EP2084648A1

EP2084648A1 - Methods and devices for authenticating a product and a two-dimensional code and novel application of a two-dimensional code

Info

Publication number: EP2084648A1
Application number: EP07866479A
Authority: EP
Inventors: Patricia Etienne Suanez; Roger Suanez
Original assignee: Algoril Holding SA
Current assignee: Algoril Holding SA
Priority date: 2006-11-03
Filing date: 2007-10-31
Publication date: 2009-08-05
Also published as: FR2908203A1; US20110053639A1; FR2908203B1; WO2008065267A1

Abstract

The invention relates to a method for authenticating a product from an analysis of the clarity of translucent blocks contained in a two-dimensional code (1), a method for authenticating a two-dimensional code (1) and devices for carrying out said methods. The two-dimensional code (1) affixed to a product is authenticated by analysing the level of clarity of translucent areas (11, 12, 14) contained in the two-dimensional code (1) and comparing the result of said analysis with a reference in a pre-established database. The two-dimensional code (1) is authenticated by selectively marking certain dark areas of the two-dimensional code (1) according to the character chain encoded during an encoding step and comparing the position of the marked dark areas with the position defined by the character chain during a decoding step. The invention also relates to a novel application of said two-dimensional codes (1).

Description

Methods and devices for authenticating a product and a two-dimensional code and new application of a two-dimensional code.

The present invention relates to a method for authenticating a product, based on the clarity analysis of translucent areas included in a two-dimensional code applied to the product, a method for authenticating a two-dimensional code by marking and analysis of certain areas of the two-dimensional code, and the devices for carrying out these methods. The present invention also relates to a new application of a two-dimensional code. Most manufactured products are marked to ensure traceability, especially when crossing borders. In particular, in order to guard against the production of counterfeits and to be able to identify fakes during a control or seizure, most manufactured products have a unique registration, and, if possible, difficult to reproduce. Registration is generally small in order to be discreet on the medium, and to make the illegal reproduction of the product registration more complex, registration is generally non-sequential.

In the prior art, there are various coding and registration systems for products known to those skilled in the art. Two-dimensional codes are notably used frequently. These are generally in the form of a matrix composed of dark squares and white or translucent squares, whose relative position makes it possible to encode a specific character string on the product. The string can be a keyword, or a concatenation of different keywords, that refer to data included in a database.

In this family of two-dimensional coding system, the "QR-Code" (registered trademark) is one of the most widespread, especially in Japanese industry. It is used in particular to quickly enter personal information on a mobile phone, the personal information being affixed for example on a business card, from the photograph of the code and information processing software. Another coding system frequently used is the public coding system called "datamatrix" (registered trademark). Its most widespread application is for the electronics industry, such as the marking of smart cards, but also sometimes for the registration of wine bottles. The matrix of the datamatrix coding system consists of a data coding area called a "data zone", having a combination of dark squares and adjacent translucent squares, this data area being surrounded on two adjacent sides by two dark lines called the "trigger bars", and on the other two sides by two other lines with alternating dark squares and translucent squares, called the "density bars". The squares are called "areas" afterwards.

The matrix coding system "datamatrix" operates as follows: A character string representing information characterizing the product, which must be encoded in the matrix, is first binarized according to a pre-defined coding protocol, for example in format 7-bit ASCII in the Extended Channel Interpretation (ECI) protocol. These binary data are then represented as translucent areas and dark areas, generally representing respectively a 0 bit and a 1 bit. The arrangement of the dark and translucent areas of the various elements of the character string in the area of data follows a specific order and known to those skilled in the art. The translucent areas allow to reveal the support. Dark areas, on the other hand, are generally opaque, created by the impression of a dark ink, and do not allow to see the support underneath.

In addition to this encoding of the information characterizing the product, a system for correcting reading errors is encoded in the "datamatrix". This allows you to reconstruct and rectify poorly printed, erased, fuzzy or torn data. The mechanism for correcting errors is based on Reed-Solomon codes, generally according to the ECC (Error Corrective Code) standard 200.

The two-dimensional coding system "datamatrix" makes it possible to encode a string of characters, typically of ten or a few dozen characters, with matrices of very small size, typically a few millimeters or ten millimeters squared, which makes this system discrete coding when affixed to the product. In addition, the reading of translucent and dark areas with a suitable optical system and their decoding can be performed even with a low contrast between the dark areas and the translucent areas.

This registration system, however, suffers from several defects. Indeed, although the reduced size of the matrix complicates its reproduction, the "datamatrix" system is not tamper-proof in the state of the prior art. A counterfeiter who has made a fake product can relatively easily add a "datamatrix" code similar to that found on an original product. In addition, this coding system encodes information, that is to say the string of characters, which are predefined and affixed to the product. The coding system therefore does not give, in the state of the prior art, information on the product itself but on the string of characters that has been encoded.

Another product identification system known in the prior art is to use a high magnification optical imaging system to analyze random variations in the structure of the product material. Each manufactured product has a specific imprint, a random structure, related to the way it was made and / or to the nature of the material that constitutes the product. By comparing the surface structure of the analyzed material with that of a reference standard, it is then possible to determine according to predefined criteria whether the product entered is false or not. However, this authentication system requires the use of two detection systems. In addition to the traditional system of reading the string of characters affixed in the form, for example, a "QR-code" or a "datamatrix", a second imaging and information processing device must be used to analyze the structure of the material.

The present invention aims to overcome one or more disadvantages of the prior art and in particular to provide a method of authenticating a product from a two-dimensional coding system.

The present invention relates to a method for authenticating a product on which is affixed a two-dimensional code representing a string of characters in the form of an arrangement of dark areas and non-dark areas, located in a coding area of data, and in the form of an arrangement of dark areas and non-dark areas, located on the periphery of the data coding area, the non-dark areas, hereinafter referred to as "translucent areas", revealing the substrate of the product, characterized in that it comprises the following steps: a step of reading and recording the two-dimensional code in the form of coded values of electrical signals associated with the intensity of a luminous flux coming from the areas of the code two-dimensional,

an image processing step, based on the recorded coded values, of creating a matrix of values in which each element is associated with an area of the two-dimensional code,

a step of decoding the value matrix, making it possible to decode the string of characters and to record it,

a step of determining an average luminous flux intensity value from at least two translucent areas located in the peripheral zone, by analysis of the coded values of the electrical signals,

an inversion / assignment step, consisting in creating a binary matrix in which each element is associated with an area of the two-dimensional code, with the value 0 for the elements associated with the dark areas and the translucent areas whose coded value is less than average value of electrical signal, and value 1 to elements associated with translucent areas whose coded value is greater than the average value of electrical signal, a calculation step on the binary matrix whose result determines a code tested,

a step of linking to a database and of comparing the tested code with a predetermined predetermined code, the two codes being associated with a reference.

According to a feature, the method is characterized in that the two-dimensional code is produced using a "datamatrix" coding system comprising a data zone, two trigger bars, and two density indicator bars, and that the Data encoding area is the data area, and the peripheral area is the two density bars.

According to another particularity, the method is characterized in that the two-dimensional code is produced using a "QR-Code" coding system, and the data coding zone corresponds to the QR code data zone. -Code, and that the peripheral zone (3) corresponds to the three trigger zones located on three of the four corners of the "QR-Code".

According to another feature, the method is characterized in that the image processing step comprises a segmentation of the areas of the two-dimensional code.

According to another feature, the method is characterized in that the decoding step is performed using a decoding protocol stored in a memory to which the image processing software has access. According to another particularity, the method is characterized in that the calculation step consists of calculating a polynomial, consisting for each bit of a binary matrix having the binary value of 1, to multiply this value by two, to raise the result to a power, this power being determined as the number of columns present in the bit matrix to which is subtracted the number of the column on which is located the bit for which the calculation is made, such that the first column is located on a predefined border of the binary matrix and then summing all of these results, ie P, with i the line number of the binary matrix such that the first line is located on a predefined border of the binary matrix, j the number of the column, Nb the number of columns present in the binary matrix, N (1) jj the binary value equal to 1 of the area on line i and column j, the term] T () signifying a summation of all terms between parentheses for j varying from 1 to N _b , and the term ^ () signifying a summation of all terms i included between parentheses on all existing values of i.

According to another particularity, the method is characterized in that the comparison and linking step defines the product as a false if the code tested and the code laid down corresponding to the same string of characters are different.

According to another feature, the method is characterized in that the code placed is calculated from the two-dimensional code of a product before it is put into circulation.

According to another particularity, the method is characterized in that the common reference, used for the comparison step, is the string of characters, or part of the string of characters.

Another object of the present invention is to propose a new application of a two-dimensional code.

The invention relates to a novel application of a two-dimensional code affixed to a product, the two-dimensional code representing a string of characters encoded in the form of an arrangement of dark areas and non-dark areas included in a coding area of data, and other non-dark areas being positioned at the periphery of the data coding area, the non-dark areas allowing the substrate of the product to appear and being referred to as "translucent areas" characterized in that the translucent areas of the two-dimensional code are used to authenticate the product, by analyzing their clarity. Another object of the present invention and to provide a method for authenticating a two-dimensional code.

A method of authenticating a two-dimensional code (1) encoding a string of characters (70) using alternating dark areas (10) and non-dark areas (11) located in a data coding area, and using other dark areas (13) and other non-dark areas (14) located in a peripheral area (3) on the periphery of the data coding area, the non-dark areas (11,

12, 14) being called thereafter "translucent areas" and revealing the substrate of the product, characterized in that it comprises a coding step and a decoding step such that the coding step comprises:

a first calculation step, by encoding software, making it possible to determine a representative digital value (30) of the encoding of the character string (70), a first density allocation step, by the coding software, determining the position of marked dark areas (17) on the peripheral area (3) by a second calculation step from the representative numerical value (30),

a step of printing and marking the two-dimensional code, consisting of printing the two-dimensional code on the product and adding a marker to the marked dark areas (17), and the decoding step comprises:

a step of reading and recording the two-dimensional code, with a suitable device, making it possible to record electrical signals associated with areas of the two-dimensional code, to determine a matrix of values representative of the two-dimensional code, and to distinguish the position of the marked dark areas (17) and unmarked dark areas (18) of the peripheral area (3),

a step of decoding the two-dimensional code, by an image processing software, making it possible to decode the string of characters (70) and to record it, a third calculation step, by a decoding software, from the encoding of the character string, and according to the same algorithm as in the first calculation step, making it possible to determine the representative numerical value (30) of the coding of the character string (70), - a second density assignment step, by the decoding software, according to the same protocol as the first density assignment step, for determining a position of the marked dark areas (17) and unmarked dark areas (18) from a calculation of the representative numerical value (30) of the string encoding (70), - a step of comparing the positions of the marked dark areas (17) and unmarked dark areas (18) determined on the one hand by the second density assignment step and on the other hand by the reading and recording step.

According to a feature, the method is characterized in that the two-dimensional code is produced using a "datamatrix" coding system comprising a data zone, two trigger bars, and two density indicator bars, and that the peripheral zone is associated with the two density indicator bars.

According to another feature, the method is characterized in that the two-dimensional code is produced by means of a coding system "QR-

Code ", and that the peripheral zone corresponds to at least one of the three trigger zones located on three of the four corners of the" QR-Code ",

According to another feature, the method is characterized in that the first step of calculating the numerical value representative of the encoding of the character string consists in calculating the remainder of a division of a first term by a second term, the second term. term being called the prime number of the character string, the first term being either a product of the ASCII codes of the characters of the character string, or the result of a multiplication of the remainders of a product's divisions of the ASCII codes of the characters of the character string by the prime number of the character string, or any other combinations of product division remains of the ASCII codes of the characters of the character string by the the first number of the character string and the product of these division residuals, so that all the characters of the character string intervene in the computation step by their ASCII code,! e prime number of the string of characters being the nearest prime number and less than the number two raised to the power of the number of characters included in the string.

According to another feature, the method is characterized in that the first and second density assignment steps consist in assigning the representative digital value to a dark area located at one end in contact with a trigger bar of one of the indicator bars. of density, to successively divide the representative numerical value by two taking into account only the whole part of the division, to successively assign each of the results of this division to a dark area of the density-indicating bars, starting with the area the darkest of the area to which the representative numerical value is associated and ending with the dark area of the density bars on the diagonally opposite side of the dark area to which the representative numerical value is assigned, to be calculated the rest of the division by the number two each of the results of the division of the representative numerical value, and to assign each of these divisional remains to the same dark area of the density indicator bars with which each of the results of the division of the representative numerical value by two is associated.

According to another feature, the method is characterized in that the marking consists of modifying the contrast of the dark areas and / or adding to the marked areas an ink having physicochemical properties different from the ink used for the unmarked areas.

Another object of the present invention and to provide a device for implementing the method of authenticating a product.

The invention relates to a device for authenticating a product on which a two-dimensional code (1) representing a string of characters in the form of an arrangement of dark areas (10) and non-dark areas (11) is affixed. , 12), comprising an optical imaging device (100), a optical signal converting device to an analog electrical signal (110), an analog / digital converter (130), a memory (140), an image processing software (150) controlled by a microprocessor, and a setting means relationship (160) with a database (170), the optical imaging device (100) consisting of at least one lens for imaging two-dimensional code (1) on the optical signal converting device in an analog electrical signal (110), the optical signal conversion device into an electrical signal (110) consisting of a set of photodetectors for converting a light signal into an analog electrical signal which is converted into a signal. digital power supply by the analog / digital converter (130) and stored in the memory (140), and characterized in that the image processing software (150) includes means for: segmenting areas of a two-dimensional code from of the analysis of the intensity of the electrical signals recorded in the memory,

- create a matrix of values according to the result of the segmentation,

extracting a string of characters by decoding the matrix of values according to a predetermined decoding protocol,

calculating an average value (22) of electrical signal from the values of the signals recorded in the memory,

creating a binary matrix whose element corresponds to an area and whose value of the element depends on the values of the signals recorded in memory and on the average value of the electrical signal,

calculate, according to a predefined algorithm, a tested code which depends on the binary matrix,

- using the linking means (160) with a database (170) for comparing the tested code with a registered code stored in a database (170), and referenced according to a string of characters.

According to a feature, the device is characterized in that the optical imaging device, the optical signal conversion device into an analog electrical signal, the analog / digital converter, the image processing software, the memory and the means of linking with a database are included in a phone - digital camera.

According to another feature, the device is characterized in that the image processing software makes it possible to recognize the type of bidimensionnei code affixed to the product by the segmentation and analysis of specific areas of the bidimensionnei code.

According to another feature, the device is characterized in that the protocol for decoding the matrix of values is stored in a memory to which the image processing software has access, and that this decoding protocol is adapted to the bidimensionnei code.

According to another feature, the device is characterized in that the predefined algorithm of the image processing software consists of calculating a polynomial consisting of each digit having the binary value of 1 of the binary matrix, to multiply this value by two, to raise the result to a power, this power being determined as the number of columns present in the binary matrix to which is subtracted the number of the column on which is located the digit of the binary matrix for which the computation is carried out, such as that the first column is located on a predefined border of the binary matrix, then summing all these results,

let P be the number of the matrix line binary such that the first line is located on a predefined border of the binary matrix, j the column number, N _b the number of columns present in the binary matrix, N (1) ιj the binary value equal to 1 of the digit located on line i and column j, the term] T () signifying a summation of j all terms between parentheses for j varying from 1 to N _b , and the term ^] () meaning a summation of all terms between i brackets on all existing i values.

According to another feature, the device is characterized in that the database is stored in a memory supported by the same device that includes the image processing software, and that the connecting means is an electrical connection.

According to another feature, the device is characterized in that the database includes codes that have been placed on products before their circulation and referenced according to a string of characters encoded on the products.

Another object of the present invention is to provide a coding device enabling the setting. in. implementation of the authentication method of a two-dimensional code. The invention relates to a coding device for authenticating a two-dimensional code representing a string of characters, comprising encoding software connected to a memory and to a printing and marking means, characterized in that the software of encoding can set binary values of markings from a calculation on the representative numerical value (30), and the printing and marking means makes it possible to print the two-dimensional code on a product and to mark certain dark areas with a marker according to the binary marking values.

According to a feature, the device is characterized in that the marker is a black ink, and / or a subtractive combination of inks of different colors, and / or an ink having metalloid elements, and / or an ink having magnetized elements. .

Another object of the present invention and to provide a decoding device for implementing the method of authentication of a two-dimensional code.

A decoding device for authenticating a two-dimensional code, representing a string of characters, consisting of dark areas, marked dark areas, and non-dark areas, including a reading and playback device. recording which includes an optical imaging device, an optical signal converting device to an analog electrical signal, an analog / digital converter, a memory and a decoding software, the optical imaging device being consisting of at least one lens for imaging the two-dimensional code on the optical signal converting device into an analog electrical signal, the optical signal converting device into an analog electrical signal consisting of a set of photodetectors for converting a light signal into an analog electrical signal which is converted into a digital electrical signal by the analog / digital converter and stored in the memory, characterized in that the software of. decoding can:

determining a matrix of values representing the two-dimensional code from the analysis of the intensity of the recorded electrical signals,

decode the matrix of values to determine the character string according to a predefined decoding protocol,

calculating, according to a predefined algorithm, a numerical value representative of the encoding of the string of characters, and determining by a calculation on the representative numerical value of the positions of marked dark areas and of unmarked dark areas,

- identify the position of marked dark areas and dark areas not marked by the analysis of the recorded electrical signals,

- compare the positions of marked dark areas and unmarked dark areas obtained on the one hand by the analysis of the recorded electrical signals and on the other hand by the calculation on the representative numerical value.

According to one feature, the device is characterized in that the optical imaging and recording device, the optical signal conversion device into an analog electrical signal, the analog / digital converter, the decoding software and the memory are included in a cell phone - digital camera.

According to another feature, the device is characterized in that the decoding protocol of the matrix of values is stored in the memory, and that this decoding protocol is adapted to the two-dimensional code. Other features and advantages of the invention will appear on reading the detailed description which follows, for the understanding of which reference will be made to the appended drawings in which:

FIG. 1 represents an example of a non-posed two-dimensional datamatrix code (called a "code before laying"), as well as a step of calculating a code before laying according to the authentication method of a product of the present invention .

FIG. 2 represents an example of a "datamatrix" code, placed on a product, initially identical to that of FIG. 1, some translucent zones of which are modified taking into account the texture of the product, with a step of calculating a "code" according to the method of authenticating a product of the present invention.

FIG. 3 schematically represents an analysis step according to the present invention in which an average intensity value of certain translucent zones of a two-dimensional code is determined.

FIG. 4 diagrammatically represents an inversion / assignment step according to the present invention, in which a bit matrix of which each element represents an area of a two-dimensional code is created, and in which the value 0 or 1 is assigned to the areas according to their intensity. FIG. 5 represents an example of a "datamatrix" code affixed to a product simulating a forgery, the result of the copying of a placed code, with respect to the product on which is affixed the "datamatrix" code of FIG. a step of calculating a code tested according to the authentication method of a product of the present invention. FIG. 6 schematically shows an example of a string of characters to be encoded in a two-dimensional code, and a determination of a numerical value representative of the binary coding of the character string according to the method of authentication of a two-dimensional code. of the present invention. FIG. 7 shows an exemplary method for authenticating a two-dimensional code according to the present invention, the two-dimensional code being a "datamatrix" code representing the character string indicated in FIG. 6 according to an ASCII coding protocol.

FIG. 8 represents an exemplary two-dimensional code "QR-code" encoding information that must be affixed to a product. Figure 9 schematically represents steps according to the method of authenticating a product of the present invention.

FIG. 10 represents an exemplary device for implementing the authentication method of a product of the present invention.

The following description shows an example of implementation of the product authentication and authentication methods of a two-dimensional code according to the present invention, as well as a description of a possible embodiment of the devices enabling the implementation of the invention. implementation of these methods. This description is presented in particular for the two-dimensional coding system "datamatrix". However, the methods and devices for implementing the methods of the present invention can be applied to all other forms of two-dimensional codes of the type

"QR-Code" or others.

In particular, the two-dimensional codes are in the form of an arrangement of dark areas and non-dark areas for coding a string of characters. The areas can be squares, but also any other forms whose arrangement allows to encode a string of characters. Thus, one can just as easily conceive that the two-dimensional code is composed of an arrangement of triangles, or diamonds, or other geometrical figures representing a variable distribution of densities.

We will now describe an example of implementation of the method of authenticating a product and a device adapted using Figures 1 to 5 and 8 to 10.

The type of two-dimensional code that is affixed to the product is generally identifiable by characteristic areas. For example, the code "datamatrix", of which FIG. 1 represents an example, comprises a data zone surrounded by two trigger bars (2) and two density indicator bars (3). The two trigger bars (2) are opaque. The density indicator bars (3) alternate dark areas (13) and non-dark areas (14). These non-dark areas allow to reveal the substrate of the product, and will be called thereafter "translucent areas". In general, the clarity of the dark areas is less than the clarity of the translucent areas. Inside the data area, the arrangement of the dark areas (10) and the translucent areas (11) makes it possible to encode information, for example in ASCII code, that is to say to code a string of data. characters, characterizing a product. The row numbers of the data area are associated with the letter i, and the column numbers of the data area are associated with the letter j. In this example, the data area has 16 rows and 16 columns. The first row and the first column, i = 1 and j ≈ 1, characterize the area located in the data area at the top left of the figure in the direction given in FIG.

The dark areas (10, 13) are made by printing a black ink on the product, so that the areas are opaque and do not allow to see the support underneath. The translucent areas (11, 14) are formed without modification of the support, and in particular without printing ink, which allows to reveal the surface of the substrate by these areas.

In the "datamatrix" coding, the dark areas (10, 13) generally correspond to a bit equal to 1, and the translucent areas (11, 14) generally correspond to a bit equal to 0. The method of authenticating a product begins with a step of reading and recording the two-dimensional code that is affixed to a product. The different steps of the process are shown in FIG. 9.

The adapted device, an example of which is given in FIG. 10, making it possible to carry out this reading and recording step (200) of the two-dimensional code comprises an optical imaging device (100), making it possible to collect a luminous flux ( 120) from the surface of the product on which the two-dimensional code is affixed, via a lens or a set of lenses. The imaging device captures the image of the surface, and in particular of an area on which the two-dimensional code is located, using an optical signal converting device to an analog electrical signal (110). The optical signal converting device to an analog electrical signal (110) consists of a set of photodetectors. The photodetectors convert the luminous flux (120) into an analog electrical signal whose intensity is dependent on the intensity of the luminous flux. Thus, a dark area of the two-dimensional code will emit a low light flux intensity compared to that of a translucent area.

Optical imaging devices (100) and optical signal conversion to an analog electrical signal (110) make it possible to collect the luminous flux of each area of the two-dimensional code and to image each of the areas on at least one photodetector, so as to be able to spatially distinguish each of the areas.

The analog electrical signals from the photodetectors are read by a suitable device for reading the photodetectors and converted into digital electrical signals by an analog / digital converter (130). The coding of the analog / digital conversion depends on the precision that one wishes to obtain on the intensity values of the analog electrical signals. One can, for example and without restriction, use a coding of the analog signal on 7 or 8 bits. The information relating to this digital coding is then stored in a memory (140). Figure 2 shows, in a dashed square, an example of signal intensity values associated with four areas with 8-bit coding, i.e., the signal representative of the area may take a value between 1 and 256.

An image processing software (150), executed by a processor, which is connected with the memory (140), will exploit the information stored in memory (140), record new information, and modify them throughout the steps the product authentication method described hereinafter. The image processing software (150) exploits the recorded information and makes it possible to "segment" the two-dimensional code, that is to say to distinguish the relative positions of the dark areas (10) and the translucent areas (11), and therefore to associate with each area of the two-dimensional code one or more photodetectors on which the photon flux has been imaged. This analysis, included in the image processing step of the method of the present invention, is performed using one or more characteristic areas of the two-dimensional codes. In the case of the two-dimensional code "datamatrix", the trigger bars (2) are opaque and perpendicular. The coded and recorded values corresponding to the intensity of the luminous flux of these areas are therefore identifiable, and make it possible to determine the reading direction of the code. The density indicator bars (3) of the "datamatrix" code have an alternation of dark areas and translucent areas, and the two bars are perpendicular to each other. These two bars are thus also clearly distinguishable and allow to define in particular the dimension of an area.

The software can thus, by the analysis of the coded values, distinguish these characteristic zones, and thus the relative position of each area of the two-dimensional code.

From this segmentation, the image processing software creates a matrix of values, each element of which is associated with an area of the data coding area. The coded values corresponding to the intensity of the luminous flux of each area are compared with a threshold intensity value. If the coded value is less than the threshold intensity value, the area is associated with a binary value in the matrix of values, and if the coded value associated with an area has a value greater than this threshold intensity value, the area is associated with the complementary binary value in the value matrix. This threshold intensity value can be predefined and pre-stored in the memory, and be close to the electrical intensity resulting from the collection and the optical / electrical conversion of the luminous flux of a dark area. known, while being slightly greater than this intensity. The threshold intensity value can also be determined by the specific analysis of each two-dimensional code. Thus, in the case of a two-dimensional code of the "datamatrix" type, the density indicator bars alternate dark areas with translucent areas in a known order. The threshold intensity value can therefore be specifically determined on each two-dimensional code as being greater than the coded value associated with a dark area, and less than the coded value associated with a translucent area.

In the case of a two-dimensional code of the "QR-code" type, an example of which is given in FIG. 8, three identical zones, called the trigger zones, are located on three of the four corners of the two-dimensional code (here at the top right and left and bottom left according to the direction of the figure). In this example, the three trigger zones consist of a central black square with nine adjacent dark areas, surrounded by translucent areas over a thickness of an area, and themselves surrounded by dark areas. A fourth area, consisting of a single dark area, is located in the fourth corner. These different zones are characteristic of the two-dimensional code of the "QR-Code" type. These three identical zones and this fourth zone allow the image processing software to determine the reading direction and the position of the different areas in the code.

The image processing software (150) stores the relative position of each area and the coded value corresponding to the intensity of the luminous flux of each area. In general, the coded value associated with each area may be a combination of the electrical intensity from several photodetectors on which the imaging device has made the imaging of an area.

The values of the elements of the matrix which is created by the image processing software are generally as follows: the dark areas, for which the coded value is lower than the threshold intensity value, correspond to a binary value of 1, and the complementary value 0 is given for the other areas. After this image processing step, a decoding step (201) is performed, making it possible to identify the string of characters affixed in the two-dimensional code. Decoding is done from the matrix of values that was determined in the previous step. The image processing software (150) decodes the two-dimensional code (1) from a decoding protocol stored in memory. Optionally, several decoding protocols are prerecorded, corresponding to several types of two-dimensional code. In this case, an analysis of the image processing software of the matrix of values makes it possible to identify the characteristic areas of the two-dimensional code, and thus to determine the type of two-dimensional code and therefore the appropriate decoding protocol. The thus decoded string of characters is stored in the memory (140).

The step of determining an average value (202) consists of analyzing the coded values representing the intensity of the luminous flux associated with certain areas of the peripheral zone (3) of the two-dimensional code. The image processing software (150) exploits the recorded encoded values and averages those encoded values associated with certain predefined areas. For example, in the case of a two-dimensional "datamatix" code, some of the translucent areas (14) of the density indicator bars (3) are used for the analysis. The coded values represent an electrical signal intensity, associated with a luminous flux intensity. The analysis therefore consists in determining an average value of these electrical intensities (22) associated with the translucent areas (14) analyzed, which will be called "average value of electrical signal". FIG. 3 thus shows a portion of one of the two density indicator bars (3) of a two-dimensional code "datamatrix". The diagram (20) schematically shows a comparison between the intensities of electrical signals (A) associated with different translucent areas (14) of the portion of one of the two indicator bars (3) of analyzed density. The average value of electrical signal (22) is thus determined by averaging these different intensities of electrical signals, or hexadecimal codes, or other, representative of the intensities. In the case of a two-dimensional code of the type "QR-Code" given as an example in FIG. 7, the translucent areas of the peripheral zone on which the analysis step is carried out can, for example, belong to one or more trigger zones.

The inversion / assignment step (203) consists in creating a binary matrix, in which each element is associated with an area of the two-dimensional code, and whose value of the elements depends on the intensity of the electrical signal and the average value. of electrical signal. Thus, the binary matrix is created such that the translucent areas, the intensity of the electrical signal is less than the average value, are associated with the binary value 0, and the translucent areas, the intensity of the electrical signal is greater than the average value, are associated with the binary value 1. The dark areas are associated with the value 0. This step is called "inversion" in the sense that the dark areas are now 0, in contrast to the matrix of values created in the image processing step where they were set to 1.

Figure 4 shows an arbitrary line (11) of the data area of a "datamatrix" code. This figure shows the inversion / assignment step of the method of the present invention. The image processing software compares the intensity of the electrical signal (A) associated with each translucent area (11, 12) of the data area with the average electrical signal value (22). The image processing software then assigns, to each element of a line (i2) of a binary matrix, values dependent on the result of this comparison: the binary value 0 is attributed to the elements associated with the areas whose intensity the electrical signal is less than the average electrical signal value (22), and the binary value 1 is assigned to the area associated elements whose electrical signal strength is greater than the average electrical signal value (22).

The translucent areas (12) for which the intensity of the electrical signal (A) is less than the average electrical value (22) are referred to as the translucent altered areas.

The calculation step is now presented using Figures 1, 2 and 5. Figure 2 shows an example of the same two-dimensional code as that of Figure 1, but this time as it is visible when it is affixed to a product. The altered translucent areas (12) (hatched areas) are less clear than other translucent areas (11). This difference in level of clarity comes from the texture of the product, which is not homogeneous and which therefore presents, among other things, asperities, deformations or marks specific to the material used and / or to the way in which the product has been designed.

In FIG. 1, numerical values (T1) represent the values obtained by calculating a polynomial Pj for each row of the binary matrix associated with the bidimensional code presented. The two-dimensional code of FIG. 1 is not placed on a product, and therefore it does not have any corrupted zones. This is why the binary matrix used in the calculation step consists, for this figure, of elements having the value 1 for the translucent areas and 0 for the dark areas. The rows i and columns j, associated with the data coding area, correspond identically to the rows and columns of the binary matrix, since each value of the binary matrix is associated with an area of the data coding area. In this example, Pi is defined for each line i by:

P _i = Σ (2xN (1) _j > ^N - ^j) j with Nb the number of columns in the data area, that is to say here N _b = 16, i is the number of the line on which the polynomial Pj is calculated, j is the number of the column considered during the calculation, N (1) _j is the binary value associated with the line i and the column j. The calculation is performed only for the areas to which the binary value of 1 is associated, that is to say the translucent areas, so N (1) j is necessarily equal to 1 in this example. However, other polynomials can be envisaged in another mode of implementation of the method. The term ^] () means that we sum the terms included between the parentheses for all existing values of j, that is, from j = 1 to j = N _b . Thus, according to this example, the calculation of the polynomial Pi for the first line gives: P = (2x l) ¹⁵ + (2xl) + ^I2 (2x l) "+ (2x l) + ^lo (2xl) ³ + ^(2xl)] = 39946.

A "before laying" code (PI) is defined by the sum of the different values (T1) obtained by the calculation of the polynomial P ₁ - for each line i.

The same calculation step is performed on the binary matrix created in the inversion / allocation step associated with the code of FIG. 2. The two-dimensional code of FIG. 2 is placed on a product, and it therefore has altered areas. The bit matrix associated with the code of FIG. 2 is therefore different from that associated with FIG. 1, because the inversion / assignment step took into account the differences in luminous intensity of the translucent areas. The calculation of the polynomial P on each of the lines of the bit matrix associated with the data area of the code of FIG. 2 thus gives different values (T2) with respect to the values obtained in FIG. 1 (TI), and the summation different values Pi, that is to say the summation of the different values (T2), which gives a "tested code" (P2), shows a result different from the before-laying code (P1) obtained previously in FIG.

FIG. 5 represents an exemplary "datamatrix" code, initially identical to that of FIG. 1, but affixed to a product different from that on which the "datamatrix" code of FIG. 2 has been affixed. The product represents here in part occurrence of a false, and its surface structure is different from that of the product on which was affixed the code "datamatrix" of Figure 2. In this example, the number and position of the translucent areas (12) altered are different from those shown in Figure 2. Thus, the application of the steps of fetching and recording, image processing, decoding, analysis, allocation / inversion and calculation according to the method of the present invention allows to obtain the same character string as that of the two-dimensional code of FIG. 2, but the code tested (P3), resulting from the sum of the results (T3) of the computation of the polynomial P ₁ for each line i, is different from the code tested (P2) of FIG.

In the database linking step, the device containing the image processing software (150) may also contain means (160) for relating to a server (170) (see FIG. ). The Linking enables the image processing software (150) to compare or have the server compare the tested code it has determined with a "code code" contained in a remote database (170). Optionally, the database (170) is directly included in the same device that contains the image processing software (150), and the latter then has the means to update this database.

The "code set" is a code that has been determined on a product according to the process steps described above, and before the product is put into circulation. It therefore represents an identification of the product by analyzing the altered areas of the two-dimensional code that has been affixed to it. The database (170) contains the code placed on each product on which a two-dimensional code is affixed. This posed code is referenced in the database (170). The reference may be, for example, the character string that is encoded on the same product, or part of the character string, or data that is obtained from the string.

Thus, the step of relating to the database (170) and comparing (205) between the code tested and the code installed makes it possible to authenticate the product. If the two values are different, for the same string of characters, the software can then conclude that it is a forgery, and send a message relative to a user.

The device comprising an optical imaging device (100), optical signal conversion to electrical signal (110), analog / digital conversion (130) and memory (140) can be, for example, a mobile phone having a camera. The image processing software (150) can be loaded into the camera phone, or the camera can connect to a server having the image processing software (150) and a memory and transfer the necessary information to the process. The database (170) can also be stored in the camera phone or remotely. The camera phone then has the possibility to connect with a server having the database (170). Possibly, if during the comparison step, the string of characters that has been decoded is not found in the database, or the string can not be decrypted because its encoding mode is not correct, the image processing software can then transmit to an operator a specific error message.

Thus, the two-dimensional code provides both the coding of information characterizing a product, but also allows the authentication of the product on which the code is affixed, by analyzing the clarity of certain areas of the two-dimensional code according to the method of authenticating a product of the present invention.

We will now describe the method of authentication of a two-dimensional code and an example of a coding device of a code and a device for decoding a code allowing the implementation of this method according to the present invention, to the FIG. 6 shows an example of a character string (70) comprising 18 characters characterizing a product, and which it is desired to encode using a two-dimensional coding system. The string (70) is symbolically placed in a matrix (71) which represents a matrix of a two-dimensional code. Each character of the character string (70) has an ASCII code known to those skilled in the art whose values (T4) are represented next to the matrix (71).

The encoding of this character string according to a known protocol thus defines a matrix of values, each bit value of which will then be associated with an area of the two-dimensional code. In the coding step, a calculation step is performed by encoding software on values of the character string (70) coded according to a predefined coding protocol, for example in ASCII, in order to determine a representative numerical value ( 30) of the character string (70). In this nonlimiting example, the calculation step consists of a succession, of calculations that are presented below:

First, the nearest prime number and less than the number two raised to the power of the number of characters (eg 18) included in the character string (70) is determined, which is the nearest prime number and less than 2 ¹⁸ , ie 262139, This prime number is subsequently called the prime number of the character string.

Then, the character string (70) is divided into four approximately equal groups. In this example, the first four characters form a first group (41), the next four characters form a second group (42), the next five characters form a third group (43), and the last five characters form a fourth group ( 44). Then, the ASCII codes (T4) of each character of the same group are multiplied between them, making it possible to obtain a single digital value produced for each group (41, 42, 43, 44). Then, the division of the numerical value produced of each group (41, 42, 43, 44) by the prime number of the string produces a remainder which makes it possible to obtain a numerical value called modulo value (51, 52, 53 , 54) for each group.

The modulo values (51, 52, 53, 54) are then multiplied between them and two by two, such that the modulo value of the first group (51) is multiplied with that of the second group (52), and the modulo value of the third group (53) is multiplied with that of the fourth group (54), thus making it possible to obtain two numerical values produced by modulo.

The remainder of the division of these two numerical values produces modulo by the prime number of the string of characters is then determined, allowing to obtain two new numerical values modulo (61, 62). Finally, these two new numerical values modulo (61, 62) are multiplied between them, and the remainder of the division of the latter produced by the first number of the string of characters is determined, this rest being the representative numerical value (30). ) in the string of characters (in the example of FIG. 6 the value 131118), In the step of assigning density, the coding software assigns, as a function of the representative digital value, a binary marking value to elements of the matrix of values that represent areas dark and which are located in a peripheral zone (3) of the bidimensionnei code. FIG. 7 thus schematically represents this attribution step in the particular case of a code of the "datamatrix" type encoding the string of characters (70) in ASCII format, and according to a possible allocation mode. The arrangement of the dark and non-dark areas of the "datamatrix" code is associated with the matrix of values: the dark areas represent for example a bit equal to 1, and the non-dark areas represent a bit equal to 0. The representative numerical value (30) obtained is related to a dark area (15) located at one end in contact with one of the trigger bars (2) of one of the density indicator bars (3), here bottom right according to the direction FIG. 7. The representative numerical value (30) is divided successively by two, taking into account only the integer part of the result of the division, and each result (T5) of this division is put in relation successively and continuously with a dark area (13) of the density indicator bars (3), starting from the dark area adjacent to the dark area (15) with which the representative numerical value is associated (30), and ending with the dark area (16) located at the diagonally opposite end, so that all the dark areas (13) of the density indicator bars (3) are associated with a numerical value (T5).

Each term of the result of the division (T5) is divided by two, making it possible to obtain a binary remainder of this division having a value equal to 0 or a value equal to 1, called a binary marking value, and each of these binary values markers being associated with the same dark area (13) of the density indicator bars (3) to which were associated the successive results (T5) of the division of the representative numerical value (30) by two.

In the case of a bidimensionnei code of the "QR-Code" type, an example of which is given in FIG. 8, the density allocation is carried out, for example, on the dark areas situated on the triggering zones, or on a only trigger zone. Following this density assignment step, a printing and marking step makes it possible to print the two-dimensional code representative of the matrix of values on a product, and to mark certain specific dark areas. The printing and marking device is, for example a printer. The dark areas (13) of the density indicator bars (3) associated with the marking bit value 1 are thus marked with the marking device, thus creating marked areas (17). Other dark areas that are associated with the binary value 0 are not marked (18). The marker may be for example and without restriction a black printing ink to which may be joined metalloid molecules, or magnetic molecules. The marking may also be in the form of a change in the contrast of the dark areas (13). In the application example where the contrast is changed, the dark areas (13) of the density indicator bars (3) are printed with gray ink. The dark areas (17) to be marked can be blackened by subtractive color synthesis with the printing and marking device.

An example decoding step of the method of the present invention is now presented: The step of reading and recording the two-dimensional code consists in using a device adapted to store the two-dimensional code (1) in a memory. For example, the device may consist of an imaging device, an optical signal conversion device into an analog electrical signal, an analog / digital converter, and a memory. The device makes it possible to record in a memory electrical signals associated with the intensity of a light flux coming from the areas of the two-dimensional code, collected by the imaging device, picked up on the optical signal converting device into an analog electrical signal. , and converted to a digital signal. The reading and recording device may also be composed of an induction sensor, in the case where the marking is carried out with an ink creating a magnetic field, or a sensitive sensor in the infrared, in the case where the marking ink has molecules emitting an infrared electromagnetic wave.

The device for reading and recording the decoding device may be, for example, a mobile phone equipped with a camera and the software performing the processing corresponding to the method.

The step of decoding the two-dimensional code is similar to the step of decoding the two-dimensional code according to the authentication method of a product of the present invention: a decoding software having access to the memory on which the electrical signals are recorded , segments the areas by recognizing characteristic areas of the two-dimensional code, creates a matrix of values each element of which is associated with an area, and decodes the matrix of values according to a pre-recorded decoding protocol in the memory. (I thus obtains the string of characters that has been encoded and stores it in the memory.) In another variant embodiment, the decoding software may, for example, be located remotely, on a server. reading and recording device is in contact with a connecting means, and communicates with the server to transmit the stored information to it The calculation step of the decoding software is identical to the calculation step coding software so that the character string (70) that was obtained is coded according to the same predefined protocol in the marking step (for example in 7-bit ASCII), and the coded values are used to determine a numerical value representative of the encoding of the string of characters.

Similarly, the density assignment step performed by the decoding software is identical to the density assignment step performed by the coding software. This step is performed from the numerical value representative of the encoding of the character string and the matrix of values that was determined during the decoding step. The decoding software thus stores binary marking values associated with marked dark areas and unmarked dark areas on the area. device (3), and stores these tagging bit values in the memory.

In the comparison step, the decoding software loads information about the position of the marked dark areas and the dark unmarked areas that were determined by the reading and recording step, and those that were obtained during of the attribution stage. This step thus makes it possible to conclude that the product is a "true" if the positions are identical and a "false" if the positions are different.

The result of this comparison is finally transmitted to an operator, for example in a "true" or "false" boolean format.

It should be obvious to those skilled in the art that the present invention allows modes of implementation of the method in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiment should be considered by way of illustration, but can be modified in the field defined by the scope of the appended claims, and the invention should not be limited to the details given above.

Claims

claims

A method of authenticating a product having a two-dimensional code (1) representing a string of characters in the form of an arrangement of dark areas (10) and non-dark areas (11, 12). , located in a data coding area, and in the form of an arrangement of dark areas (13) and non-dark areas (14), located on the periphery of the data coding area, the non-dark areas (11, 12, 14), hereafter called "translucent areas", revealing the substrate of the product, characterized in that it comprises the following steps: a step of reading and recording (200) of the two-dimensional code in the form of coded values of electrical signals associated with the intensity of a luminous flux coming from the areas of the two-dimensional code,

a step of decoding (201) the matrix of values, making it possible to decode the string of characters and to record it,

a step of determining (202) an average luminous flux intensity value from at least two translucent areas (14) located in the peripheral zone (3), by analysis of the coded values of the electrical signals,

an inversion / assignment step (203), consisting of creating a binary matrix in which each element is associated with an area of the two-dimensional code, with the value 0 for the elements associated with the dark areas and the translucent areas (12) whose coded value is less than the average electrical signal value (22), and the value 1 to the elements associated with the translucent areas (12) whose coded value is greater than the average value of the electrical signal (22),

a calculation step (204) on the binary matrix whose result determines a code tested, a step of linking to a database and of comparing (205) between the tested code and a predetermined set code, the two codes being associated with a reference.

2. Method according to claim 1 characterized in that the two-dimensional code (1) is produced using a coding system "datamatrix" comprising a data area, two trigger bars (2), and two indicator bars of density (3), and that the data coding zone corresponds to the data zone, and that the peripheral zone (3) corresponds to the two density indicator bars (3).

3. Method according to claim 1 characterized in that the two-dimensional code (1) is produced using a coding system "QR-Code", and that the data coding zone corresponds to the data zone of the QR-Code code, and that the peripheral zone (3) corresponds to the three trigger zones located on three of the four corners of the "QR-Code".

4. Method according to claim 1 characterized in that the image processing step comprises a segmentation of the areas of the two-dimensional code.

5. Method according to claim 1, characterized in that the decoding step (201) is carried out using a decoding protocol stored in a memory to which the image processing software has access.

6. Method according to any one of the preceding claims, characterized in that the computing step consists in calculating a polynomial (P), consisting for each bit of a binary matrix having the binary value of 1, to multiply this value. in pairs, to raise the result to a power, this power being determined as the number of columns present in the bit matrix to which is subtracted the number of the column on which is located the bit for which the calculation is performed, such as the first column is located on a predefined border of the binary matrix and then to sum

the set of these results, P = Σ Σ (2χN (l) y) ^{(Nb "j)} , with i the number of the binary matrix line such that the first line is located on a predefined border of the binary matrix, j the number of the column, N _b the number of columns present in the binary matrix, N (1) j, _j la a binary value equal to 1 of Cairo located on the line i and the column j, the term Σ () signifying a summation of all the terms between the j j parentheses for j varying from 1 to N _b , and the term] T () meaning a summation of all the terms between parentheses on all existing values of i.

7. Method according to any one of the preceding claims, characterized in that the comparison step (205) and setting the relationship defines the product as a false if the code tested and the code laid corresponding to the same string of characters are different .

8. Method according to any one of the preceding claims, characterized in that the code is calculated from the bidimensionnei code of a product before its circulation.

9. Method according to any one of the preceding claims, characterized in that the common reference used for the comparison step (205) is the character string, or part of the string of characters.

10. Method according to claim 1 characterized in that the bidimensionnei code (1) is authenticated by a coding step and a decoding step such that the coding step comprises:

a first calculation step, by encoding software, making it possible to determine a representative digital value (30) of the encoding of the string of characters (70),

a first density assignment step, by the coding software, of determining the position of marked dark areas (17) on the peripheral zone (3) by a second calculation step starting from the representative numerical value ( 30), a step of printing and marking the three-dimensional code, consisting of printing the two-dimensional code on the product and adding a marker to the marked dark areas (17), and the decoding step comprises: a reading step and for recording the bidimensional code, with a suitable device, for recording electrical signals associated with areas of the two-dimensional code, for determining a matrix of values representative of the two-dimensional code, and for distinguishing the position of the dark marked areas (17) and unmarked dark areas (18) of the peripheral zone (3),

a step of decoding the two-dimensional code, by an image processing software, making it possible to decode the string of characters (70) and to record it,

a third calculation step, using a decoding software, from the encoding of the character string, and according to the same algorithm as in the first calculation step, making it possible to determine the representative numerical value (30) of the coding of the string of characters (70),

a second step of assigning density, using the decoding software, according to the same protocol as the first density assignment step, making it possible to determine a position of the marked dark areas (17) and dark unmarked areas (18); ) from a calculation on the representative numerical value (30) of the encoding of the character string (70),

a comparison step between the positions of the marked dark areas (17) and dark unmarked areas (18) determined on the one hand by the second density assignment step and on the other hand by the reading step and recording.

11. Method according to claim 10, characterized in that the two-dimensional code (1) is produced by means of a coding system "datamatrix" comprising a data zone, two trigger bars (2), and two bars. density indicators (3), and that the peripheral zone (3) is associated with the two density indicator bars (3).

12. Method according to claim 10 characterized in that the two-dimensional code (1) is produced using a coding system "QR-Code", and that the peripheral zone (3) corresponds to at least one of the three trigger zones located on three of the four corners of the "QR-Code".

13. The method as claimed in claim 10, characterized in that the first step of calculating the representative digital value (30) of the encoding of the character string consists in calculating the remainder of a division of a first term by a second term, the second term being called the prime number of the character string, the first term being either a product of the ASCII codes of the characters of the character string (70), or the result of a multiplication of the remainders of divisions of a product ASCII codes of the characters of the character string (70) by the prime number of the character string, or any other combinations of product division remains of the ASCII codes of the characters of the character string (70) by the number first of the character string and the product of these divisional residues, so that all the characters of the character string (70) intervene in the calculation step by their ASCII code, the first number of the character string being the nearest prime number and less than the number two raised to the power of the number of characters included in the character string (70).

14, Method according to any one of claims 10 to 13 characterized in that the first and second density allocation steps consist in assigning the representative digital value (30) to a dark area (15) located at an end in contact with a trigger bar (2) of one of the density indicator bars (3), to successively divide the representative numerical value (30) by two, taking into account only the entire part of the division, to successively assign each of the results of this division (T5) to a dark area (13) of the density indicator bars (3) starting with the darkest area closest to the area (15) to which the representative numerical value (30) is associated and W

36

ending with the dark area (16) of the density indicator bars located diagonally opposite the dark area (15) to which the representative numerical value (30) is assigned, calculating the remainder of the division by the number two of each of the results (T5) of the division of the representative numerical value (30), and to assign each of these divisional residues to the same dark area (13) of the density indicator bars (3) with which each of the results (T5) of the division of the numerical value (30) representative by two.

15. Method according to claim 10, characterized in that the marking consists in modifying the contrast of the dark areas and / or in adding to the marked areas an ink having physicochemical properties different from the ink used for the non-dark areas. marked (18).

16. Device for authenticating a product on which a two-dimensional code (1) representing a string of characters in the form of an arrangement of dark areas (10) and non-dark areas (11, 12) is affixed , allowing the implementation of the method according to one of claims 1 to 9, comprising an optical imaging device (100), an optical signal converting device to an analog electrical signal (110), an analog / digital converter (130) , a memory (140), an image processing software (150) controlled by a microprocessor, and a means (160) for relating to a database (170), the optical imaging device (100) consisting of at least one lens for imaging the two-dimensional code (1) on the optical signal converting device into an analog electrical signal (110), the optical signal converting device into an electrical signal (110) being consisting of a set of phot odetectors for converting a light signal into an analog electrical signal which is converted into a digital electrical signal by the analog-to-digital converter (130) and stored in the memory (140), and characterized in that the image processing software ( 150) includes means of:

- Segment areas of a two-dimensional code from the analysis of the intensity of the electrical signals recorded in the memory, create a matrix of values according to the result of the segmentation,

17. Device for authenticating a product according to claim 16, characterized in that the optical imaging device (100), the optical signal converting device into an analog electrical signal (110), the analog / digital converter (130). ), the memory (140), the image processing software (150) and the means (160) for relating to a database are included in a digital camera phone.

18. Device for authenticating a product according to any one of claims 16 to 17, characterized in that the image processing software (150) makes it possible to recognize the type of two-dimensional code affixed to the product by the segmentation and the analysis of specific areas of the two-dimensional code.

19. Device for authenticating a product according to any one of claims 16 to 18 characterized in that the decoding protocol of the matrix of values is stored in a memory to which the image processing software has access, and that this decoding protocol is adapted to the two-dimensional code.

20. Device for authenticating a product according to any one of claims 16 to 19, characterized in that the predefined algorithm of the image processing software consists of calculating a polynomial consisting of each digit having the binary value of 1 of the binary matrix, to multiply this value by two, to raise the result to a power, this power being determined as the number of columns present in the binary matrix to which is subtracted the number of the column on which is located the digit of the binary matrix for which the calculation is performed, such that the first column is located on a predefined border of the binary matrix,

then to sum up all these results, either with i the number of the line of the binary matrix such that the first line is on a predefined border of the binary matrix, j the number of the column, Nb the number of columns present in the binary matrix, N (1) i, j the binary value equal to 1 of the digit located on the line i and the column j, the

term meaning a summation of all the terms between

parentheses for j varying from 1 to Nb, and the term meaning a summation of all the terms between parentheses on all existing values of i.

21. Device for authenticating a product according to any one of claims 16 to 20 characterized in that the database (170) is stored in a memory supported by the same device which includes the image processing software (150). ), and that the connecting means is an electrical connection.

22. Device for authenticating a product according to any one of claims 16 to 21 characterized in that the database (170) includes codes which have been placed on products before their circulation and referenced in a chain of characters coded on the products.

23. Encoding device for the authentication of a three-dimensional code for implementing the method according to one of claims 10 to 15 and representing a character string, comprising coding software connected to a memory and a means for printing and marking, characterized in that the encoding software can define mark binary values from a calculation on the representative numerical value (30), and the printing and marking means can print the code two-dimensional on a product and mark some dark areas with a marker based on the binary marking values.

Coding device according to claim 23, characterized in that the marker is a black ink, and / or a subtractive combination of inks of different colors, and / or an ink having metalloid elements, and / or an ink having magnetized elements.

25. Decoding device for authentication of a two-dimensional code for implementing the method according to one of claims 10 to 15 and representing a string of characters, consisting of dark areas (10, 18), dark areas. labeled (17) and non-dark areas (11, 14), comprising a reading and recording device which includes an optical imaging device, an optical signal converting device to an analog electrical signal, an analog-to-digital converter digital, a memory and a decoding software, the optical imaging device consisting of at least one lens for imaging the two-dimensional code on the optical signal conversion device into an analog electrical signal, the conversion device optical signal into an analog electrical signal consisting of a set of photodetectors for converting a light signal into an analog electrical signal which is converted into a digital electrical signal by the analog / digital converter and stored in the memory, characterized in that the decoding software can: determining a matrix of values representing the two-dimensional code from the analysis of the intensity of the recorded electrical signals,

decoding the matrix of values to determine the character string according to a predefined decoding protocol; calculating, according to a predefined algorithm, a representative numerical value (30) of the encoding of the string of characters and determining by a calculation on the numerical value; representative (30) positions of marked dark areas (17) and dark unmarked areas (18),

- identify the position of marked dark areas (17) and unmarked dark areas (18) by analyzing the recorded electrical signals,

compare the positions of the marked dark areas (17) and the dark unmarked areas (18) obtained on the one hand by the analysis of the recorded electrical signals and on the other hand by the calculation on the representative numerical value (30). ).

26. The decoding device as claimed in claim 25, characterized in that the optical imaging and recording device, the optical signal conversion device into an analog electrical signal, the analog / digital converter, the decoding software and the memory are included in a cell phone - digital camera.

27. New application of a two-dimensional code (1) affixed to a product, allowing the use of the method according to claim 1, the two-dimensional code (1) representing a string of characters coded in the form of an array of areas dark (10) and non-dark areas (11, 12) included in a data coding area, and other non-dark areas (14) positioned at the periphery (3) of the data coding area; non-dark areas for revealing the substrate of the product and being called "translucent areas" characterized in that the translucent areas (11, 12, 14) of the two-dimensional code are used to authenticate the product, by analyzing their clarity.