various sizes and / or the entire document;

- the signs to be measured depend on the document and the manufacturing process for its receipt;

- Signs that depend on the interaction between at least two different processes.

[0071] In the particular case of obtaining features from digital images, in any light, the image is taken so that it emphasizes those parts that are subject to certification. For example, it may be interesting to certify only the half or quarter size of a protected document or to create multiple certifications using different messages for one document.

[0072] A certification and authentication system is disclosed with reference to the figures.

[0073] The manufacturing process of a security document according to embodiments of the present invention comprises:

[0074] a) ensuring the availability of suitable consumables (step 11a) comprising: a substrate, ink, security features such as watermarks, threads, transparent windows, dyed fibers, foil or linings, etc.

[0075] b) the implementation of the manufacturing process of the security document (step 13a), which involves combining all consumables, the process comprising: placing a variety of features, characters or images on a substrate using at least two different manufacturing processes; and applying or placing the serial number of the document or any other identification data of the document;

[0076] c) certification of a security document:

[0077] i. obtaining a digital image of the document (step 10) and obtaining data (20) corresponding to a group of unique characteristics selected for each document and identification data of the document. These unique characteristics are the result of variations in the manufacturing process and the consumables used;

[0078] ii. forming a message (30) by using a metric function to determine the relative position of points previously selected as a group of unique characteristics, as well as document identification data;

[0079] iii. generating a hashed message by applying a hash function (40), the hashed message (50) being a message received by applying a one-way cryptographic hash function;

[0080] iv. encrypting the hashed message with a public key cryptographic system (60) to obtain a digital certificate (80) using the private key (70) and

[0081] v. storing a digital certificate in the database (90) of data and / or,

[0082] vi. Drawing on a protected document (10) or printing (97) on it a digital certificate.

[0083] FIG. 2, a security document is depicted in accordance with embodiments of the present invention. Some processes are involved in the production of a security document; Four processes are shown as an example (A, B, C, E). A protected document includes many images and symbols belonging to various manufacturing processes. In the case of Figure 2, Process A provides an initial substrate for a security document, the substrate including some security features such as a thread or foil (ai) and a watermark or electroforming image (aii). Process B provides a set of images (bi), for example, in the form of offset printing. Process C provides the protected document with an image (ci), as well as a symbol (ciii), in this example, referring to the name, and a symbol (cii), referring to the name of the issuing institution; as an example, this could be an engraving process. Similarly, process E provides the serial number of the security document (e1), illustrated as a banknote. In some embodiments, the security document is certified according to the process of FIG. one; as a result, a digital certificate obtained through the certification process may, as an additional feature, be printed on a secure document as an attribute (fi).

[0084] According to embodiments of the present invention, at least one of the following unique characteristics of a document is considered during certification of a document, and these unique characteristics are obtained from the following:

[0085] an electromagnetic reaction (in the infrared (IR), visible, ultraviolet (UV) spectral range),

[0086] degree of coincidence

[0087] the number and position of the fluorescent fibers

[0088] print errors or print rejection: arbitrary ink spots, blank lines, color, etc.

[0089] physical parameters,

- Acoustic properties,

- Electrical properties,

- Magnetic properties,

- etc.

[0090] and require at least one document identification:

- serial number,

- Title of the document,

- names

- dates, etc.

[0091] In FIG. 1 discloses a certification process according to embodiments of the present invention; the security document is produced according to known processes of the prior art (Step 10), which includes the steps of providing special supplies 11a, manufacturing the substrate 13a, and conducting a manufacturing process comprising the various steps (13a).

[0092] The document thus produced is then subjected to a data acquisition process (step 20), in FIG. 1 to obtain specific data of each manufactured object and, in particular, information regarding relative positions between the variety of characters or images present in a security document.

[0093] Data from the relative position of images and characters present in a security document is used to generate a numerical message. In FIG. Figure 3 shows an option for obtaining data from a protected document. The message (30) received in step (20) consists of data regarding the relative positions between images and symbols, the positions of which depend on the process by which such images and symbols are placed in a secure document. For example, Figure 3 shows a security document containing images produced by the process sequence A, B, C, and E. As shown, a set of reference points (A1, A2, ..., AN), (B1, B2, ..., BN) are defined , (C1, C2, ..., CN), (E1, E2, ..., EN), etc. for each image or process, in a given arbitrary position, providing easy access or identification, for example, specific corners of the image, some plotted points, etc., and then the first relative position [D1 (A1, A2)] of the first relative point ( A2) is calculated in the image A with respect to the reference point A1; the second relative position [D2 (A1, B1)] of the relative point B1 is calculated in the image B with respect to the reference point A1. In the same way, the third relative position [D3 (A1, C1)] of the relative point C1 in the image C is calculated; and as an optional feature, the fourth relative position (D4 (A1, E1)] of the relative point (E1) in the image D is also calculated. In some embodiments, other relative positions are also calculated with reference to the second reference point in the image B (B2) , the third anchor point in the symbol C (C2) or the fourth initial position in the symbol E (E2). Metrics for each relative position from each anchor point are also calculated, as well as other trigonometric values and other mathematical ichestvennye values associated with the distance between points. It may thus be given a variety of reference points and a variety of measurements.

[0094] The security document data is then associated with a mathematical function, such as a mathematical matrix, as shown in FIG. 4, which is consistent with the “Message” of a protected document. As shown, it is possible to generate one common protected message M _D for all measured features or it is also possible to generate many messages coming from specific parts of the protected document, for example Message M _DA relating to the relative position of point A with respect to the remaining points A, B, C and E, or Post M _DCB, refer to relative positions between the points C and B, or the message M _DEC, referring to the relative position of points C and E. figures This is particularly useful when it is desired to authenticate umenta, in which case only part of the document is available, for example, in the case of parts of a document or a torn security documents.

[0095] There are some mathematical methods in the prior art for obtaining a message from the collected information. For example, a protocol that follows the value of relative positions or mathematical regression, for example, linear regression, logarithmic regression, or another type of mathematical regression. In some embodiments, it is preferable to use a metric function.

[0096] To obtain many different reference points and relative positions, the process of digitization or image capture is carried out, for example, using a digital photograph or a scanning device; as well as any other physical and / or chemical measurements of unique characteristics for each document, for example, paper type, paper weight, paper texture, paper color, ink type, ink color, etc. The digitization step can be carried out in the digitization module following fabrication (13a).

[0097] As an example, when a subset of the unique characteristics comes from the degree of coincidence between the various processes involved in the production of the security document, the deviations between the result of the images and symbols that take into account the process A, B, C and E will ultimately give the order of several quintillion in depending on the resolution of the digital image of the document.

[0098] As shown, the level of deviation provides a unique and non-repeatable way to identify documents whose accurate reproduction is extremely difficult even for the original manufacturer.

[0099] In addition, if not only the degree of coincidence, but also other unique characteristics, such as the number and position of colored or fluorescent fibers, is used, the number of deviations will increase by several hundred orders of magnitude.

[00100] By selecting points according to embodiments of the present invention, it is possible to obtain several quintillions of possible combinations; thus, it is very unlikely that the counterfeiter receives a document with the same unique characteristics as those contained in the digital certificate created according to the embodiments.

[00101] In the particular case of banknotes, even if the original manufacturer wants to fake an exact copy of one document, he will have to produce many documents (in quintillion order) and then select one that has the same deviation, and then insert the identification data of the document together with the same certificate of the original. Therefore, in particular, for banknotes, this method using the degree of coincidence does not make counterfeiting impossible, but rather makes it economically unfeasible, which makes counterfeiting a very complex and inefficient process.

[00102] However, to prevent an attacker from statistically examining deviations from the official manufacturer, the message obtained in step (30) is then transformed in step 40 using a mathematical hash function and then encrypted in step 60 to obtain a unique digital certificate.

[00103] In step 40 of FIG. 1, the message obtained in step (30) is then converted using a mathematical function such as a hash function to obtain a hashed message containing at least one character string in step 50 of FIG. 1. There are some mathematical methods for running a hash function, for example, through a mathematical unidirectional process or a model (algorithm) that delivers a string of characters.

[00104] The hashed function is then encrypted in step (60) to obtain an encrypted hashed message or digital certificate. To encrypt a hashed message, an asymmetric encryption algorithm is used, which requires a private key (70) to generate a digital certificate (80) in the form of an encrypted alphanumeric chain.

[00105] As shown in FIG. 1, the digital certificate, in turn, is stored in the database (90) of the data, which can be located on the server located in the protected buildings, and / or it can be applied / printed (97) back on the document (10) in a readable way through one and the same mechanism for receiving data (20), such as a barcode, code, or plain text (fi). When using a database (90) of data, in addition to storing a digital certificate (80), it can also be useful to associate this digital certificate in a database with other identification information such as the serial number of the protected document, a scanned copy of the document, and details of the place and time of manufacture document, etc.

[00106] The digital certificate is then an authentication element associated with the identity of the document of said security document, and refers to a single relationship between images and characters that exist in a unique way for each security document.

[00107] Digital certificate 80 acts as an obstacle for an unauthorized third party with a reader who wants to read forged documents or banknotes and print on them a sign that represents the result of scanning the reader according to an encryption scheme. Typically, a digital certificate (for example, a barcode label or other label) is a cryptogram that can be decrypted using a public key, and the private key is reserved for an authorized certifying party or authority. However, as mentioned, a digital certificate may not be included in a secure document. As mentioned earlier, a digital certificate represents the unique and unique physical characteristics of images and characters present in a security document and will not disclose additional information on how to make a fake copy.

[00108] The encrypted information is then placed as a printed label or printed back in step 97 of FIG. 1. A digital certificate 80 and a hashed message 50, as well as partial hashed messages and document identification data of the aforementioned secure document, are stored in the database 90, placed on a server accessible for open access. A digital certificate in the form of an element (fi) may be inserted as an additional feature on a security document 10.

[00109] In some embodiments of the present invention, a digital certificate may be selected from a barcode or a two-dimensional barcode element or character string (f1).

[00110] Thus, the digital certificate 80 is the result of a unique and non-repeatable relationship between many different images and characters due to the degree of coincidence that, due to their manufacturing processes, is present in the security document.

[00111] Authentication Process

[00112] Protected documents that have been certified are further authenticated. The authentication process of a secure document in an implementation is shown in FIG. 5 and 6. Authentication of a protected document is a task carried out by an authorized authentication body, for example, an authorized authentication body of a issuing institution, but can also be performed both by a user of a document and an authorized authentication body when a user wishes to confirm the authenticity of a document. According to FIG. 5, the user or authorized authentication body who wants to know whether the issued document (110) is genuine or not, must first (step 120) verify the consumables and security features (watermarks, security threads, security inks, security processes) etc.) which are implied to be used in the original document; simple photocopies and rough copies are detected at step 120 in FIG. 5 and step 121 in FIG. 6 and is considered a low-quality fake (122, Fig. 6).

[00113] Then, if the source materials and printing processes used in the authenticated document are considered genuine (step 123, Fig. 6), then a hashed message should be generated according to the characteristics of the user document. For such purposes, the authorized authentication body / user must obtain the data of the protected documents (step 130) through any device configured to take the necessary digital image, then generate a message using the metric function and the identification data of the document (step 140), and apply the hash function (150) to receive a hashed message (160) for authentication.

[00114] In the next step, the user is provided with a smartphone, tablet or other processing device with an application capable of receiving data (130) and automatically building the message (140) via the metric function, and also apply the hash function (150) to the message to receive the hashed message (160) for authentication.

[00115] To authenticate a secure document, a hashed message (160) for authentication is compared with a decrypted hashed message (260). A digital certificate (80, FIG. 1) must be retrieved in some way to receive a decrypted hashed message (260). One of the sources of digital certificates (80, Fig. 1) for authentication is the database (280) of data created during certification. Given that the data acquisition and processing module is capable of accessing a database managed by an authorized authentication authority, the digital certificate can be decrypted (250) using a public key (230) to obtain a decrypted hashed message (260). The database may be part of a mass storage device that forms part of a reader, or may be a remote location accessed by a reader via a telecommunication line. A telecommunication line can take any conventional form, including wireless and fixed lines, and can be accessed via the Internet. The data acquisition and processing module may be configured to, at least in some operating modes, add a signature to the database if no match is found. This feature will usually be provided only to authorized persons for obvious reasons. It should be noted that misuse of the public key does not contribute to falsification of the document, since the public key is useful for decrypting a digital certificate, but is useless for encrypting a hashed message.

[00116] In some embodiments of the present invention, the hashed message (160) for authenticating the security document is provided to an authentication authority that is able to obtain the corresponding decrypted hashed message (260) from the database (280) as described above and make a comparison to establish whether the hashed message (160) for authentication is consistent with the decrypted hashed message (260).

[00117] Another source for extracting a digital certificate (80, in FIG. 1) is a barcode or a two-dimensional barcode element or character string (f1, in FIG. 2) printed / printed on a security document.

[00118] In some embodiments of the present invention, the digital certificate can be decrypted (250) by means of a public key (230) to provide a decrypted hashed message (260) and used to perform a comparison to determine whether the hashed message (160) is consistent for authentication with a decrypted hashed message (260), which can be performed locally by the user.

[00119] Finally, if the hashed message (160) for authentication and the decrypted hashed message (260) are consistent, the document is hereinafter considered an authentic document (400 in FIG. 6). On the other hand, if the hashed message (160) for authentication is not consistent with the corresponding decrypted hashed message (260), then the document is considered a high-quality fake (305). The number of such fakes can provide elements / evidence to investigate the picture of the crime.

[00120] As shown in FIG. 6, the user must first perform an authentication step 121 to determine the availability of genuine raw materials and initial security manufacturing processes used in security documents such as banknotes. If such materials and processes are not used, then the document is considered a low-quality fake (122). If the expected materials and processes are used in the document and are considered authentic, then the user must perform the step (130) of obtaining data.

[00121] In some embodiments of the present invention, the authentication process is performed using an application for a smart device, such as a smartphone or tablet. The application helps the user to get an accurate image and provides a means to connect with the Authorized body for authentication. After authentication, the Authorized body for authentication delivers the result of the comparison process.

[00122] The method provides the ability to classify fakes by their manufacturing characteristics; for such purposes, equipment for automatic classification and registration (ID) of fakes is necessary, which is responsible for registering the signs of all fakes entering the issuing institution, to create a database with all the information extracted from the fakes, for the statistical linking of servings to “Counterfeiters” ( not necessarily human) and detecting even minor improvements. Such information is useful in the investigation and prosecution of criminal elements involved in counterfeiting documents.

[00123] For certification, image acquisition systems (digital camera, scanning devices), image processing equipment (such as CPU, GPU, FPGA), storage system (data servers) are required. In case 97, the labeling / printing device may be an inkjet printer, a numbering machine, laser marking devices, marking devices, etc.

[00124] For authentication, an imaging system (digital cameras, a cell phone camera, a scanning device, etc.), an image processing system (such as a CPU [PC, servers, tablet, smartphones, etc.], GPU, FPGA). In the case of 280: access to the database is required (Internet, SMS, LAN, WAN, VPN, etc.).

[00125] Although embodiments of the present invention are described in this manner, it will be apparent that the same embodiments may vary in different ways. Such modifications should not be construed as a departure from the essence and scope of the present invention, and all such modifications, as is obvious to a person skilled in the art, should be included in the scope of the following claims.

Claims (31)

1. A computer-implemented certification method for a security document (10), according to which: providing a security document having features selected from the group consisting of (a) watermarks, magnetic threads, transparent windows, engraved reliefs, (b) images obtained by offset printing, (c) images obtained by gravure printing, or ( d) a serial number, wherein the security document (10) has a set of unique characteristics of the degree of coincidence of features relative to other security documents produced by the same process, and the specified set of unique characteristics of penalties coincidence signs differ from document to document due to natural variations of manufacturing processes; choose, by one or more computer processors, a specific set of places in the document having a set of unique characteristics of the degree of coincidence of features, receive, through one or more computer processors, a digital image of a security document (10) having a set of unique characteristics of the degree of coincidence of features; receiving a plurality of measurements (20) regarding the relative positions of the features of the security document (10) having a set of unique characteristics of the degree of coincidence of the features; form, by one or more computer processors, from the specified set of measurements (20) of the relative positions obtained from a certain set of document locations, a hashed message (50) obtained by encoding the specified message using a unidirectional cryptographic hash function (40), encrypt, using one or more computer processors, the hashed message (50) using a private key (70) using a public key cryptographic system (60) to obtain a digital certificate (80) and save, by one or more computer processors, a digital certificate (80) and the serial number of the document in an external database (90) of data. 2. The method of certification of a security document according to claim 1, according to which the number, barcode or label associated with the digital certificate (80) is applied to or printed on the security document (10). 3. The method of certification of a security document according to claim 1, according to which a digital image is obtained using light with a wavelength between 200 and 1500 nm. 4. The method of certification of a security document according to claim 1, according to which a digital image is obtained using visible light. 5. The method of certification of a security document according to claim 1, according to which many parts of the same document are certified independently of each other. 6. The method of certification of a security document according to claim 1, according to which the security document (10) is a banknote, check, passport, visa, identification document or birth certificate. 7. The method of certification of a security document according to claim 1, according to which the specified data (20) of a set of unique characteristics of the degree of coincidence of attributes are obtained during the production of security documents (10). 8. The method of certification of a security document according to claim 1, according to which the specified data (20) of a set of unique characteristics of the degree of coincidence of attributes are obtained during a quality check. 9. A computer-based authentication method for a certified security document, according to which: provide a security document (10) to be authenticated, having features selected from the group consisting of (a) watermarks, magnetic threads, transparent windows, engraved reliefs, (b) images obtained by offset printing, (c) images obtained by intaglio printing, or (d) a serial number, the security document (10) having a set of unique characteristics of the degree of coincidence of features relative to other security documents produced by the same process; verify that the security document uses genuine protective starting materials and the indicated watermarks, magnetic threads, transparent windows or engraved reliefs, receive from the user, through one or more computer processors, a digital image of a secure document to be authenticated, receiving a plurality of measurements (20) regarding the relative positions of the features of the security document (10) having a set of unique characteristics of the degree to which the features match form, by one or more computer processors, a hashed message to be checked for authenticity from the specified set of measurements (20) of relative positions obtained from a specific set of document locations, the hashed message being obtained by encoding the specified message using a unidirectional cryptographic hash function ( 40) receive a digital certificate encrypted using a certification tool associated with the document (10) from an external database (90) of data, moreover, (a) the serial number of the document, (b) the barcode or characters are printed on the protected document (10) or printed on dumb decrypting the digital certificate of the certification tool using a public key to obtain a hashed message of the certification tool, and authenticate, by one or more computer processors, the specified document by comparing the hashed message of the certification tool and the hashed message for authentication, while if the hashed message of the certification tool and the hashed message for authentication are consistent, the specified document is considered authentic, and if the hashed message of the certification tool and the hashed message for authentication do not agree, the specified document is considered a fake. 10. The authentication method of a security document according to claim 9, according to which the source materials are checked for authenticity using image analysis and pattern recognition methods. 11. The method of authentication of a security document according to claim 9, according to which the security document (10) is a banknote. 12. The authentication method of a security document according to claim 9, wherein the authentication is carried out by means of scanning devices available on the market or digital cameras connected to computers. 13. The authentication method of a secure document according to claim 9, according to which authentication is carried out by means of smartphones or tablets. 14. The authentication method of a security document according to claim 9, according to which authentication is carried out by means of cash settlement equipment.

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