LoRa physical layer data tamper-proofing method based on signal orthogonality

Abstract

The application discloses a LoRa physical layer data tamper-proofing method based on signal orthogonality, which comprises the following steps: obtaining a to-be-embedded position based on a payload in LoRa physical layer data; embedding original mark information in the to-be-embedded position to obtain a composite signal; transmitting the composite signal; decoding the composite signal to obtain a position change condition of the original mark information in transmission; and obtaining a judgment result of whether the LoRa physical layer data is tampered with based on the position change condition. The LoRa physical layer data tamper-proofing method based on signal orthogonality fully utilizes inherent characteristics of LoRa physical layer signals, embeds mark information in the form of low-power and low-spread factor orthogonal signals into a frequency spectrum leakage area of LoRa physical layer data, and realizes high-security data transmission without significantly increasing hardware complexity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of data security, and in particular to a LoRa physical layer data tamper-proofing method based on signal orthogonality. BACKGROUND

[0002] With the popularity of intelligent charging piles, LoRa-based intelligent charging piles have become common. The importance of network security in new energy vehicle charging infrastructure, such as charging piles, is increasing. Charging equipment networks may face the risk of multiple network attacks. For example, if a large number of devices are charged uncontrollably, illegal communication or disconnection may have a potential impact on the local power distribution network. Specifically, if the LoRa data sent by the charging pile is tampered with, it is easy to cause electricity stealing behavior.

[0003] A Chinese invention patent with the authorized publication number CN111614648B discloses an industrial Internet of Things anti-active eavesdropping physical layer security transmission method, but the implementation of the invention is too complex, especially the complex data processing process is not suitable for large-scale use of charging piles.

[0004] In summary, there is an urgent need for a new data tamper-proofing method that balances the use cost while improving the data security of charging piles. SUMMARY

[0005] The main purpose of the present application is to provide a LoRa physical layer data tamper-proofing method based on signal orthogonality, which aims to solve the technical problems of poor data security of charging piles in the prior art and high cost of maintaining the data security of charging piles.

[0006] To achieve the above-mentioned purpose, the present application provides a LoRa physical layer data tamper-proofing method based on signal orthogonality, which comprises the following steps:

[0007] S1: obtaining a to-be-embedded position based on the payload in the LoRa physical layer data;

[0008] S2: embedding original marker information into the to-be-embedded position corresponding to the payload in the LoRa physical layer data to obtain a composite signal; wherein the position change of the original marker information in transmission is used to determine whether the LoRa physical layer data is tampered with;

[0009] S3: transmitting the composite signal from a preset sending end to a preset receiving end;

[0010] S4: decoding the composite signal at the receiving end to obtain the position change of the original marker information in transmission;

[0011] S5: obtaining a judgment result of whether the LoRa physical layer data is tampered based on the position change, the judgment result including that the LoRa physical layer data has been tampered and that the LoRa physical layer data has not been tampered.

[0012] As preferred, the obtaining the to-be-embedded position based on the payload in the LoRa physical layer data comprises:

[0013] obtaining a spectrum corresponding to the payload in the LoRa physical layer data, obtaining a leakage position of the spectrum based on a spectrum feature corresponding to the spectrum, and defining the leakage position as the to-be-embedded position.

[0014] As preferred, the leakage position is a position corresponding to a jump from a highest frequency position of a chirp pulse of the payload in the LoRa physical layer data to a lowest frequency position.

[0015] As preferred, the original marking information is set to be orthogonal to the LoRa physical layer data at the to-be-embedded position.

[0016] As preferred, the original marking information is further set to be encoded based on the required identity information, and a result of the encoding is used for identity authentication.

[0017] As preferred, the embedding the original marking information into the to-be-embedded position corresponding to the payload in the LoRa physical layer data to obtain a composite signal comprises:

[0018] determining a power ratio between a power of the original marking information and a power of the payload based on a spreading factor of the original marking information, a spreading factor of the payload, and an encoding condition of the original marking information when embedding the original marking information into the to-be-embedded position;

[0019] obtaining the power of the original marking information based on the power ratio and embedding the original marking information after setting into the to-be-embedded position to obtain the composite signal.

[0020] As preferred, the preset transmitting end transmits the composite signal to a preset receiving end, comprising:

[0021] determining a repetition number of transmission of the original marking information based on a difference between the spreading factor of the original marking information and the spreading factor of the payload when the transmitting end transmits the composite signal, and repeatedly transmitting based on the repetition number.

[0022] As preferred, a calculation formula of the repetition number is:

[0023]

[0024] wherein, a repetition number calculated, a spreading factor of the payload, a spreading factor of the original mark information.

[0025] As preferred, the receiving end decodes the composite signal to obtain the position change of the original mark information in transmission, including:

[0026] Obtaining the spectrum of the composite signal, based on the spectrum feature corresponding to the spectrum, obtaining the new position corresponding to the original mark information, comparing the new position with the to-be-embedded position to obtain the position change.

[0027] As preferred, the judgment result of whether the LoRa physical layer data is tampered based on the position change, including:

[0028] When the new position corresponding to the original mark information is still in the to-be-embedded position, the judgment result is that the LoRa physical layer data is not tampered;

[0029] When the new position corresponding to the original mark information is not in the to-be-embedded position, the judgment result is that the LoRa physical layer data is tampered.

[0030] Beneficial effects: the LoRa physical layer data anti-tampering method based on signal orthogonality of the application makes full use of the inherent characteristics of the LoRa physical layer signal, embeds the mark information in the form of low-power and low-spreading factor orthogonal signal into the spectrum leakage area of the LoRa physical layer data, realizes high-security data transmission without significantly increasing the hardware complexity, has the ability of anti-eavesdropping, anti-tampering and identity verification, effectively prevents illegal device access and data injection attacks; at the same time, it is compatible with existing LoRa communication equipment, without additional security chips or complex peripheral circuits, has the advantages of low deployment cost, strong universality and good environmental adaptability, and maintains the original long-distance transmission and low-power characteristics of LoRA, which is very suitable for widely distributed and power-limited intelligent charging pile scenarios, and can realize stable and reliable long-distance secure communication in complex electromagnetic environment. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0032] Figure 1 The LoRa physical layer data anti-tampering method based on signal orthogonality provided by the embodiment of the application is aimed at an attack model;

[0033] Figure 2 A flowchart of the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application is shown in the figure.

[0034] Figure 3 The frequency spectrum leakage effect when the orthogonal signal is embedded in the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application;

[0035] Figure 4 The frequency spectrum leakage effect when the orthogonal signal is not embedded in the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application;

[0036] Figure 5 The initial frequency of the decoded original data in the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application;

[0037] Figure 6 The initial frequency of the decoded orthogonal signal in the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application;

[0038] Figure 7 The time domain single-sided amplitude spectrum of the visual signal in the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application;

[0039] Figure 8 The LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application is shown in the figure.

[0040] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0041] It should be understood that the specific embodiments described herein are intended to explain the present application and are not intended to limit the present application.

[0042] LoRa (Long Range Radio) is a low-power wireless standard designed to address the trade-off between power consumption and transmission range. Generally, low power consumption results in short transmission range, and high power consumption results in long transmission range. LoRa technology solves the technical problem of transmitting farther than other wireless methods under the same power consumption conditions, achieving a balance between low power consumption and long transmission range. LoRa is a wireless communication scheme based on CSS (Chirp Spread Spectrum) spread spectrum modulation technology. Its working principle is to generate a "chirp" signal (i.e., a linear frequency modulation pulse) through linear frequency modulation (LFM). The carrier frequency of each data packet changes linearly with time. This modulation method allows the signal to maintain good penetration and anti-multipath fading capability in strong interference environments, thereby achieving long-distance transmission. LoRa technology uses forward error correction coding (FEC) to enhance the reliability of data transmission, ensuring a certain level of data integrity even in low signal strength conditions. In addition, it supports multiple spreading factor options to adapt to different transmission rate and distance requirements. Given the significant advantages of LoRa in terms of coverage distance and deployment cost, LoRa has been widely deployed in various IoT scenarios in recent years, such as smart meters (e.g., smart water meters and smart electricity meters), smart cities, intelligent transportation data collection, and wildlife monitoring.

[0043] The security mechanism of the traditional LoRa protocol uses the AES-128 encryption algorithm to encrypt data to ensure the security of wireless communication. However, there are some security vulnerabilities in the key update and session key generation of LoRaWAN. Specifically, although LoRaWAN uses encryption keys for several security mechanisms such as authentication, encryption, and integrity checking, the partial update of these keys provided by the current LoRaWAN specification may require end nodes to continue using certain keys without changing them during their lifetime in some cases. Therefore, at some point in the future, if the keys are compromised, all data on the end nodes can be passed to the attacker. Each session key is used in different layers, which may violate the independence between layers if the current method of creating two session keys only by the network server.

[0044] Referring to Figure 1 , as shown, Figure 1The LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application is aimed at an attack model. In the attack model, a legal user sends a charging request to a charging pile, and the charging pile sends charging data to the legal user for charging. However, in this process, an attacker may intercept the communication data between the legal user and the charging pile and tamper with the data. The embodiment designs to embed an orthogonal signal at the spectrum leakage of the payload data of the LoRa data packet to realize the data tamper-proofing function, so as to combine the traditional LoRa security mechanism with the physical layer security solution, so as to further improve the security of the system and the data tamper-proofing property.

[0045] Specifically, the embodiment of the present application provides a LoRa physical layer data tamper-proofing method based on signal orthogonality. Figure 2 , Figure 2 The flowchart of the LoRa physical layer data tamper-proofing method based on signal orthogonality provided by the embodiment of the present application is shown in the figure, and the method comprises the following steps:

[0046] S1: obtaining a to-be-embedded position based on the payload in the LoRa physical layer data.

[0047] Specifically, obtaining the to-be-embedded position based on the payload in the LoRa physical layer data comprises:

[0048] Obtaining the spectrum corresponding to the payload in the LoRa physical layer data, obtaining the leakage position of the spectrum based on the spectrum feature corresponding to the spectrum, and defining the leakage position as the to-be-embedded position.

[0049] Specifically, the leakage position is the position corresponding to the jump from the highest frequency to the lowest frequency of the chirp pulse of the payload in the LoRa physical layer data.

[0050] It should be noted that the prior art mainly inserts the signal orthogonal to the payload into the data itself and encodes the signal orthogonal to the payload into the inter-packet delay to improve the security of LoRa by using the signal orthogonal technology. However, there is a step deficiency caused by the insertion position. Therefore, the insertion position is optimized in the embodiment.

[0051] Specifically, the original mark information is set to be orthogonal to the LoRa physical layer data at the to-be-embedded position.

[0052] In combination with the optimization of the embodiment, the deficiencies of the prior art are analyzed as follows:

[0053] (1) The shortcomings of inserting the orthogonal signal into the data itself

[0054] Inserting the orthogonal signal into the data itself means constraining the change in the transmitted message to the least significant bits (LSB) of the transmitted data word. The incoming data is first buffered into fixed-size groups. Then, a hash function with a fixed output size is applied to the concatenated payload bytes, including the key and the sequence number. In the next step, each bit from the hash is used to replace the LSB of a specific data word in the current group.

[0055] This method has the disadvantage of changing the payload data. For many data types, such as binary values, counters (rpm) or other noiseless data, the "invisibility" property of the orthogonal signal cannot be maintained when the data changes.

[0056] In contrast, the method of the present embodiment is to embed a signal orthogonal to the payload at the spectral leakage of the payload data, without changing the original payload data, and the orthogonal signal has invisibility.

[0057] (2) Disadvantages of encoding the orthogonal signal into inter-packet delay

[0058] The principle of encoding the orthogonal signal into the inter-packet delay is to combine the concept of sensor data orthogonal signal with side channel exploitation to meet the integrity protection of sensor data without sacrificing the payload size of the message authentication code (MAC). Practical experiments using LoRaWAN over the Internet of Things (TTN) show that the orthogonal signal can be embedded in the side channel without significantly changing the channel characteristics, making security completely transparent to the original data transmission, both in terms of payload and timing characteristics.

[0059] In contrast, the design of the present embodiment does not need to consume extra channels, but directly embeds the orthogonal signal into the spectral leakage of the payload data of the physical layer of the LoRa data packet, saving energy consumption. And the only prerequisite of this method is that it needs continuous and predictable data transmission, i.e. applications that send data within a defined time slot mode, and our design does not need it.

[0060] Based on the above, the advantages of the present embodiment compared to the above two insertions are:

[0061] Using the existing LoRa signal orthogonal technology to realize a system that can enhance the security of LoRa data, prevent tampering, and has identity verification function, which can be applied to intelligent charging piles. The system has the characteristics of simple device composition, high universality, no strict requirements on the environment, high security, high tamper-proofing ability, identity verification, long transmission distance, low power consumption, etc.

[0062] As a preferred embodiment of the present embodiment, the original marking information is also set to be encoded based on the required identity information, and the result of the encoding is used for identity verification.

[0063] By the above, the embodiment realizes the security of LoRa physical layer data by combining the traditional security mechanism with the unique properties of the physical layer, which embeds the signal orthogonal to the payload at the payload spectrum leakage, has good concealment, and when the data is tampered with, the position of the signal orthogonal to the payload will change obviously, and it will be known that the data packet is tampered data. In addition, by encoding the orthogonal signal through the existing encoding technology, the identity information can be carried, and the function of identity authentication of the sender at the receiving end is further realized.

[0064] S2: embedding the original mark information into the to-be-embedded position corresponding to the payload in the LoRa physical layer data to obtain a composite signal; wherein the position change of the original mark information in transmission is used to judge whether the LoRa physical layer data is tampered with.

[0065] Specifically, the original mark information is embedded into the to-be-embedded position corresponding to the payload in the LoRa physical layer data to obtain a composite signal, comprising:

[0066] When embedding the original mark information into the to-be-embedded position, the power ratio between the power of the original mark information and the power of the payload is determined based on the spreading factor of the original mark information, the spreading factor of the payload, and the encoding condition of the original mark information;

[0067] The power of the original mark information is obtained based on the power ratio and set, and the set original mark information is embedded into the to-be-embedded position to obtain a composite signal.

[0068] The original mark information of the embodiment adopts an orthogonal signal. When the orthogonal signal is embedded into the spectrum leakage from the highest frequency of the payload data to the lowest frequency, the larger the difference between the spreading factors SF of the payload and the orthogonal signal, the better the hiding effect. Referring to Figure 3 , which is the embedding effect corresponding to the spreading factor SF=10 of the payload and the spreading factor SF=6 of the orthogonal signal. Figure 4 is the spectrum leakage effect when the orthogonal signal is not embedded. In order to make the orthogonal signal have better concealment, the orthogonal signal power should be small, so as to achieve the similar intensity and leakage brightness in the figure. Figure 4 The power ratio of the orthogonal signal power to the payload power set in the embodiment is 1:2, as shown in Figure 4 , it can be seen that the hiding effect is good. Of course, the smaller the power and the smaller the spreading factor SF, the better the hiding effect, but the encoding of the orthogonal signal and the subsequent demodulation should be considered. If the spreading factor SF is too small, it cannot carry enough encoding information, and if the power is too small, the orthogonal signal information may be buried in the noise, so that the orthogonal signal information cannot be correctly extracted. Combined with Figure 3 and Figure 4A small piece of chirp intercepted in the entire payload data and amplified, after comparison, it can be clear that in the condition of power ratio of 1:2, the effect of orthogonal signal embedding is good hidden effect relative to the overall payload.

[0069] S3: The preset sending end transmits the composite signal to the preset receiving end;

[0070] In a specific application of the embodiment, two USRPs (Universal Software Radio Peripheral) are used as the preset sending end and the preset receiving end, one for sending signals and the other for receiving signals, and GNU Radio (open source software radio) is used to realize the transmission. The environment requirement is relatively small, and it can be used indoors or outdoors. The transmission and reception distance can reach about one hundred meters in an outdoor environment. After the data to be sent is embedded in the corresponding orthogonal signal code, the data packet is written into the flowchart of GNU Radio, and then the data is sent through the USRP. After receiving the data packet, the other USRP stores it in the corresponding file through GNU Radio for subsequent extraction and decoding of the original signal and the orthogonal signal.

[0071] Specifically, the preset sending end transmits the composite signal to the preset receiving end, including:

[0072] When transmitting the composite signal at the sending end, the number of repetitions of the transmission of the original marker information is determined based on the difference between the spreading factor of the original marker information and the spreading factor of the payload, and the repeated transmission is performed based on the number of repetitions.

[0073] In actual application, the larger the spreading factor SF in LoRa is, the farther the transmission distance is. The spreading factor SF determines the speed and distance of data transmission, while the signal-to-noise ratio limit decreases with the increase of SF. Generally, for every increase of 1 in the spreading factor SF, the signal-to-noise ratio limit decreases by 2.5 dB. The reception sensitivity S is proportional to the signal-to-noise ratio limit. In the case of no electromagnetic interference in the line of sight, the wireless communication in the ideal environment follows the following formula:

[0074]

[0075] wherein, is the transmitter power.

[0076] Combined with some constant parameters such as the gain of the receiving antenna, the gain of the transmitting antenna, the carrier frequency, and the distance between the receiving antenna and the transmitting antenna, the ratio of the distance between two different spreading factors SF is:

[0077]

[0078] Assuming the number of repetitions of the orthogonal signal is The gain of the signal-to-noise ratio is expressed as follows:

[0079]

[0080] In theory, when the spreading factor SF differs by 4, a gain of 10 dB needs to be added to achieve equivalence, which means should be equal to 10. However, in order to hide the orthogonal signal, its power will be reduced, which will also affect its transmission distance. Therefore, more repetitions are needed to enhance the transmission range. Based on the above analysis, the number of repetitions required to ensure transmission quality is determined by the calculation formula of the number of repetitions.

[0081] Specifically, the calculation formula of the number of repetitions is:

[0082]

[0083] wherein, is the calculated number of repetitions, is the spreading factor of the payload, is the spreading factor of the original marking information.

[0084] S4: The receiving end decodes the composite signal to obtain the position change of the original marking information in transmission.

[0085] Specifically, the receiving end decodes the composite signal to obtain the position change of the original marking information in transmission, including:

[0086] Obtaining the spectrum of the composite signal, based on the spectrum features corresponding to the spectrum, obtaining the new position of the original marking information, comparing the new position with the position to be embedded, and obtaining the position change.

[0087] Based on the conventional analysis method, we decode the received signal in Matlab. The decoding results are shown in Figure 5 , 6 and 7. Among them Figure 5 and Figure 6 are the initial frequencies of the decoded original data and the orthogonal signal, respectively. We can compare the initial transmitted data packet to see if the data has been tampered with. Figure 7 is the time-domain one-sided amplitude spectrum of the visual signal. Figure 7 The points on the horizontal coordinate represent different time sample values, and the points on the vertical coordinate represent the signal amplitude at these samples.

[0088] S5: Based on the position change, a judgment result of whether the LoRa physical layer data has been tampered with is obtained, including that the LoRa physical layer data has been tampered with and that the LoRa physical layer data has not been tampered with.

[0089] Since we embed the orthogonal signal at the spectrum leakage from the highest frequency jump to the lowest frequency of the data, once the data is tampered, the position of the orthogonal signal will not be in the spectrum leakage of the tampered data, not only can be seen by the above-mentioned corresponding sending data and receiving data packet initial frequency, but also can be seen by directly drawing the received data packet, as shown in Figure 8 The figure after embedding the orthogonal signal normally is Figure 3 , Figure 8 After tampering the data, it is obvious that the position of the orthogonal signal will change.

[0090] Specifically, based on the position change, the judgment result of whether the LoRa physical layer data is tampered is obtained, including:

[0091] When the new position corresponding to the original mark information is still in the embedding position, the judgment result is that the LoRa physical layer data is not tampered;

[0092] When the new position corresponding to the original mark information is not in the embedding position, the judgment result is that the LoRa physical layer data is tampered.

[0093] Through the above, we realize a set of system which can be very simple and has strong anti-tamper function of embedding the orthogonal signal at the spectrum leakage from the highest frequency jump to the lowest frequency of the LoRa effective data payload. In addition, we encode the orthogonal signal to send the sender identity information, and through demodulation, the end-to-end identity verification function can also be realized simply.

[0094] In summary, the embodiment has the following beneficial effects:

[0095] Firstly, the security improvement scheme based on the physical layer can further improve the security of the system and the anti-tamper property of the data by complementing the traditional LoRa security mechanism with the physical layer security solution.

[0096] Secondly, the orthogonal signal can be encoded. According to the used scene, if the security does not need to be high, a simple password can be encoded, and if the security requirement is high, the sender identity information can be encoded to realize the identity verification function of the receiving end to the sending end.

[0097] Finally, the whole set of equipment is easy to deploy and can be used in indoor and outdoor environments, has high practical value and market prospect, and has a wide range of applications.

[0098] It is proved that the tamper-proofing method of embedding the orthogonal signal at the spectrum leakage of the LoRa data packet payload data is feasible through experiments. The experiments show that embedding the orthogonal signal at the spectrum leakage from the highest frequency to the lowest frequency has good concealment and does not affect the original data transmission. And once the data is tampered with, the receiving end will easily find it due to the existence of the orthogonal signal. In the scene with higher security requirements, we can also encode the identity information for the orthogonal signal to realize the identity authentication of the receiving end and the sending end. In summary, the whole technology shows good working performance, has the advantages of low power consumption and high security, and can meet the needs of balancing the use cost of the intelligent charging pile while improving the data security of the charging pile.

[0099] It should be understood that the above is only illustrative, and does not constitute any limitation on the technical solutions of the present application. In specific applications, those skilled in the art can set it up according to the needs, and the present application does not limit this.

[0100] It should be noted that the above-described workflow is only illustrative and does not limit the scope of protection of the present application. In actual application, those skilled in the art can select part or all of them to achieve the purpose of the embodiment scheme according to actual needs, which is not limited here.

[0101] It should be noted that in this paper, the term "includes", "contains" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or system. Without more limitations, the element defined by the sentence "includes a" does not exclude the presence of another identical element in the process, method, article or system including the element.

[0102] From the above description of the embodiments, those skilled in the art can clearly understand that the above embodiment method can be realized by software plus the necessary general hardware platform, of course, it can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory / random access memory, a magnetic disk, an optical disk) and includes a plurality of instructions for making a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) execute the method described in each embodiment of the present application.

[0103] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application, and any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which are made by using the content of the present application specification and drawings, are also included in the patent protection scope of the present application.

Claims

1. A LoRa physical layer data anti-tampering method based on signal orthogonality, characterized in that, The method includes the following steps: S1: Based on the payload in the LoRa physical layer data, the embedding location is obtained; S2: Embed the original tag information into the payload corresponding to the position to be embedded in the LoRa physical layer data to obtain a composite signal; wherein, the position change of the original tag information during transmission is used to determine whether the LoRa physical layer data has been tampered with; S3: The preset transmitting end transmits the composite signal to the preset receiving end; S4: The receiving end decodes the composite signal to obtain the positional changes of the original marker information during transmission; S5: Based on the location change, obtain a judgment result on whether the LoRa physical layer data has been tampered with. The judgment result includes whether the LoRa physical layer data has been tampered with or not. The payload based on the LoRa physical layer data is used to obtain the embedding location, including: Obtain the spectrum corresponding to the payload in the LoRa physical layer data, and based on the spectral characteristics of the spectrum, find the leakage point of the spectrum, and define the leakage point as the embedding location; The leakage point is the location where the frequency of the linear frequency modulated pulse of the payload in the LoRa physical layer data jumps from the highest frequency to the lowest frequency. The original tag information is set to be orthogonal to the LoRa physical layer data at the location to be embedded.

2. The LoRa physical layer data anti-tampering method based on signal orthogonality as described in claim 1, characterized in that, The original tag information is also set to be encoded based on the required identity information, and the result of this encoding is used for authentication.

3. The LoRa physical layer data anti-tampering method based on signal orthogonality as described in claim 2, characterized in that, The process of embedding the original marker information into the LoRa physical layer data at the location corresponding to the payload to be embedded, to obtain a composite signal, includes: When embedding the original tag information into the embedding position, the power ratio between the power of the original tag information and the power of the payload is determined based on the spreading factor of the original tag information, the spreading factor of the payload, and the encoding of the original tag information. Based on the power ratio, the power of the original marker information is obtained and set. The set original marker information is then embedded into the position to be embedded to obtain the composite signal.

4. The LoRa physical layer data anti-tampering method based on signal orthogonality as described in claim 1, characterized in that, The preset transmitting end transmits the composite signal to the preset receiving end, including: When transmitting the composite signal at the transmitting end, the number of repetitions of the original tag information transmission is determined based on the difference between the spreading factor of the original tag information and the spreading factor of the payload, and repeated transmission is performed based on the number of repetitions.

5. The LoRa physical layer data anti-tampering method based on signal orthogonality as described in claim 4, characterized in that, The formula for calculating the number of repetitions is: in, To calculate the number of repetitions, The spreading factor of the payload. The spreading factor is the original tag information.

6. The LoRa physical layer data anti-tampering method based on signal orthogonality as described in claim 1, characterized in that, The receiving end decodes the composite signal to obtain the positional changes of the original marker information during transmission, including: The spectrum of the composite signal is obtained. Based on the spectral features corresponding to the spectrum, a new position corresponding to the original tag information is obtained. The new position is compared with the position to be embedded to obtain the position change.

7. The LoRa physical layer data anti-tampering method based on signal orthogonality as described in claim 6, characterized in that, The determination of whether LoRa physical layer data has been tampered with based on the location change includes: When the new location corresponding to the original tag information is still in the location to be embedded, the judgment result is that the LoRa physical layer data has not been tampered with; When the new location corresponding to the original tag information is not in the location to be embedded, the judgment result is that the LoRa physical layer data has been tampered with.

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