Tag Authentication Method and System for Physical Layer Characteristics of Ultra-High Frequency Radio Frequency Identification Tags

Abstract

The present invention discloses a tag authentication method and system for the physical layer characteristics of ultra-high frequency radio frequency identification tags. By utilizing the physical layer characteristics of ultra-high frequency radio frequency identification tags, reliable tag authentication is achieved without modifying the commercial protocol of ultra-high frequency radio frequency identification technology and the tag hardware. Compared with the authentication method based on the tag product number, the security and reliability are improved. Compared with the method based on encryption algorithms, the present invention does not rely on the protection of tag keys. Even if an attacker knows the physical layer characteristics of a legitimate tag, it is difficult to find a counterfeit tag that meets the requirements. Compared with other physical layer authentication methods, the present invention has the advantages of short authentication time, small feature storage capacity, and being free from external environmental interference, and has high security and practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency identification, and particularly relates to a tag authentication method and system for the physical layer characteristics of ultra-high frequency radio frequency identification tags. Background Art

[0002] In the development of global trade, consumers have an increasingly urgent need for commodity authentication. Commodity authentication refers to the use of certain technologies to distinguish the authenticity of products. Existing product authentication methods are mainly divided into two categories, namely those based on product label content and those based on encryption algorithms. The method based on product label content is mainly in the form of two-dimensional codes, barcodes, and traditional labels. This authentication method uses the content of the product label, such as the product number, as the basis for authentication. This type of method has a simple authentication method, but the label content is extremely easy to copy, and counterfeits can pass the authentication by simply copying the genuine product label. Therefore, the security of this type of method is not high. The method based on encryption algorithms mainly uses tags that support encryption, such as NFC, high-frequency RFID, etc. This type of method has a high security factor, but this type of method overly relies on the key of the tag. If the key is broken or stolen, attackers can still manufacture counterfeit products. Moreover, the communication distance of the tags used in this type of method is relatively short (usually within 10 centimeters), which is not suitable for large-scale product authentication scenarios such as logistics and warehousing. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a tag authentication method and system for the physical layer characteristics of ultra-high frequency radio frequency identification tags in view of the above deficiencies in the prior art, and utilize the characteristics of the physical layer of low-cost ultra-high frequency radio frequency tags to achieve efficient and reliable tag authentication.

[0004] The present invention adopts the following technical solutions:

[0005] A tag authentication method for the physical layer characteristics of ultra-high frequency radio frequency identification tags, comprising the following steps:

[0006] S1. Select N different reader sending parameters, send M Query signals under each reader sending parameter, collect the RN16 replied by the target tag, generate the distribution of the tag backscatter frequency BLF under different reader sending parameters according to the collection results and perform normalization processing to complete tag feature registration;

[0007] S2. Send reader commands according to the N reader sending parameters set in step S1, and use the high-efficiency comparison method or the high-quality comparison method to perform tag authentication through the tag backscatter frequency BLF shown by the tag under different reader sending parameters.

[0008] Specifically, in step S1, the reader sending parameters include the division ratio and the tag-reader calibration signal.

[0009] Specifically, in step S1, N is greater than or equal to 8 times, and M is greater than or equal to 200 times.

[0010] Specifically, in step S1, the tag backscatter frequency BLF is specifically:

[0011]

[0012] Wherein, DR and TRcal are the departure ratio and the tag-reader calibration signal respectively.

[0013] Furthermore, the fluctuation range of the tag backscatter frequency BLF under the given reader transmission parameters is ±4% to ±22%, and the fluctuation range of the same tag under the same parameters is ±2.5%.

[0014] Specifically, in step S2, the high-efficiency comparison method is specifically:

[0015] Traverse the N transmission parameters set in step S1 for the reader transmission parameters, each transmission parameter is sent only once, collect the RN16 returned by the target tag, calculate the BLF characteristics of RN16 under each parameter, and compare with the BLF distribution map after normalization during feature registration in step S1. Take the values in the BLF distribution map as probabilities, multiply the N probabilities under the N transmission parameters to obtain the probability of whether the corresponding tag is a legal tag, compare the probability of whether the tag is a legal tag with the threshold, and take the tag with a probability higher than the threshold as a legal tag.

[0016] Furthermore, if the probability is lower than the threshold, the high-quality comparison method is used for tag authentication, or it is directly determined as an illegal tag.

[0017] Specifically, in step S2, the high-quality comparison method is specifically:

[0018] Traverse the N transmission parameters set in step S1 for the reader transmission parameters, each transmission parameter is sent M times, both N and M are the same as those during tag registration, collect the BLF distribution returned by the tag, after normalization, compare with the BLF distribution map during tag registration, and take the tag with a comparison result greater than the threshold as a legal tag, otherwise directly determine it as an illegal tag.

[0019] Furthermore, the comparison method uses the DL divergence.

[0020] In a second aspect, an embodiment of the present invention provides a tag authentication system for the physical layer characteristics of ultra-high frequency radio frequency identification tags, including:

[0021] Registration module: Select N different reader sending parameters, send M Query signals under each reader sending parameter, collect the RN16 replied by the target tag, generate the distribution of the tag backscatter frequency BLF under different reader sending parameters according to the collection results and perform normalization processing to complete tag feature registration;

[0022] Authentication module: Send reader commands according to the N reader sending parameters set by the registration module, and adopt the high-efficiency comparison method or the high-quality comparison method to perform tag authentication through the tag backscatter frequency BLF demonstrated by the tag under different reader sending parameters.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] The tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag of the present invention uses the backscatter frequency of the tag under different reader parameters as the authentication feature. The range of the backscatter frequency is specified by the tag commercial protocol (EPC C1G2 protocol), so it has high availability; in addition, compared with other physical layer authentication schemes based on physical layer signal characteristics in the early stage, the backscatter frequency collected by the present invention has the huge advantage of small storage capacity. The tag backscatter frequency distribution under each reader parameter is divided into 50 equal parts, and each equal part has 101 probability possibilities (2^7) from 0% to 100%, that is, a total of 7 bits * 50 equal parts * N of binary is required for storage, and the feature storage capacity of 100 MB can be reduced to 3 Kb.

[0025] Furthermore, the reader sending parameters include the division ratio and the tag-reader calibration signal, which comply with the existing commercial protocol's regulations on the calculation of the tag backscatter frequency. In addition, both of these two parameters can be effectively controlled by controlling the sending signal of the reader, so as to achieve reliable authentication of the tag.

[0026] Furthermore, since the tag backscatter frequency BLF demonstrated by some tags under some reader sending parameters has relatively similar characteristics, the present application adopts the setting of N greater than or equal to 8 times, which can greatly increase the feature space of the tag. In addition, the number of times M of sending reader parameters greater than or equal to 200 times can also obtain a better authentication effect while saving authentication time and reducing the influence of accidental factors on the authentication result.

[0027] Furthermore, the high-efficiency method proposed by the present invention can greatly reduce the authentication time, reduce the number of communication times required for authentication from N*M to N, and at the same time, through experiments, it can be known that the high-efficiency method can ensure a good authentication accuracy rate.

[0028] Furthermore, the high-efficiency method authenticates the tags by comparing the relative magnitudes of probabilities and thresholds, significantly reducing the authentication complexity and the authentication time. Meanwhile, for those tags that may have authentication errors, a supplementary high-quality method is also provided, reducing the possibility of misjudgment.

[0029] Furthermore, as an effective supplement to the high-efficiency method, the high-quality method enables each authentication end to adopt the same feature acquisition method as the registration end, which can better avoid the influence of accidental factors on tag authentication and has a relatively high authentication accuracy.

[0030] Furthermore, the comparison method of the high-quality method uses the DL divergence, which is a classic method for comparing whether two distributions are similar and can quickly and accurately obtain the tag authentication result.

[0031] It can be understood that the beneficial effects of the second aspect above can be referred to the relevant descriptions in the first aspect above and will not be elaborated here.

[0032] In summary, the present invention has the advantages of short authentication time (as low as 55 milliseconds), small feature storage capacity (as low as 3 Kb), and being free from external environmental interference, and can achieve high-accuracy tag authentication without modifying the existing commercial protocols and tag hardware.

[0033] Next, through the accompanying drawings and embodiments, the technical solution of the present invention will be further described in detail. Description of the Drawings

[0034] Figure 1 It is a graph of the rated value and fluctuation range of the tag BLF under different parameter settings of the reader;

[0035] Figure 2 It is a BLF feature graph of different tags / same tags under different parameter settings. Among them, (a) shows that different tags exhibit similar BLF features under certain parameter settings, and (b) shows that different tags exhibit similar BLF features under all parameter settings;

[0036] Figure 3 It is a BLF feature graph of different tags / same tags under all parameters. Among them, (a) is Tag1: 30 cm, (b) is Tag2: 30 cm, and (c) is Tag2: 80 cm;

[0037] Figure 4 It is a feature confusion matrix graph of 50 tags;

[0038] Figure 5 It is a schematic diagram of a computer device provided by an embodiment of the present invention. Detailed Embodiments

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] In the description of the present invention, it should be understood that the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0041] It should also be understood that the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0042] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the contextually related objects.

[0043] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present invention to describe preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0044] Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determining" or "when detected (stated condition or event)" or "in response to detecting (stated condition or event)".

[0045] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0046] The present invention provides a tag authentication method for the physical layer characteristics of ultra-high frequency radio frequency identification tags. By using the physical layer characteristics of ultra-high frequency radio frequency identification tags, reliable tag authentication is achieved without modifying the commercial protocol of ultra-high frequency radio frequency identification technology and the tag hardware. Compared with the tag content-based authentication method, the security and reliability of the present invention are greatly improved; compared with the method based on encryption algorithms, the present invention does not rely on the protection of tag keys. Even if an attacker knows the physical layer characteristics of a legitimate tag, it is difficult to find a counterfeit tag that meets the requirements. Compared with other physical layer authentication methods, the present invention has the advantages of short authentication time (as low as 55 milliseconds), small feature storage capacity (as low as 3 Kb), and being unaffected by the external environment, and has high security and practicability.

[0047] A tag authentication method for the physical layer characteristics of an ultra-high frequency radio frequency identification tag according to the present invention is divided into two parts: tag feature registration and tag feature comparison. The specific steps are as follows:

[0048] S1. Tag feature registration

[0049] According to the provisions of the commercial protocol, select N different reader transmission parameters, including the division ratio (DivideRatio, DR) and the tag-to-reader calibration signal (Tag-to-Reader calibration symbol, TRcal). Send M Query signals under each parameter and collect the RN16 replied by the target tag.

[0050] To ensure the effect of feature registration, N is not less than 8 times and M is not less than 200 times.

[0051] Figure 1 An example with N being 8 is given. According to the provisions of the commercial protocol, when the tag receives the signal from the reader, it adjusts its own backscattering frequency BLF according to the parameters of the reader. The specific calculation is as follows:

[0052]

[0053] Among them, DR and TRcal are the division ratio and the tag-to-reader calibration signal respectively, and both of these parameters are specified by the reader when sending the Query command.

[0054] When the tag receives the Query command sent by the reader, it calculates its own frequency BLF value according to the values of the two parameters DR and TRcal and replies with a signal according to formula (1). However, due to the slight hardware errors caused during the production of the tag, the actual BLF value exhibited by the tag fluctuates within a range, which is specified by the protocol. For all tags, the fluctuation range of BLF under the given reader transmission parameters is ±4% to ±22%, and the fluctuation range of the same tag under the same parameters is ±2.5%.

[0055] Therefore, this application performs tag authentication through the BLF exhibited by the tag under different reader transmission parameters.

[0056] S2. Tag feature comparison.

[0057] The feature comparison of tags is divided into two types: high-efficiency comparison method and high-quality comparison method.

[0058] S201. High-efficiency comparison method

[0059] During tag authentication, the reader transmission parameters are traversed through the N types of transmission parameters set in step S1, and each parameter is sent only once. The RN16 returned by the target tag is collected, and its BLF feature under each parameter is calculated. This feature is compared with the BLF distribution map during feature registration. The values in the distribution map are used as probabilities, and the N probabilities under the N types of transmission parameters are multiplied together to obtain the probability of whether the corresponding tag is a legal tag. This probability is compared with a threshold. If it is higher than the threshold, it is considered a legal tag; otherwise, the second tag authentication method can be further performed, or it can be directly determined as an illegal tag.

[0060] S202. High-quality comparison method

[0061] During tag authentication, the reader transmission parameters are traversed through the N types of transmission parameters set in step S1, and each parameter is sent M times. Here, both N and M are the same as those during tag registration. The BLF distribution returned by the tag is collected, and after normalization, it is compared with the distribution map during tag registration. The comparison method is such as the DL divergence, etc. If the comparison result is greater than a certain threshold, it is considered a legal tag; otherwise, it is directly determined as an illegal tag.

[0062] In another embodiment of the present invention, a tag authentication system for the physical layer characteristics of ultra-high frequency radio frequency identification tags is provided. This system can be used to implement the tag authentication method for the physical layer characteristics of the above ultra-high frequency radio frequency identification tags. Specifically, the tag authentication system for the physical layer characteristics of the ultra-high frequency radio frequency identification tags includes a registration module and an authentication module.

[0063] Among them, the registration module selects N different reader sending parameters, sends M Query signals under each reader sending parameter, collects the RN16 replied by the target tag, generates the distribution of the tag backscatter frequency BLF under different reader sending parameters according to the collection results, and performs normalization processing to complete the tag feature registration;

[0064] The authentication module sends a reader command according to the N reader sending parameters set by the registration module, and adopts an efficient comparison method or a high-quality comparison method to perform tag authentication through the tag backscatter frequency BLF shown by the tag under different reader sending parameters.

[0065] Please refer to Figure 5 , the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and operable on the processor 61. When the computer program 63 is executed by the processor 61, it implements the tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag in the embodiment. To avoid repetition, it will not be elaborated here one by one. Or, when the computer program 63 is executed by the processor 61, it implements the functions of each model / unit in the tag authentication system for the physical layer characteristics of the ultra-high frequency radio frequency identification tag in the embodiment. To avoid repetition, it will not be elaborated here one by one.

[0066] The computer device 60 can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art can understand that Figure 5 merely examples of the computer device 60 do not constitute a limitation on the computer device 60, and may include more or fewer components than shown in the figure, or combine certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0067] The so-called processor 61 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0068] The memory 62 can be an internal storage unit of the computer device 60, such as the hard disk or memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk equipped on the computer device 60, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc.

[0069] Furthermore, the memory 62 can also include both the internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0071] Please refer to Figure 2 , to verify the effect of the BLF, the present invention collects the BLF distribution maps of two tags under two different parameters ( Figure 1 parameter 1 and parameter 8). As Figure 2 (a) shows, when parameter 1 is adopted, the same tag shows almost the same BLF distribution at different distances, which reflects the independence of the BLF from the environment. However, the BLF distribution maps of different tags are also very close under this parameter. However, when parameter 8 is adopted, the same tag still shows a very close BLF distribution under this parameter, but the BLFs of different tags are very different under this parameter. Figure 1 parameter 1, the same tag shows almost the same BLF distribution at different distances, which reflects the independence of the BLF from the environment. However, the BLF distribution maps of different tags are also very close under this parameter. However, when parameter 8 is adopted, the same tag still shows a very close BLF distribution under this parameter, but the BLFs of different tags are very different under this parameter. Figure 1 parameter 8, the same tag still shows a very close BLF distribution under this parameter, but the BLFs of different tags are very different under this parameter.

[0072] This application also collects the BLF distributions of these two tags under Figure 1 all parameters, and after normalizing the distribution, presents it in the form of a heat map in Figure 3 . As Figure 3 (a) and Figure 3As shown in (b), for the two tags under different parameter settings, the difference in the BLF distribution is very obvious. However, even if the placement distance / environment of the same tag is changed, the BLF distribution is very similar. According to such characteristics, this patent collects the distribution of the backscattering frequency BLF of the tags under different parameters, normalizes this distribution, and uses the normalized value as the probability of the BLF of the tag appearing under the given parameters.

[0073] Please refer to Figure 4 , in order to verify the authentication effect of the present invention, the BLFs of 50 similar tags under N different parameters are collected. After multiplying by the BLF probability at the time of tag registration through the method of the present invention, the confusion matrix is as Figure 4 shown. It can be seen from Figure 4 that the method of the present invention can well distinguish even for similar tags.

[0074] The authentication time can be calculated by the following formula:

[0075]

[0076] where t p is the tag password verification time. According to the commercial protocol regulations and experimental results, this time is 44.8 ms. t M is the time used to send the reader parameters once. This time varies from 0.67 ms to 2.2 ms according to different sending parameters. N is the number of types of sending parameters, and M is the number of times each sending parameter is sent. Therefore, the tag authentication time is 55.4 ms.

[0077] In this application, the backscattering frequency distribution of the tags under each reader parameter is divided into 50 equal parts. Each equal part has 101 probability possibilities from 0% to 100% (2^7), that is, a total of 7 bits * 50 equal parts * N of binary is required for storage. Taking N = 8 as an example, a total of 7 * 50 * 8 = 2800 b = 2.8 Kb is required.

[0078] In summary, the present invention provides a tag authentication method and system for the physical layer characteristics of ultra-high frequency radio frequency identification tags. By using the differences in the backscattering frequencies caused by the hardware characteristics of different tags and expanding the tag feature space by using multiple reader sending parameters, an efficient, accurate, and small-storage tag physical layer authentication method is realized, which can achieve trusted tag authentication without modifying the tag hardware and commercial protocol.

[0079] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0080] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0081] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0082] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0083] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention fall within the protection scope of the claims of the present invention.

Claims

1. A tag authentication method for the physical layer characteristics of ultra-high frequency radio frequency identification tags, characterized in that, Including the following steps: S1. Select N different reader sending parameters, send M Query signals under each reader sending parameter, collect the RN16 replied by the target tag, and generate the distribution of the tag backscattering frequency under different reader sending parameters according to the collection results and perform normalization processing to complete tag feature registration; to complete the tag feature registration; S2. Send a reader command according to the N types of reader sending parameters set in step S1, and use the high-efficiency comparison method or the high-quality comparison method to perform tag authentication based on the tag backscattering frequency shown by the tag under different reader sending parameters. The high-efficiency comparison method is specifically as follows: Perform tag authentication. The high-efficiency comparison method is specifically as follows: Traverse the N types of transmission parameters set in step S1 of the reader sending parameters. Each type of transmission parameter is sent only once, collect the RN16 returned by the target tag, and calculate the characteristics under each parameter, and compare them with the distribution map during the normalization process when registering the characteristics in step S1. Use the values in the distribution map as probabilities, multiply the N probabilities under the N types of transmission parameters to obtain the probability of whether the corresponding tag is a legal tag. Compare the probability of whether the tag is a legal tag with the threshold. Tags with probabilities higher than the threshold are regarded as legal tags. If the probability is lower than the threshold, use the high-quality comparison method for tag authentication or directly identify it as an illegal tag; The high-quality comparison method is specifically as follows: The reader traverses the N types of transmission parameters set in step S1 of the transmission parameter, and each type of transmission parameter is transmitted M times. Both N and M are the same as those at the time of tag registration, and collect the distribution. After normalization, compare it with the distribution map at the time of tag registration. Tags with a comparison result greater than the threshold are regarded as legal tags, otherwise they are directly identified as illegal tags.

2. The tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag according to claim 1, characterized in that In step S1, the parameters sent by the reader include the division ratio and the tag-reader calibration signal.

3. The tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag according to claim 1, characterized in that, In step S1, N is greater than or equal to 8 times, and M is greater than or equal to 200 times.

4. The tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag according to claim 1, characterized in that, In step S1, the tag backscattering frequency Specifically: wherein, and are the division ratio and the tag-reader calibration signal, respectively.

5. The tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag according to claim 4, wherein Label backscattering frequency The fluctuation range under given reader transmission parameters is 4% to 22%, and the fluctuation range of the same label under the same parameters is 2.5%.

6. The tag authentication method for the physical layer characteristics of the ultra-high frequency radio frequency identification tag according to claim 1, wherein The comparison method uses the DL divergence.

7. A tag authentication system for the physical layer characteristics of ultra-high frequency radio frequency identification tags, characterized in that, Including: Registration module, select N different reader sending parameters, send M Query signals under each reader sending parameter, collect RN16 replied by the target tag, and generate the tag backscattering frequency under different reader sending parameters according to the collection results for distribution and normalization processing to complete tag feature registration; The authentication module sends reader commands according to the N types of reader sending parameters set by the registration module, and uses the high-efficiency comparison method or the high-quality comparison method to perform tag authentication based on the tag backscattering frequency exhibited by the tag under different reader sending parameters The high-efficiency comparison method for performing tag authentication is specifically as follows: Traverse the N sending parameters set by the reader, send each sending parameter only once, collect the RN16 returned by the target tag, and calculate the features under each parameter, and compare them with the distribution map during the normalization process when registering the features in step S1. Take the values in the distribution map as probabilities, multiply the N probabilities under the N sending parameters to obtain the probability of whether the corresponding tag is a legal tag, compare the probability of whether the tag is a legal tag with the threshold, take the tags higher than the threshold as legal tags. If the probability is lower than the threshold, use the high-quality comparison method for tag authentication or directly determine it as an illegal tag; The high-quality comparison method is specifically as follows: Traverse the N sets of transmission parameters sent by the reader, each set of transmission parameters is sent M times, where N and M are the same as those during tag registration, and collect the distribution. After normalization, compare it with the distribution map during tag registration. Tags with a comparison result greater than the threshold are regarded as legal tags, otherwise they are directly identified as illegal tags.

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