RU2608259C2 - Method of improving protective properties of identification saw-mark - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to piezoelectric devices in the form of an identification mark operating with surface acoustic waves (SAW) for identification systems. Method of improving protective properties of a SAW-mark (hereinafter SAW-mark) means, that a SAW-mark consisting of deposited on a substrate interdigital transducers (IDT) and reflectors through a connected to the IDT antenna is affected with an electromotive force by radiating with an analogue probing radio signal followed by a response from the SAW-mark for its further analysis to obtain an identification code of the SAW-mark, which is a digital display of the reflectors arrangement on the substrate, herewith additionally received is an encryption key – an electronic digital signature of the SAW-mark and an electronic certificate of authenticity of the SAW-mark by calculating the encryption key basing on the analysis of individual features of amplitude-phase-frequency characteristics of the radio signal response from the SAW-mark. When using the SAW-mark the obtained encryption key – the electronic digital signature of the SAW-mark – is used to identify the SAW-mark authenticity.

EFFECT: technical result is improvement of protective properties of an identification SAW-mark.

1 cl, 6 dwg

Description

The claimed technical solution relates to radio electronics, in particular to piezoelectric devices in the form of an identification tag (ID-Tag), working with surface acoustic waves (SAW), for identification systems. It can be used to increase the protective properties of passive radio-frequency identification (RFID) tags for SAWs (hereinafter SAW-tags) for the identification of various objects, as well as for their automatic control.

The well-known "Passive radio frequency identification tag on surface acoustic waves" according to the patent for the invention of the Russian Federation (RU 2534733 C1, dated 10.12.2014, IPC H01L 41/08 [1]) and the method of its operation. The tag contains an antenna, a piezoelectric substrate with an interdigital transducer (IDT) located on it and a system of reflectors. Such a label works as follows. An external reader (or reader) device generates a radio frequency pulse received by the tag antenna, the electrodes of which are connected to the IDT electrodes via contact buses. The latter transforms the electric field of the radio pulse into the acoustic field of a surfactant, which propagates along the piezoelectric substrate at right angles to the IDT electrodes. Reflectors influence the further spread of surfactants over the surface of a piezoelectric crystal. A small part of the surfactant is reflected from each reflector and moves back along the piezoelectric substrate in the direction of the IDT.

The rest of the surfactant continues to move to the edge of the piezoelectric substrate and is extinguished there. The sequence of pulses generated by the reflection of the surfactant from the system of reflectors comes to IDT, where it is converted into a high-frequency sequence of electromagnetic pulses. The signal encoded by the pulse train is emitted by the antenna and can be received and decoded by the reader.

Also known:

- "Radio frequency identification device for surface acoustic waves" according to the patent for the invention of the Russian Federation (RU 2410716 C2, dated January 27, 2011, IPC G01S 13/75 [2]) - allows you to increase the capacity of the identification code through the use of additional reflectors located on the other side IDT (comb converter);

- "Passive identification tag on surface acoustic waves with a resonator" according to the patent for the invention of the Russian Federation (RU 2350982 C2, 03/27/2009, IPC G01S 13/75 [3]) - allows you to reduce the linear dimensions of passive identification tags on surface acoustic waves and expand their functionality by simultaneously identifying and measuring the physical quantities of deformation, pressure, forces, acceleration, temperature and displacement;

- "Radio-interrogated element on surface acoustic waves with an optimal code size" according to the patent for the invention of the Russian Federation (RU 2253149 C2, dated May 27, 2005, IPC G06K 19/067, G01S 13/75 [4]) - allows you to do for a given in particular a high, code size with a comparatively shorter length / size of the substrate plate and / or possibly fewer code elements per separate code;

- "Marker device for a radio frequency identification system" according to the patent for the invention of the Russian Federation (RU 2176092 C1, dated 20.11.2001, IPC G01S 13/79 [5]) - allows to reduce the loss of electromagnetic energy during reception and radiation and thereby increase the radius of action of the marker devices.

A disadvantage of the known devices [1], [2], [3], [4] and [5] is that they mainly remove only the identification ID signal, knowing which it is easy to fake (play) this tag with the same ID -signal, having similar technological equipment (process).

Known is the “Territorial control system for the transportation of especially important and dangerous goods” according to the patent of the applicant for the invention of the Russian Federation (RU 2403623 C1, 10.11.2010, IPC G08B 25/10 [6]), which allows you to expand the functionality and provide increased reliability of transportation control especially important and dangerous goods by remote registration of the fact and time of passage of special vehicles carrying the specified cargo through control posts. The SAW identification tags of the system are placed on a special vehicle in the direct line of sight of the antennas of the scanning device (on the windshield, bumper, license plate, bottom, etc.). The exchange of discrete information between the control room and special vehicles is confidential. At the same time, the protection of confidential information has three levels: cryptographic, energy, and structural. The cryptographic level is provided by special methods of encryption, coding and conversion of discrete information, as a result of which its content becomes inaccessible without presenting the cryptogram key and the inverse transformation. The energy and structural levels are provided by the use of complex PSK signals - which have high energy and structural secrecy.

The disadvantage of the analogue [6] is the need for the presence (and storage) of a separate cryptogram key, which significantly complicates the system and requires additional costs for the generation, storage and transmission of these keys. At the same time, the issue of copy protection of the SAW tag remains open, since it can also be copied.

It is known to use SAW tags for identifying and positioning vehicles, for example, according to patents of the Russian Federation (RU 2185663 C1, 07/20/2002, IPC G08G 1/017, B60R 25/00, B60R 13/10, “Electronic vehicle identification system ( Variants) ”[7] and RU 125535 U1, dated 10.03.2013, IPC B61L 25/00,“ Radio frequency identification and positioning device for railway vehicles ”[8]).

Analogs [7] and [8] also used typical SAW tags that carry an ID signal. At the same time, these SAW tags solve the problem of positioning automobile and railway vehicles in the conditions of industrial interference and do not set themselves the task of protecting them from copying.

The well-known "Method for identifying the authenticity of objects put into circulation" according to the patent for the invention of the Russian Federation (RU 2309453 C1, dated October 27, 2007, IPC G06K 1/12, G06K 5/00 [9]) solves the problem of protection against counterfeiting of mass-produced mass-produced products. The invention increases the degree of protection of products from counterfeiting, a faster search for information on an identifiable subject in the database and simplification of the method by transmitting information through open information channels. The administrator of the identification system makes and provides the manufacturer with a predetermined number of identification tags. Each label includes a character set consisting of the serial number of the label open for reading and an identification combination that is closed from visual perception by a protective agent. The manufacturer informs the administrator of descriptive information about items marked with tags that are stored in the manufacturer’s database. The person conducting the identification opens the protective device and, using the means of communication, sends the administrator a request indicating the serial number and identification combination. The administrator finds the identification combination in the database by the serial number and compares it with the identification combination specified in the request. If they coincide, sends descriptive information about the subject to the person conducting the identification, on the basis of which a conclusion is made about the authenticity of the subject.

The disadvantage of the analogue [9] is that the method can practically be implemented once with a mechanical opening of the identification combination, which is closed from visual perception by a protective agent. With the further use of the marked object, a known identification mark can be faked and it can be used to mark similar counterfeit objects, for example, selling them as they were in small (in time) use. In addition, this identification method is not applicable to identifying SAW tags.

Known identification tag for the video stream containing a sequence of scenes and their duration according to the application for the invention of the Russian Federation (RU 2009100847 A, 07/20/2010, IPC H04N 7/24, "Identification tag, device, method for identifying and synchronizing video data" [10] ) A method for using this tag may include synchronization steps in the playback device of the video stream and the auxiliary storage medium simultaneously for the user, based on the auxiliary storage medium associated with identifiers corresponding to changes in the scenes in the video stream. According to a known method, communication between identifiers and an auxiliary storage medium is included in the auxiliary storage medium. The use of an identification tag can be used to identify a video data stream that contains a comparison of a partial identification tag obtained from a part of a video data stream with respect to a part of an identification tag. The signal for reporting the identity of the video stream may contain identification marks. That is, an external medium is used in the identification tag — a tag that is used as a “key”.

The disadvantage of the analogue [10] is the need to use an auxiliary storage medium along with an identification mark for the video stream. The presence of an auxiliary storage medium significantly complicates both the identification device and the method of its implementation. In addition, this identification method is not applicable to identifying SAW tags. In the claimed technical solution, in comparison with the analogue [10], in addition to the predetermined predetermined identifier ID, the sequence contains a sequence that cannot be initially set, is random in nature, but can be uniquely identified through analysis of individual (non-deterministic, random) properties of the SAW tag associated with technological spread of sizes, topological elements in its manufacture.

There is a method of inserting an identification tag in the data on the patent for the invention of the Russian Federation (RU 2339091 C2, dated November 20, 2008, IPC G11B 20/10, H04L 9/00, "Insert an identification tag in the data" [11]), which provides more high efficiency and reliability in the production of storage media with inserted identification tags. Allows you to protect copyright holders from problems associated with pirated copies. The method of inserting an identification mark includes operations in which a plurality of original datasets are received, each original dataset being divided into a plurality of input segments, wherein at least one of the plurality of original datasets is uniquely marked, and an output dataset is obtained having many output segments, and each output segment of the specified output data set is formed by selecting the corresponding input segment from one of the specified set of original data sets and inserting the selected corresponding input segment into the specified each output segment, while the location of the specified set of output segments in the specified output data set as a result of the selection of input segments from the specified set of original data sets provides an identification mark in the output data set so that the number of output segments in the specified output dataset is equal to the number of input segments in each original dataset. When implementing the method, at least one original data set from a plurality of original data sets may include an unmarked data set. Moreover, the selection of the corresponding input segment from one of the specified set of data sets-originals may include pseudo-random selection of the corresponding input segment from one of the specified set of data sets-originals. And it may further include creating a pseudo-random sequence to enable pseudo-random selection of the corresponding input segment. Selecting the appropriate input segment from one of the specified set of original data sets may include pseudo-random selection of the sequence of input segments from the specified set of original data sets, so that the selected sequence provides a relatively high probability of unique identification of the specified output data set, even when the specified output data set is copied partially. Also, selecting a sequence of input segments may include constructing a pseudo-random sequence of segments, the pseudo-random sequence providing information about which input segment was used to construct the corresponding output segment.

The device for inserting an identification mark contains a plurality of receiving units for receiving a plurality of input data sets, each of a plurality of input data sets being divided into a plurality of input segments, at least one of the plurality of input data sets being uniquely marked.

The disadvantages of the analogue method [11] are its complexity and the impossibility of its application to identification SAW tags and methods for their use.

The well-known "Optical disk and the format of the physical address", as well as the method of its use according to the patent for the invention of the Russian Federation (RU 2262141 C2, 10.10.2005, IPC G11B 7/00 [12]), which uses identification marks created by resizing and physical properties of the disk material. The invention allows to reduce the amount of service data while reducing the likelihood of an increase in the number of errors. The optical disc carrier includes a track groove along which basic information is recorded in which the track groove is divided into a plurality of blocks, each of the plurality of blocks comprising a plurality of frames. In an optical disc carrier, a track groove may have an identification mark formed therein indicating the beginning of each of the plurality of blocks. In this case, the identification tag can be created by:

- cutting track grooves;

- local change in the width of the track groove;

- local changes in the amplitude of the form of vibrations.

In the process of reproducing an optical disc medium, there is a step of detecting a block tag signal from an RF signal and generating a sub information signal from a clock signal, a two-level pulse signal and a block tag signal.

The disadvantage of the technical solution of the analogue [12] (optical disks created by changing the size and physical properties of the disk material with their identification marks) is that the manufacturer himself is able to make the necessary (necessary) number of copies that are not distinguishable from the original. In the claimed technical solution, the issue of protecting the receipt of copies of SAW tags, both by third-party manufacturers and directly by the manufacturer, is largely addressed. It should be noted the impossibility of applying the methods of creation and application, identification marks of the optical disk to identification SAW tags and methods of their use.

The well-known "Semiconductor device with an authentication system based on a hidden label in the topological layer" according to the patent for a utility model of the Russian Federation (RU 127512 U1, from 04/27/2013, IPC H01L 21/70 [13]), the manufacturing features of the identification tag which allow you to establish the authenticity semiconductor device. At the same time, the authenticity of such semiconductor devices, which can be established at one or another stage of its life cycle. The essence of the technical solution lies in the fact that an identification tag made of a material opaque to infrared radiation is introduced into a semiconductor device that includes a housing and an integrated circuit chip on one of the inner layers of the device's crystal, and the geometrical dimensions of the mark coincide with the geometrical dimensions of topological elements on the carrier layer. In this case, the presence of the aforementioned label is determined using infrared radiation, and the authenticity condition for a semiconductor device containing the indicated label is both the fact of the presence of such a label and the coincidence of its morphological features with the reference ones.

The disadvantage of the technical solution of the analogue [13] is that the authentication of the product can be checked only by using additional equipment. In an analogue, images covertly printed on each product are compared with a reference image, while the error in comparing images is not defined, and in the proposed technical solution, the label itself acts as a carrier of unique information.

It is known "Device and method for recording / reproducing information, a carrier of recorded information and a means of servicing a program for recording / reproducing information" according to the patent for the invention of the Russian Federation (RU 2273893 C2, dated 10.04.2006, IPC G11B 20/10, [14], the technical result of which is to increase data protection. A block key for encrypting block data is generated using an entry time stamp attached to each packet included in the transport stream according to the entry time of the packet. The entry time stamp contains random yes depending on the entry time, and thus it is possible to generate a unique block key that improves data protection from cryptanalysis.The block key is generated based on a combination of a timestamp with a key unique to a device, storage medium or the like, such as the main a key, a unique disk key, a unique title key, etc. Since the entry time stamp is used to generate the block key, it is possible not to provide a zone on the storage medium for storing the encryption key for each block.

As the disadvantages of the analogue [14], it can be noted: its comparative complexity, the presence of additional devices of the encoder - the decoder, as well as the traditional view of the use of large integrated circuits operating on Boolean algebra. In this regard, the device and the method of its application retains the possibility of falsification: knowing the value of the code label by issuing microcircuits containing the digital value of this code label. In the claimed technical solution, even knowing the values of the encryption code of a particular label, repeating the physical structure of the label giving a similar code is a difficult task, due to the influence of a huge number of physical factors affecting the specific value of the encryption code.

The well-known "Interaction system of divided databases of personal data of an information system" according to the patent for a utility model of the Russian Federation (RU 103414 U8, dated 10.04.2011, IPC G06F 17/40 [15]), which solves the problem of constructing an information system in such a way as to connect it in a single database identifying an individual and anonymized data, including without the need for an external storage medium. The system contains an input, registration, processing unit for identifying an individual in an identification database (DB1), an input, registration, processing unit for anonymized information of an individual in an anonymized database (DB2), while both databases contain devices for reading information from an external medium characterized in that the ISPDn1 system is divided into ISPDn1 and ISPdn2, and BD1 and BD2 are located in these systems, respectively, and the external medium contains a personal anonymous identifier of an individual, with Corresponding to a single individual, DB1 and DB2 contain the specified identifier of the individual, while the external medium contains internal and / or external identifying elements, in addition, the individual has at least one external medium with one personal anonymous identifier. The personal anonymous identifier BD1 and BD2 may contain identical values for one individual, and at least one external medium may contain elements of visual differences. Moreover, external visual differences of at least one external medium can be made in the form of, for example, a pattern, contrasting color, etc.

As a drawback of the analogue [15], it should be noted that the issue of protecting cards identifying an individual has not been resolved in principle. In the claimed technical solution in the alleged information systems (where it will be used), the presence of a label - an identifier with a built-in encryption key, including an open one, but strongly protected from copying is fundamental for the task of identifying and obtaining a digital signature for related information.

The well-known "Method of accounting and control of objects with identification marks" according to the application for the invention of the Russian Federation (RU 2001125831 A, dated 09/20/2003, IPC G06K 5/00 [16]), using an additional mark for access to classified information. It includes putting into circulation by transferring the appropriate space to the subjects, reading labels at the accounting points, entering them into a single electronic data bank, and analyzing the circulation based on the data being read. The objects are provided with an additional identification tag, which is a code key to the private information contained in a single data bank, and at the same time, all metering stations are equipped with reading and identification devices for the specified tag. Upon receipt of documents, securities, banknotes at accounting points from entities and reading information, they request additional closed information through an identification tag and, based on the analysis, judge the reliability and nature of the circulation of objects in the appropriate space. As an identification tag can use: barcode; miniature numerical information processor; electromagnetic coating; electron beam identification tags; electronic identification tags; original alphanumeric code.

The disadvantage of the analogue [16] is the need to use an additional tag, which can be easily faked, as well as the main one, and to get easy access to classified information, which can lead to the creation of objects - copies of the originals.

The well-known "Identification tag for marking and recognition of objects" according to the patent for a utility model of the Russian Federation (RU 1161 U1, dated 16.11.1995, IPC G09F 03/02 [17]), which is made on a dielectric film and fixed on the object or its packaging. At the same time, an electric oscillating circuit made of an electrically conductive material, for example, electrically conductive paint, paste or foil, is placed on the surface of the dielectric film. The inductive element of the oscillatory circuit is made in the form of two flat spirals located on both sides of the dielectric film, the direction of twist of one flat spiral from its center is opposite to the direction of twist of the other flat spiral, in the center of each flat spiral there are contact pads interconnected through a metallized hole, internal turns of flat spirals are connected to the indicated pads, and capacitive elements of the oscillatory circuit are made in the form of strip metal izirovannyh sites with a slot, covering inductive elements, the external turns of which are connected with strip metallized sites. A protective opaque film with line marks or other images may be pasted on the label, the coding features of which differ from the identification features of the object. The label can be fixed on the inner surface of the package of the object, and the position of the center of the inductive elements is marked on the outer surface of the package with a corresponding marker.

The disadvantage of the analogue [17] is the use of a completely different physical principle than that of RFID surfactants, while the use of an oscillatory LC circuit tuned to a specific resonant frequency cannot act as a counterfeit encryption key.

The well-known "Method and device for creating an identification mark for a wireless network" according to the patent for the invention of the Russian Federation (RU 2384982 C2, 03/20/2010, IPC H04W 64/00, Н04В 7/26 [18]) allows to detect wireless local area networks and wide area networks using cellular technology. The analogue [18] contains: a processor configured to generate information related to the location of the first communication network based on one or more reference signals from the second communication network, the information containing an identification mark of the first communication network, and the identification label contains phase information and signal strength information for one or more reference signals; and a memory configured to store said information.

Moreover, the label in the analogue is a mathematical image without reference to the physical information carrier, which cannot be used to identify physical objects and protect them from copying, which is a drawback of the analogue [19].

The prototype of the proposed technical solution is the way the identification tag according to the patent for the invention of the Russian Federation (RU 2158936 C2, from 10.11.2000, IPC G01S 13/02, G01S 13/75, G06K 7/10, “Identification tag that works with surface acoustic waves” [19]). The method consists in the fact that an electromotive force (EMF) is induced through irradiation with an analog sounding radio signal, followed by the response from the tag for subsequent analysis, to an identification tag consisting of interdigital transducers (IDTs) and reflectors deposited on a substrate and connected to an IDTs with obtaining identification (ID) code label, which is a digitized display of the placement of reflectors on the substrate. The technical solution of the analogue [19] eliminates the need for a constant mode of operation of the interrogating system, due to the fact that at least one of the reflectors has a higher reflectivity relative to the reflectivity of the other reflectors.

The disadvantage of the prototype [19], as well as analogues [1], [2], [3], [4] and [5] is that when working with them, they remove the identification ID signal, knowing which it is easy to reproduce this label with same ID signal, having similar technological equipment.

A feature of the SAW tag - prototype [19] is that this SAW tag is a simple and collective image of the SAW tags and how they work.

The ability to copy SAW tags jeopardizes the very idea of identifying and unambiguously fixing the authenticity of objects. This creates favorable conditions for the creation and promotion of counterfeit products and discredits the identification mechanism itself.

In this regard, at present, despite the certain complexity of the production of SAW tags, the urgent task is to identify (determine, identify) copies of tags from the original SAW tag. That is, the task is to obtain a higher degree of protection of SAW tags from fakes, including by the manufacturer of SAW tags.

In other words, the task is to create an improved method for using a SAW tag - a prototype [19], in which, in addition to determining the ID, an encryption key calculation function is added, that is, a SAW tag is additionally used as an encryption key carrier.

The essence of the invention lies in the fact that in the claimed method of increasing the protective properties of a SAW tag, namely, that a SAW tag consisting of interdigital transducers (IDTs) and reflectors deposited on a substrate, an electromotive force is induced through an antenna connected to the IDT irradiation with an analog sounding radio signal with the subsequent acceptance of the response from the SAW tag for its subsequent analysis with obtaining the identification code of the SAW tag, which is a digitized display of the placement of reflectors on on the fly

additionally receive an encryption key - an electronic digital signature of the SAW tag and an electronic certificate of authenticity of the SAW tag, by calculating the encryption key based on an analysis of the individual characteristics of the amplitude-phase frequency response of the radio signal from the SAW tag, while the encryption key is an electronic digital signature of the SAW tag determine the technological spread of the coordinates of application and the size of the reflectors, physical and chemical properties used in the production of materials. In the process of calculating the encryption key - electronic digital signature of the label, such features of the amplitude-phase frequency response of the radio signal from the SAW tag are used that either do not depend on external environmental influences, or the ratio of their parameters (characteristics) relative to each other mutually compensate for these effects. When applying a SAW tag, the obtained encryption key - electronic digital signature of the tag is used to determine the authenticity of the SAW tag identification itself.

In the manufacture of SAW tags in a random manner within the permissible limits, they can introduce an additional spread (permissible errors) into the coordinates and mode of electrode application of its topology into the technological process of its manufacture.

The encryption key - the electronic digital signature of the SAW tag - can act as a public encryption key and together with the identification code forms an electronic certificate of authenticity of the SAW tag.

The technical result consists in increasing the protective properties of a SAW tag by additionally obtaining an encryption key - an electronic digital signature of the tag, which is calculated based on an analysis of the individual characteristics of the amplitude-phase frequency response of the radio signal from the SAW tag.

In the claimed technical solution, in addition to the predetermined predetermined identifier ID, the sequence contains a sequence that cannot be initially set, is random in nature, but can be unambiguously identified by analyzing the individual (non-deterministic, random) properties of the SAW tag associated with technological variation in its manufacture.

The claimed invention to a large extent solves the issue of protection for obtaining copies of a SAW tag, both by third-party manufacturers and directly by the manufacturer, since the SAW tag itself acts as a carrier of unique information.

Therefore, even knowing the value of the encryption key of a specific SAW tag, repeating the physical structure of the SAW tag giving a similar code is a difficult task, due to the influence of a huge number of physical factors affecting the specific value of the encryption key.

When applying the claimed invention, the presence of a SAW tag — an identifier with a built-in encryption key, including an open one, but strongly protected from copying is fundamental for solving the identification problem and obtaining a digital signature for related information.

The introduction of the distinguishing features into the claims: “they additionally receive an encryption key - an electronic digital signature of the SAW tag and an electronic certificate of authenticity of the SAW tag, by calculating the encryption key based on the analysis of the individual characteristics of the amplitude-phase frequency response of the radio signal from the SAW tag” is necessary to create the ability to determine the authenticity of the SAW tag itself and to create the ability to use the encryption key to generate a digital signature of object descriptions, dentifitsiruemyh of the SAW tag.

The introduction of the distinguishing features into the claims: “an encryption key - an electronic digital signature of a SAW tag is obtained from the technological tolerance for applying reflectors (which is determined by the accuracy of positioning and focusing of the equipment), the physical and chemical properties of the materials used in the production” is necessary in order to obtain a strictly individual encryption key for each SAW tag, including the same ID, which will significantly increase its protection against copying and fakes.

Introduction to the claims of the invention, the distinguishing features: “to obtain an encryption key - an electronic digital signature of a SAW tag and an electronic certificate of authenticity, the SAW tag selects such features of the amplitude-phase-frequency characteristics of the response of the radio signal from the SAW tag that either are independent of external environmental influences, or the relationship of their characteristics relative to each other mutually compensate for these effects ”is necessary in order to ensure the invariance of the value of the encryption key - electronic digitally the first signature of the SAW tag from fluctuations in ambient temperature.

The introduction of the distinguishing features into the claims: “when applying a SAW tag, the obtained encryption key - electronic digital signature of the SAW tag is used to determine the authenticity of the SAW tag itself” is necessary in order to verify the authenticity of the SAW tag itself, to exclude its falsification and protection against counterfeit products.

The introduction of the distinguishing features into the claims: “when manufacturing a SAW tag randomly within the acceptable limits, add an additional spread to the coordinates and the mode of applying reflectors of its topology to the manufacturing process”, it is necessary to additionally specify a “spread” of values of the encryption key, then there is to increase the "individuality" of each surfactant tag.

The claimed method of increasing the protective properties of the identification tag is illustrated by the images presented in the following figures.

FIG. 1 - Topology of SAW tags.

FIG. 2 - An enlarged fragment of the topology of the SAW tag (View A in Fig. 1), where a is the width of the information group, 6 is the width of the guaranteed gap between the information groups.

FIG. 3 - Possible topologies of two ID-identical SAW tags.

FIG. 4 - Location of the reflector inside the information group consisting of 16 slots.

FIG. 5 - An enlarged fragment of the location of the reflector relative to the central axis of the slot (View B in Fig. 4), where -2 -1 0 +1 +2 are the displacements of the reflector by a multiple of λ / 4, and λ is the wavelength of the propagation of vibrations on the surfactant substrate - tags.

FIG. 6 - Photo of the substrate (region) of the SAW tag with visible reflectors (under the microscope).

To explain the implementation of the proposed method in FIG. Figure 1 shows a typical SAW tag (1), which consists of a piezoelectric substrate (2) with IDT (3) deposited on it from an electrically conductive material and reflectors (4) - (reflectors). An antenna (5) is connected to the IDT (3).

In the process, a SAW tag (1) consisting of IDT (3) and reflectors (4) deposited on a substrate of piezoelectric material (2) and reflectors (4) are used to induce EMF by irradiation with an analog sounding radio signal through an antenna connected to IDT (5). Next, a response from the SAW tag (1) is received, it is analyzed in a reader (reader), and the identification code of the SAW tag is obtained, which is a digitized display of the placement of reflectors (4) on the substrate (2).

At the same time (and / or sequentially) additionally receive an encryption key - an electronic digital signature of the SAW tag and an electronic certificate of authenticity of the SAW tag, which is calculated based on the analysis of individual characteristics of the amplitude-phase-frequency characteristics of the response of the radio signal from the SAW tag, while the encryption key is electronic digital signature of SAW tags is obtained from the technological tolerance for applying reflectors (due to the accuracy of positioning and focusing of equipment), as well as physical and chemical properties CTB used in the manufacture of materials. To obtain an encryption key - an electronic digital signature of a SAW tag, one selects such features of the amplitude-phase-frequency characteristic of the response of the radio signal from the tag that either does not depend on external environmental influences, or the ratio of their characteristics relative to each other mutually cancels out these effects. When applying a SAW tag, the obtained encryption key - an electronic digital signature of the SAW tag is used to determine the authenticity of the SAW tag itself.

At the same time, in the manufacture of surfactant tags randomly within the permissible limits, they can introduce into the technological process of its manufacturing an additional spread (permissible errors) in the coordinates and electrode application mode of its topology.

One of the implementation algorithms of the claimed technical solution - a method of increasing the protective properties of a SAW tag is as follows.

To reliably calculate the encryption key of a SAW tag, for example, one can analyze a particular case of the amplitude-phase-frequency characteristic — the phase shift of the responses of the reflectors. The produced SAW tags contain 6 information groups of reflectors. Each group has 16 slots. The position of the reflector in a particular slot determines the current value of the tag ID. The total number of codes for this topology is 16 to the 6th degree, i.e. 16777216 combinations. The resolution calculation performed allows us to determine the phase shift, which may be due to a shift in the position of the reflector relative to the central axis of the slot and (or) a change in the reflection coefficient of the reflector (reflector) with an accuracy of no worse than 0.4 μm for 2.45 GHz, which corresponds to the wavelength λ / 4 for the substrate material is lithium niobate. Thus, a shift in the position of the reflector within ± 1 μm with a slot width of 25 μm) relative to the central axis of the slot allows you to identify 5 possible positions of the reflector inside each slot.

The presence of a start and stop reflector, as well as a group of reflectors of the checksum, allows one to unambiguously calculate the temperature compensation parameters of a specific SAW tag. Since the physical location of all reflectors remains unchanged on the surface of the plate, and their movement can be caused only by a change in the linear dimensions of the SAW tag under the influence of temperature factors, and there is no mechanical deformation factor, if there is a constant computational algorithm for determining the phase shift, the compensation according to the start, stop the reflector and the checksum reflectors will calculate the exact position of the information reflectors within each slot.

As a result, we get 5 to 6 degrees of possible options for a SAW tag with the same ID. Statistically, this means that a copy of the SAW tag will match the original with a probability of 1/15625. Since the number of information groups and, correspondingly, the number of combinations may be different for SAW tags of a different bit capacity (for the topology of a Pav tag with 8 information groups of reflectors - 4 billion combinations, the probability of coincidence is less than 3 × 10 ^-6 ), it is advisable representation of the encryption key as a hash function of a fixed length. To do this, you can combine the values of the positions of the reflectors in the slots with the value of the ID of the SAW tag in any predetermined way and calculate the hash function, for example, according to the MD5 algorithm (https://ru.wikipedia.org/wiki/MD5 - [23]). MD5 (Message Digest 5) is a 128-bit hash algorithm. Designed to create “fingerprints” or message digests of arbitrary length and subsequent verification of their authenticity.

For SAW tags with ID equal 01041210030570 and position of reflectors:

+1 -2 -1 0 +2 -2 λ / 4 relative to the central axis of the slot, presented as a sequence of character codes of the ASCII-ISO 8859-1 standard in the DEC format: 43 49 45 50 45 49 48 43 50 45 50 we have: md5 ( 010412100305704349455045494843504550) => f613d847d9c5eb4bf2162c53c30cc81a - 128-bit encryption key of the SAW tag (electronic digital signature of the SAW tag).

The combination of the ID of the label and the position of the reflectors is necessary to obtain encryption keys, the probability of repetition of which tends to zero due to the properties of the avalanche effect of the MD5 algorithm, the high dispersion of the result and the hash information capacity of 16 to the power of 32 (3.4 × 10 ³⁸ ).

Bringing the totality of characteristics of the characteristics of the tags to a 128-bit key of a fixed length allows you to further use the new characteristics of the amplitude-frequency and phase characteristics of the SAW tags, defining its "unique portrait", while the output format of the reader remains unchanged: ID of the SA tag ID and 128-bit MD5 hash.

The sequence of operations when calculating the encryption key - electronic digital signature of the label is as follows:

1. Determining the ID of the SAW tag, calculating the checksum and comparing it with the checksum stored in the tag (using a conventional SAW tag).

2. Based on the tag ID, determine the algorithm for calculating the encryption key (it can be the same for all SAW tags or different for different ID ranges).

3. Determining according to a given algorithm the features of the amplitude-phase-frequency characteristics of the response of the radio signal from the SAW tag and calculating the value of the hash function, ie encryption key - electronic digital signature of the SAW tag.

We believe that the proposed "Method for improving the protective properties of the identification SAW tag" has all the criteria of the invention, since the combination of restrictive and distinctive features of the claims is new to such methods, and therefore meets the criterion of "novelty", since the proposed method may be implemented with all types of surfactant tags.

The set of features of the claims of the proposed method is unknown at this level of development of technology and does not follow well-known rules for the development of surfactant labels, namely:

- obtaining an additional encryption key - an electronic digital signature of the SAW tag, which is calculated based on the analysis of individual characteristics of the amplitude-phase-frequency characteristics of the response of the radio signal from the SAW tag,

- obtaining an encryption key from the technological tolerance for applying reflectors, physical and chemical properties of materials used in the production,

- to obtain an encryption key, select such features of the amplitude-phase-frequency characteristics of the response of the radio signal from the SAW tag, which either do not depend on external environmental influences, or the ratio of their characteristics relative to each other mutually compensate for these effects,

- when applying a SAW tag, the obtained encryption key is used to determine the authenticity of the SAW tag itself,

which proves compliance with the criterion of "inventive step".

In addition, it should be noted that the application of the claimed method does not reduce the bit depth of the SAW tag ID for this topology, but uses additional parameters (a more in-depth analysis of the characteristics) of the SAW tag to verify its authenticity. The claimed algorithm of the technical solution of the method, namely: determining the ID tag (I), and then calculating the electronic digital signature of the tag (I) according to the algorithms for a given ID range, allows over time (for developed SAW tags - with new ranges of SAW IDs - tags) to find better combinations of characteristics and complicate the digital portrait of a SAW tag without affecting the digital signature algorithms for existing SAW tags with previous ID ranges.

The development, construction and implementation of the proposed "Method for improving the protective properties of the identification SAW tag" does not present any structural, technical and technological difficulties. The method was developed by the applicant, and at present, according to its features (the claimed claims), tests are carried out made of surfactant labels, which proves compliance with the criterion of "industrial applicability".

Information sources

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20. https://m.wikipedia.org/wiki/MD5.

Claims (2)

1. A method of increasing the protective properties of an identification SAW tag (hereinafter SAW tag), namely, that a SAW tag consisting of interdigital transducers (IDTs) and reflectors deposited on a substrate electromotive force is connected through an antenna connected to the IDT irradiation with an analog sounding radio signal and then receiving a response from the SAW tag for subsequent analysis to obtain a SAW tag identification code, which is a digitized display of the placement of reflectors on the substrate, characterized I mean that they additionally receive an encryption key - an electronic digital signature of a SAW tag and an electronic certificate of authenticity of a SAW tag, by calculating an encryption key based on an analysis of the individual characteristics of the amplitude-phase frequency response of the radio signal from the SAW tag, while the encryption key is electronic digital the signature of the SAW tag - is determined by the technological spread of the coordinates of deposition and the size of the reflectors, physical and chemical properties used in the production of materials, in the process The encryption key — the electronic digital signature of the SAW tag — uses such features of the amplitude-phase-frequency characteristic of the response of the radio signal from the SAW tag that either does not depend on external environmental influences, or the ratio of their parameters relative to each other mutually cancel these effects, and when using the SAW -markets the obtained encryption key - electronic digital signature of the SAW-tag - is used to determine the authenticity of the SAW-tag itself. 2. A method for increasing the protective properties of a SAW tag, according to claim 1, characterized in that, when manufacturing a SAW tag, they randomly add acceptable variation to the coordinates and application mode of reflectors of its topology in the manufacturing process of its manufacture.

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