Physical layer security communication method against eavesdropping attack

Abstract

This invention discloses a physical layer secure communication method to counter eavesdropping attacks. The communication process consists of two time slots. In the first time slot, a roadside base station selects an antenna to transmit a NOMA signal, while nearby and distant user vehicles simultaneously transmit artificial noise to interfere with the eavesdropping user vehicle. In the second time slot, the nearby user vehicle acts as a relay node, XORing the decoded distant user message with the artificial noise signal generated in the first time slot, and then sending the mixed signal to the distant user vehicle. The distant user vehicle simultaneously transmits artificial noise to interfere with the eavesdropping user. In the vehicle-to-everything (V2X) network, the nearby user, the distant user, and the eavesdropping user calculate their respective required signal-to-interference-plus-noise ratio (SIR) based on the received signals, and calculate the system user's interruption probability and interception probability. Compared with existing secure communication schemes in V2X networks, the secure communication scheme of this invention can significantly enhance the physical layer security of nearby and distant user vehicles.

Description

Technical Field

[0001] This invention belongs to the field of vehicle network communication security technology, and more specifically, relates to a physical layer secure communication method to combat eavesdropping attacks. Background Technology

[0002] With the increasing prevalence of automobiles, they are becoming more and more integrated into people's daily lives, leading to higher demands for vehicle information transmission. Traditional intelligent transportation systems can no longer meet these communication needs. The rapid development of wireless communication technology, especially the Internet of Things (IoT), has brought significant progress to in-vehicle wireless communication technology. The combination of in-vehicle communication and IoT technology, forming a wireless communication network with vehicles as nodes, is the Internet of Vehicles (IoV). The development of IoV technology enables in-vehicle office work, navigation, entertainment, and monitoring, while also placing higher demands on data transmission. NOMA (Noise, Noise, and Mahine) data transmission technology allows multiple different users to share spectrum resources, improving the utilization rate of wireless spectrum resources. Applying NOMA communication technology to IoV improves the service quality of in-vehicle communication.

[0003] NOMA technology allows more vehicle users to connect to the vehicle-to-everything (V2X) network, expanding the coverage of V2X signals. However, the broadcast nature of wireless signals makes data transmission within the V2X network vulnerable to eavesdropping attacks, posing a serious challenge to the security of V2X data transmission. In recent years, emerging physical layer security technologies have emerged that can effectively combat eavesdropping attacks in V2X networks, enhancing the security of system data transmission. Physical layer security technologies primarily utilize the physical characteristics of wireless signals and channels to construct secure communication schemes, counteract eavesdropping attacks, and achieve secure communication. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a physical layer secure communication method to combat eavesdropping attacks. It combines artificial noise technology and one-time pad encryption technology in physical layer security to construct a novel physical layer secure communication method. Compared with traditional physical layer secure communication schemes in vehicle-to-everything (V2X) networks, the secure communication method proposed in this invention can significantly enhance the confidentiality performance of V2X networks.

[0005] A vehicle-mounted embedded platform, a driver gaze point detection method and system with strong anti-interference capabilities and no need for additional equipment.

[0006] To address at least one of the aforementioned technical problems, according to one aspect of the present invention, a physical layer secure communication method for resisting eavesdropping attacks is provided, comprising the following steps:

[0007] In the first time slot, equipment Roadside base station with one antenna Select an antenna based on channel state information to transmit the NOMA signal. Send to nearby user vehicles acting as relays ; in the signal middle, and The roadside base station sends data to nearby user vehicles. information Heyuan vehicles information The power allocation factor, and , The full-duplex near-user vehicle, acting as a relay, receives the NOMA signal from the source while simultaneously transmitting artificial noise signals. Interfering with eavesdropping users The two-antenna vehicle, acting as a remote user, operates in full-duplex mode, simultaneously receiving signals and transmitting artificial noise signals. The eavesdropping attack is weakened; then, the near-user vehicle, the far-user vehicle, and the eavesdropping user vehicle calculate their respective required signal-to-interference-plus-noise ratios based on the received signals.

[0008] In the second time slot, the vehicle closest to the user acts as a relay node, first decoding the source message. and Then Artificial noise in the first time slot Looking at the bit string, XORing and adding the two signals together, we get the signal. Finally, the signal is sent to the remote user vehicle; while receiving the signal, the remote user vehicle simultaneously sends an artificial noise signal. Interfering with eavesdroppers; in this vehicle-to-everything (V2X) communication system, the channel state information of different channels is independent of each other, and the channel state information of the same channel in different time slots is independent of each other, and the eavesdropping user is a strong eavesdropper; then, the remote user vehicle and the vehicle acting as the eavesdropper calculate the corresponding signal-to-interference-plus-noise ratio (SIR) based on their respective received signals.

[0009] Finally, based on the signal-to-interference-plus-noise ratio (SIR) of the near-user vehicle, the far-user vehicle, and the external eavesdropping vehicle, the interruption probability and interception probability of each user vehicle in the vehicle-to-everything (V2X) communication system are calculated.

[0010] The first time slot full-duplex near-user vehicle As a remote user vehicle Friendly interference nodes can eliminate artificial noise signals transmitted by distant user vehicles, while nearby user vehicles act as relay nodes, based on the NOMA signals they receive. The decoded signal can be calculated. and The signal-to-interference-plus-noise ratios are as follows:

[0011]

[0012]

[0013] in, This indicates the base station selected as the information source. Channel state information from the root antenna to the nearest user vehicle. The power at which the base station transmits NOMA signals. For residual self-interference, The residual self-interference channel coefficient near the user, This refers to the Gaussian white noise power at the near-user vehicle location. Because the near-user signal, acting as a relay node in the vehicle-to-everything (V2X) network, uses digital network coding technology to encode the far-user signal, the far-user vehicle needs to decode the artificial noise signal. Only then can we obtain information from the source. The artificial noise signal decoded by the remote user vehicle can be obtained through calculation. The signal noise is as follows:

[0014]

[0015] in, This refers to the channel state information from near-user vehicles to far-user vehicles. For residual self-interference, For the residual self-interference channel coefficient of distant users, It is the Gaussian white noise power at the remote user vehicle;

[0016] eavesdropping on users It is necessary to steal source messages based on the NOMA signal in the first time slot. and Because the relay node uses digital network coding technology to construct the signal in the second time slot. And transmit it, so the eavesdropper needs to decode the artificial noise signal. Based on the NOMA transmission mechanism, the first time slot is used to eavesdrop on vehicles. The signal-to-interference-plus-noise ratios (SIRs) for each signal are as follows:

[0017]

[0018]

[0019]

[0020] in, , and These are the channel state information from the base station, the nearby user vehicle, and the distant user vehicle to the eavesdropping user. To steal the Gaussian white noise power from the user's location.

[0021] The first time slot serves as a relay node for full-duplex near-user vehicle decoding messages. and Signal-to-interference-plus-noise ratio, remote user vehicle decoding of artificial noise signals Signal-to-interference-to-noise ratio, eavesdropping on user vehicle decoding messages , and The signal-to-interference-plus-noise ratio (SIR) calculation process is as follows: First, the roadside base station, as the signal source, from... One antenna is selected from the root antennas to transmit the NOMA signal. The specific antenna selection rules are as follows:

[0022]

[0023] in, A set consisting of antenna labels. Indicates the first Root antenna to the user vehicle Channel state information; base station The selected antenna transmits a NOMA signal, while simultaneously transmitting artificial noise signals near the user's vehicle to receive the signal. Remote user vehicles also send artificial noise signals. To mitigate eavesdropping attacks; since the distant user vehicle is a friendly interference node for the near user vehicle, the near user vehicle can eliminate the artificial noise signals transmitted by the distant user vehicle. Therefore, the received signals of the near user vehicle, the distant user vehicle, and the eavesdropping user vehicle are as follows:

[0024]

[0025]

[0026]

[0027] in, , and Let $\mathbf{ ... , and The signal-to-interference-plus-noise ratio (SIR) for eavesdropping on user vehicles and decoding the required messages based on the received signals is as follows: , and .

[0028] After the second time slot signal transmission ends, the remote user vehicle needs to decode the signal. The corresponding signal-to-interference-plus-noise ratio is calculated as follows:

[0029]

[0030] in, This represents the channel state information from the near-user vehicle to the far-user vehicle in the second time slot. The near-user vehicle acts as a relay node, and the power of its transmitted signal is... , For residual self-interference, For remote user vehicles, residual self-interference channel coefficients are required; eavesdropping users also need to decode. Combined with the signal obtained from decoding the first time slot Perform an XOR operation to obtain the signal. Based on the received signal, the decoding of the eavesdropping user is calculated. The signal-to-interference-plus-noise ratio is:

[0031]

[0032] in, and These represent the channel state information from the near-user vehicle and the far-user vehicle to the eavesdropping user vehicle in the second time slot, respectively. The power of sending artificial noise signals for the second time slot of remote user vehicles;

[0033] The signal-to-interference-plus-noise ratio (SIR) calculation process for the received signal in the second time slot is as follows: the second time slot near the user vehicle acts as a relay node, transmitting the signal encoded by the digital network. To the remote user vehicle, the remote user vehicle simultaneously sends artificial noise signals. The signal received by the eavesdropping user is weakened, resulting in the following differences between the signals received by the remote user's vehicle and the eavesdropping user's vehicle:

[0034]

[0035]

[0036] The remote user vehicle calculates the nearby user's decoded signal based on the received data. The signal-to-interference-plus-noise ratio is To eavesdrop on user vehicles and steal information from the source, it is also necessary to decode the signal. The decoded signal is calculated. The signal-to-interference-plus-noise ratios are respectively .

[0037] The process for calculating the outage probability of two NOMA users in the vehicle network is as follows: In the first time slot, according to the NOMA criterion, as long as the condition is met... and The source message can be successfully decoded when it is near the user's vehicle. and Based on this analysis, the user vehicle decoding message... The interruption probability is:

[0038]

[0039] For remote user vehicles to be successfully decoded First, the nearest user vehicle, acting as a relay, needs to successfully decode in the first time slot. and The remote user's vehicle also needs to meet the conditions. and In this way, the remote user vehicle can successfully decode the message. Therefore, the probability of vehicle outage for remote users in this vehicle-to-everything (V2X) network is:

[0040]

[0041] Messages sent to nearby user vehicles and distant user vehicles and The interception probability calculation process is as follows: eavesdropping on user vehicles to steal signals The method is to directly decode the eavesdropped mixed signal, therefore, the message The probability of being eavesdropped on is:

[0042]

[0043] Eavesdropping on user vehicles and stealing information from remote user vehicles There are two approaches: one is to directly decode the remote user message from the message obtained in the first time slot, and the other is to decode the artificial noise signal in the first time slot. Then decode the message in the second time slot. By combining the two, we can obtain the information. In summary, the probability that remote user vehicle messages are being eavesdropped on is:

[0044] .

[0045] According to another aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the physical layer secure communication method against eavesdropping attacks of the present invention.

[0046] According to another aspect of the present invention, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the physical layer secure communication method against eavesdropping attacks of the present invention.

[0047] Compared with existing technologies, the beneficial effects of the above-described method of the present invention are as follows:

[0048] This invention uses NOMA technology in the Internet of Vehicles (IoV) to effectively improve the spectrum utilization efficiency of the IoV. This invention applies relay technology and NOMA transmission mechanism to the IoV simultaneously, which significantly improves the spectrum utilization of the IoV system and enables data transmission for more users.

[0049] This invention combines one-time key and artificial noise technology, so that the encryption and decryption of the constructed secure communication scheme only require XOR operations; this secure communication scheme not only has low computational load, but also does not require key management, which greatly reduces the network resource consumption of the implementation of the secure communication scheme;

[0050] Compared with existing physical layer security communication schemes in vehicle networking, the security communication scheme proposed in this invention can more effectively combat eavesdropping users and improve the system's confidentiality performance. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0052] Figure 1 This is a system model diagram of a physical layer secure communication scheme according to a preferred embodiment of the present invention;

[0053] Figure 2 This is a flowchart of a preferred embodiment of the present invention;

[0054] Figure 3 This is a comparison chart showing the safety-reliability balance performance of the present invention and traditional physical layer secure communication schemes for near-user and far-user vehicles. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

[0056] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0057] Example 1:

[0058] like Figure 1-3 As shown, the present invention provides a physical layer secure communication method to combat eavesdropping attacks, comprising the following steps:

[0059] The model of a two-user collaborative NOMA vehicle-to-everything (V2X) communication system under eavesdropping attack includes a roadside base station with 3 antennas, a near-user vehicle with 2 antennas (which also acts as a relay node), a far-user device with 2 antennas, and a vehicle equipped with a single antenna for eavesdropping.

[0060] Step 1: As a roadside base station serving as the signal source Using NOMA technology, construct a signal Then select another antenna to transmit the signal; at the same time, the nearby user vehicle Employing full-duplex technology, it simultaneously receives signals and transmits artificial noise signals. Weakening eavesdroppers, remote user vehicles It also sends artificial noise signals. Interfering with eavesdropping users ;

[0061] Step 2, the signal received by the vehicle near the user is The signal is calculated from this. and The corresponding signal-to-interference-plus-noise ratios are respectively and The signals received by the remote user vehicle and the eavesdropping user vehicle are respectively and Therefore, the signal-to-interference-plus-noise ratio required by the distant user is calculated to be: The signal-to-interference-plus-noise ratio required for an eavesdropper to directly decode the signal is respectively , and ;

[0062] Step 3, Second Time Slot, Near User Vehicle As a relay node, it will decode the obtained message. Artificial noise generated in the first time slot As a bit sequence, XORing and adding them together yields the signal. And send the signal, while at the same time the remote user vehicle sends an artificial noise signal. Interfering with or eavesdropping on users;

[0063] Step 4, Remote User and eavesdropping users The received signals are respectively and The calculation is close to the user's decoding. The signal-to-interference-plus-noise ratio is Remote user vehicle decoding The signal-to-interference-plus-noise ratio is And combined with the signals eavesdropped in the first time slot Stealing information from sources ;

[0064] Step 5: Based on the signal-to-interference-plus-noise ratio (SINR) calculated from the received signals in the first and second time slots for both near-user and far-user vehicles, the following outage probability calculation formula is obtained. Specifically, for near-user messages... The interruption probability is:

[0065]

[0066] Remote user messages The interruption probability is:

[0067]

[0068] The eavesdropping user successfully obtained the information. and The interception probabilities are as follows:

[0069]

[0070] and

[0071]

[0072] The following Matlab simulation experiment is used to verify the interruption probability and interception probability of vehicles near and far from the user in the vehicle-to-everything (V2X) communication system. In the simulation experiment, the channel gain follows a Rayleigh distribution, and the signal transmit power of each node is set to a constant. The power of Gaussian white noise at each user vehicle is Then the transmission signal-to-noise ratio is Its variation ranges from 0 to 40 dB. The number of antennas at the roadside base station is... In a vehicle-to-everything (V2X) network subjected to eavesdropping attacks, the power allocation factor for NOMA user vehicles is... and Near-user vehicle communication interruption signal-to-noise ratio threshold The signal-to-noise ratio threshold for remote user vehicle communication interruption is The threshold value for an eavesdropper to successfully steal information is... The average values ​​of the channel gains are as follows: , , , ,and This invention will use the Security-Reliability Tradeoff (SRT) performance to characterize the physical layer security of eavesdropping on connected vehicles.

[0073] Figure 3 This is a comparison of the SRT performance curves of near-user and far-user vehicles when applying the present invention and traditional physical layer secure communication schemes to vehicular networks under eavesdropping attacks; from Figure 3 As can be seen, compared with traditional physical layer secure communication schemes in vehicle-to-everything (V2X) systems, the SRT performance of both near-user vehicles and far-user vehicles in the scheme proposed in this invention is significantly improved. Therefore, the secure communication scheme based on one-time pad and artificial noise in this invention can effectively enhance the physical layer security of near-user and far-user vehicles in V2X systems.

[0074] Example 2:

[0075] The computer-readable storage medium of this embodiment stores a computer program that, when executed by a processor, implements the steps of the physical layer secure communication method against eavesdropping attacks in Embodiment 1.

[0076] The computer-readable storage medium in this embodiment can be an internal storage unit of the terminal, such as the terminal's hard disk or memory; the computer-readable storage medium in this embodiment can also be an external storage device of the terminal, such as a plug-in hard disk, smart memory card, secure digital card, flash memory card, etc. equipped on the terminal; furthermore, the computer-readable storage medium can include both the terminal's internal storage unit and external storage devices.

[0077] The computer-readable storage medium of this embodiment is used to store computer programs and other programs and data required by the terminal. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0078] Example 3:

[0079] The computer device of this embodiment includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the physical layer secure communication method against eavesdropping attacks in Embodiment 1.

[0080] In this embodiment, the processor can be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The memory can include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0081] Those skilled in the art will understand that the content disclosed in the embodiments can be provided as a method, system, or computer program product. Therefore, this solution can take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this solution 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 and optical storage) containing computer-usable program code.

[0082] This solution is described with reference to flowchart illustrations and / or block diagrams of methods and computer program products according to embodiments of this solution. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0083] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0084] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0085] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0086] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

[0087] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the specific embodiments described above. The specific embodiments and descriptions in the specification are merely for further illustrating the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A physical layer secure communication method to counter eavesdropping attacks, characterized in that, Includes the following steps: In the first time slot, equipment The roadside base station with one antenna selects one antenna based on channel state information to transmit the NOMA signal. Send to nearby user vehicles acting as relays ; in the signal middle, and The roadside base station sends data to nearby user vehicles. information Heyuan vehicles information The power allocation factor, and , The full-duplex near-user vehicle, acting as a relay, receives the NOMA signal from the source while simultaneously transmitting artificial noise signals. Interfering with eavesdropping users The two-antenna vehicle, acting as a remote user, operates in full-duplex mode, simultaneously receiving signals and transmitting artificial noise signals. The eavesdropping attack is weakened; then, the near-user vehicle, the far-user vehicle, and the eavesdropping user vehicle calculate their respective required signal-to-interference-plus-noise ratios based on the received signals. In the second time slot, the vehicle closest to the user acts as a relay node, first decoding the source message. and Then Artificial noise in the first time slot Looking at the bit string, XORing and adding the two signals together, we get the signal. Finally, the signal is sent to the remote user vehicle; While receiving signals, remote user vehicles simultaneously transmit artificial noise signals. Interfering with eavesdroppers; In the vehicle-to-everything (V2X) communication system, the channel state information of different channels is independent of each other, and the channel state information of the same channel in different time slots is independent of each other, and the eavesdropping user is a strong eavesdropper; Then, the remote user vehicle and the vehicle acting as the eavesdropper calculate the corresponding signal-to-interference-plus-noise ratio (SIR) based on their respective received signals. Finally, based on the signal-to-interference-plus-noise ratio (SIR) of nearby user vehicles, distant user vehicles, and external eavesdropping vehicles, the interruption probability and interception probability of each user vehicle in the vehicle-to-everything (V2X) communication system are calculated.

2. The method as described in claim 1, characterized in that, The first time slot full-duplex near-user vehicle As a remote user vehicle Friendly interference nodes are used to eliminate artificial noise signals transmitted by distant user vehicles, while nearby user vehicles act as relay nodes, based on the NOMA signals they receive. The decoded signal is calculated. and The signal-to-interference-plus-noise ratios are as follows: ； ； in, This indicates the base station selected as the information source. Channel state information from the root antenna to the nearest user vehicle. The power at which the base station transmits NOMA signals. For residual self-interference, The residual self-interference channel coefficient near the user, This refers to the Gaussian white noise power at the near-user vehicle location. Because the near-user signal, acting as a relay node in the vehicle-to-everything (V2X) network, uses digital network coding technology to encode the far-user signal, the far-user vehicle needs to decode the artificial noise signal. Only then can we obtain information from the source. The calculation yields the artificial noise signal decoded from the remote user vehicle. The signal noise is as follows: ； in, This refers to the channel state information from near-user vehicles to far-user vehicles. For residual self-interference, For the residual self-interference channel coefficient of distant users, It is the Gaussian white noise power at the remote user vehicle; eavesdropping on users It is necessary to steal source messages based on the NOMA signal in the first time slot. and Because the relay node uses digital network coding technology to construct the signal in the second time slot. And transmit it, so the eavesdropper needs to decode the artificial noise signal. Based on the NOMA transmission mechanism, the first time slot is used to eavesdrop on vehicles. The signal-to-interference-plus-noise ratios (SIRs) for each signal are as follows: ； ； ； in, , and These are the channel state information from the base station, the nearby user vehicle, and the distant user vehicle to the eavesdropping user. To steal the Gaussian white noise power from the user's location.

3. The method as described in claim 2, characterized in that, The first time slot serves as a relay node for full-duplex near-user vehicle decoding messages. and Signal-to-interference-plus-noise ratio, remote user vehicle decoding of artificial noise signals Signal-to-interference-to-noise ratio, eavesdropping on user vehicle decoding messages , and The signal-to-interference-plus-noise ratio (SIR) calculation process is as follows: First, the roadside base station, as the signal source, from... One antenna is selected from the root antennas to transmit the NOMA signal. The specific antenna selection rules are as follows: ； in, A set consisting of antenna labels. Indicates the first Root antenna to the user vehicle Channel state information; the base station transmits NOMA signals using the selected antenna, and simultaneously transmits artificial noise signals to the user vehicle while the vehicle is receiving the signal. Remote user vehicles also send artificial noise signals. To mitigate eavesdropping attacks; the distant user vehicle acts as a friendly interference node for the near user vehicle, and the near user vehicle can eliminate the artificial noise signals transmitted by the distant user vehicle. Therefore, the received signals of the near user vehicle, the distant user vehicle, and the eavesdropping user vehicle are as follows: ； ； ； in, , and Let $\mathbf{ ... , and The signal-to-interference-plus-noise ratio (SIR) for eavesdropping on user vehicles and decoding the required messages based on the received signals is as follows: , and .

4. The method as described in claim 3, characterized in that, After the second time slot signal transmission ends, the remote user vehicle needs to decode the signal. The corresponding signal-to-interference-plus-noise ratio is calculated as follows: ； in, This represents the channel state information from the near-user vehicle to the far-user vehicle in the second time slot. The near-user vehicle acts as a relay node, and the power of its transmitted signal is... , For residual self-interference, For remote user vehicles, residual self-interference channel coefficients are required; eavesdropping users also need to decode. Combined with the signal obtained from decoding the first time slot Perform an XOR operation to obtain the signal. Based on the received signal, the decoding of the eavesdropping user is calculated. The signal-to-interference-plus-noise ratio is: ； in, and These represent the channel state information from the near-user vehicle and the far-user vehicle to the eavesdropping user vehicle in the second time slot, respectively. The power of sending artificial noise signals for the second time slot of remote user vehicles.

5. The method as described in claim 4, characterized in that, The signal-to-interference-plus-noise ratio (SIR) calculation process for the received signal in the second time slot is as follows: the second time slot near the user vehicle acts as a relay node, transmitting the signal encoded by the digital network. To the remote user vehicle, the remote user vehicle simultaneously sends artificial noise signals. The signal received by the eavesdropping user is weakened, resulting in the following differences between the signals received by the remote user's vehicle and the eavesdropping user's vehicle: ； ； The remote user vehicle calculates the nearby user's decoded signal based on the received data. The signal-to-interference-plus-noise ratio is To eavesdrop on user vehicles and steal information from the source, it is also necessary to decode the signal. The decoded signal is calculated. The signal-to-interference-plus-noise ratios are respectively .

6. The method as described in claim 5, characterized in that, The process for calculating the outage probability of two NOMA users in the vehicle network is as follows: In the first time slot, according to the NOMA criterion, as long as the condition is met... and The source message can be successfully decoded when it is near the user's vehicle. and ; Based on this analysis, near-user vehicle decoding messages The interruption probability is: ； For remote user vehicles to be successfully decoded First, the nearest user vehicle, acting as a relay, needs to successfully decode in the first time slot. and The remote user's vehicle also needs to meet the conditions. and ; Only remote user vehicles can successfully decode messages. Therefore, the probability of vehicle outage for remote users in the Internet of Vehicles is: ； Messages sent to nearby user vehicles and distant user vehicles and The interception probability calculation process is as follows: eavesdropping on user vehicles to steal signals The method is to directly decode the eavesdropped mixed signal, message The probability of being eavesdropped on is: ； Eavesdropping on user vehicles and stealing information from remote user vehicles There are two approaches: one is to directly decode the remote user message from the message obtained in the first time slot, and the other is to decode the artificial noise signal in the first time slot. Then decode the message in the second time slot. By combining the two, we can obtain the information. The probability that remote user vehicle messages are being eavesdropped on is: 。 7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it implements the steps of the physical layer secure communication method against eavesdropping attacks as described in any one of claims 1 to 6.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the physical layer secure communication method against eavesdropping attacks as described in any one of claims 1 to 6.

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