Internet of vehicles trust management method and system based on block chain

Abstract

The invention provides an Internet of Vehicles trust management method and system based on a block chain, and the method comprises the steps: dividing intelligent networked vehicles running on a road into a plurality of vehicle groups according to a preset region coverage range, calculating a group trust value set of vehicles in each group in a node dimension and a trust value offset set and a vehicle message score set in a message dimension in a vehicle group form, and calculating a global trust value and a total trust value offset amount of each vehicle in different vehicle groups based on the group trust value set, the trust value offset set and the vehicle message score set; carrying out weighted summation to obtain a comprehensive trust value of each vehicle; comparing a preset warning trust threshold value with a malicious trust threshold value based on the comprehensive trust value, and endowing each vehicle with a vehicle label; and performing communication management on the corresponding vehicle based on the vehicle management rule matched with the vehicle label. According to the invention, malicious nodes in the network can be effectively identified and processed in real time, the trust value is prevented from being maliciously tampered, the communication delay is reduced, the network load is reduced, and the vehicle privacy is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of Internet of Things, and in particular to a blockchain-based Internet of Vehicles trust management method and system. Background Art

[0002] The Internet of Vehicle (IoV) uses intelligent sensing devices deployed on the vehicle side and roadside to achieve real-time communication between vehicle and cloud, vehicle and vehicle, vehicle and road, and vehicle and equipment, which can improve traffic efficiency and safety. However, due to the 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, a secure identity authentication system for Internet of Vehicles communication is established during the Internet of Vehicles communication process, giving vehicles, roadside equipment, information service platforms and other infrastructure a credible "digital identity", which helps to resist security attacks such as information forgery and tampering, and ensure 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 vehicle-mounted equipment, roadside equipment, etc. During the production stage of intelligent connected vehicles, the on-board device certificate can be initialized through operator channel configuration, server token authorization, etc. When the vehicle is started, the registration operation is first completed with the security certificate management system; when the vehicle communicates with the cloud, vehicle and vehicle, vehicle and road, and vehicle and equipment, 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 together to the target object. After the target object receives the message, it 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. After both are passed, the data is deemed to be authentic 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 synchronization of the trusted root certificate list (TRCL) from the security certificate management system to determine the validity of the signing certificate in the message.

[0004] However, the above solutions, such as using digital certificates, digital signatures, data encryption, PKI (Public Key Infrastructure) and other technologies, can achieve the authentication of the source of the message and the protection of the integrity of the message, but there are still 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 vehicles communicate with the cloud, vehicles with vehicles, vehicles with roads, or vehicles with devices, certificates need to be carried in messages. The identities of each node will be frequently authenticated, and frequent signing, verification, encryption, and decryption operations will consume a large amount of computing and communication resources.

[0007] (3) The traditional centralized architecture has problems such as single point failure and communication delay, while the traditional distributed architecture faces problems such as unreliable vehicles and RSU being vulnerable to attacks. Summary of the invention

[0008] To this end, the present invention provides a blockchain-based Internet of Vehicles trust management method and system, which aims to solve the technical problems in the prior art that malicious nodes within the Internet of Vehicles cannot be accurately identified to cause security risks, and frequent vehicle identity authentication leads to heavy network load and communication delays.

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

[0010] According to a first aspect of the present invention, the present invention provides a blockchain-based Internet of Vehicles trust management method, the method comprising:

[0011] Divide the intelligent networked vehicles on the road into a number of vehicle groups according to the preset area coverage, and determine the leader vehicle of the vehicle group;

[0012] The group leader vehicle calculates the group trust value set in the node dimension and the trust value offset set and the vehicle message score set in the message dimension of each vehicle in each group, and uploads the group trust value set, the trust value offset set and the vehicle message score set to the RSU;

[0013] The RSU aggregates the group trust value sets to calculate the global trust value of each vehicle in different vehicle groups; and the RSU aggregates the trust value offset sets and the vehicle message score sets to calculate the total trust value offset of each vehicle in different vehicle groups;

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

[0015] Based on the comprehensive trust value, a preset warning trust threshold and a malicious trust threshold are compared, and a vehicle label is assigned 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 tag, communication management is performed on the corresponding vehicle.

[0017] Furthermore, the method further comprises:

[0018] The group leader vehicle and / or the vehicles in the group periodically query the RSU through the trust value query interface of the RSU for the global trust value and / or the total amount of trust value deviation of each vehicle in the vehicle group;

[0019] The group leader vehicle broadcasts an early warning within the group based on the global trust value and / or the total amount of trust value deviation of the vehicles in each group.

[0020] Furthermore, the method further comprises:

[0021] 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;

[0022] The blockchain is deployed with 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 offset of each vehicle.

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

[0024] The vehicle that first enters the coverage area of ​​the preset area is regarded as the leader vehicle, and the vehicle that enters the coverage area of ​​the preset area second is regarded as the deputy leader vehicle;

[0025] The team leader vehicle calculates the group trust value of each vehicle in the group according to the behavior / communication status of other vehicles, updates the team leader vehicle with the vehicle with the highest group trust value, and updates the deputy team leader vehicle with the vehicle with the second highest group trust value;

[0026] If the team leader vehicle leaves the coverage of the preset area or exhibits malicious behavior / communication, the team leader vehicle is updated with the deputy team leader vehicle, and the deputy team leader vehicle is updated with the vehicle with the second highest trust value in the current group.

[0027] Furthermore, the method further comprises:

[0028] The team leader vehicle performs identity verification and vehicle information management on new vehicles entering the coverage area of ​​the preset area; the vehicle information includes the vehicle VIN code and vehicle safety key;

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

[0030] Furthermore, the step of respectively calculating the group trust value set of the vehicles in each group in the node dimension and the trust value offset set and the vehicle message score set in the message dimension includes:

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

[0032] According to the situation of regular broadcasting of BSM messages by vehicles in each group, the message receiving vehicles and message sending vehicles are determined;

[0033] Calculating a direct trust value of the message receiving vehicle for the message sending vehicle, and integrating direct trust values ​​of multiple neighboring vehicles of the message receiving vehicle for the message sending vehicle as an indirect trust value;

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

[0035] The group leader vehicle aggregates 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 each group in the message dimension, including:

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

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

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

[0041] and / or,

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

[0043] The group leader vehicle regularly summarizes the vehicle message scores of the vehicles in each group that send warning messages and / or forward RSM messages sent by roadside equipment for multiple traffic events, and calculates the message trust value offset of the vehicles in each group based on 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] According to the trust value offset set summarized by the RSU, the sum of the absolute values ​​of the vehicle trust value offset set is calculated as stakes, and the formula is as follows:

[0046]

[0047] Among them, ASToff i is the sum of the absolute values ​​of the vehicle trust value offset set; the min() function represents the minimum value; ASToff max ASToff i The upper limit of

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

[0049]

[0050] Among them, Diff i The computational difficulty of the RSU publishing block; N tot Indicates the total number of digits when the difficulty of operation is expressed in binary; N0 indicates the number of consecutive 0 digits starting from the first digit when the difficulty of operation is expressed in binary; ASToff i is the sum of the absolute values ​​of the vehicle trust value offset set; η and μ are the control N0 with Diff i The rate of change and offset of

[0051] and / or,

[0052] If 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 forked blocks.

[0053] Furthermore, the method of assigning a vehicle label to each vehicle based on the comparison of the comprehensive trust value with the preset warning trust threshold and malicious trust threshold includes:

[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 preset observation time expires, if the comprehensive trust value of the warning vehicle is still lower 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 trusted vehicle;

[0057] If the comprehensive trust value is lower 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 rules matching the vehicle tag includes:

[0059] For the trusted vehicle, when sending a message, there is no need to carry the vehicle certificate, and the symmetric key is directly used for encryption and the vehicle private key is signed; when receiving a message, there is no need to verify the validity of the vehicle certificate, and the symmetric key is directly used for decryption and the vehicle public key is used for signature verification;

[0060] For the warning vehicle, the vehicle certificate needs to be carried when sending the message, and the vehicle private key needs to be used for signing; when receiving the message, the validity of the vehicle certificate needs to be verified, and then the vehicle public key needs to be extracted from the vehicle certificate for signature verification;

[0061] For the malicious vehicle, the vehicle certificate is revoked and it cannot participate in Internet of Vehicles communications.

[0062] According to a second aspect of the present invention, the present invention provides a blockchain-based Internet of Vehicles trust management system, the system comprising:

[0063] A trust value storage module is used to store a trust value offset set and a vehicle message score set of a vehicle using blockchain technology; a smart 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;

[0064] A trust value calculation module is used to divide the intelligent networked vehicles traveling on the road into several vehicle groups according to the preset area coverage, and determine the leader vehicle of the vehicle group; use the leader vehicle to respectively calculate the group trust value set of the vehicles in each group in the node dimension and the trust value offset set and 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 summarize the group trust value set and calculate the global trust value of each vehicle in different vehicle groups; and use the RSU to summarize the trust value offset set and the vehicle message score set to 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, a weighted sum is taken to calculate the comprehensive trust value of each vehicle;

[0065] A trust value sharing module is used to set a trust value query interface of the RSU, and the group leader vehicle and / or the vehicles in the group periodically query the RSU for the global trust value and / or the total amount of trust value deviation of each vehicle in the vehicle group through the trust value query interface; the group leader vehicle broadcasts an early warning within the group based on the global trust value and / or the total amount of trust value deviation of each vehicle in the group;

[0066] The trust value application module is used to assign a vehicle label 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; and 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 solution and has at least the following beneficial effects:

[0068] Through the scheme of the present invention, in the Internet of Vehicles environment, when a vehicle communicates with the cloud, another vehicle, a vehicle with a road, or a vehicle with a device, it is not necessary to frequently authenticate the identity of the vehicle, which consumes a large amount of computing and communication resources. The network is divided into several groups according to geographical intervals, and the trust values ​​of the vehicles participating in the 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 value is stored in the blockchain. The trust value algorithm is written into the smart contract, and a consensus mechanism combining PoW and PoS is constructed. The mechanism can effectively identify and process malicious nodes in the network in real time, prevent the trust value from being maliciously tampered with, reduce communication delays, reduce network load, and protect vehicle privacy.

[0069] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0071] Figure 1 A schematic diagram of a process of a blockchain-based Internet of Vehicles trust management method provided by an embodiment of the present invention is shown;

[0072] Figure 2 A schematic diagram of the process of blockchain fork processing provided by an embodiment of the present invention is shown;

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

[0074] Figure 4 A schematic diagram of a process of assigning a vehicle label to each vehicle according to an embodiment of the present invention is shown;

[0075] Figure 5 A schematic diagram of the structure of a blockchain-based Internet of Vehicles trust management system provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0076] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying 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 to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0077] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0078] The embodiment of the present invention provides a blockchain-based Internet of Vehicles trust management method, such as Figure 1 As shown, at least the following steps S101 to S106 may be included:

[0079] Step S101: divide the intelligent networked vehicles traveling on the road into several vehicle groups according to the preset area coverage, and determine the leader vehicle of the vehicle group.

[0080] The embodiment of the present invention evaluates the degree of trust of vehicles in the form of vehicle groups. Specifically, the circular area coverage with a radius of 150 meters and a certain intelligent networked vehicle as the center can be divided into groups to form multiple vehicle groups whose coverage can intersect with each other. It should be noted that in actual applications, the size of the preset area coverage can be set according to actual needs, and the present invention does not limit it.

[0081] In the embodiment of the present invention, a leader vehicle is set in each vehicle group, and 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 detailed in the subsequent description). The role of the leader vehicle includes: verifying the identity information of the vehicles in the group; generating and distributing group keys; calculating the group trust value and trust value offset of the vehicles in the group, and uploading them to the RSU; regularly obtaining the latest trust value of the vehicles in the group from the RSU and broadcasting it in the group.

[0082] The following is a detailed description of the selection of the leader vehicle: the vehicle that first enters the coverage of the preset area is the leader vehicle, and the vehicle that enters the coverage of the preset area second is the deputy leader vehicle; the leader vehicle verifies the identity of new vehicles that enter the coverage of the preset area and manages vehicle information; it can also create a symmetric key and a set of public and private key pairs, and broadcast them to the vehicles in the group, which are used to send encrypted warning messages when the vehicles in the group encounter traffic emergencies. Then, the leader vehicle calculates the group trust value of each vehicle in the group based on the behavior / communication of other vehicles, updates the leader vehicle with the vehicle with the highest group trust value, and updates the deputy leader vehicle with the vehicle with the second highest group trust value; if the leader vehicle leaves the coverage of the preset area or exhibits malicious behavior / communication, the deputy leader vehicle is used to update the leader vehicle, and the vehicle with the second highest current group trust value is used to update the deputy leader vehicle.

[0083] That is to say, in the initial stage, the first vehicle entering the target area is the team leader vehicle, and the second vehicle is the deputy team leader vehicle; when a new vehicle enters the coverage area of ​​the group, the team leader verifies the identity of the new vehicle. After the verification, the team leader vehicle adds the vehicle VIN code, public key and other information to the group vehicle list; then, based on the behavior and communication status of the vehicles in the group, the group trust value is calculated, and the vehicle with the highest score is elected as the team leader vehicle, and the vehicle with the second highest score is elected as the deputy team leader vehicle; when the team leader vehicle leaves the target area or exhibits malicious behavior, the deputy team leader vehicle takes over, and the vehicle with the second highest score is re-elected as the deputy team leader vehicle.

[0084] Among them, the team leader's vehicle verification of the new vehicle identity refers to the identity verification of the vehicle information, which may include the vehicle VIN code and vehicle security key. i The vehicle has a unique identification, namely the VIN code, at the factory stage. When the vehicle is started, the OBU will initiate a registration request to the ECA (Enrollment CA) and pass in the VIN code. The vehicle security key refers to the security certificate (including the public key Pu) returned to the vehicle through the secure channel after the ECA verifies it. i 、Private key Pr i ); then request PCA (Pseudonym CA) to obtain several pseudonymous certificates (including public key Pupse i、Private key Prpse i ), used to sign the BSM message to avoid leaking the vehicle itinerary and protect the vehicle privacy. In addition, in the embodiment of the present invention, when a new vehicle successfully joins the 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 incident occurs, the vehicle can directly send an alarm message, or forward the RSM message sent by the roadside equipment, and use the group key for encryption and decryption and signature verification.

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

[0086] Under normal circumstances, intelligent connected vehicles will broadcast BSM messages regularly, and when encountering emergencies, they will send warning messages. Due to the existence of malicious nodes, the messages received by the vehicle may not be authentic and reliable. Therefore, it is necessary to formulate some rules to evaluate the authenticity of the received messages and then evaluate the trust value of the vehicle. The embodiment of the present invention adopts two trust value calculation methods, namely, trust value calculation based on node dimension and trust value calculation based on message dimension, which are described in detail below:

[0087] Calculating the group trust value of the vehicles in each group in the node dimension may specifically include: determining the message receiving vehicles and the message sending vehicles according to the situation of the vehicles in 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 neighboring vehicles of the message receiving vehicle for the message sending vehicle as the indirect trust value; taking 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 summarizes the vehicle trust values ​​of all the message receiving vehicles in the group for the message sending vehicle and takes the arithmetic average to obtain the group trust value of the message sending vehicle.

[0088] That is to say, the vehicles in the group can periodically send BSM messages containing data such as VIN code, location, speed, heading angle, running status, etc. In the calculation, 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 irepresents the parameters that affect the trust value of the vehicle, including communication frequency, driving speed, received signal strength, number of trusted neighbors, vehicle spacing, degree of compliance with traffic signal rules, etc.; 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 it and adds it into the BSM message, which is broadcast to multiple neighboring vehicles of the message receiving vehicle r.

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

[0094]

[0095] in, It represents the direct trust value of the message-sending vehicle s calculated by the neighboring vehicle of the message-receiving vehicle r. The message-receiving vehicle r parses the direct trust value of the message-sending vehicle s from the BSM message broadcast by its neighboring vehicles, 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 The calculation is performed by weighted sum of direct trust value and indirect trust value. The calculation formula is as follows:

[0097]

[0098] Among them, α∈(0.5,1), which means 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, the message sending vehicle s sends the vehicle VIN code and direct trust value Indirect Trust Value Vehicle Trust Value The trust value of the vehicle is stored in the local lightweight database SQLite, and sent to the team leader vehicle.

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

[0101]

[0102] in, It represents the vehicle trust value calculated by the vehicles in the group for the message sending vehicle s. It can be understood that after the leader vehicle completes the calculation of the group trust value, it is sorted in reverse order according to the trust score, and the first and second ranked vehicles will serve as the leader and deputy leader respectively in the next leader election. When the leader vehicle passes the RSU, the group trust value set of all vehicles in the group is synchronized to the RSU.

[0103] Calculating the trust value offset of the vehicles in each group in the message dimension may specifically include: determining the message receiving vehicles and the message sending vehicles according to the situation in which the vehicles in each group send warning messages and / or forward RSM messages sent by the roadside equipment for a certain traffic event; calculating the trust value scores of the message receiving vehicles for the target messages sent by different message sending vehicles for traffic events respectively; calculating the authenticity probability of the traffic event using Bayesian inference based on multiple trust value scores, 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 in each group that send warning messages and / or forward RSM messages sent by the roadside equipment for multiple traffic events, and calculates the message trust value offset of the vehicles in each group according to the vehicle message scores and the true or false attributes of the corresponding traffic events.

[0104] It is understandable that when a traffic incident occurs, the vehicles in the group can directly send warning information or forward the RSM message sent by the roadside equipment. In the embodiment of the present invention, the traffic incident is defined as e, the message reflecting the traffic incident 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] in, It represents the trust value score of the message receiving vehicle r on the message sending vehicle s sending the message m; It represents the distance between the message sending vehicle s and the place where the traffic event e occurs when the message sending vehicle s sends the message m; γ represents the rate of change of the message trust value with the distance between the vehicle and the place where the event occurs; f represents the lower limit of the message trust value.

[0108] For the same traffic event e, the message trust values ​​of 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 calculate the message trust value set TM r Based on this, the authenticity probability of traffic event e is judged as follows:

[0109]

[0110] in, is a mutually exclusive event of traffic event e (for example, e means that vehicle A has a collision at intersection 1, then It means that vehicle A is passing through intersection 1 normally), therefore, P(e) is the prior probability of traffic event e, Prior events The prior probability, P(e / TM r )∈[0,1].

[0111] The embodiment of the present invention can set P(e / TM r ) threshold: If P(e / TM r ) is greater than or equal to the threshold, the message receiving vehicle r considers the event state to be e, otherwise, the state is Therefore, the message m of the event will be broadcast truthfully. The score of the message m that falsely broadcasts the event is recorded as +1, and the score of the message m that falsely broadcasts the event is recorded as -1.

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

[0113]

[0114] Among them, Toff s is the trust value offset calculated based on the message sent by the message sending vehicle s, C p express The number of messages, C n express The number of messages, θ p and θ n Represent the weights of the number of real and false broadcast messages, respectively, and 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 is; conversely, the smaller S(x) is, the higher the sensitivity to minority scores is.

[0117] Understandably, it is unlikely that an attacker would be able to control a large number of vehicles, so it can be assumed that most The rating is real 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. The embodiment of the present invention can introduce a penalty mechanism for the message receiving vehicle r that sends a malicious score, and multiply the trust value of the message receiving vehicle r based on the message by the penalty coefficient λ, λ∈(0,1).

[0118] Furthermore, the leader vehicle will eventually upload the calculated trust value offset set and vehicle message score set of multiple vehicles in the group to the RSU, and the RSUs will compete with each other to add the newly created block to the blockchain. In other words, the RSU creates a block and tries to add it to the blockchain to store the trust value offset and vehicle message score corresponding to each vehicle through the blockchain. A consensus mechanism based on the combination of 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 stakes. The larger the stakes of the RSU, the lower the difficulty, the easier it is to calculate the appropriate nonce, and the faster the block will be released.

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

[0120]

[0121] Among them, ASToff i For RSU i The sum of the absolute values ​​of the vehicle trust value offset set stored in; the min() function represents the minimum value; ASToff max ASToff i The upper limit of

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

[0123]

[0124] Among them, Diff i The computational difficulty of publishing blocks for RSU; N tot The total number of bits in binary representation of the difficulty of the operation depends on the hash algorithm used, such as SM3 algorithm, N tot =256; N0 represents the difficulty of operation. When expressed in binary, the number of consecutive 0 bits starting from the first bit; ASToff i is the sum of the absolute values ​​of the vehicle trust value offset set; η and μ are the control N0 with Diff iThe rate of change and offset, reference values: v = 0.01, μ = 3.

[0125] It should be noted that if multiple RSUs add new blocks to the blockchain at the same time as an RSU publishes a new block, the longest fork consensus algorithm will be used to discard the redundant forked blocks. In other words, when an RSU receives a new block, it will first verify whether the Nonce in the block meets the difficulty requirements, 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 publish new blocks at the same time. Other RSUs will first verify the new blocks and add the blocks that meet the difficulty 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, such as Figure 2 As shown in the figure, the algorithm flow is described as follows: RSU randomly selects a fork and continues to perform 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 will add the block to the blockchain. Next, RSU will select a longer blockchain to carry out a new round of tasks. Over time, the longest fork will be recognized by the blockchain, and other forks will be discarded. At this time, RSU will re-collect the blocks published by itself in the discarded forks, extract the trust value offset set and vehicle message score set in the block body, and re-add them to the current block to compete for subsequent tasks.

[0126] Thus, the trust value offset and vehicle message score corresponding to each vehicle can be stored based on blockchain technology. Figure 3 FIG. 1 is a schematic diagram of a block data structure provided by an embodiment of the present invention. 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 hash value of the previous block; it is also used 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 of the vehicle and the vehicle message score set, including: vehicle identifier (VIN), trust value offset (Toff), and vehicle message score set (Ratings). It should also be noted that the blockchain in the embodiment of the present invention is also deployed with 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. Therefore, even if an attacker invades the RSU, the smart contract algorithm cannot be changed. Therefore, the trust value calculation and update algorithm is 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 group trust value set and calculates the global trust value of each vehicle in different vehicle groups; and the RSU aggregates the trust value offset set and the vehicle message score set and calculates the total trust value offset of each vehicle in different vehicle groups.

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

[0129]

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

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

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

[0133] The embodiment of the present invention is provided with an RSU trust value query interface, through which the leader vehicle and / or vehicles in the group can periodically query the RSU for the global trust value and / or the total amount of trust value offset of each vehicle in the vehicle group.

[0134] That is to say, RSU provides a vehicle trust value query interface / trust / query, and the request parameters include: request vehicle VIN code reqVin, target vehicle VIN code set targetVins, and request vehicle public key pubKey. After receiving the request to query the trust value, 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 , the calculation formula is as follows:

[0135]

[0136] Among them, SToff s Indicates the total amount of trust value deviation of the message sending vehicle s; Toff jRepresents the trust value offset of the message sending vehicle s calculated by different group leaders.

[0137] Step S104, calculating the comprehensive trust value of each vehicle by weighted summation based on the global trust value and the total trust value offset.

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

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

[0140] Among them, the reference values ​​τ1=0.5, τ2=0.5 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 comprehensive trust value set of the message-sending vehicle and returns it to the requesting vehicle. Normally, the leader vehicle can periodically query the RSU for the comprehensive trust value of all vehicles in the group and then broadcast it within the group; if there are special circumstances, it is also supported for the vehicles in the group to directly initiate a vehicle trust value query to the leader or RSU.

[0142] It should be noted that in the embodiment of the present invention, the leader vehicle and / or the vehicles in the group can also query the comprehensive trust value of each vehicle through the trust value query interface for the RSU. In addition, the leader vehicle and / or the vehicles in the group can also broadcast an early warning within the group based on the global trust value, the total trust value offset and / or the comprehensive trust value of each vehicle.

[0143] Step S105 , assigning a vehicle label to each vehicle based on the comparison between the comprehensive trust value and the preset warning trust threshold and malicious trust threshold.

[0144] In the embodiment of the present invention, a warning trust threshold T is defined. warn and malicious trust threshold T mal Two thresholds, T warn >T mal ,define three labels: trusted vehicle, warning vehicle, and malicious vehicle.

[0145] Figure 4 FIG. 1 is a logic flow chart of adding a vehicle tag to a vehicle according to an embodiment of the present invention. Figure 4 As shown in the figure, when the comprehensive trust value of the vehicle Toverall sHigher than T warn , the vehicle will be marked as trusted.

[0146] When the comprehensive trust value of the vehicle Toverall s ∈(T rev ,T warn ], the vehicle will be marked as a warning state; for vehicles in the warning state, the embodiment of the present invention monitors the trust value during a preset observation time, which can last from 300ms to 5min. At this time, the warning vehicle needs to actively perceive the surrounding environment and broadcast a true message to increase the trust value. When the trust value is higher than T warn , you can get rid of the warning label and turn to a trusted state; when the observation period ends, if the trust value Toverall s Still lower than T warn , it is marked as a malicious vehicle.

[0147] When the comprehensive trust value of the vehicle Toverall s Lower than T mal , the vehicle will be marked as malicious and handed over to MA (Misbehavior Authority) for processing. MA will revoke the vehicle's certificate, and the vehicle will no longer receive any messages from the Internet of Vehicles, nor can it send messages to the Internet of Vehicles.

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

[0149] When trusted vehicles communicate, 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. The group symmetric key is directly used for encryption and decryption, and the private key signature and public key verification of the message sending vehicle are used to reduce communication resource consumption and improve communication efficiency.

[0150] When warning vehicles communicate, the message sending vehicle signs with a private key and carries a certificate. The message receiving vehicle needs to first use the CA certificate to verify the authenticity and validity of the certificate used by the sender for signing, and then extract the public key from the certificate for signature verification;

[0151] Malicious vehicles have their certificates revoked by MA and cannot participate in IoV communications.

[0152] The embodiment of the present invention provides a blockchain-based Internet of Vehicles trust management method, including: dividing the intelligent networked vehicles traveling on the road into several vehicle groups according to the preset area coverage, and determining the leader vehicle of the vehicle group; the leader vehicle respectively calculates the group trust value set of the vehicles in each group in the node dimension and the trust value offset set and vehicle message score set in the message dimension, and uploads the group trust value set, trust value offset set and vehicle message score set to the RSU; the RSU summarizes the group trust value set, calculates the global trust value of each vehicle in different vehicle groups; and, the RSU summarizes the trust value offset set and the vehicle message score set, and calculates the total trust value offset of each vehicle in different vehicle groups; according to the global trust value and the total trust value offset, the weighted sum is used to calculate the comprehensive trust value of each vehicle; based on the comprehensive trust value, the preset warning trust threshold and malicious trust threshold are compared, and a vehicle label is assigned 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, the corresponding vehicle is managed for communication. Through the scheme of the present invention, at least the following effects can be achieved:

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

[0154] (2) The trust value algorithm proposed in the present invention defines a node-based trust value and a message-based trust value: in the node-based trust value algorithm, both direct trust value and indirect trust value are taken into account, and the global trust value is calculated from three dimensions: vehicle, team leader, and RSU; in the message-based trust value algorithm, the credibility of the message, the message score, the message trust value offset, and the total trust value offset are calculated respectively; the vehicle comprehensive trust value finally calculated can more comprehensively and accurately reflect the trust status of the vehicle;

[0155] (3) When calculating the message-based trust value, the present invention takes into account the situation where the leader vehicle maliciously uploads an erroneous message score, and penalizes the trust value of the leader vehicle, thereby comprehensively improving the security of IoV.

[0156] (4) The present invention defines two trust value thresholds, warning and malicious, and three vehicle status labels, trusted, warning and malicious. After calculating the trust value of the vehicle, if the vehicle is marked as malicious, the certificate will be handed over to the MA to revoke, even though these vehicles have valid certificate credentials and can effectively identify internal attacks; if the vehicle is marked as trusted, when communicating with other vehicles, the group symmetric key can be directly used for encryption and decryption, vehicle private key signature, and public key verification. There is no need to carry a certificate in the message, and the vehicle receiving the message does not need to verify the validity of the signature certificate with the CA, which reduces the size of the communication message and reduces the consumption of communication resources and computing resources required for frequent verification.

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

[0158] (6) The present invention defines a consensus mechanism combining PoW and PoS, so that the RSU storing the larger absolute value of the vehicle trust value offset can find the nonce that meets the difficulty requirement faster and the easier it is 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 share the latest vehicle trust value and trust status with the outside world in real time.

[0160] Further, as Figure 1 The specific implementation of the present invention provides a blockchain-based Internet of Vehicles trust management system, such as Figure 5 As 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 trust value offset set and the vehicle message score set of the vehicle using blockchain technology; a smart 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;

[0162] The trust value calculation module 520 can be used to divide the intelligent networked vehicles traveling on the road into several vehicle groups according to the preset area coverage, and determine the leader vehicle of the vehicle group; use the leader vehicle to respectively calculate the group trust value set of the vehicles in each group in the node dimension and the trust value offset set and 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 summarize the group trust value set and calculate the global trust value of each vehicle in different vehicle groups; and use the RSU to summarize the trust value offset set and the vehicle message score set to 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, the comprehensive trust value of each vehicle is calculated by weighted summation;

[0163] The trust value sharing module 530 can be used to set the trust value query interface of the RSU. The team leader vehicle and / or the vehicles in the group periodically query the RSU for the global trust value and / or the total trust value offset of each vehicle in the vehicle group through the trust value query interface; the team leader vehicle broadcasts an intra-group warning based on the global trust value and / or the total trust value offset of each vehicle in the group.

[0164] The trust value application module 540 can be used to assign a vehicle label 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; and communication management is performed on the corresponding vehicles based on the vehicle management rules that match the vehicle labels.

[0165] It should be noted that for other corresponding descriptions of the functional modules involved in the blockchain-based Internet of Vehicles trust management system provided by the embodiment of the present invention, please refer to Figure 1 The corresponding description of the method shown will not be repeated here.

[0166] Those skilled in the art can clearly understand that the specific working processes of the systems, devices, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and for the sake of brevity, they are not further described here.

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

[0168] Those skilled in the art can understand that if the integrated functional unit is implemented in the form of software and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can essentially 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, which includes a number of instructions to enable 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 method described in each embodiment of the present invention when running the instructions. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk and other media that can store program codes.

[0169] Alternatively, all or part of the steps of implementing the aforementioned method embodiments may be accomplished by hardware associated with program instructions (such as a computing device such as a personal computer, a server, or a network device), and the program instructions may be stored in a computer-readable storage medium. When the program instructions are executed by a processor of a 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, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that within the spirit and principles of the present invention, the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not deviate from the protection scope of the present invention.

Claims

1. A blockchain-based Internet of Vehicles trust management method, characterized in that: The method comprises: Divide the intelligent networked vehicles on the road into a number of vehicle groups according to the preset area coverage, and determine the leader vehicle of the vehicle group; The group leader vehicle calculates the group trust value set in the node dimension and the trust value offset set and the vehicle message score set in the message dimension of each vehicle in each group, and uploads the group trust value set, the trust value offset set and the vehicle message score set to the RSU; The RSU aggregates the group trust value sets to calculate the global trust value of each vehicle in different vehicle groups; and the RSU aggregates the trust value offset sets and the vehicle message score sets to 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 amount of the trust value offset; Based on the comprehensive trust value, a preset warning trust threshold and a malicious trust threshold are compared, and a vehicle label is assigned 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 tag, communication management is performed on the corresponding vehicle.

2. The method according to claim 1, characterized in that The method further comprises: The group leader vehicle and / or the vehicles in the group periodically query the RSU through the trust value query interface of the RSU for the global trust value and / or the total amount of trust value deviation of each vehicle in the vehicle group; The group leader vehicle broadcasts an early warning within the group based on the global trust value and / or the total amount of trust value deviation of the vehicles in each group.

3. The method according to claim 1, characterized in that The method further comprises: 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 is deployed with 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 offset of each vehicle.

4. The method according to claim 1, characterized in that: The step of determining a leader vehicle of the vehicle group comprises: The vehicle that first enters the coverage area of ​​the preset area is regarded as the leader vehicle, and the vehicle that enters the coverage area of ​​the preset area second is regarded as the deputy leader vehicle; The team leader vehicle calculates the group trust value of each vehicle in the group according to the behavior / communication status of other vehicles, updates the team leader vehicle with the vehicle with the highest group trust value, and updates the deputy team leader vehicle with the vehicle with the second highest group trust value; If the team leader vehicle leaves the coverage of the preset area or exhibits malicious behavior / communication, the team leader vehicle is updated with the deputy team leader vehicle, and the deputy team leader vehicle is updated with the vehicle with the second highest trust value in the current group.

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

6. The method according to claim 1, characterized in that The step of respectively calculating the group trust value set of the vehicles in each group in the node dimension and the trust value offset set and the vehicle message score set in the message dimension includes: Calculate the group trust value of vehicles in each group in the node dimension, including: According to the situation of regular broadcasting of BSM messages by vehicles in each group, the message receiving vehicles and message sending vehicles are determined; Calculating a direct trust value of the message receiving vehicle for the message sending vehicle, and integrating direct trust values ​​of multiple neighboring vehicles of the message receiving vehicle for the message sending vehicle as an indirect trust value; Performing a weighted summation on the direct trust value and the indirect trust value to obtain a 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 in the group for the message sending vehicle and performs arithmetic averaging to obtain the group trust value of the message sending vehicle; and / or, Calculate the vehicle message score of each group in the message dimension, including: Determine the message receiving vehicle and the message sending vehicle according to the situation that the vehicles in each group send warning messages and / or forward the RSM messages sent by the roadside equipment for a certain traffic event; For the traffic event, respectively calculating the trust value scores of the message receiving vehicle for the target messages sent by different message sending vehicles; Based on the multiple trust value scores, using Bayesian inference to calculate the authenticity probability of the traffic event, and determining the vehicle message score of the vehicle sending the message for the traffic event according to the authenticity probability; and / or, Calculate the trust value offset of the vehicles in each group in the message dimension, including: The group leader vehicle regularly summarizes the vehicle message scores of the vehicles in each group that send warning messages and / or forward RSM messages sent by roadside equipment for multiple traffic events, and calculates the message trust value offset of the vehicles in each group based on the vehicle message scores and the true or false attributes of the corresponding traffic events.

7. The method according to claim 3, characterized in that 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 trust value offset set summarized by the RSU, the sum of the absolute values ​​of the vehicle trust value offset set is calculated as stakes, and the formula is as follows: Among them, ASToff i is the sum of the absolute values ​​of the vehicle trust value offset set; the min() function represents the minimum value; ASToff max ASToff i The upper limit of Use the following formula to calculate ASToff i The computational difficulty of the RSU publishing the block is positively correlated to obtain a nonce that meets the computational difficulty and successfully publish the block: Among them, Diff i The computational difficulty of the RSU publishing block; N tot Indicates the total number of digits when the difficulty of operation is expressed in binary; N0 indicates the number of consecutive 0 digits starting from the first digit when the difficulty of operation is expressed in binary; ASToff i is the sum of the absolute values ​​of the vehicle trust value offset set; η and μ are the control N0 with Diff i The rate of change and offset of and / or, If 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 forked blocks.

8. The method according to claim 1, characterized in that: The method of comparing the preset warning trust threshold and malicious trust threshold based on the comprehensive trust value and assigning a vehicle label to each vehicle 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 preset observation time expires, if the comprehensive trust value of the warning vehicle is still lower 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 trusted vehicle; If the comprehensive trust value is lower than or equal to the malicious trust threshold, the corresponding vehicle is marked as a malicious vehicle.

9. The method according to claim 5, characterized in that The communication management of the corresponding vehicle based on the vehicle management rule matching the vehicle tag includes: For the trusted vehicle, when sending a message, there is no need to carry the vehicle certificate, and the symmetric key is directly used for encryption and the vehicle private key is signed; when receiving a message, there is no need to verify the validity of the vehicle certificate, and the symmetric key is directly used for decryption and the vehicle public key is used for signature verification; For the warning vehicle, the vehicle certificate needs to be carried when sending the message, and the vehicle private key needs to be used for signing; when receiving the message, the validity of the vehicle certificate needs to be verified, and then the vehicle public key needs to be extracted from the vehicle certificate for signature verification; For the malicious vehicle, the vehicle certificate is revoked and it cannot participate in Internet of Vehicles communications.

10. A blockchain-based Internet of Vehicles trust management system, characterized in that: The system comprises: A trust value storage module is used to store a trust value offset set and a vehicle message score set of a vehicle using blockchain technology; a smart 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 is used to divide the intelligent networked vehicles traveling on the road into several vehicle groups according to the preset area coverage, and determine the leader vehicle of the vehicle group; use the leader vehicle to respectively calculate the group trust value set of the vehicles in each group in the node dimension and the trust value offset set and 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 summarize the group trust value set and calculate the global trust value of each vehicle in different vehicle groups; and use the RSU to summarize the trust value offset set and the vehicle message score set to 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, a weighted sum is taken to calculate the comprehensive trust value of each vehicle; A trust value sharing module is used to set a trust value query interface of the RSU, and the group leader vehicle and / or the vehicles in the group periodically query the RSU for the global trust value and / or the total amount of trust value deviation of each vehicle in the vehicle group through the trust value query interface; the group leader vehicle broadcasts an early warning within the group based on the global trust value and / or the total amount of trust value deviation of each vehicle in the group; The trust value application module is used to assign a vehicle label 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; and communication management is performed on the corresponding vehicles based on the vehicle management rules matching the vehicle labels.

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