A mobile group key management method based on Chinese remainder theorem and vehicle clustering

Abstract

The application discloses a mobile group key management method based on Chinese remainder theorem and vehicle clustering, which comprises the following steps: initializing parameters of two running systems of a tracking center and a key generation center; registering ordinary vehicles, generating pseudo identities, partial private keys of the ordinary vehicles, private keys and public keys of the ordinary vehicles, and receiving generated key information of the public vehicles; generating public vehicle node messages and signatures of the messages, and broadcasting messages of related parameters of the public vehicle nodes; the ordinary vehicles initiate a group entry request to a communication group managed by the public vehicle nodes, and aggregate verification is conducted on the communication group, a shared key is generated; the public vehicle nodes generate group keys for the ordinary vehicles in the same communication group; when the ordinary vehicles in the communication group managed by the public vehicle nodes change, the group keys of the communication group managed by the public vehicle nodes are updated; the method can not only quickly search out invalid signatures, but also improves the efficiency of group key distribution and updating.

Description

Technical Field

[0001] This invention relates to the field of vehicle network traffic management technology, specifically to a mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering. Background Technology

[0002] The rapid development of vehicle-to-everything (V2X) technology has brought great convenience to people's lives, but it has also brought a series of information security issues. Intelligent transportation systems (ITS) achieve intelligent traffic management by collecting sensory information about themselves and their surroundings from vehicles and roadside facilities. If the legitimacy and integrity of the sensory information uploaded by terminals cannot be guaranteed, it will lead to incorrect decisions by the ITS, resulting in traffic congestion or even paralysis. Therefore, it is necessary to authenticate the sensory data transmitted by terminals in the V2X to ensure its authenticity and integrity. However, most traditional wireless communication security technologies do not take into account the special characteristics of the V2X wireless communication environment, such as high vehicle speed, large number of vehicles, and frequent information interaction, and cannot meet the needs of V2X to verify massive amounts of messages in a short period of time.

[0003] With the rapid development of vehicle-to-everything (V2X) technology, in addition to collecting traffic environment information for traffic control centers and realizing intelligent traffic management, various commercial service applications catering to the personalized needs of vehicle users have emerged. Unlike traffic environment information, these personalized services often involve vehicle privacy information or paid information provided by service providers. Failure to guarantee the confidentiality of such information could lead to privacy breaches for users or financial losses for service providers. Therefore, encryption of this data is necessary to ensure its confidentiality. These services typically provide information to users through group-based applications, distributing data via multicast by grouping users. Therefore, encrypting messages using a group key is the most effective way to ensure the confidentiality of messages within the group. However, the mobility of vehicle nodes in V2X leads to instability in communication groups, requiring frequent updates to group communication parameters. Traditional wireless communication security technologies largely do not consider this characteristic.

[0004] Traffic data transmission scenarios for the Internet of Vehicles (IoV) do not require data confidentiality, but they do need to ensure authentication and integrity. Message authentication is typically used to meet these security requirements. However, existing message authentication methods suffer from drawbacks such as high computational overhead and complex error detection processes.

[0005] For data transmission in commercial applications of connected vehicles, not only is it necessary to authenticate the message source, but its confidentiality must also be ensured. Group key encryption is typically used to meet these security requirements. However, traditional group key management methods suffer from the drawbacks of communication group instability and frequent key updates. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, this invention provides a mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering. Utilizing a batch message authentication method with error detection capabilities and a mobile group key management method based on the Chinese Remainder Theorem, the method ensures mobile group key management through vehicle clustering within a public transportation system. This approach safeguards vehicle privacy while constructing a stable communication group, thereby improving the stability of the communication group and reducing the frequency of group key updates.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0008] A mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering includes the following steps:

[0009] S1. Initialize the parameters of the two operating systems, the tracking center and the key generation center, to obtain the initial parameters of the tracking center and the key generation center;

[0010] S2. Based on the initial parameters in step S1, the tracking center generates a pseudo identity for ordinary vehicles, the key generation center generates a partial private key for ordinary vehicles, and generates the private key and public key for ordinary vehicles. At the same time, the city public information center receives the key information of public buses generated by the key generation center.

[0011] S3. Based on the initial parameters of the key generation center in step S1 and the key information of the bus generated by the key generation center received by the city public information center in step S2, the message generated by the bus node and the signature of the message generated by the bus node are obtained. At the same time, the bus node broadcasts the message of its own relevant parameters.

[0012] S4. Based on the messages of the bus vehicle node’s own relevant parameters broadcast in step S3, the ordinary vehicle initiates a group joining request to the communication group managed by the bus vehicle node. At the same time, the bus vehicle node aggregates and verifies the ordinary vehicle’s group joining request and generates a shared key between the ordinary vehicle and the bus vehicle.

[0013] S5. Based on the shared key between ordinary vehicles and public transport vehicles generated in step S4, the public transport vehicle node generates a group key for ordinary vehicles in the same communication group and distributes it to the ordinary vehicles in the group.

[0014] S6. When the number of ordinary vehicles in the communication group managed by the bus vehicle node changes, update the group key of the communication group managed by the bus vehicle node.

[0015] The present invention has the following beneficial effects:

[0016] 1. The mobile group key management method proposed in this invention based on the Chinese Remainder Theorem and vehicle clustering has batch message authentication with error detection function. It realizes batch message authentication by using certificateless public key cryptography and aggregate signature technology. It designs an error detection algorithm using uniform threshold set, which can quickly retrieve invalid signatures and improve retrieval efficiency.

[0017] 2. For the transmission scenario of commercial service data in vehicle networks, the efficiency of group key distribution and update is optimized by using the Chinese Remainder Theorem, thus ensuring the confidentiality of commercial application data;

[0018] 3. By using vehicle clustering to build a stable communication group, the problem of frequent group key updates caused by communication group instability is solved, reducing the update frequency and improving the update efficiency;

[0019] 4. The mobile group key management method proposed in this invention, based on the Chinese Remainder Theorem and vehicle clustering, improves the cluster-through election mechanism to the selection of public buses by ordinary vehicles, reducing the communication overhead in the communication group generation stage, while avoiding the privacy leakage of ordinary vehicles, thus ensuring the privacy of vehicles and building a stable communication group. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating a mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering proposed in this invention.

[0021] Figure 2 This is a schematic diagram of the system model of the present invention. Detailed Implementation

[0022] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0023] like Figure 1 As shown, a mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering includes the following steps:

[0024] S1. Initialize the parameters of the two operating systems, the tracking center and the key generation center, to obtain the initial parameters of the tracking center and the key generation center.

[0025] like Figure 2 As shown, Figure 2This is a schematic diagram of the system model of the present invention. In this embodiment, urban blocks are used as the application scenario. An architecture without fixed roadside units is adopted, and vehicles are divided into two types: ordinary vehicles and public transport vehicles. Public transport vehicles are used as mobile roadside units to manage communication groups. Figure 2 Within the communication range of public transport vehicles, ordinary vehicles need to authenticate the broadcast messages of public transport vehicles and generate a group joining request message and its signature. When a public transport vehicle receives a group joining request from an ordinary vehicle, it performs batch verification. If the verification is successful, the public transport vehicle will add the ordinary vehicle to the communication group managed by the public transport vehicle based on the shared key generated from the group joining request message, and publish a response message indicating that the ordinary vehicle has successfully joined the group. At the same time, the ordinary vehicle calculates its shared key based on the received response message, verifies the message authentication code to obtain its own group key factor, and calculates the group key of the communication group it has joined. Whenever a node joins, the newly joined ordinary vehicle must complete a group key negotiation process with the group key manager. After publishing the response message indicating that the newly joined ordinary vehicle has successfully joined the group, the group manager updates the published group key. Ordinary vehicles in the group only need to verify the updated message. When a node leaves, the group key manager will publish group key update information. Ordinary vehicles in the group only need to verify the updated message.

[0026] In this embodiment, the parameters of the two independent trusted centers, namely the tracking center and the key generation center, are initialized to facilitate subsequent operation steps.

[0027] Specifically, step S1 includes S11-S15:

[0028] S11. To trace the center, first select two prime numbers p and q, then select two prime numbers a, b ∈ F. p , of which F p Represent a finite field of prime numbers, and generate a path from the equation y based on the chosen prime numbers. 2 =x 3 The elliptic curve E is determined by +ax+bmodp such that Δ=4a 3 +27b 2 ≠0 (mod p), determine a point P on the elliptic curve E and generate the q-order cyclic additive group G of point P.

[0029] S12. The tracking center selects a random number as its private key and ensures that it satisfies the following conditions: in, Let represent a non-zero element field, α represent the private key of the tracking center, and calculate the public key of the tracking center, i.e.:

[0030] PK TRA =α·P

[0031] Among them, PK TRA This represents the public key of the tracking center.

[0032] In this embodiment, the purpose of selecting a random number as the private key for the tracking center is to track the true identity of ordinary vehicles.

[0033] S13. The key generation center selects a random number as its private key and ensures that it satisfies the following conditions. Where β represents the private key of the key generation center, and the public key of the key generation center is calculated, i.e.:

[0034] PK KGC =β·P

[0035] Among them, PK KGC This represents the public key of the key generation center.

[0036] S14. The key generation center selects three hash functions, namely:

[0037]

[0038]

[0039]

[0040] In this embodiment, the purpose of constructing the hash function is to map an input of arbitrary size to a hash value of fixed size through hash calculation.

[0041] S15. Based on the above steps S11-S14, the initial parameters of the tracking center and the key generation center are obtained, namely:

[0042] {p,q,a,b,P,PK TRA PK KGC ,h1,h2,h3}

[0043] S2. Based on the initial parameters in step S1, the tracking center generates a pseudo identity for ordinary vehicles, the key generation center generates a partial private key for ordinary vehicles, and generates the private and public keys for ordinary vehicles. At the same time, the city public information center receives the key information of public buses generated by the key generation center.

[0044] In this embodiment, ordinary vehicles register with the tracking center, which generates a pseudo-identity for them. Ordinary vehicles also register with the key generation center, which generates a portion of their private key. After registration is completed at both the tracking center and the key generation center, the private and public keys of the ordinary vehicles are finally generated. Since the information of bus vehicle nodes is publicly available, there is no need to set up a pseudo-identity update mechanism for buses.

[0045] Specifically, step S2 includes S201-S214:

[0046] S201, the tracking center uses RID as the real identity. i ordinary vehicles V i Randomly select a secret parameter γ i And make it satisfy Among them, RID i V represents the true identity of the i-th ordinary vehicle. i Let γ represent the i-th ordinary vehicle. i This represents the secret parameter of the i-th ordinary vehicle. Represent a non-zero element field and a public commitment to compute the secret parameters of ordinary vehicles in the tracking center, namely:

[0047] P i =γ i ·P

[0048] Among them, P i V represents the i-th ordinary vehicle in the tracking center. i The secret parameter γ i The public commitment is that P represents a point P defined on the elliptic curve E.

[0049] S202. Based on the initial parameters of the tracking center in step S1 and the true identity of the ordinary vehicle in step S201, calculate the intermediate parameters of the pseudo-identity of the ordinary vehicle, that is:

[0050]

[0051] Among them, ID i V represents the i-th ordinary vehicle. i The pseudo-identity intermediate parameters, h1 represents the hash function, α represents the private key of the tracking center, and PK TRA T represents the public key of the tracking center. i V represents the i-th ordinary vehicle. i pseudo-identity intermediate parameter ID i The validity period.

[0052] S203. Based on the public commitment to the secret parameters of the ordinary vehicle calculated in step S201 and the intermediate parameters of the pseudo-identity of the ordinary vehicle calculated in step S202, generate the pseudo-identity of the ordinary vehicle, that is:

[0053] PID i ={ID i ,P i ,T i}

[0054] Among them, PID i V represents the i-th ordinary vehicle. iA false identity.

[0055] S204. The tracking center sends the pseudo-identity of the ordinary vehicle generated in step S203 to the key generation center and the ordinary vehicle through a secure channel.

[0056] In this embodiment, steps S201-S204 are the process of generating a fake identity for a regular vehicle, and the generated fake identity is sent to the key production center and the regular vehicle.

[0057] S205. The key generation center receives the pseudo identity of the ordinary vehicle generated in step S203, and identifies it as ordinary vehicle V. i Randomly select a secret parameter v i And make it satisfy Where, δ i Let represent the secret parameters of the i-th ordinary vehicle, and calculate the public commitment of the secret parameters of the ordinary vehicles at the key generation center, i.e.:

[0058] Q i =δ i ·P

[0059] Among them, Q i V represents the i-th ordinary vehicle. i The secret parameter δ i A public commitment.

[0060] S206. Based on the initial parameters of the key generation center in step S1 and the secret parameters of the ordinary vehicle in step S205, generate a partial private key for the ordinary vehicle, namely:

[0061] psk i =δ i +h2(ID i ||Q i )×β(modq)

[0062] Among them, psk i V represents the i-th ordinary vehicle. i The private key is a subset of the key, h2 represents the hash function, β represents the private key of the key generation center, mod represents the modulo operation, and q represents a prime number.

[0063] S207. The key generation center uses the public promise of the secret parameters of the ordinary vehicle calculated in step S205 and the partial private key of the ordinary vehicle generated in step S206, in {Q i ,psk i Send it to ordinary vehicles in the form of}.

[0064] In this embodiment, steps S205-S207 are the process of generating a partial private key for a regular vehicle, and then sending the generated partial private key to the regular vehicle.

[0065] S208. The ordinary vehicle receives a portion of the ordinary vehicle's private key sent by the key generation center, and then uses it according to equation psk. i ·P=Q i +h2(ID i ||Q i )×PK KGC The system checks whether (modq) is true. If it is true, it checks whether the private key of a regular vehicle was generated by the key generation center. Otherwise, it rejects the relevant message.

[0066] S209. A secret parameter x is randomly selected for ordinary vehicles. i And make it satisfy Where, x i V represents the i-th ordinary vehicle. i The secret parameters are used to calculate the public commitment to the secret parameters of ordinary vehicles, namely:

[0067] X i =x i ·P

[0068] Among them, X i V represents the i-th ordinary vehicle. i The secret parameter x i A public commitment.

[0069] S210. Based on the secret parameters of the ordinary vehicle in step S209 and the partial private key of the ordinary vehicle generated in step S206, generate the private key of the ordinary vehicle. And based on the public commitment to calculate the secret parameters of the ordinary vehicle in step S209 and the public commitment to calculate the secret parameters of the ordinary vehicle of the key generation center in step S205, generate the public key of the ordinary vehicle.

[0070] SK i ={psk i ,x i}

[0071] PK i ={Q i ,X i}

[0072] Among them, SK i V represents the i-th ordinary vehicle. i public key, PK i V represents the i-th ordinary vehicle. i The private key.

[0073] In this embodiment, steps S208-S210 are the process of generating the private and public keys for ordinary vehicles.

[0074] S211, The key generation center is a private identity, BID.j Buses BN j Choose a random number as the private key for the bus and ensure that it satisfies the following conditions: Among them, BID j Let b represent the private identity of the j-th bus. j Let BN represent the private key of the j-th bus. j Let j represent the j-th bus, and calculate the public key of the bus, i.e.:

[0075] BPK j =b j ·P

[0076] Among them, BPK j This represents the public key of the j-th bus.

[0077] S212. The key generation center randomly selects a secret parameter k. j And make it satisfy Where, k j Let represent the secret parameters of the j-th bus, and calculate the public commitment to the secret parameters of the bus, i.e.:

[0078] K j =j j ·P

[0079] Among them, K j The secret parameter k represents the j-th bus. j A public commitment.

[0080] S213. Based on the private key of the bus in step S211, generate the signature information of the bus's private key, namely:

[0081] Sig j =b j +h(BID j ||BPK j ||K j ||T use )×β(modq)

[0082] Among them, Sig j b represents the private key of the j-th bus. j The signature information, where h represents the hash function, T use This indicates the expiration date of the private key.

[0083] S214. The key information of the bus vehicle is encoded in {BID} j ,K j BPK j Sig j ,T use The form is sent to the city's public information center.

[0084] In this embodiment, steps S210-S214 are the process of private key signing and key information generation for public buses, and the generated key information is sent to the city public information center. After receiving the key information of the public buses, the city public information center broadcasts it in a loop so that subsequent ordinary vehicles can easily download the key information of the city's public buses from the city public information center when they enter the city area.

[0085] S3. Based on the initial parameters of the key generation center in step S1 and the key information of the bus generated by the key generation center received by the city public information center in step S2, the message generated by the bus node and the signature of the message generated by the bus node are obtained. At the same time, the bus node broadcasts the message with its own relevant parameters.

[0086] In this embodiment, the bus vehicle node signs the message with its own private key and will broadcast messages with its own relevant parameters in a loop.

[0087] Specifically, step S3 includes S31-S35:

[0088] S31. Based on the bus's location coordinates, speed, and direction of travel, obtain the message generated by the bus node, namely:

[0089] M j ={(Lx j ,Ly j Speed j Radian j}

[0090] Among them, M j This represents the message generated by the j-th bus node, (Lx j ,Ly j ) represents the location coordinates of the j-th bus, Speed j Represents the speed of the j-th bus, Radian j This indicates the direction of travel of the j-th bus.

[0091] S32. Based on the initial parameters of the key generation center in step S1, randomly select a secret parameter r for the bus. j And make it satisfy Where, r j Let represent the secret parameters of the j-th bus, and calculate the public commitment to the secret parameters of the bus, i.e.:

[0092] R j =r j ·P

[0093] Among them, Rj The secret parameter r of the j-th bus j The public commitment is that P represents a point P defined on the elliptic curve E.

[0094] S33. Based on the key information of the public transport vehicle received by the city public information center from the key generation center in step S2, and based on the secret parameters of the public transport vehicle in step S32, generate the signature information of the secret parameters of the public transport vehicle, that is:

[0095]

[0096] Among them, S j The secret parameter r of the j-th bus j The signature information, b j H represents the private key of the j-th bus. j Let represent the hash function of the j-th bus, Time1 represent the time when the bus message was published, and mod represent the modulo operation.

[0097] S34. The public commitment of the secret parameters of the bus calculated in step S32 and the signature information of the secret parameters of the bus generated in step S33 are used as the signature of the message generated by the bus node in step S31, that is:

[0098] σ j =(R j ,S j )

[0099] Where, σ j The message M represents the message generated by the j-th bus node. j The signature.

[0100] S35, the bus vehicle node sends its own relevant parameter information in {M j ,σ j BID j ,BPK j Broadcast in the format of ,Time1}.

[0101] S4. Based on the messages of the bus vehicle node's own relevant parameters broadcast in step S3, ordinary vehicles initiate a group joining request to the communication group managed by the bus vehicle node. At the same time, the bus vehicle node aggregates and verifies the ordinary vehicles' group joining requests and generates a shared key between ordinary vehicles and buses.

[0102] In this embodiment, ordinary vehicles decide whether to join the communication group managed by the bus vehicle node based on the broadcast message and their own relevant parameters. If the bus vehicle node meets the needs of the ordinary vehicle, it sends a group joining request to the bus vehicle node. At the same time, the bus vehicle node aggregates and verifies the group joining request and generates a shared key with the group members.

[0103] Specifically, step S4 includes S401-S415:

[0104] S401. Ordinary vehicles, based on the received messages containing the bus node's relevant parameters broadcast in step S3, check the timestamp attached to the broadcast message. If the following formula is satisfied, proceed to step S402; otherwise, discard the received broadcast message.

[0105] Time now -Time1≤ΔT

[0106] Among them, Time now The timestamp represents the current moment, Time1 represents the time when the bus message was published, and ΔT represents the maximum interval acceptable to the operating system.

[0107] In this embodiment, the key information of the bus is checked based on the identification code of the bus. First, the bus information stored by the usage period of the bus's private key is checked to see if it has expired. If it has expired, the bus node information is updated again.

[0108] S402. Ordinary vehicles judge the validity of the public key of the public bus and the validity of the message generated by the public bus node according to Formula 1 and Formula 2 respectively. If the equations are true, then proceed to step S403, that is:

[0109] Formula 1: Sig j ·P=K j +h3(BID j ||BPK j ||K j ||T use )PK KGC

[0110] Formula 2: S j ·P=BPK j +h3(M j )R j

[0111] Among them, Sig j b represents the private key of the j-th bus. j The signature information, P represents a point P on the elliptic curve E, K j The secret parameter k represents the j-th bus. jThe public commitment, h3 represents the hash function, BID j Denotes the private identity of the j-th bus, BPK j T represents the public key of the j-th bus. use Indicates the expiration date of the private key for a public transport vehicle, PK. KGC S represents the public key of the key generation center. j The secret parameter r of the j-th bus j The signature information, M j R represents the message generated by the j-th bus node. j The secret parameter r of the j-th bus j A public commitment.

[0112] S403. Ordinary vehicles receive the messages broadcast in step S3 regarding their own relevant parameters from the bus node, and calculate the distance between ordinary vehicles, the speed difference between ordinary vehicles, the distance between the destination of an ordinary vehicle and the nearest bus stop, the similarity between ordinary vehicles, and the travel direction of ordinary vehicles and buses, i.e.:

[0113]

[0114] VS i,j =|Speed i -Speed j |

[0115]

[0116] S i,j =w1c1VL i,j +w2c2VS i,j +w3c3VD i,jmin

[0117]

[0118] Among them, VL i,j Lx represents the distance between the i-th and j-th ordinary vehicles. i Ly represents the distance of the i-th ordinary vehicle on the x-axis. i Lx represents the distance of the i-th ordinary vehicle on the y-axis. j Ly represents the distance of the j-th ordinary vehicle on the x-axis. j VS represents the distance of the j-th ordinary vehicle on the y-axis. i,j Speed ​​represents the speed difference between the i-th and j-th ordinary vehicles. i Speed ​​represents the speed of the i-th ordinary vehicle. j VD represents the speed of the j-th ordinary vehicle. i,jminDx represents the distance between the destination of the i-th regular vehicle and the nearest stop of the j-th bus. i Dy represents the position of the destination of the i-th ordinary vehicle on the x-axis. i Dx represents the position of the destination of the i-th ordinary vehicle on the y-axis. jk Dy represents the position of the j-th bus at the k-th stop on the x-axis. jk This represents the position of the j-th bus on the y-axis at the k-th stop, where k represents the number of stops. i,j This represents the similarity between the i-th and j-th ordinary vehicles, where w1, w2, and w3 are weighting factors, c1, c2, and c3 are normalization parameters, and flag represents the similarity. i,j Indicates the direction of travel of the i-th ordinary vehicle and the j-th bus, Radian i Indicates the direction of travel of the i-th ordinary vehicle, Radian. j Let pi represent the direction of travel of the j-th bus, and let pi represent a constant, i.e., the value of π.

[0119] S404. If the driving direction of the ordinary vehicle and the bus calculated in step S403 is 1 and the similarity between the ordinary vehicles is less than or equal to 1, then the ordinary vehicle initiates a request to join the communication group managed by the bus node.

[0120] In this embodiment, steps S402-S403 determine whether both sides of equations 1 and 2 are true. If they are true, ordinary vehicles receive the broadcast message from the bus node and send a request to join the group to the bus node.

[0121] S405. Based on the similarity between ordinary vehicles in step S403 and the bus stop closest to the ordinary vehicle's destination, the ordinary vehicle generates a group joining request, that is:

[0122] Request i ={Target i,j ,S i,j}

[0123] Among them, Request i Target represents the group entry request generated by the i-th ordinary vehicle. i,j This represents the stop closest to the destination of the i-th regular vehicle, which is the j-th bus stop.

[0124] S406. Randomly select a secret parameter r for ordinary vehicles. i And make it satisfy Where, r i Let represent the secret parameters of the i-th ordinary vehicle, and calculate the public commitment to the secret parameters of the ordinary vehicle, i.e.:

[0125] R i =r i ·P

[0126] Among them, R i The secret parameter r represents the i-th ordinary vehicle. i The public commitment is that P represents a point P defined on the elliptic curve E.

[0127] S407. Generate a temporary identity for a regular vehicle, namely:

[0128]

[0129] Among them, PID i,R V represents the i-th ordinary vehicle. i Temporary identity, ID i,R V represents the i-th ordinary vehicle. i Temporary identity intermediate parameter, P i V represents the i-th ordinary vehicle in the tracking center. i The secret parameter γ i public commitment, T i V represents the i-th ordinary vehicle. i pseudo-identity intermediate parameter ID i Validity period, ID i V represents the i-th ordinary vehicle. i The pseudo-identity intermediate parameter, h2 represents the hash function, PK TRA This represents the public key of the tracking center.

[0130] S408. Generate signature information for the secret parameters of ordinary vehicles, namely:

[0131]

[0132] Where, n i G i These represent intermediate temporary parameters, which have no practical meaning. Q i V represents the i-th ordinary vehicle. i The secret parameter δ i public commitment, h i S represents a hash function. i The secret parameter r represents the i-th ordinary vehicle. i Signature information, x i V represents the i-th ordinary vehicle. i The secret parameter, psk i V represents the i-th ordinary vehicle. i Partial private key, h3 represents hash function, VPK i V represents ordinary vehicles iThe public key, Time2 represents the time when the ordinary vehicle message was published.

[0133] S409. The public commitment of the secret parameters of the ordinary vehicle calculated in step S406 and the signature information of the secret parameters of the ordinary vehicle generated in step S408 are used as the message signature of the group entry request generated by the ordinary vehicle in step S405, that is:

[0134] σ i =(R i ,S i )

[0135] Where, σ i This represents the group entry request generated by the i-th ordinary vehicle. i Message signature.

[0136] In this embodiment, steps S405-S409 generate a message signature for the group joining request based on the group joining request from ordinary vehicles.

[0137] S410, Messages from ordinary vehicles are sent in {Request i ,σ j BID j ,BPK j Broadcast in the form of Time2}.

[0138] S411. The bus vehicle node checks the timestamp attached to the broadcast ordinary vehicle message based on the ordinary vehicle message broadcast in step S410. If the following formula relationship is satisfied, proceed to step S412; otherwise, discard the ordinary vehicle message broadcast in step S410, that is:

[0139] Time now -Time2≤ΔT

[0140] Among them, Time now The timestamp represents the current moment, Time2 represents the time when a message from a regular vehicle was published, and ΔT represents the maximum interval acceptable to the operating system.

[0141] S412. The bus vehicle node aggregates and verifies N group entry requests received from ordinary vehicles within the same unit, calculates the hash function corresponding to each message, and uniformly calculates the following parameters:

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] S, X, R, Q, and H represent intermediate temporary parameters that have no practical significance.

[0149] S413. Based on the parameters calculated in step S412, determine whether the equation S·P=X+R+Q+H(mod q) is true. If the equation is true, then the N group entry requests received by ordinary vehicles in step S412 are valid and all vehicles that sent the group entry requests are valid vehicles. Otherwise, proceed to step S414.

[0150] S414. Use an error signature detection algorithm to filter out the legitimate messages of N group joining requests received in step S412 from ordinary vehicles.

[0151] In this embodiment, a faulty signature detection algorithm is used to filter out legitimate messages. Then, based on the group joining requests of ordinary vehicles, their communication groups are divided and key negotiation is conducted with them. The faulty signature detection algorithm involves grouping the signature set based on a uniform (k,n) threshold set.

[0152] Specifically, step S414 includes S4141-S4146:

[0153] S4141. Based on the statistical data of invalid signatures in the past, obtain the expected value err for batch authentication errors, and divide the message signatures of the N group entry requests of ordinary vehicles received in step S412 into err+1 groups, where the first err group contains m = N / err signatures and the last group contains Nmoderr messages.

[0154] S4142, the signature of each group of messages in step S4141 is {M i ,σ i ,n i G i ,PID i,R PK i Time i} (i = 1, 2, ..., m), and calculate the aggregate signature corresponding to each group of m message signatures.

[0155] S4143. Determine whether the aggregate signature corresponding to each group of m message signatures calculated in step S4142 passes the verification. If yes, add the message signature to the valid set; otherwise, input the message signature set A = {a1, a2, ..., a...}. m In the formula, parameters k and n are defined, and k-1 elements are selected from n elements to form a valid set B.

[0156] S4144. Determine whether the valid set B in step S4143 contains an element identical to the message signature set. If so, remove element a from the message signature set. i Remove and generate a uniform (k,n) threshold set (A1,A2,...,A1) corresponding to the message signature set A. n ).

[0157] S4145. For the uniform (k,n) threshold set (A1,A2,...,A1) corresponding to the generated message signature set A, ... n If the verification is successful, the message signature is placed into the valid set B. After verifying all the elements of the message signature set, the error set C is set to AB. If the number of verified message sets is k-1, the invalid signatures of the group are stored in the error set, and the error signature detection of the group is completed. Otherwise, the error signature set C is checked one by one.

[0158] S4146. Output the set of invalid signatures in the message signature set.

[0159] S415. Based on the error signature detection algorithm used in step S414, the legitimate messages of the N group joining requests received from ordinary vehicles in step S412 are filtered out. The bus vehicle constructs a shared key between the ordinary vehicles and the bus vehicle based on the parameters in the received group joining requests, i.e.:

[0160] K i,j =h3((X i +R i )b j )

[0161] Among them, K i,j v represents the i-th ordinary vehicle i With the j-th bus BN j The shared key.

[0162] S5. Based on the shared key between ordinary vehicles and public transport vehicles generated in step S4, the public transport vehicle node generates a group key for ordinary vehicles in the same communication group and distributes it to the ordinary vehicles in the group.

[0163] Specifically, step S5 includes S501-S509:

[0164] S501. The bus vehicle node stores the n ordinary vehicles of the constructed communication group in the same list, generates a communication group identifier, and assigns a key factor λ to each ordinary vehicle in the communication group. i And make it satisfy Where, λi V represents the i-th ordinary vehicle. i key factor, Represent the non-zero element field, and calculate the intermediate parameters of the key factors corresponding to the communication group and ordinary vehicles, i.e.:

[0165]

[0166]

[0167] Where G represents the communication group, n represents the number of ordinary vehicles, and g i This represents the intermediate parameter of the key factor corresponding to a regular vehicle.

[0168] S502. Based on the intermediate parameters of the key factor corresponding to the ordinary vehicle calculated in step S501, calculate the required value of the group key, i.e.:

[0169]

[0170]

[0171] Among them, c i represents an intermediate temporary parameter with no practical meaning, and C represents the necessary value for calculating the group key using the Chinese Remainder Theorem.

[0172] S503. Based on the required value of the group key calculated in step S502, the Chinese Remainder Theorem can be used to obtain C mod λ. i ≡1 (i = 1, 2, ..., n).

[0173] S504. Select a random number as the group key for the communication group and ensure that it satisfies the following conditions: in, K represents the non-zero field. G This represents the group key of the communication group, and the first message authentication code for ordinary vehicles is calculated, i.e.:

[0174] M=K G ×C

[0175]

[0176] MAC i =h(M,K i ,K i,j ,PID i,R BID j (GID,Time3)

[0177] Among them, M and K i These represent intermediate temporary parameters, which have no practical meaning. K i,j V represents the i-th ordinary vehicle.i With the j-th bus BN j The shared key, h represents the hash function, MAC i The PID represents the first message authentication code of the i-th ordinary vehicle. i,R V represents the i-th ordinary vehicle. i temporary identity, BID j This represents the private identity of the j-th bus, HID represents the communication group identifier, and Time3 represents the time when the message was published by a regular vehicle.

[0178] In this embodiment, the first message authentication code for ordinary vehicles is K. i,j For key pair messages, i.e. (M,K) i ,PID i,R BID j The message authentication code is obtained by performing a keyed hash operation on GID and Time3.

[0179] S505, {M,K i ,K i,j ,PID i,R BID j The message 'GID,Time3' is used as a response to the group joining request and broadcast.

[0180] S506. After receiving the response message of the group joining request in step S505, the ordinary vehicle checks the timestamp attached to the response message. If it satisfies the following formula relationship, it continues to execute step S507; otherwise, it discards the received response message of the group joining request in step S505.

[0181] Time now -Time3≤ΔT

[0182] Among them, Time now The timestamp represents the current moment, Time3 represents the time when a message from a regular vehicle was published, and ΔT represents the maximum interval acceptable to the operating system.

[0183] S507, Using ordinary vehicles and private identities as BID j The shared key of the bus vehicle nodes, namely:

[0184] K′ i,j =h3((x i +r i )BPK j )

[0185] Among them, K i, ′ j This indicates that the identity of a regular vehicle is BIDj. j The shared key for the bus vehicle nodes, h3 represents the hash function, xi V represents the i-th ordinary vehicle. i The secret parameter, r i BPK represents the secret parameter of the i-th ordinary vehicle. j This represents the public key of the j-th bus.

[0186] S508. Using the ordinary vehicle and private identity BID retrieved in step S507. j The shared key of the bus vehicle nodes is used to calculate the second message authentication code for ordinary vehicles, i.e.:

[0187] MAC i =h(M,K) i ,K′ i,j ,PID i,R BID j (GID,Time3)

[0188] Among them, MAC′ i This represents the second message verification code for the i-th ordinary vehicle.

[0189] In this embodiment, the second message authentication code for ordinary vehicles is K′ i,j For key pair messages, i.e. (M,K) i ,PID i,R BID j The message authentication code is obtained by performing a keyed hash operation on GID and Time3.

[0190] S509. If the second message verification code calculated in step S508 is equal to the first message authentication code calculated in step S504, use the formula... Get key factor λ i And using formula K G =Mmod λ i =K G ×Cmodλ i Obtain the group key of the communication group.

[0191] S6. When the number of ordinary vehicles in the communication group managed by the bus vehicle node changes, update the group key of the communication group managed by the bus vehicle node.

[0192] In this embodiment, when there are changes in the ordinary vehicles (i.e., group members) of the communication group, the group key of the communication group will also be updated accordingly. Specifically, the newly added ordinary member of the communication group confirms the validity of the message through a message verification code, while the existing members of the communication group, i.e., the remaining ordinary vehicles, confirm the validity of the message through a message signature and update the group key accordingly.

[0193] Specifically, step S6 includes S601-S611:

[0194] S601. Based on the identity information of the ordinary vehicles that have left the communication group, obtain the key factor λ of the ordinary vehicles that have left the communication group. nj (j=1,2,…,m2), and remove the identity information of ordinary vehicles that have left the communication group from the member list, while backing up the identity information of the remaining ordinary vehicles in the communication group.

[0195] S602. Based on the identity information of the remaining ordinary vehicles in step S601, and based on the n1 ordinary vehicles in the communication group, calculate the intermediate parameters of the key factors corresponding to the ordinary vehicles leaving the communication group, that is:

[0196]

[0197] Among them, G cut The intermediate parameter represents the key factor corresponding to the ordinary vehicle that leaves the communication group, and m2 represents the total number of ordinary vehicles that leave the communication group.

[0198] S603. Based on the m1 newly added ordinary vehicles in the communication group, assign a key factor to each newly added ordinary vehicle and ensure that it satisfies the following conditions: Add information about the newly added m1 ordinary vehicles to the members of the communication group, and calculate the intermediate parameters of the key factor corresponding to the newly added ordinary vehicles, that is:

[0199]

[0200] Among them, G add The intermediate parameter represents the key factor corresponding to the newly added ordinary vehicle, and m1 represents the total number of ordinary vehicles newly added to the communication group.

[0201] S604. Based on the intermediate parameters of the key factors corresponding to the newly added ordinary vehicles in step S603 and the intermediate parameters of the key factors corresponding to the ordinary vehicles leaving the communication group in step S602, calculate the updated communication group and the intermediate parameters of the key factors corresponding to the ordinary vehicles, i.e.:

[0202] G N =G×G add / G cut

[0203]

[0204] Among them, G N This indicates the updated communication group, where G represents the communication group, and g Ni The intermediate parameter represents the key factor corresponding to the ordinary vehicle, and m represents the number of ordinary vehicles in the updated communication group.

[0205] S605. Based on the intermediate parameters of the key factor corresponding to the ordinary vehicle calculated in step S604, calculate the following parameters:

[0206]

[0207]

[0208] Among them, c i This represents an intermediate temporary parameter with no practical meaning. (C) N This represents the required value for calculating the updated group key of the communication group using the Chinese Remainder Theorem.

[0209] S606. Select a random number as the updated group key for the communication group and ensure that it satisfies the following conditions: in, K represents the non-zero field. N This represents the updated group key of the communication group, and the first message authentication code for newly joined ordinary vehicles is calculated, i.e.:

[0210] M N =K N ×C N

[0211]

[0212] MAC ni =h(M N ,K ni,j ,K ni ,PID ni,R BID j (i = 1, 2, ..., m1)

[0213] Among them, M N K ni K represents an intermediate temporary parameter in the calculation process, which has no practical meaning. ni,j This represents the newly added ni-th ordinary vehicle and the j-th bus vehicle, BN. j The shared key, λ ni MAC represents the key factor of the newly added ni-th ordinary vehicle. ni This indicates the first message authentication code (PID) of the newly added ni-th ordinary vehicle. ni,R This indicates the temporary identity of the newly added nth ordinary vehicle, BID. j This represents the private identity of the j-th bus, GID represents the communication group identifier, and Time4 represents the time when the message was published by a regular vehicle.

[0214] In this embodiment, the first message authentication code for ordinary vehicles is K. ni,j For key pair messages, i.e. (M)N ,K ni ,PID i,R BID j The message authentication code is obtained by performing a keyed hash operation on GID and Time4.

[0215] S607, Generate Message M up ={M N BID j ,GID}, and randomly select a secret parameter r up And make it satisfy Where, r up Let the secret parameter be represented, and the public commitment to the secret parameter be calculated, i.e.:

[0216] R up =r up ·P

[0217] h up =h3(M up ||BID j ||BPK j ||GID||R up ||Time4)

[0218] S up =b j +h up r up (mod q)

[0219] Among them, R up Representing the secret parameter r up The public commitment, P represents determining a point P, M on the elliptic curve E. up Indicates the generated message, b j This represents the private key of the j-th bus.

[0220] S608, with {M N ,K ni ,PID ni,R BID j GID, MAC ni Time4} is broadcast as a response message to the request of a newly added ordinary vehicle to join the group, and is marked with {M up ,R up ,S up The format ,Time4} is broadcast as an update message for the updated communication group.

[0221] S609. After the remaining ordinary vehicles in the communication group receive the update message from step S608, they determine equation S. up ·P=BPK j +h3(Mup )R up If it is true, then use formula K. N =M N mod λ ni =K N ×C N mod λ ni Obtain the updated group key for the communication group; otherwise, proceed to step S610.

[0222] S610, Using formula K′ ni,j =h3((x ni +r ni )BPK j Calculate the shared key between the newly added regular vehicle and bus vehicle nodes, and based on the obtained shared key, calculate the second message authentication code for the newly added regular vehicle, i.e.:

[0223] MAC' ni =h(M N ,K′ ni,j ,K ni ,PID ni,R BID j (GID,Time4)

[0224] Among them, MAC′ ni This indicates the second message authentication code for the newly added nith ordinary vehicle.

[0225] In this embodiment, the first message authentication code for ordinary vehicles is K′. ni,j For key pair messages, i.e. (M) N ,K ni ,PID i,R BID j The message authentication code is obtained by performing a keyed hash operation on GID and Time4.

[0226] S611. If the second message authentication code of the newly added ordinary vehicle in step S610 is equal to the first message authentication code of the newly added ordinary vehicle in S606, then the formula is used. Obtain the key factor of the newly added ordinary vehicle, and use formula K. N =M N modλ ni =K N ×C N mod λ ni Obtain the updated group key for the communication group.

[0227] The mobile group key management method for vehicle clustering proposed in this embodiment has the following advantages: First, the method of using buses as mobile roadside units for vehicle clustering, compared to the method of using fixed roadside units as group management, ensures that the manager and group members (i.e., ordinary vehicles) are in the same traffic environment when buses are the group managers. Therefore, the communication group constructed in this real-time example is more stable, and the group key update operation when group members change is significantly reduced. Using buses as group managers can avoid the communication overhead caused by the election mechanism. At the same time, the destination information of group members does not need to be propagated in the channel, which improves data security. Second, a batch message authentication method with detection function is proposed. It uses a uniform threshold set to realize error signature detection, which can quickly and effectively retrieve error signatures from the aggregated signatures that have failed to be verified. Third, the vehicle clustering method using buses as mobile roadside units and the error-detectable batch authentication method realize the authentication and integrity, traceability, non-repudiation, and non-linkability of vehicle network data transmission, while also realizing the confidentiality, forward security, and backward security of messages.

[0228] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0229] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering, characterized in that, Includes the following steps: S1. Initialize the parameters of the two operating systems, the tracking center and the key generation center, to obtain the initial parameters of the tracking center and the key generation center; S2. Based on the initial parameters in step S1, the tracking center generates a pseudo identity for ordinary vehicles, the key generation center generates a partial private key for ordinary vehicles, and generates the private key and public key for ordinary vehicles. At the same time, the city public information center receives the key information of public buses generated by the key generation center. S3. Based on the initial parameters of the key generation center in step S1 and the key information of the buses generated by the key generation center received by the city public information center in step S2, the message generated by the bus node and the signature of the message generated by the bus node are obtained. At the same time, the bus node broadcasts its own relevant parameter messages, specifically: S31. Based on the bus's location coordinates, speed, and direction of travel, obtain the message generated by the bus node, namely: in, Indicates the first Messages generated by a bus vehicle node Indicates the first Location coordinates of the bus. Indicates the first The speed of the bus Indicates the first The direction of travel of the buses; S32. Based on the initial parameters of the key generation center in step S1, randomly select a secret parameter for the bus. And make it satisfy ,in, Indicates the first Secret parameters of a bus Represent a non-zero element field and compute the public commitment to the secret parameters of the bus, namely: in, Indicates the first Secret parameters of a bus public commitment In elliptic curves A point determined on the surface; S33. Based on the key information of the public transport vehicle received by the city public information center from the key generation center in step S2, and based on the secret parameters of the public transport vehicle in step S32, generate the signature information of the secret parameters of the public transport vehicle, that is: wherein, represents the -th bus's secret parameter signature information, represents the -th bus's private key, represents the -th bus's hash function, is a prime number, is a hash function, represents the -th bus's private identity, represents the -th bus's public key, represents the release time of the bus message, represents modulo operation; S34. The public commitment of the secret parameters of the bus calculated in step S32 and the signature information of the secret parameters of the bus generated in step S33 are used as the signature of the message generated by the bus node in step S31, that is: in, Indicates the first Messages generated by bus vehicle nodes The signature; S35, bus vehicle nodes will send their own relevant parameter information to Broadcast in a formatted manner; S4. Based on the messages of the bus vehicle node’s own relevant parameters broadcast in step S3, the ordinary vehicle initiates a group joining request to the communication group managed by the bus vehicle node. At the same time, the bus vehicle node aggregates and verifies the ordinary vehicle’s group joining request and generates a shared key between the ordinary vehicle and the bus vehicle. S5. Based on the shared key between ordinary vehicles and public transport vehicles generated in step S4, the public transport vehicle node generates a group key for ordinary vehicles in the same communication group and distributes it to the ordinary vehicles in the group. S6. When the number of ordinary vehicles in the communication group managed by the bus vehicle node changes, update the group key of the communication group managed by the bus vehicle node.

2. The mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering as described in claim 1, characterized in that, Step S1 specifically includes: S11. The tracking center first selects two prime numbers. Then select two prime numbers ,in, Represent a finite field of prime numbers, and generate an equation based on the chosen prime numbers. Determined elliptic curve To satisfy In elliptic curves Determine a point on And generate points of Cyclic addition group ; S12. The tracking center selects a random number as its private key and ensures that it satisfies the following conditions: ,in, Represents a non-zero field. This represents the private key of the tracking center, and the public key of the tracking center is calculated, i.e.: in, This represents the public key of the tracking center; S13. The key generation center selects a random number as its private key and ensures that it satisfies the following conditions. ,in, This represents the private key of the key generation center, and the public key of the key generation center is calculated, i.e.: in, This represents the public key of the key generation center; S14. The key generation center selects three hash functions, namely: ； ； ； S15. Based on the above steps S11-S14, the initial parameters of the tracking center and the key generation center are obtained, namely: 。 3. The mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering as described in claim 1, characterized in that, Step S2 specifically includes: S201, the tracking center is for real identities ordinary vehicles Randomly select a secret parameter And make it satisfy ,in, Indicates the first The true identity of an ordinary vehicle Indicates the first A regular vehicle, Indicates the first Secret parameters of an ordinary vehicle Represent a non-zero element field and a public commitment to compute the secret parameters of ordinary vehicles in the tracking center, namely: in, Indicates the tracking center ordinary vehicles secret parameters public commitment In elliptic curves A point determined on the surface; S202. Based on the initial parameters of the tracking center in step S1 and the true identity of the ordinary vehicle in step S201, calculate the intermediate parameters of the pseudo-identity of the ordinary vehicle, that is: in, Indicates the first ordinary vehicles The pseudo-identity intermediate parameters, Represents a hash function. This represents the private key of the tracking center. This represents the public key of the tracking center. Indicates the first ordinary vehicles pseudo-identity intermediate parameters Validity period; S203. Based on the public commitment to the secret parameters of the ordinary vehicle calculated in step S201 and the intermediate parameters of the pseudo-identity of the ordinary vehicle calculated in step S202, generate the pseudo-identity of the ordinary vehicle, that is: in, Indicates the first ordinary vehicles A false identity; S204. The tracking center sends the pseudo identity of the ordinary vehicle generated in step S203 to the key generation center and the ordinary vehicle through a secure channel. S205. The key generation center receives the pseudo identity of the ordinary vehicle generated in step S203, and identifies it as an ordinary vehicle. Randomly select a secret parameter And make it satisfy ,in, Indicates the first The secret parameters of a regular vehicle are calculated, and the public commitment of the secret parameters of the regular vehicle at the key generation center is calculated, namely: in, Indicates the first ordinary vehicles secret parameters Public commitment; S206. Based on the initial parameters of the key generation center in step S1 and the secret parameters of the ordinary vehicle in step S205, generate a partial private key for the ordinary vehicle, namely: in, Indicates the first ordinary vehicles Part of the private key, Represents a hash function. This represents the private key of the key generation center. Indicates the remainder. Represents prime numbers; S207. The key generation center uses the public promise of the secret parameters of the ordinary vehicle calculated in step S205 and the partial private key of the ordinary vehicle generated in step S206 to... The format is sent to ordinary vehicles; S208. The ordinary vehicle receives a portion of the ordinary vehicle's private key sent by the key generation center, and performs a peer-to-peer operation. The system checks whether the condition is met. If it is met, it checks whether the private key for ordinary vehicles was generated by the key generation center. Otherwise, it rejects the relevant message. S209, a secret parameter is randomly selected for ordinary vehicles. And make it satisfy ,in, Indicates the first ordinary vehicles The secret parameters are used to calculate the public commitment to the secret parameters of ordinary vehicles, namely: in, Indicates the first A regular vehicle secret parameters Public commitment; S210. Based on the secret parameters of the ordinary vehicle in step S209 and the partial private key of the ordinary vehicle generated in step S206, generate the private key of the ordinary vehicle. And based on the public commitment to calculate the secret parameters of the ordinary vehicle in step S209 and the public commitment to calculate the secret parameters of the ordinary vehicle of the key generation center in step S205, generate the public key of the ordinary vehicle. in, Indicates the first ordinary vehicles public key, Indicates the first ordinary vehicles The private key; S211, The key generation center is a private entity. public buses Choose a random number as the private key for the bus and ensure that it satisfies the following conditions: ,in, Indicates the first The private identity of a bus. Indicates the first The private key of a bus vehicle. Indicates the first For each bus, calculate its public key, i.e.: in, Indicates the first The public key of a bus vehicle; S212. The key generation center randomly selects a secret parameter. And make it satisfy ,in, Indicates the first The secret parameters of a bus, and the public commitment to calculate the secret parameters of the bus, namely: in, Indicates the first Secret parameters of a bus Public commitment; S213. Based on the private key of the bus in step S211, generate the signature information of the bus's private key, namely: in, Indicates the first Private key of a bus Signature information, Represents a hash function. Indicates the expiration date of the private key; S214. Transfer the key information of the bus vehicle to The form is sent to the city's public information center.

4. The mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering as described in claim 1, characterized in that, Step S4 specifically includes: S401. Ordinary vehicles, based on the received messages containing the bus node's relevant parameters broadcast in step S3, check the timestamp attached to the broadcast message. If the following formula is satisfied, proceed to step S402; otherwise, discard the received broadcast message. in, The timestamp represents the current moment. Indicates the time when the bus vehicle information was released. Indicates the maximum acceptable interval for the operating system; S402. Ordinary vehicles judge the validity of the public key of the public bus and the validity of the message generated by the public bus node according to Formula 1 and Formula 2 respectively. If the equations are true, then proceed to step S403, that is: Official 1: Official 2: in, Indicates the first Private key of a bus Signature information, In elliptic curves A point determined on the surface, Indicates the first Secret parameters of a bus public commitment Represents a hash function. Indicates the first The private identity of a bus. Indicates the first The public key of a bus vehicle. This indicates the expiration date of the public transport vehicle's private key. This represents the public key of the key generation center. Indicates the first Secret parameters of a bus Signature information, Indicates the first Messages generated by a bus vehicle node Indicates the first Secret parameters of a bus Public commitment; S403. Ordinary vehicles receive the messages broadcast in step S3 regarding their own relevant parameters from the bus node, and calculate the distance between ordinary vehicles, the speed difference between ordinary vehicles, the distance between the destination of an ordinary vehicle and the nearest bus stop, the similarity between ordinary vehicles, and the travel direction of ordinary vehicles and buses, i.e.: in, Indicates the first With the The distance between ordinary vehicles Indicates the first The distance of a typical vehicle on the x-axis. Indicates the first The distance of a regular vehicle on the y-axis. Indicates the first The distance of a typical vehicle on the x-axis. Indicates the first The distance of a typical vehicle on the y-axis. Indicates the first With the The speed difference between two ordinary vehicles Indicates the first The speed of an ordinary vehicle Indicates the first The speed of an ordinary vehicle Indicates the first The destination of the ordinary vehicle and the first The distance of the nearest bus stop to the bus. Indicates the first The location of the destination of a regular vehicle on the x-axis. Indicates the first The location of the destination of a regular vehicle on the y-axis. Indicates the first The bus in the The location of each station on the x-axis Indicates the first The bus was in The location of each station on the y-axis Indicates the number of sites. Indicates the first With the Similarity between ordinary vehicles , , These are the weighting factors, , , These are the normalization parameters, Indicates the first ordinary vehicles and the first The direction of travel of the buses. Indicates the first The direction of travel of an ordinary vehicle. Indicates the first The direction of travel of the buses. It represents a constant, namely the value of pi; S404. If the driving direction of the ordinary vehicle and the bus calculated in step S403 is 1 and the similarity between the ordinary vehicles is less than or equal to 1, then the ordinary vehicle initiates a request to join the communication group managed by the bus node. S405. Based on the similarity between ordinary vehicles in step S403 and the bus stop closest to the ordinary vehicle's destination, the ordinary vehicle generates a group joining request, that is: in, Indicates the first Group join requests generated by ordinary vehicles Indicates the distance to the first The nearest destination for ordinary vehicles Bus stop; S406, Randomly select a secret parameter for ordinary vehicles. And make it satisfy ,in, Indicates the first The secret parameters of a common vehicle, and the public commitment to calculate the secret parameters of the common vehicle, namely: in, Indicates the first Secret parameters of an ordinary vehicle public commitment In elliptic curves A point determined on the surface; S407. Generate a temporary identity for a regular vehicle, namely: in, Indicates the first ordinary vehicles Temporary identity, Indicates the first ordinary vehicles Temporary identity intermediate parameters, Indicates the tracking center ordinary vehicles secret parameters public commitment Indicates the first ordinary vehicles pseudo-identity intermediate parameters The validity period, Indicates the first ordinary vehicles The pseudo-identity intermediate parameters, Represents a hash function. This represents the public key of the tracking center; S408. Generate signature information for the secret parameters of ordinary vehicles, namely: in, , These represent intermediate temporary parameters, which have no practical meaning. Indicates the first ordinary vehicles secret parameters public commitment Represents a hash function. Indicates the first Secret parameters of an ordinary vehicle Signature information, Indicates the first ordinary vehicles The secret parameters, Indicates the first ordinary vehicles Part of the private key, Represents a hash function. Indicates ordinary vehicles public key, Indicates the time when the information about ordinary vehicles was released; S409. The public commitment of the secret parameters of the ordinary vehicle calculated in step S406 and the signature information of the secret parameters of the ordinary vehicle generated in step S408 are used as the message signature of the group entry request generated by the ordinary vehicle in step S405, that is: in, Indicates the first Group join requests generated by ordinary vehicles Message signature; S410, transmitting information about ordinary vehicles Broadcast in a specific format; S411. The bus vehicle node checks the timestamp attached to the broadcast ordinary vehicle message based on the ordinary vehicle message broadcast in step S410. If the following formula relationship is satisfied, proceed to step S412; otherwise, discard the ordinary vehicle message broadcast in step S410, that is: in, The timestamp represents the current moment. Indicates the time when the news about ordinary vehicles was released. Indicates the maximum acceptable interval for the operating system; S412, Ordinary vehicles received between units at bus vehicle nodes. Each incoming group request is aggregated and verified. The hash function corresponding to each message is calculated separately, and the following parameters are calculated uniformly: in, , , , , These represent intermediate temporary parameters and have no practical meaning. S413. Based on the parameters calculated in step S412, determine the equation. Whether the equation holds true, and if it does, then the ordinary vehicle received in step S412... If the group join request is valid and all vehicles sending the group join request are valid vehicles, otherwise proceed to step S414; S414. Use an error signature detection algorithm to filter out the ordinary vehicles received in step S412. A legitimate message requesting to join the group; S415. Based on the error signature detection algorithm used in step S414, filter out the ordinary vehicles received in step S412. Upon receiving a legitimate group join request message, the bus vehicle constructs a shared key between the bus and regular vehicles based on the parameters in the received group join request, namely: in, Indicates the first ordinary vehicles With the bus The shared key.

5. A mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering as described in claim 4, characterized in that, Step S414 specifically includes: S4141. Based on historical statistics of invalid signatures, obtain the expected value of batch authentication errors. and the ordinary vehicle received in step S412 The message signature for a group join request is divided into Group, of which the first Group contains The last group contains a signature. Message; S4142, the signature of each group of messages in step S4141 is: And calculate each group The aggregate signature corresponding to each message signature; S4143. For each group calculated in step S4142 The system checks whether the aggregate signature corresponding to each message signature passes verification. If it does, the message signature is added to the valid set; otherwise, the input message signature set is not checked. In, and define parameters and ,from Select from elements The elements constitute a valid set. ; S4144, For the legal set in step S4143 Check if there is an element that is the same as the one in the message signature set. If so, then add the element from the message signature set. Remove and generate a set of message signatures. Corresponding uniformity Threshold set ; S4145. The generated message signature set Corresponding uniformity Threshold set The system checks whether the message signature passes verification; if so, it adds the message signature to the valid set. In the process, after verifying all elements of the message signature set, the error set is... Set as And check if the number of verified message sets is [number missing]. If the invalid signatures in the group are found to be invalid, they are added to the error set, and the error signature detection for that group is completed. Otherwise, the error signature set is... Test them one by one; S4146. Output the set of invalid signatures in the message signature set.

6. The mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering as described in claim 1, characterized in that, Step S5 specifically includes: S501, the communication group that the bus vehicle node will construct All ordinary vehicles are stored in the same list, and a communication group identifier is generated. A key factor is assigned to each ordinary vehicle in the communication group. And make it satisfy ,in, Indicates the first ordinary vehicles key factor, Represent the non-zero element field, and calculate the intermediate parameters of the key factors corresponding to the communication group and ordinary vehicles, i.e.: in, Indicates a communication group. This indicates the number of ordinary vehicles. The intermediate parameter representing the key factor corresponding to a regular vehicle; S502. Based on the intermediate parameters of the key factor corresponding to the ordinary vehicle calculated in step S501, calculate the required value of the group key, i.e.: in, This represents an intermediate, temporary parameter with no practical meaning. This represents the required value for computing the group key using the Chinese Remainder Theorem; S503. Based on the required value of the group key calculated in step S502, the Chinese Remainder Theorem can be used to obtain... ; S504. Select a random number as the group key for the communication group and ensure that it satisfies the following conditions: ,in, Represents a non-zero field. This represents the group key of the communication group, and the first message authentication code for ordinary vehicles is calculated, i.e.: in, , These represent intermediate temporary parameters, which have no practical meaning. Indicates the first ordinary vehicles With the bus Shared key, Represents a hash function. Indicates the first The first message authentication code for a regular vehicle. Indicates the first ordinary vehicles Temporary identity, Indicates the first The private identity of a bus. Indicates the communication group identifier. Indicates the time when the information about ordinary vehicles was released; S505, will It is broadcast as a response message to the request to join the group; S506. After receiving the response message of the group joining request in step S505, the ordinary vehicle checks the timestamp attached to the response message. If the following formula relationship is satisfied, the process continues to step S507; otherwise, the received response message of the group joining request in step S505 is discarded, that is: in, The timestamp represents the current moment. Indicates the time when the news about ordinary vehicles was released. Indicates the maximum acceptable interval for the operating system; S507, Using ordinary vehicles and private identities The shared key of the bus vehicle nodes, namely: in, Indicates the difference between ordinary vehicles and private vehicles. The shared key for the bus vehicle nodes. Represents a hash function. Indicates the first ordinary vehicles The secret parameters, Indicates the first Secret parameters of an ordinary vehicle Indicates the first The public key of a bus vehicle; S508, Using the ordinary vehicle and private identity retrieved in step S507 as... The shared key of the bus vehicle nodes is used to calculate the second message authentication code for ordinary vehicles, i.e.: in, Indicates the first The second message authentication code for a regular vehicle; S509. If the second message authentication code calculated in step S508 is equal to the first message authentication code calculated in step S504, use the formula... Get key factor and using the formula Obtain the group key of the communication group.

7. The mobile group key management method based on the Chinese Remainder Theorem and vehicle clustering as described in claim 1, characterized in that, Step S6 specifically includes: S601. Based on the identity information of the ordinary vehicles that have left the communication group, obtain the key factors of the ordinary vehicles that have left the communication group. The identity information of ordinary vehicles that have left the communication group is removed from the member list of the communication group, and the identity information of the remaining ordinary vehicles in the communication group is backed up. S602. Based on the identity information of the remaining ordinary vehicles in step S601, and based on the information in the communication group... For each ordinary vehicle, calculate the intermediate parameters of the key factor corresponding to the ordinary vehicle leaving the communication group, i.e.: in, The intermediate parameter representing the key factor corresponding to a regular vehicle leaving the communication group. This represents the total number of regular vehicles that have left the communication group; S603, based on newly added members in the communication group For each newly added ordinary vehicle, assign a key factor and ensure that it satisfies the following conditions: Add new members to the communication group. The information of each ordinary vehicle is used to calculate the intermediate parameters of the key factor corresponding to the newly added ordinary vehicle, namely: in, This represents the intermediate parameter of the key factor corresponding to the newly added ordinary vehicle. This indicates the total number of regular vehicles newly added to the communication group; S604. Based on the intermediate parameters of the key factors corresponding to the newly added ordinary vehicles in step S603 and the intermediate parameters of the key factors corresponding to the ordinary vehicles leaving the communication group in step S602, calculate the updated communication group and the intermediate parameters of the key factors corresponding to the ordinary vehicles, i.e.: in, This indicates the updated communication group. Indicates a communication group. The intermediate parameter representing the key factor corresponding to a regular vehicle. This indicates the number of regular vehicles in the updated communication group; S605. Based on the intermediate parameters of the key factor corresponding to the ordinary vehicle calculated in step S604, calculate the following parameters: in, This represents an intermediate, temporary parameter with no practical meaning. This represents the required value for calculating the updated group key of the communication group using the Chinese Remainder Theorem; S606. Select a random number as the updated group key for the communication group and ensure that it satisfies the following conditions: ,in, Represents a non-zero field. This represents the updated group key of the communication group, and the first message authentication code for newly joined ordinary vehicles is calculated, i.e.: in, , This represents an intermediate, temporary parameter in the calculation process; it has no practical meaning. Indicates the newly added number ordinary vehicles and the first bus Shared key, Indicates the newly added number Key factors for a typical vehicle Indicates the newly added number The first message authentication code for a regular vehicle. Indicates the newly added number The temporary status of an ordinary vehicle, Indicates the first The private identity of a bus. Indicates the communication group identifier. Indicates the time when a message is released for a regular vehicle; S607, Generate Message And randomly select a secret parameter And make it satisfy ,in, Let the secret parameter be represented, and the public commitment to the secret parameter be calculated, i.e.: in, Representing secret parameters public commitment In elliptic curves A point determined on the surface, This indicates the generated message. Indicates the first The private key of a bus vehicle; S608, with It is broadcast as a response message to the request of a newly joined ordinary vehicle to join the group, and with The format is broadcast as an update message for the updated communication group; S609. After the remaining ordinary vehicles in the communication group receive the update message from step S608, they determine the equation. Is it true? If so, then use the formula. Obtain the updated group key for the communication group; otherwise, proceed to step S610. S610, Using the formula Calculate the shared key between the newly added regular vehicle and bus vehicle nodes, and based on the obtained shared key, calculate the second message authentication code for the newly added regular vehicle, i.e.: in, Indicates the newly added number The second message authentication code for a regular vehicle; S611. If the second message authentication code of the ordinary vehicle newly added in step S610 is equal to the first message authentication code of the ordinary vehicle newly added in S606, then the formula is used. Obtain the key factor of the newly added ordinary vehicle, and use the formula Obtain the updated group key for the communication group.

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