A blockchain-based vehicle networking trust management method and system

Abstract

The present invention provides a blockchain-based trust management method and system for the Internet of Vehicles. The method includes: dividing the intelligent connected vehicles driving on the road into several vehicle groups according to a preset regional coverage range, calculating the set of group trust values of the vehicles within each group in the node dimension, the set of trust value offsets and the set of vehicle message scores in the message dimension in the form of vehicle groups, and calculating the global trust values of each vehicle within different vehicle groups and the total trust value offset based on this, and obtaining the comprehensive trust value of each vehicle by weighted summation; comparing the comprehensive trust value with a preset warning trust threshold and a malicious trust threshold to assign vehicle labels to each vehicle; and performing communication management on the corresponding vehicle based on the vehicle management rules matching the vehicle labels. Through the present invention, malicious nodes inside the network can be effectively identified and processed in real time, the trust value can be prevented from being maliciously tampered with, communication delay can be reduced, network load can be decreased, and vehicle privacy can be protected.

Description

Technical Field

[0001] The present invention relates to the technical field of the Internet of Things, and particularly to a vehicle networking trust management method and system based on blockchain. Background Art

[0002] The Internet of Vehicles (IoV) realizes real-time communication between vehicles and the cloud, vehicles and vehicles, vehicles and roads, and vehicles and devices through intelligent sensing devices deployed on vehicle terminals, roadside, etc., which can improve traffic efficiency and safety. However, due to characteristics such as an open and complex network environment and the high-speed movement of vehicles, it is difficult to ensure the reliability and authenticity of communication nodes and communication data.

[0003] Therefore, in order to identify false messages sent by malicious vehicles and protect normal vehicles from attacks, during the communication process of the Internet of Vehicles, establishing a communication security identity authentication system for the Internet of Vehicles and endowing infrastructure such as vehicles, roadside devices, and information service platforms with a trustworthy "digital identity" helps to resist security attacks such as information forgery and tampering, and ensures the safe and reliable operation of the Internet of Vehicles system. Among them, the C-V2X security certificate management system can provide full-life-cycle certificate management services such as certificate issuance, update, and revocation for in-vehicle devices, roadside devices, etc. During the production stage of intelligent connected vehicles, the initialization of in-vehicle device certificates can be achieved through methods such as operator channel configuration and server token authorization; when the vehicle starts, it first completes a registration operation with the security certificate management system; when the vehicle communicates with the cloud, vehicles, roads, and devices, the vehicle uses the private key corresponding to the certificate to sign the data to be sent, and then sends the data to be sent, the signature value, and the certificate to the target object together. After receiving the message, the target object first uses the certificate of the Certificate Authority (CA) that issued the certificate to verify whether the certificate used for signing in the received message is valid, and then verifies whether the signature value in the message is correct through the public key in the certificate. If both pass, it is determined that the data is true and valid; if the certificate of the CA that issued the certificate is not cached on the target object side, it is also necessary to request the security certificate management system to synchronize the Trusted Root Certificate List (TRCL) to further determine the validity of the signature certificate in the message.

[0004] However, the above solutions, such as using technologies such as digital certificates, digital signatures, data encryption, and PKI (Public Key Infrastructure), although they can achieve authentication of message sources, integrity protection of messages, etc., still have the following problems:

[0005] (1) If a vehicle or device that has completed certificate initialization and registration operations is maliciously controlled, the current security identity authentication system cannot effectively identify internal attacks because these devices already have valid certificate credentials.

[0006] (2) When the vehicle communicates with the cloud, vehicle-to-vehicle, vehicle-to-road, and vehicle-to-device, the message needs to carry a certificate, and the identity of each node will be frequently authenticated. Frequent signature, signature verification, encryption, and decryption operations will consume a large amount of computing and communication resources.

[0007] (3) Traditional centralized architectures have problems such as single-point failures and communication delays, while traditional distributed architectures face problems such as untrusted vehicles and vulnerable RSU attacks. Summary of the Invention

[0008] Therefore, the present invention provides a blockchain-based vehicle networking trust management method and system, aiming to solve the technical problems in the prior art that malicious nodes inside the vehicle networking cannot be accurately identified, resulting in security risks, and the frequent vehicle identity authentication leads to a large network load and communication delays.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions:

[0010] According to the first aspect of the present invention, the present invention provides a blockchain-based vehicle networking trust management method, and the method includes:

[0011] Dividing the intelligent connected vehicles driving on the road into several vehicle groups according to a preset regional coverage range, and determining the leader vehicle of the vehicle group;

[0012] The leader vehicle respectively calculates the set of group trust values of the vehicles in each group in the node dimension, the set of trust value offsets and the set of vehicle message scores in the message dimension, and uploads the set of group trust values, the set of trust value offsets and the set of vehicle message scores to the RSU;

[0013] The RSU aggregates the set of group trust values and calculates the global trust value of each vehicle in different vehicle groups; and, the RSU aggregates the set of trust value offsets and the set of vehicle message scores and calculates the total trust value offset of each vehicle in different vehicle groups;

[0014] Calculating the comprehensive trust value of each vehicle by weighted summation according to the global trust value and the total trust value offset;

[0015] Based on the comprehensive trust value, comparing the preset warning trust threshold and malicious trust threshold, and assigning a vehicle label to each vehicle; the vehicle label includes a trusted vehicle, a warning vehicle, and a malicious vehicle;

[0016] Based on the vehicle management rules matching the vehicle label, performing communication management on the corresponding vehicle.

[0017] Further, the method further includes:

[0018] The leader vehicle and / or the vehicles within the group regularly query the RSU through the trust value query interface of the RSU for the global trust values and / or the total trust value offsets of each vehicle within the vehicle group where they are located;

[0019] Based on the global trust values and / or the total trust value offsets of each vehicle within the group, the leader vehicle conducts in-group broadcast warnings.

[0020] Further, the method further includes:

[0021] The RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS to store the trust value offsets and vehicle message scores corresponding to each vehicle through the blockchain;

[0022] The blockchain deploys a smart contract containing a trust value algorithm, and the RSU obtains the trust value algorithm through the blockchain to calculate or verify the trust value offsets of each vehicle.

[0023] Further, determining the leader vehicle of the vehicle group includes:

[0024] Taking the vehicle that first enters the coverage area of the preset area as the leader vehicle, and taking the vehicle that enters the coverage area of the preset area second as the deputy leader vehicle;

[0025] The leader vehicle calculates the in-group trust values of each vehicle according to the behaviors / communication situations of other vehicles, updates the leader vehicle with the vehicle having the highest in-group trust value, and updates the deputy leader vehicle with the vehicle having the second highest in-group trust value;

[0026] If the leader vehicle leaves the coverage area of the preset area or shows malicious behaviors / communication situations, update the leader vehicle with the deputy leader vehicle, and update the deputy leader vehicle with the vehicle having the second highest current in-group trust value.

[0027] Further, the method further includes:

[0028] The leader vehicle conducts identity verification and vehicle information management for new vehicles entering the coverage area of the preset area; the vehicle information includes the vehicle VIN code and the vehicle security key;

[0029] The leader vehicle creates a symmetric key and a set of public-private key pairs and broadcasts them to the vehicles within the group for sending encrypted warning messages when the vehicles within the group encounter traffic emergencies.

[0030] Further, respectively calculating the in-node dimension in-group trust value sets, the trust value offset sets in the message dimension, and the vehicle message score sets of each vehicle within the group includes:

[0031] Calculate the group trust value of vehicles in each group at the node dimension, specifically including:

[0032] Determine the message receiving vehicle and the message sending vehicle according to the situation of vehicles in each group regularly broadcasting BSM messages;

[0033] Calculate the direct trust value of the message receiving vehicle for the message sending vehicle, and integrate the direct trust values of multiple neighbor vehicles of the message receiving vehicle for the message sending vehicle as the indirect trust value;

[0034] Perform weighted summation on the direct trust value and the indirect trust value to obtain the vehicle trust value of the message receiving vehicle for the message sending vehicle;

[0035] The group leader vehicle summarizes the vehicle trust values of all message receiving vehicles in the group for the message sending vehicle and performs arithmetic averaging to obtain the group trust value of the message sending vehicle;

[0036] And / or,

[0037] Calculate the vehicle message score of vehicles in each group at the message dimension, specifically including:

[0038] Determine the message receiving vehicle and the message sending vehicle according to the situation of vehicles in each group sending warning messages for a certain traffic event and / or forwarding RSM messages sent by roadside devices;

[0039] For the traffic event, calculate the trust value scores of the target messages sent by the message receiving vehicle for different message sending vehicles respectively;

[0040] Based on multiple trust value scores, use Bayesian inference to calculate the authenticity probability of the traffic event, and determine the vehicle message score of the message sending vehicle for the traffic event according to the authenticity probability;

[0041] And / or,

[0042] Calculate the trust value offset of vehicles in each group at the message dimension, specifically including:

[0043] The group leader vehicle regularly summarizes the vehicle message scores of vehicles in each group sending warning messages for multiple traffic events and / or forwarding RSM messages sent by roadside devices, and calculates the message trust value offset of vehicles in each group according to the vehicle message scores and the true or false attributes of the corresponding traffic events.

[0044] Furthermore, the RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS, including:

[0045] Based on the set of trust value offsets summarized by the RSU, calculate the sum of the absolute values of the set of vehicle trust value offsets as stakes, with the formula as follows:

[0046]

[0047] where ASToff i is the sum of the absolute values of the set of vehicle trust value offsets; the min() function represents taking the minimum value; ASToff max represents i the upper limit of ASToff

[0048] Use the following formula to calculate the computational difficulty of the block published by the RSU that is positively correlated with SSToff i to obtain a nonce that meets the computational difficulty and successfully publish the block:

[0049]

[0050] where Diff i is the computational difficulty of the block published by the RSU; N tot represents the total number of bits when the computational difficulty is represented in binary; N0 represents the number of consecutive 0s starting from the first bit when the computational difficulty is represented in binary; ASToff i is the sum of the absolute values of the set of vehicle trust value offsets; η and μ are the change rate and offset that control N0 with respect to Diff i ;

[0051] And / or

[0052] If when the RSU publishes a new block, multiple other RSUs simultaneously add the new block to the blockchain, use the longest fork consensus algorithm to discard the redundant fork blocks.

[0053] Furthermore, comparing the comprehensive trust value with the preset warning trust threshold and malicious trust threshold, and assigning vehicle tags to each vehicle, including:

[0054] If the comprehensive trust value is higher than the warning trust threshold, the corresponding vehicle is marked as a trusted vehicle;

[0055] If the comprehensive trust value is lower than or equal to the warning trust threshold and higher than the malicious trust threshold, the corresponding vehicle is marked as a warning vehicle, and the trust value of the warning vehicle is monitored for a preset observation time;

[0056] After the expiration of the preset observation time, if the comprehensive trust value of the warning vehicle is still less than or equal to the warning trust threshold, the warning vehicle is marked as a malicious vehicle; if the comprehensive trust value of the warning vehicle is higher than the warning trust threshold, the warning vehicle is marked as a trustworthy vehicle;

[0057] If the comprehensive trust value is less than or equal to the malicious trust threshold, the corresponding vehicle is marked as a malicious vehicle.

[0058] Further, the communication management of the corresponding vehicle based on the vehicle management rule matching the vehicle tag includes:

[0059] For the trustworthy vehicle, when sending a message, there is no need to carry a vehicle certificate, and it is directly encrypted with the symmetric key and signed with the vehicle private key; when receiving a message, there is no need to verify the validity of the vehicle certificate, and it is directly decrypted with the symmetric key and verified with the vehicle public key;

[0060] For the warning vehicle, when sending a message, it is necessary to carry a vehicle certificate and sign it with the vehicle private key; when receiving a message, it is necessary to verify the validity of the vehicle certificate, and then extract the vehicle public key from the vehicle certificate for signature verification;

[0061] For the malicious vehicle, revoke the vehicle certificate and it cannot participate in vehicle network communication.

[0062] According to the second aspect of the present invention, the present invention provides a blockchain-based vehicle network trust management system, and the system includes:

[0063] A trust value storage module for storing a set of trust value offsets and a set of vehicle message scores of vehicles by using blockchain technology; an intelligent contract including a trust value algorithm is deployed in the blockchain; the RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS;

[0064] A trust value calculation module for dividing the intelligent connected vehicles driving on the road into several vehicle groups according to a preset area coverage range, and determining the leader vehicle of the vehicle group; using the leader vehicle to calculate the set of group trust values of the vehicles in each group in the node dimension, the set of trust value offsets and the set of vehicle message scores in the message dimension respectively, and uploading the set of group trust values, the set of trust value offsets and the set of vehicle message scores to the RSU; using the RSU to aggregate the set of group trust values and calculate the global trust value of each vehicle in different vehicle groups; and, using the RSU to aggregate the set of trust value offsets and the set of vehicle message scores, and calculate the total trust value offset of each vehicle in different vehicle groups; according to the global trust value and the total trust value offset, calculate the comprehensive trust value of each vehicle by weighted summation;

[0065] A trust value sharing module is used to set the trust value query interface of the RSU. The group leader vehicle and / or the vehicles within the group regularly query the global trust value and / or the total trust value offset of each vehicle in the vehicle group where they are located from the RSU through the trust value query interface. The group leader vehicle conducts in-group broadcast warnings based on the global trust value and / or the total trust value offset of each vehicle within the group.

[0066] A trust value application module is used to assign vehicle labels to each vehicle based on the comprehensive trust value by comparing the preset warning trust threshold and malicious trust threshold. The vehicle labels include trusted vehicles, warning vehicles, and malicious vehicles. Communication management is performed on the corresponding vehicles based on the vehicle management rules matching the vehicle labels.

[0067] The present invention adopts the above technical solutions and has at least the following beneficial effects:

[0068] Through the solution of the present invention, in the vehicle networking environment, when vehicles communicate with the cloud, vehicle-to-vehicle, vehicle-to-road, and vehicle-to-device, there is no need to frequently authenticate the identities of vehicles, consuming a large amount of computing and communication resources. The network is divided into several groups according to geographical intervals, the trust values of the vehicles participating in communication in the network are calculated based on nodes and messages, the vehicle with the highest trust value is elected as the group leader, and the trust values are stored in the blockchain. The trust value algorithm is written into the smart contract, and a consensus mechanism combining PoW and PoS is constructed, which can effectively identify and real-time process malicious nodes inside the network, prevent the trust values from being maliciously tampered with, reduce communication latency, lower network load, and protect vehicle privacy.

[0069] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0071] Figure 1 The flowchart shows the process of a vehicle networking trust management method based on blockchain provided by an embodiment of the present invention;

[0072] Figure 2 The flowchart shows the process of blockchain fork processing provided by an embodiment of the present invention;

[0073] Figure 3A schematic diagram showing the block data structure provided by an embodiment of the present invention is shown;

[0074] Figure 4 A schematic flowchart showing the process of assigning vehicle tags to each vehicle provided by an embodiment of the present invention is shown;

[0075] Figure 5 A schematic diagram showing the structure of a vehicle networking trust management system based on blockchain provided by an embodiment of the present invention is shown. Detailed implementation manners

[0076] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be completely conveyed to those skilled in the art.

[0077] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, elements defined by the statement "including..." do not exclude the presence of additional identical elements in the process, method, article or device including the said elements.

[0078] An embodiment of the present invention provides a vehicle networking trust management method based on blockchain, as Figure 1 shown, which may at least include the following steps S101 to S106:

[0079] Step S101, dividing the intelligent connected vehicles driving on the road into several vehicle groups according to a preset regional coverage range, and determining the leader vehicle of the vehicle group.

[0080] In an embodiment of the present invention, the vehicle trust level is evaluated in the form of vehicle groups. Specifically, a circular area with a radius of 150 meters centered on a certain intelligent connected vehicle can be divided into groups to form multiple vehicle groups with overlapping coverage ranges. It should be noted that in practical applications, the size of the preset regional coverage range can be set according to actual needs, and the present invention does not limit this.

[0081] In each vehicle group in the embodiments of the present invention, a leader vehicle is set. The setting principle is to use the vehicle with the highest group trust value as the leader vehicle (the calculation method of the group trust value is described in detail later). The functions of the leader vehicle include: verifying the identity information of the vehicles within the group; generating and distributing the group key; calculating the group trust value and the trust value offset of the vehicles within the group, and uploading them to the RSU; regularly obtaining the latest trust values of the vehicles within the group from the RSU and broadcasting them within the group.

[0082] The selection of the leader vehicle is described in detail below: The vehicle that first enters the coverage area of the preset area is used as the leader vehicle, and the vehicle that enters the coverage area of the preset area second is used as the deputy leader vehicle; the leader vehicle verifies the identity of the new vehicles entering the coverage area of the preset area and manages the vehicle information; it can also create a symmetric key and a set of public-private key pairs, and broadcast them to the vehicles within the group for sending encrypted warning messages when the vehicles within the group encounter traffic emergencies. Furthermore, the leader vehicle calculates the group trust value of each vehicle within the group based on the behavior / communication situation of other vehicles, uses the vehicle with the highest group trust value to update the leader vehicle, and uses the vehicle with the second highest group trust value to update the deputy leader vehicle; if the leader vehicle leaves the coverage area of the preset area or shows malicious behavior / communication situation, use the deputy leader vehicle to update the leader vehicle, and use the vehicle with the second highest current group trust value to update the deputy leader vehicle.

[0083] That is to say, in the initial stage, the first vehicle entering the target area is used as the leader vehicle, and the second vehicle is used as the deputy leader vehicle; when a new vehicle enters the coverage range of the group, the group leader vehicle verifies the identity of the new vehicle. After passing the verification, the leader vehicle adds information such as the vehicle VIN code and public key to the group vehicle list; then, according to the behavior and communication situation of the vehicles within the group, calculates the group trust value, elects the vehicle with the highest score as the leader vehicle, and the vehicle with the second highest score is elected as the deputy leader vehicle; when the leader vehicle leaves the target area or shows malicious behavior, it is replaced by the deputy leader vehicle, and the vehicle with the second highest current score is re-elected as the deputy leader vehicle.

[0084] Among them, when the leader vehicle verifies the identity of the new vehicle, it means verifying the identity of the vehicle information. The vehicle information can include the vehicle VIN code and the vehicle security key. The vehicle V i has a unique identifier at the factory stage, that is, the VIN code. When the vehicle is in the startup stage, the OBU will send a registration request to the ECA (Enrollment CA), passing in the VIN code. The vehicle security key refers to after the ECA verification passes, it returns a security certificate Certificate (including the public key Pu i and the private key Pr i ) to the vehicle through a secure channel; then requests several pseudonym certificates (including the public key Pupse i, Private key Prpse i ), which is used to sign BSM messages to avoid disclosing vehicle trips and protect vehicle privacy. In addition, in the embodiments of the present invention, when a new vehicle successfully joins a vehicle group, the leader vehicle can create and broadcast a symmetric key Kgr i and a set of public-private key pairs Pugr i , Prgr i . When a traffic event occurs, the vehicle can directly send an alarm message or forward the RSM message sent by the roadside device, and use the group key for encryption, decryption, signature verification and signature signing.

[0085] Step S102, the leader vehicle calculates the set of group trust values of each vehicle in the group in the node dimension, the set of trust value offsets in the message dimension, and the vehicle message score set, and uploads the group trust value set, the trust value offset set, and the vehicle message score set to the RSU.

[0086] Under normal circumstances, intelligent connected vehicles will regularly broadcast BSM messages, and when an emergency occurs, they will send alarm messages. Due to the existence of malicious nodes, the messages received by the vehicle may not be true and reliable. Therefore, some rules need to be formulated to evaluate the authenticity of the received messages, and then evaluate the trust value of the vehicle. The embodiments of the present invention adopt two trust value calculation methods, namely the trust value based on the node dimension and the trust value calculation based on the message dimension, which are described in detail below:

[0087] Calculating the group trust value of each vehicle in the group in the node dimension may specifically include: determining the message receiving vehicle and the message sending vehicle according to the situation of each vehicle regularly broadcasting BSM messages; calculating the direct trust value of the message receiving vehicle for the message sending vehicle, and integrating the direct trust values of multiple neighbor vehicles of the message receiving vehicle for the message sending vehicle as the indirect trust value; performing a weighted sum of the direct trust value and the indirect trust value to obtain the vehicle trust value of the message receiving vehicle for the message sending vehicle; the leader vehicle summarizes the vehicle trust values of all message receiving vehicles in the group for the message sending vehicle and performs an arithmetic average to obtain the group trust value of the message sending vehicle.

[0088] That is to say, the vehicles in the group can regularly send BSM messages including data such as VIN code, positioning, speed, heading angle, and operating status. When calculating, the message sending vehicle is defined as s, and the message receiving vehicle is defined as r.

[0089] The direct trust value of the message receiving vehicle r for the message sending vehicle s The calculation formula is as follows:

[0090]

[0091] Among them, p iParameters affecting the vehicle trust value, including N parameters such as communication frequency, driving speed, received signal strength, number of trusted neighbors, vehicle spacing, and degree of compliance with traffic signal rules; w i Represents the weights of different parameters.

[0092] Furthermore, after the message receiving vehicle r calculates the direct trust value of the message sending vehicle s, it encrypts and adds it to the BSM message and broadcasts it to multiple neighbor vehicles of the message receiving vehicle r.

[0093] The indirect trust value of the message receiving vehicle r for the message sending vehicle s Is the average of the direct trust values calculated by multiple neighbor vehicles of the message receiving vehicle r for the message sending vehicle s. The calculation formula is as follows:

[0094]

[0095] Among them, Represents the direct trust value calculated by the neighbor vehicle of the message receiving vehicle r for the message sending vehicle s. The message receiving vehicle r parses the direct trust value of the message sending vehicle s from the BSM message broadcast by its neighbor vehicle, and then calculates the indirect trust value of the message sending vehicle s.

[0096] Furthermore, the vehicle trust value of the message receiving vehicle r for the message sending vehicle s Is calculated by the weighted sum of the direct trust value and the indirect trust value. The calculation formula is as follows:

[0097]

[0098] Among them, α ∈ (0.5, 1), indicating that the vehicle trust value pays more attention to the direct trust value, but does not ignore the indirect trust value.

[0099] In the embodiment of the present invention, after the message receiving vehicle r completes the calculation of the vehicle trust value, it stores the vehicle VIN code, direct trust value Indirect trust value Vehicle trust value Of the message sending vehicle s in the local lightweight database SQLite, and sends the vehicle trust value to the group leader vehicle.

[0100] Furthermore, the group trust value of the group leader vehicle g for the message sending vehicle s Is the arithmetic average of the vehicle trust values of all vehicles in the group for the message sending vehicle s. The calculation formula is as follows:

[0101]

[0102] Among them, It represents the vehicle trust value calculated by the vehicles within the group for the message - sending vehicle s. It can be understood that after the group leader vehicle completes the calculation of the group trust value, it arranges the vehicles in reverse order according to the trust scores, and takes the vehicle ranked first and second as the group leader and deputy group leader respectively in the next group leader election. When the group leader vehicle passes by the RSU, it synchronizes the group trust value sets of all vehicles within the group to the RSU.

[0103] Calculate the trust value offset of the vehicles within each group in the message dimension, which specifically can include: determining the message - receiving vehicle and the message - sending vehicle according to the situation of the vehicles within each group sending warning messages for a certain traffic event and / or forwarding the RSM messages sent by the roadside devices; for the traffic event, calculating the trust value scores of the message - receiving vehicle for the target messages sent by different message - sending vehicles respectively; based on multiple trust value scores, using Bayesian inference to calculate the authenticity probability of the traffic event, and determining the vehicle message score of the message - sending vehicle for the traffic event according to the authenticity probability; the group leader vehicle regularly summarizes the vehicle message scores of the vehicles within each group for sending warning messages for multiple traffic events and / or forwarding the RSM messages sent by the roadside devices, and calculates the message trust value offset of the vehicles within each group according to the vehicle message scores and the true - false attributes of the corresponding traffic events.

[0104] It can be understood that when a traffic event occurs, the vehicles within the group can directly send warning information or forward the RSM messages sent by the roadside devices. In the embodiments of the present invention, the traffic event is defined as e, the message reflecting the traffic event is defined as m, the message - sending vehicle is defined as s, and the message - receiving vehicle is defined as r.

[0105] The message - receiving vehicle r calculates the trust value score for the message m reflecting the traffic event e The formula is as follows:

[0106]

[0107] Wherein, represents the trust value score of the message - receiving vehicle r for the message m sent by the message - sending vehicle s; represents the distance of the message - sending vehicle s from the location where the traffic event e occurs when sending the message m; γ represents the change rate of the message trust value with the distance of the vehicle from the event occurrence location; f represents the lower limit of the message trust value.

[0108] For the same traffic event e, the message trust values sent by different message - sending vehicles to the same message - receiving vehicle r can form a set The message - receiving vehicle r can use Bayesian inference to judge the authenticity probability of the traffic event e based on the message trust value set TM r The formula is as follows:

[0109]

[0110] Among them, is the mutually exclusive event of traffic event e (for example: if e represents that vehicle A has a collision at intersection 1, then represents that vehicle A passes through intersection 1 normally). Therefore, P(e) is the prior probability of traffic event e, is the prior probability of the prior event , and P(e / TM r ) ∈ [0, 1].

[0111] In the embodiment of the present invention, a threshold Threshold of P(e / TM r ) can be set: if P(e / TM r ) is greater than or equal to the threshold, the message receiving vehicle r considers the event status to be e; otherwise, the status is Therefore, the message m score that truthfully broadcasts this event is recorded as +1, and the message m score that falsely broadcasts this event is recorded as -1.

[0112] Furthermore, the message receiving vehicle r regularly sends the message m score sent by the message sending vehicle s to the group leader vehicle, and the group leader vehicle calculates the message trust value offset of the message sending vehicle s, and the value range is [-1, 1]. The calculation formula is as follows:

[0113]

[0114] Among them, Toff s is the trust value offset calculated according to the message sent by the message sending vehicle s, C p represents the number of messages, C n represents the number of messages, θ p and θ n respectively represent the weights of the number of true and false broadcast messages. The calculation formula is as follows:

[0115]

[0116] Among them, S(x) represents the sensitivity to minority scores. The larger S(x) is, the lower the sensitivity to minority scores; conversely, the smaller S(x) is, the higher the sensitivity to minority scores.

[0117] It can be understood that it is unlikely for an attacker to control most vehicles, so it can be considered that the majority scores are true and reliable. Therefore, by comparing Toff s and If the product of the two is less than 0, it is considered that the message receiving vehicle r has sent a malicious score. In the embodiment of the present invention, a penalty mechanism can be introduced for the message receiving vehicle r that sends a malicious score, and the trust value of the message receiving vehicle r based on the message is multiplied by a penalty coefficient λ, where λ ∈ (0, 1).

[0118] Further, the leader vehicle finally uploads the calculated set of trust value offsets and the set of vehicle message scores of multiple in-group vehicles to the RSU, and the RSU competes with each other to add the newly created block to the blockchain. That is, the RSU creates a block and tries to add it to the blockchain to store the trust value offset and the vehicle message score corresponding to each vehicle through the blockchain. A consensus mechanism combining PoW (Proof of stake) and PoW (Proof of Work) can be adopted, and the sum of the absolute values of the vehicle trust value offsets stored in the RSU is used as the stakes. The greater the stakes of the RSU, the lower the difficulty Difficulty, and the easier it is to calculate an appropriate nonce, and then the faster the block is published.

[0119] Specifically, according to the set of trust value offsets summarized by the RSU, the sum of the absolute values of the set of vehicle trust value offsets is calculated as the stakes, and the formula is as follows:

[0120]

[0121] where ASToff i is the sum of the absolute values of the set of vehicle trust value offsets stored in the RSU; the min() function represents taking the minimum value; ASToff i represents the upper limit of ASToff max denotes ASToff i ;

[0122] Furthermore, the RSUi uses the following formula to calculate the operation difficulty positively correlated with ASToffii to obtain a nonce that meets the operation difficulty and successfully publishes the block:

[0123]

[0124] where Diff i is the operation difficulty for the RSU to publish the block; N tot represents the total number of bits when the operation difficulty is represented in binary, which depends on the adopted hash algorithm. For example, for the SM3 algorithm, N tot = 256; N0 represents the number of consecutive 0s starting from the first bit when the operation difficulty is represented in binary; ASToff i is the sum of the absolute values of the set of vehicle trust value offsets; η and μ are used to control N0 with respect to Diff iThe rate of change and offset, reference values: v = 0.01, μ = 3.

[0125] It should be noted that when the RSU publishes a new block, if multiple other RSUs simultaneously add the new block to the blockchain, the longest fork consensus algorithm is used to discard the redundant fork blocks. That is to say, when the RSU receives a new block, it will first verify whether the Nonce in the block meets the difficulty requirement, and then add the block to the stored blockchain; the RSU that successfully publishes the block will clear the stored trust value offset and compete for subsequent tasks. However, sometimes multiple RSUs may publish new blocks at the same time. Other RSUs will also first verify the new blocks and add the blocks that meet the difficulty value requirements to the blockchain. At this time, the blockchain will fork, and each forked block is valid. The "longest fork" consensus algorithm can solve this problem. As Figure 2 shown, the algorithm process is described as follows: The RSU randomly selects a fork and continues with subsequent tasks. There will always be a fork that successfully publishes a new block first. After other RSUs complete the verification of the new block, they add the block to the blockchain. Next, the RSU will select the longer blockchain to carry out a new round of tasks. Over time, the longest fork will be recognized by the blockchain, and the other forks will be discarded. At this time, the RSU will re-collect the blocks published by itself in the discarded forks, extract the trust value offset set and the vehicle message score set in the block body, and re-add them to the current block to compete for subsequent tasks.

[0126] Thus, the storage of the trust value offset and vehicle message score corresponding to each vehicle based on blockchain technology is realized. As Figure 3 shown, it is a schematic diagram of the block data structure provided by the embodiment of the present invention. According to Figure 3 it can be seen that the data structure of the block includes a block header and a block body: The block header is used to store the basic information of the current block, including: block identifier, RSU identifier, block creation time, and the hash value of the previous block; it is also used for the information to verify the validity of the current block, including: Nonce and difficulty value Difficulty. The block body is used to store the trust value offset set and vehicle message score set of the vehicle, including: vehicle identifier (VIN), trust value offset (Toff), and vehicle message score set (Ratings). In addition, it should be noted that the blockchain in the embodiment of the present invention also deploys a smart contract containing a trust value algorithm. The RSU obtains the trust value algorithm through the blockchain to calculate or verify the trust value offset of each vehicle. Thus, even if an attacker invades the RSU, the smart contract algorithm cannot be changed. Therefore, the trust value calculation and update algorithm are written into the smart contract of the blockchain. When the RSU needs to calculate the trust value offset of the vehicle or verify whether the trust value offset stored in the block is accurate, it only needs to call the algorithm of the smart contract.

[0127] Step S103, the RSU aggregates the set of group trust values and calculates the global trust value of each vehicle within different vehicle groups; and, the RSU aggregates the set of trust value offsets and the set of vehicle message scores, and calculates the total trust value offset of each vehicle within different vehicle groups.

[0128] RSU i For the global trust value TtotRsu of the message-sending vehicle s s , it refers to the geometric mean of the group trust values of the message-sending vehicle s by different group leaders, and the calculation formula is as follows:

[0129]

[0130] Among them, TtotRsu s represents the global trust value of the message-sending vehicle s; represents the group trust value of the message-sending vehicle s by different group leaders; when TtotRsu s When the data needs to be updated, a smooth update method is adopted, and the calculation formula is as follows:

[0131] Val New = β * Val New + (1 - β) * Val old

[0132] Among them, β ∈ (0.5, 1), indicating that more attention is paid to the latest calculation result, but the historical result will not be ignored.

[0133] In the embodiment of the present invention, a trust value query interface of the RSU is provided, and the leader vehicle and / or the vehicle within the group can regularly query the global trust value and / or the total trust value offset of each vehicle within the vehicle group where they are located through the trust value query interface of the RSU.

[0134] That is to say, the RSU provides a vehicle trust value query interface / trust / query, and the request parameters include: the VIN code reqVin of the requesting vehicle, the set of VIN codes targetVins of the target vehicle, and the public key pubKey of the requesting vehicle. After receiving the request to query the trust value, the RSU first verifies the authenticity of reqVin, and then calculates the total trust value offset STOff of the target vehicle stored in the blockchain s , and the calculation formula is as follows:

[0135]

[0136] Among them, STOff s represents the total trust value offset of the message-sending vehicle s; Toff jIndicates the trust value offset for the message - sending vehicle s calculated by different group leaders.

[0137] Step S104: Calculate the comprehensive trust value of each vehicle by weighted summation according to the global trust value and the total trust value offset.

[0138] Specifically, by integrating the global trust value TtotRsu based on nodes s and the total trust value offset SToff based on messages s , calculate the comprehensive trust value Toverall of the message - sending vehicle s s , and the calculation formula is as follows:

[0139] Toverall s = τ1 * TtotRsu s + τ2 * SToff s

[0140] Among them, the reference values are τ1 = 0.5 and τ2 = 0.5, which can be fine - tuned according to the composition of the vehicle's comprehensive trust value.

[0141] Finally, the RSU uses the public key pubKey of the requesting vehicle to encrypt the set of comprehensive trust values of the message - sending vehicle and return it to the requesting vehicle. Usually, the leader vehicle can regularly query the comprehensive trust values of all vehicles in the group from the RSU and then broadcast them within the group; in case of special circumstances, it also supports that vehicles within the group directly initiate vehicle trust value queries to the leader or the RSU.

[0142] It should be noted that in the embodiments of the present invention, the leader vehicle and / or vehicles within the group can also query the comprehensive trust values of each vehicle through the trust value query interface for the RSU. In addition, the leader vehicle and / or vehicles within the group can also perform in - group broadcast warnings based on the global trust values, total trust value offsets, and / or comprehensive trust values of each vehicle.

[0143] Step S105: Based on the comprehensive trust value, compare with the preset warning trust threshold and malicious trust threshold, and assign vehicle labels to each vehicle.

[0144] In the embodiments of the present invention, by defining two thresholds, the warning trust threshold T warn and the malicious trust threshold T mal , where T warn > T mal , three labels, namely trusted vehicle, warning vehicle, and malicious vehicle, are defined.

[0145] Figure 4 is the logical flowchart for adding vehicle labels to vehicles proposed in the embodiments of the present invention. As Figure 4 shown, when the comprehensive trust value Toverall of the vehicle sHigher than T warn , the vehicle will be marked as a trusted state.

[0146] When the overall trust value of the vehicle Toverall s ∈(T rev , T warn , the vehicle will be marked as a warning state; in the embodiments of the present invention, for vehicles in the warning state, the trust value is monitored during a preset observation time, and the preset observation time can last from 300 ms to 5 min. At this time, the warning vehicle needs to actively sense the surrounding environment and broadcast real messages to increase the trust value. When the trust value is higher than T warn , it can be detached from the warning label and converted into a trusted state; when the observation period ends, if the trust value Toverall s is still lower than T warn , it will be marked as a malicious vehicle.

[0147] When the overall trust value of the vehicle Toverall s is lower than T mal , the vehicle will be marked as a malicious state and handed over to the MA (Misbehavior Authority) for processing. The MA revokes the vehicle's certificate, and the vehicle will no longer receive any messages in the vehicle network and cannot send messages to the vehicle network.

[0148] Step S106, based on the vehicle management rules matching the vehicle label, perform communication management on the corresponding vehicle.

[0149] When a trusted vehicle communicates, the message - sending vehicle does not need to carry the vehicle certificate, and the message - receiving vehicle does not need to verify the authenticity and validity of the vehicle certificate. It directly uses the group symmetric key for encryption and decryption, and the private key of the message - sending vehicle for signature and the public key for verification, reducing communication resource consumption and improving communication efficiency;

[0150] When a warning vehicle communicates, the message - sending vehicle uses the private key for signature and carries the certificate. The message - receiving vehicle needs to first use the CA's certificate to verify the authenticity and validity of the certificate used by the sender for signature, and then extract the public key from the certificate for verification;

[0151] The malicious vehicle has its certificate revoked by the MA and cannot participate in vehicle - network communication.

[0152] An embodiment of the present invention provides a blockchain-based vehicle networking trust management method, including: dividing intelligent connected vehicles driving on the road into several vehicle groups according to a preset regional coverage range, and determining the leader vehicle of each vehicle group; the leader vehicle calculates the set of group trust values of the vehicles in each group in the node dimension, the set of trust value offsets and the set of vehicle message scores in the message dimension respectively, and uploads the set of group trust values, the set of trust value offsets and the set of vehicle message scores to the RSU; the RSU aggregates the set of group trust values and calculates the global trust values of each vehicle in different vehicle groups; and, the RSU aggregates the set of trust value offsets and the set of vehicle message scores, and calculates the total trust value offsets of each vehicle in different vehicle groups; calculates the comprehensive trust value of each vehicle by weighted summation according to the global trust value and the total trust value offset; based on the comprehensive trust value, compares the preset warning trust threshold and malicious trust threshold, and assigns a vehicle label to each vehicle; the vehicle label includes a trusted vehicle, a warning vehicle, and a malicious vehicle; based on the vehicle management rules matching the vehicle label, conducts communication management on the corresponding vehicle. Through the solution of the present invention, at least the following effects can be achieved:

[0153] (1) The trust management model proposed by the present invention integrates the centralized (based on security facilities such as CA) and distributed (based on vehicles, group leaders, RSU) trust management architectures, combines the advantages of the two architectures, and eliminates problems such as single point of failure in the traditional centralized architecture;

[0154] (2) The trust value algorithm proposed by the present invention defines the trust value based on nodes and the trust value based on messages: in the trust value algorithm based on nodes, both the direct trust value and the indirect trust value are taken into account, and the global trust value is calculated from three dimensions of vehicles, group leaders, and RSU; in the trust value algorithm based on messages, the reputation of the message, the message score, the message trust value offset, and the total trust value offset are calculated respectively; the finally calculated comprehensive trust value of the vehicle can more comprehensively and accurately reflect the trust state of the vehicle;

[0155] (3) When calculating the trust value based on messages, the present invention considers the situation where the group leader vehicle maliciously uploads incorrect message scores, punishes the trust value of the group leader vehicle, and comprehensively improves the security of IoV.

[0156] (4) The present invention defines two trust value thresholds for warning and malicious, and three vehicle status tags of trusted, warning, and malicious. After calculating the trust value of the vehicle, if the vehicle is marked as malicious, it will be handed over to the MA to revoke the certificate. Although these vehicles have valid certificate vouchers, they can effectively identify internal attacks. If the vehicle is marked as trusted, when communicating with other vehicles, it can directly use the group symmetric key for encryption and decryption, the vehicle private key for signing, and the public key for signature verification. There is no need to carry the certificate in the message, and the receiving vehicle does not need to verify the validity of the signature certificate from the CA, reducing the volume of communication packets and the consumption of communication resources and the computing resources required for frequent signature verification.

[0157] (5) The present invention stores the trust value in the blockchain. With the characteristics of decentralization, immutability, transparency, and traceability of the blockchain, it can prevent the trust value from being maliciously tampered with, making the trust value public, transparent, and the calculation process traceable.

[0158] (6) The present invention defines a consensus mechanism combining PoW and PoS, enabling the RSU that stores the larger absolute value of the vehicle trust value offset to find the nonce that meets the difficulty requirement faster and is more likely to add the block to the blockchain.

[0159] (7) The present invention provides a trust value query interface and a trust value regular broadcast mechanism, which can externally share the latest vehicle trust value and trust status in real time.

[0160] Further, as Figure 1 a specific implementation, the embodiment of the present invention provides a blockchain-based vehicle networking trust management system, as Figure 5 shown. The system may include: a trust value storage module 510, a trust value calculation module 520, a trust value sharing module 530, and a trust value application module 540.

[0161] The trust value storage module 510 can be used to store the vehicle trust value offset set and the vehicle message score set using blockchain technology; a smart contract containing the trust value algorithm is deployed in the blockchain; the RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS.

[0162] The trust value calculation module 520 can be used to divide the intelligent connected vehicles driving on the road into several vehicle groups according to a preset area coverage range, and determine the leader vehicle of each vehicle group; use the leader vehicle to calculate the set of group trust values of the vehicles in each group in the node dimension, the set of trust value offsets and the set of vehicle message scores in the message dimension respectively, and upload the set of group trust values, the set of trust value offsets and the set of vehicle message scores to the RSU; use the RSU to aggregate the set of group trust values and calculate the global trust values of each vehicle in different vehicle groups; and, use the RSU to aggregate the set of trust value offsets and the set of vehicle message scores, and calculate the total trust value offsets of each vehicle in different vehicle groups; calculate the comprehensive trust value of each vehicle by weighted summation according to the global trust value and the total trust value offset;

[0163] The trust value sharing module 530 can be used to set the trust value query interface of the RSU. The leader vehicle and / or the vehicles within the group regularly query the global trust values and / or the total trust value offsets of each vehicle in the vehicle group where they are located through the trust value query interface; the leader vehicle performs in-group broadcast warnings based on the global trust values and / or the total trust value offsets of the vehicles within each group.

[0164] The trust value application module 540 can be used to assign vehicle labels to each vehicle based on the comprehensive trust value by comparing with a preset warning trust threshold and a malicious trust threshold; the vehicle labels include trusted vehicles, warning vehicles, and malicious vehicles; perform communication management on the corresponding vehicles based on the vehicle management rules matching the vehicle labels.

[0165] It should be noted that for other corresponding descriptions of each functional module involved in the vehicle networking trust management system based on blockchain provided in the embodiments of the present invention, reference can be made to Figure 1 the corresponding description of the method shown, which will not be elaborated here.

[0166] Those skilled in the art can clearly understand that the specific working processes of the above-described system, device, module, and unit can refer to the corresponding processes in the foregoing method embodiments. For the sake of brevity, they will not be described in detail here.

[0167] In addition, each functional unit in the various embodiments of the present invention can be physically independent of each other, or two or more functional units can be integrated together, or all functional units can be integrated in a processing unit. The above integrated functional units can be implemented in the form of hardware, or in the form of software or firmware.

[0168] Those of ordinary skill in the art can understand that if the integrated functional units are implemented in software form and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computing device (such as a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the embodiments of the present invention when the instructions are run. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs.

[0169] Alternatively, all or part of the steps of implementing the foregoing method embodiments can be completed by hardware related to program instructions (such as a computing device like a personal computer, a server, or a network device, etc.). The program instructions can be stored in a computer-readable storage medium. When the program instructions are executed by the processor of the computing device, the computing device executes all or part of the steps of the methods described in the embodiments of the present invention.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that within the spirit and principles of the present invention, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the corresponding technical solutions to deviate from the protection scope of the present invention.

Claims

1. A blockchain-based trust management method for the Internet of Vehicles, characterized in that, The method includes: Dividing the intelligent connected vehicles running on the road into several vehicle groups according to a preset regional coverage range, and determining the leader vehicle of the vehicle group; The leader vehicle calculates the set of group trust values of the vehicles in each group in the node dimension, the set of trust value offsets and the set of vehicle message scores in the message dimension respectively, and uploads the set of group trust values, the set of trust value offsets and the set of vehicle message scores to the RSU; The RSU aggregates the set of group trust values and calculates the global trust values of each vehicle in different vehicle groups; and, the RSU aggregates the set of trust value offsets and the set of vehicle message scores and calculates the total trust value offsets of each vehicle in different vehicle groups; Calculating the comprehensive trust value of each vehicle by weighted summation according to the global trust value and the total trust value offset; Based on the comprehensive trust value, comparing with a preset warning trust threshold and malicious trust threshold, and assigning vehicle labels to each vehicle; the vehicle labels include trusted vehicles, warning vehicles and malicious vehicles; Based on the vehicle management rules matching the vehicle labels, performing communication management on the corresponding vehicles; The RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS, so as to store the trust value offsets and vehicle message scores corresponding to each vehicle through the blockchain; The blockchain deploys a smart contract including a trust value algorithm, and the RSU obtains the trust value algorithm through the blockchain to calculate or verify the trust value offsets of each vehicle; Wherein, the RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS, including: According to the set of trust value offsets aggregated by the RSU, calculating the sum of the absolute values of the vehicle trust value offset set as stakes, and the formula is as follows: wherein, is the sum of the absolute values of the set of vehicle trust value offsets; The function represents taking the minimum value; represents the upper limit of; Calculate using the following formula for the computational difficulty of the RSU release block that is positively correlated to obtain a nonce that meets the computational difficulty and successfully release the block: Among them, is the computational difficulty of the RSU publishing block; represents the total number of bits when the computational difficulty is represented in binary; represents the number of consecutive 0s starting from the first bit when the computational difficulty is represented in binary; is the sum of the absolute values of the vehicle trust value offset set; and is for controlling along with the change rate and offset.

2. The method according to claim 1, characterized in that, The method further includes: The leader vehicle and / or the in-group vehicles regularly query the global trust values and / or the total trust value offsets of each vehicle in the vehicle group where they are located from the RSU through the trust value query interface of the RSU; The leader vehicle conducts in-group broadcast warnings based on the global trust values and / or the total trust value offsets of the vehicles in each group.

3. The method according to claim 1, wherein The determining the leader vehicle of the vehicle group includes: Taking the vehicle that first enters the preset regional coverage range as the leader vehicle, and the vehicle that enters the preset regional coverage range second as the deputy leader vehicle; The leader vehicle calculates the group trust values of each vehicle in the group according to the behaviors / communication situations of other vehicles, updates the leader vehicle with the vehicle having the highest group trust value, and updates the deputy leader vehicle with the vehicle having the second highest group trust value; If the leader vehicle leaves the preset regional coverage range or shows malicious behaviors / communication situations, updating the leader vehicle with the deputy leader vehicle, and updating the deputy leader vehicle with the vehicle having the second highest current group trust value.

4. The method according to claim 3, characterized in that The method further includes: The leader vehicle performs identity verification and vehicle information management on the new vehicles entering the preset regional coverage range; the vehicle information includes vehicle VIN code and vehicle security key; The group leader vehicle creates a symmetric key and a set of public-private key pairs, and broadcasts them to the vehicles within the group for sending encrypted warning messages when the vehicles within the group encounter traffic emergencies.

5. The method according to claim 1, wherein Calculating the set of group trust values of vehicles within each group in the node dimension, the set of trust value offsets in the message dimension, and the vehicle message score set for each group respectively, includes: Calculating the group trust values of vehicles within each group in the node dimension, specifically including: Determining the message receiving vehicles and the message sending vehicles according to the situation of vehicles within each group regularly broadcasting BSM messages; Calculating the direct trust value of the message receiving vehicle for the message sending vehicle, and integrating the direct trust values of multiple neighbor vehicles of the message receiving vehicle for the message sending vehicle as the indirect trust value; Performing a weighted sum of the direct trust value and the indirect trust value to obtain the vehicle trust value of the message receiving vehicle for the message sending vehicle; The group leader vehicle aggregates the vehicle trust values of all message receiving vehicles within the group for the message sending vehicle and performs an arithmetic average to obtain the group trust value of the message sending vehicle; and / or Calculating the vehicle message scores of vehicles within each group in the message dimension, specifically including: Determining the message receiving vehicles and the message sending vehicles according to the situation of vehicles within each group sending warning messages for a certain traffic event and / or forwarding RSM messages sent by roadside units; For the traffic event, respectively calculating the trust value scores of the target messages sent by the message receiving vehicle for different message sending vehicles; Based on multiple trust value scores, using Bayesian inference to calculate the authenticity probability of the traffic event, and determining the vehicle message score of the message sending vehicle for the traffic event according to the authenticity probability; and / or Calculating the trust value offsets of vehicles within each group in the message dimension, specifically including: The group leader vehicle regularly aggregates the vehicle message scores of vehicles within each group for sending warning messages for multiple traffic events and / or forwarding RSM messages sent by roadside units, and calculates the message trust value offsets of vehicles within each group according to the vehicle message scores and the true or false attributes of the corresponding traffic events.

6. The method according to claim 3, wherein The RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS, and further includes: When the RSU publishes a new block and multiple other RSUs add the new block to the blockchain at the same time, the longest fork consensus algorithm is used to discard the redundant fork blocks.

7. The method according to claim 1, wherein Assigning vehicle tags to each vehicle based on the comprehensive trust value compared with the preset warning trust threshold and malicious trust threshold, includes: If the comprehensive trust value is higher than the warning trust threshold, the corresponding vehicle is marked as a trusted vehicle; If the comprehensive trust value is lower than or equal to the warning trust threshold and higher than the malicious trust threshold, the corresponding vehicle is marked as a warning vehicle, and the trust value of the warning vehicle is monitored for a preset observation time; After the expiration of the preset observation time, if the comprehensive trust value of the warning vehicle is still less than or equal to the warning trust threshold, the warning vehicle will be marked as a malicious vehicle; if the comprehensive trust value of the warning vehicle is higher than the warning trust threshold, the warning vehicle will be marked as a trusted vehicle; If the comprehensive trust value is less than or equal to the malicious trust threshold, the corresponding vehicle will be marked as a malicious vehicle.

8. The method according to claim 4, characterized in that Based on the vehicle management rules matching the vehicle label, the communication management of the corresponding vehicle includes: For the trusted vehicle, when sending a message, there is no need to carry a vehicle certificate, and it is directly encrypted with the symmetric key and signed with the vehicle private key; when receiving a message, there is no need to verify the validity of the vehicle certificate, and it is directly decrypted with the symmetric key and verified with the vehicle public key; For the warning vehicle, when sending a message, it is necessary to carry a vehicle certificate and sign it with the vehicle private key; when receiving a message, it is necessary to verify the validity of the vehicle certificate, and then extract the vehicle public key from the vehicle certificate for signature verification; For the malicious vehicle, revoke the vehicle certificate and it cannot participate in vehicle networking communication.

9. A blockchain-based trust management system for the Internet of Vehicles, characterized in that, The system includes: A trust value storage module, which is used to store the trust value offset set and the vehicle message score set of the vehicle by using blockchain technology; an intelligent contract containing a trust value algorithm is deployed in the blockchain; the RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS; A trust value calculation module, which is used to divide the intelligent connected vehicles driving on the road into several vehicle groups according to the preset regional coverage range, and determine the leader vehicle of the vehicle group; use the leader vehicle to calculate the group trust value set of the vehicles in each group in the node dimension, as well as the trust value offset set and the vehicle message score set in the message dimension, and upload the group trust value set, the trust value offset set and the vehicle message score set to the RSU; use the RSU to aggregate the group trust value set and calculate the global trust value of each vehicle in different vehicle groups; and, use the RSU to aggregate the trust value offset set and the vehicle message score set, and calculate the total trust value offset of each vehicle in different vehicle groups; calculate the comprehensive trust value of each vehicle by weighted summation according to the global trust value and the total trust value offset; A trust value sharing module, which is used to set the trust value query interface of the RSU, and the leader vehicle and / or the vehicle within the group regularly query the global trust value and / or the total trust value offset of each vehicle in the vehicle group where they are located through the trust value query interface; the leader vehicle conducts in-group broadcast warning based on the global trust value and / or the total trust value offset of the vehicles within each group; A trust value application module, which is used to assign vehicle labels to each vehicle based on the comparison of the comprehensive trust value with the preset warning trust threshold and malicious trust threshold; the vehicle labels include trusted vehicles, warning vehicles and malicious vehicles; based on the vehicle management rules matching the vehicle label, conduct communication management on the corresponding vehicle; The RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS, so as to store the trust value offset and vehicle message score corresponding to each vehicle through the blockchain; The blockchain deploys a smart contract containing a trust value algorithm, and the RSU obtains the trust value algorithm through the blockchain to calculate or verify the trust value offset of each vehicle; Among them, the RSU creates a block and adds the block to the blockchain through a consensus mechanism based on PoW and PoS, including: According to the set of trust value offsets summarized by the RSU, calculate the sum of the absolute values of the set of vehicle trust value offsets as stakes, and the formula is as follows: Wherein, is the sum of the absolute values of the vehicle trust value offset set; The function represents taking the minimum value; represents the upper limit of; Calculate using the following formula for the computational difficulty of the RSU release block that is positively correlated to obtain a nonce that meets the computational difficulty and successfully release the block: Among them, is the computational difficulty of the RSU publishing block; represents the total number of bits when the computational difficulty is represented in binary; represents the number of consecutive 0s starting from the first bit when the computational difficulty is represented in binary; is the sum of the absolute values of the vehicle trust value offset set; and is for controlling along with the change rate and offset.

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