Intelligent traffic certificate authentication and revocation method and device

Abstract

The invention discloses an intelligent traffic certificate authentication and revocation method and device, and relates to the technical field of vehicle identity authentication, and the method comprises the steps: generating a signature certificate, initializing a vehicle, obtaining a vehicle registration certificate in combination with the signature certificate, and transmitting the vehicle registration certificate to the vehicle; generating a pseudonym certificate for the vehicle by using the vehicle public key, the SA and the PCA, and feeding back the pseudonym certificate to the SA; generating confirmation information for all the received pseudonym certificates, inserting the received pseudonym certificates into the database in the next update, and simultaneously generating certificates for all the pseudonym certificates in batches; the pseudonym certificate and the certification thereof are obtained and share information with the verification mechanism, the verification mechanism authenticates the certificate and the certification and shares the certificate and the certification with the vehicles in the communication range, and certificate revocation is carried out on the malicious vehicles. The pseudonym certificate not only protects the privacy of the vehicle, but also realizes vehicle correspondence, and the registration certificate of the vehicle is pulled into the blacklist in a manner of revoking the pseudonym certificate, so that the problems of vehicle privacy leakage, identity verification and difficulty in revoking malicious vehicles are solved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle identity authentication, and in particular to a method and device for authenticating and revoking an intelligent transportation certificate. Background Art

[0002] The intelligent transportation system effectively integrates advanced information technology, data communication technology, sensor technology, electronic control technology and computer technology into the entire transportation management system, thereby establishing a comprehensive transportation and management system that is real-time, accurate and efficient and can function in a wide range and in all directions. While the intelligent transportation system brings convenience to urban transportation, it is also accompanied by security and privacy issues. On the one hand, open wireless communications may expose vehicle and infrastructure information to cyber attacks; on the other hand, the leakage of real identity information may lead to serious security and privacy risks.

[0003] To solve these problems, experts and scholars have proposed different VPKI certificate revocation schemes to protect the communication security in intelligent transportation systems. The ETSI (European Telecommunications Standards Institute) system proposes to cancel the certificate status check to achieve the maximum number of authentications per second. This system is a relatively simple VPKI solution. Further, Correia et al. proposed a range-based certificate revocation method to enhance its performance. In contrast, the SCMS system (Supply Chain Management System) proposed by Brecht et al. is more complex. It ensures that the distribution between device certificates is unassociable and provides stronger privacy protection. The SCMS system relies on a certificate revocation list and reduces the growth of CRL by using a single revoked certificate. Rabiah et al. proposed TVSS (Token-based Vehicle Security System), which ensures scalable revocation and frequent certificate updates. However, the TVSS system relies on unforgeable tokens for faster verification. In order to protect identity privacy, Zhou et al. used pseudonym information to digitally sign vehicles in different areas, but adopted a one-by-one verification method when verifying the signature.

[0004] The above schemes are all solutions proposed for untrusted network communications. As for network attacks on vehicle trust storage, how to propose an effective pseudonymous certificate identity authentication and certificate revocation mechanism is a major challenge that needs to be solved in the current intelligent transportation system. Summary of the invention

[0005] In order to solve the above technical problems, this application proposes the following technical solutions: In a first aspect, an embodiment of the present application provides a method for authenticating and revoking a smart transportation certificate, including: Generate a signature certificate to initialize the vehicle and obtain a vehicle registration certificate in combination with the signature certificate and send it to the vehicle; Generate a pseudonym certificate for the vehicle using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA, and store the pseudonym certificate and then feed it back to SA; Generate confirmation information for all pseudonym certificates received and insert the received pseudonym certificates into the database in the next update, and generate proofs for all pseudonym certificates in batches; Obtain a pseudonymous certificate and its proof and share the information with a verification agency, the verification agency authenticates the certificate and proof, and shares the certificate and proof with vehicles within the communication range to revoke the certificate of a malicious vehicle.

[0006] In a possible implementation, generating a signature certificate to initialize a vehicle and obtaining a vehicle registration certificate in combination with the signature certificate and sending the certificate to the vehicle includes: Embed the root certificate authority RCA that meets trusted security standards into the blockchain; The RCA inserts the certificates of the registered certificate authorities ECA and PCA into the blockchain, and delegates the signing authority to the said ECA and PCA; The RCA generates a signed certificate for the trusted party and records it on the blockchain, and then uses the signed certificate to initialize the vehicle; The vehicle generates a public key and sends it to ECA for signing. ECA generates a vehicle registration certificate based on the signed certificate, registers it in the distributed ledger CDLM, and sends the registration certificate to the vehicle.

[0007] In a possible implementation, the generating of a pseudonym certificate for the vehicle using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA, and storing the pseudonym certificate and then feeding it back to the SA includes: The vehicle sends the public key to the shuffling agency SA, which generates a public key seed using the butterfly key expansion method and sends the public key seed to the pseudonymous certificate authority PCA for key signing; PCA uses the signed public key seed to generate a pseudonym certificate for the vehicle, stores the pseudonym certificate in CDLM, and sends the certificate to SA in ciphertext.

[0008] In a possible implementation, the vehicle sends the public key to a shuffling agency SA, which generates a public key seed using a butterfly key expansion method, and sends the public key seed to a pseudonymous certificate authority PCA for key signing, including: The vehicle generates a public key (a, Ag) and uses the (a, Ag) to generate a pseudonymous certificate signing request Forward to SA: ), where: Ecert is the vehicle's registration certificate, is the public key of the shuffling agency, is the private key of the vehicle, is a signature function, is the encryption function; The SA verifies that the vehicle's registration certificate has not been revoked and that it is the only pseudonymous certificate signing request for the vehicle, and then uses butterfly key expansion to generate n cocoon-shaped public keys; The SA mixes the extended public keys from different vehicles and sends the message Forward to PCA, , is the extended public key, is the public key of PCA, is the registration certificate, is a pseudonymous certificate signing request, is a hash function.

[0009] In a possible implementation, the PCA generates a pseudonym certificate for the vehicle using the signed public key seed, stores the pseudonym certificate in the CDLM, and sends the certificate in ciphertext to the SA, including: PCA generates a pseudonym certificate , where metainfo is metadata, is the digital signature secret identifier, , , where: ri is a random number, g is a generator, It is a digital signature; PCA sends the signed log registration request message RegReq to CDLM. ,in: is the public key of CDLM; CDLM returns the signed timestamp of the registration request to PCA , , where: t represents the current time, is the private key of CDLM; PCA creates an encrypted packet And return to SA, ,in: yes 's public key; SA accepts the After that, bundle each vehicle , for vehicles to download; The vehicle downloads the bundled encrypted package and passes the decryption algorithm Decryption To obtain ,in: Decryption The private key of Final SA execution and algorithm to verify each pseudonym certificate and the corresponding Correctness, where Is the verification function, used to verify the digital signature.

[0010] In a possible implementation, the generating of confirmation information for all received pseudonym certificates and inserting the received pseudonym certificates into the database in the next update, and generating batch certificates for all pseudonym certificates, including: CDLM generates confirmation information for all received certificates and inserts the received certificates into the database in the next update, and the update process is as follows: Assume is a set of unexpired pseudonym certificates, then the new pseudonym certificate set is , the cumulative value is , , , , Is the private key.

[0011] In a possible implementation, the obtaining of the pseudonym certificate and its proof and sharing the information with a verification agency, the verification agency authenticating the certificate and the proof, and sharing the certificate and the proof with vehicles within the communication range, and revoking the certificate of the malicious vehicle include: The aggregator downloads the newly inserted pseudonymous certificate and its proof from the blockchain and CDLM and shares that information with the edge server; The edge server verifies the batch proofs and corresponding pseudonym certificates received from vehicles within the communication range; The edge server then generates a hash list of pseudonym certificates in the communication proof and shares the hash list and batch proof with vehicles within the communication range; The vehicle verifies the pseudonym certificate against the hash list shared by the edge server; The vehicle caches the batch certificate and verifies whether the pseudonym certificate has been revoked based on the batch certificate; When a vehicle is found to be using an unexpired pseudonym certificate and engaging in malicious behavior, the vehicle and pseudonym certificate are tracked, and the registration certificate is associated with the corresponding pseudonym certificate and blacklisted.

[0012] In a possible implementation, the vehicle verifies the pseudonym certificate according to the hash list shared by the edge server, including: Hash the PCA certificate and compare the hash value with the PCA certificate hash value recorded on the blockchain to check whether the PCA certificate is recorded in the blockchain; Each pseudonymous certificate is then hashed and checked for the presence of its hash value in a hash list shared by the edge server; if the hash value of the pseudonymous certificate matches a hash value in the list, the pseudonymous certificate is accepted as a valid certificate.

[0013] In a possible implementation, when it is found that a vehicle is using an unexpired pseudonym certificate and malicious behavior occurs, the vehicle and the pseudonym certificate are tracked, and the registration certificate is associated with the corresponding pseudonym certificate and blacklisted, including: The edge server sends the hash value to PCA Request to implement pseudonym certificate mapping to PSR; SA forwards the registration certificate and PSR hash value List of; PCA further concatenates the collection of pseudonymous certificates to the PSR hash value and forwards them to CDLM for undo operations.

[0014] In one possible implementation, the PCA further concatenates the set of pseudonymous certificates to the PSR hash value , and forwards them to CDLM for undo operations, including: Compute the new list The new cumulative value of , deletes the pseudonymous certificate set belonging to the malicious vehicle in the CDLM ledger: , where: L is a list of pseudonym certificates, is a list of pseudonymous certificates to be deleted; Deleting the pseudonymous certificate from the CDLM database stops the malicious vehicle from being used and adds it to the blacklist; The SA side retains the registration certificate and the corresponding hash value The PCA only keeps the pseudonym certificate and the associated hash value. 's mapping.

[0015] In a second aspect, an embodiment of the present application provides a smart traffic certificate authentication and revocation device, comprising: An information initialization module, used to generate a signature certificate to initialize the vehicle and obtain a vehicle registration certificate in combination with the signature certificate and send it to the vehicle; A pseudonym certificate generation module, used to generate a pseudonym certificate for the vehicle using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA, and store the pseudonym certificate and then feed it back to SA; The proof generation module is used to generate confirmation information for all pseudonymous certificates received, insert the received pseudonymous certificates into the database in the next update, and generate proofs for all pseudonymous certificates in batches; The authentication revocation module is used to obtain the pseudonym certificate and its proof and share the information with the verification agency. The verification agency authenticates the certificate and proof and shares the certificate and proof with vehicles within the communication range to revoke the certificate of malicious vehicles.

[0016] In the embodiment of the present application, a pseudonym certificate is generated based on the vehicle's registration certificate within the trust network, and the pseudonym certificates all have corresponding certificates, which not only protects the privacy of the vehicle, but also enables the correspondence of the vehicle. In the later stage of vehicle verification, if malicious behavior is found in the vehicle, the registration certificate of the vehicle is added to the blacklist by revoking the pseudonym certificate, thereby realizing batch verification of vehicles in the communication area and solving the problems of difficulty in vehicle identity authentication, privacy leakage and difficulty in revoking malicious vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flowchart of a method for authenticating and revoking a smart transportation certificate provided in an embodiment of the present application; Figure 2 A schematic diagram of initializing the trust storage settings provided in an embodiment of the present application; Figure 3 A schematic diagram of issuing a certificate for legal initialization of a vehicle provided in an embodiment of the present application; Figure 4 A schematic diagram of a registered pseudonym certificate provided in an embodiment of the present application; Figure 5 A schematic diagram of a typical network attack provided in an embodiment of the present application; Figure 6 A schematic diagram of vehicle identity authentication and revocation provided in an embodiment of the present application; Figure 7 A schematic diagram of an intelligent transportation certificate authentication and revocation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] The present solution is described below in conjunction with the accompanying drawings and specific implementation methods.

[0019] See also Figure 1 The intelligent transportation certificate authentication and revocation method in this embodiment includes: S101, generating a signature certificate to initialize the vehicle and combining the signature certificate to obtain a vehicle registration certificate and send it to the vehicle.

[0020] like Figure 2As shown, this step mainly performs the initialization of the trust storage setting and the download of the trust storage of the device. First, RCA (Root Certification Authority) is embedded in the blockchain after its security standards are strictly reviewed by a group of trusted voters. Subsequently, RCA will have the right to sign the certificates of ECA (Enrolment Certification Authority) and PCA (Pseudonym Certification Authority) and insert them into the blockchain, while delegating the signing authority to them. After the trust storage is successfully set up, the vehicle will download the trust storage from the blockchain. RCA then generates a signed certificate for the trusted party and records it on the blockchain, and then initializes the vehicle with the signed certificate. Finally, these vehicles can maintain a complete blockchain in the memory to act as a full node, or they can only download the certificate or the hash value of the certificate from the blockchain to act as a lightweight node.

[0021] like Figure 3 , then, the vehicle sends a registration certificate signing request to ECA in order to obtain a registration certificate. If the vehicle is initialized correctly, ECA grants the registration certificate. At the same time, ECA sends a logging request to CDLM (Credential Distributed LedgerMaintainer) to insert the registration certificate into its database. After being inserted into the database, the registration certificate will be open to public review and supervision.

[0022] S102, using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA to generate a pseudonym certificate for the vehicle, and then storing the pseudonym certificate and feeding it back to SA.

[0023] Generating a pseudonym certificate is the most complex step in this embodiment, mainly because it needs to protect the real identity of the vehicle while ensuring the transparency and legitimacy of the information flow at this stage. Figure 4 Message flow for issuance and registration of a pseudonym certificate for a vehicle is shown.

[0024] First, the vehicle sends the public key to the shuffling agency SA, which generates a public key seed using the butterfly key expansion method and sends the public key seed to the pseudonymous certificate authority PCA for key signing.

[0025] Specifically, the vehicle generates a public key (a, Ag) and uses the (a, Ag) to generate a pseudonymous certificate signature request Forward to SA: ), where: Ecert is the vehicle's registration certificate, is the public key of the shuffling agency, is the private key of the vehicle, is a signature function, is an encryption function. SA verifies that the vehicle's registration certificate has not been revoked and that it is the only pseudonymous certificate signature request for the vehicle, then the vehicle's butterfly key expansion is applied to generate n cocoon-shaped public keys, otherwise this step process ends.

[0026] SA mixes the extended public keys from different vehicles and sends the message Forward to PCA, , is the extended public key, is the public key of PCA, is the registration certificate, is a pseudonymous certificate signing request, is a hash function.

[0027] Subsequently, PCA generates a pseudonym certificate for the vehicle using the signed public key seed, stores the pseudonym certificate in CDLM, and sends the certificate to SA in ciphertext.

[0028] Specifically, PCA generates a pseudonym certificate , where metainfo is metadata, is the digital signature secret identifier, , , where: ri is a random number, g is a generator, It is a digital signature.

[0029] PCA sends the signed log registration request message RegReq to CDLM. ,in: is the public key of CDLM.

[0030] CDLM returns the signed timestamp of the registration request to PCA , , where: t represents the current time, Is the private key of CDLM.

[0031] PCA creates an encrypted packet And return to SA, ,in: yes The public key of

[0032] SA accepts the After that, bundle each vehicle , for the vehicle to download. The vehicle downloads the bundled encrypted package and passes the decryption algorithm Decryption To obtain ,in: Decryption The SA executes and algorithm to verify each pseudonym certificate and the corresponding Correctness, where Is the verification function, used to verify the digital signature.

[0033] From the above process, it can be seen that the SA provides the pseudonym certificate to the vehicle for download, but cannot extract the pseudonym certificate data from the encrypted package. At the same time, the pseudonym certificate ensures the privacy of the vehicle during the entire process of the vehicle obtaining the encrypted package. In addition, the SA and PCA cannot match the issued pseudonym certificates with the registration certificates one by one. Finally, CDLM inserts a batch of pseudonym certificates in the next update.

[0034] S103, generating confirmation information for all received pseudonym certificates, inserting the received pseudonym certificates into the database in the next update, and generating proofs for all pseudonym certificates in batches.

[0035] As can be seen from S102, the SA provides the pseudonym certificate to the vehicle for downloading, but cannot extract the pseudonym certificate data from the encrypted package. At the same time, the pseudonym certificate ensures the privacy of the vehicle during the entire process of the vehicle obtaining the encrypted package. In addition, the SA and PCA cannot match the issued pseudonym certificate with the registration certificate one by one.

[0036] To this end, in this embodiment, confirmation information is generated for all received pseudonym certificates, and the received pseudonym certificates are inserted into the database in the next update, and proofs are generated for all pseudonym certificates in batches. The update process is as follows: is a set of unexpired pseudonym certificates, then the new pseudonym certificate set is , the cumulative value is , , , , Is the private key.

[0037] S104, obtaining a pseudonym certificate and its proof and sharing the information with a verification agency, the verification agency authenticates the certificate and proof, and shares the certificate and proof with vehicles within the communication range, and revokes the certificate of malicious vehicles.

[0038] After the pseudonym certificate Pcert is provided, each vehicle holds a set of Pcerts. Once these pseudonym certificates Pcerts are inserted into the CDLM database, they generate validity certificates in batches for pseudonym certificates within the communication range to prove the legitimacy of these certificates. These certificates act as batch activation codes, simplifying the activation process. Compared with the CRL-based VPKI system, it is capable of batch revocation status verification. The aggregator downloads batch certificates of pseudonym certificates and shares them with the edge server.

[0039] The edge server verifies the batch certificate and the corresponding pseudonym certificate received from the vehicle within the communication range. Then, the edge server generates a hash list of the pseudonym certificates in the communication certificate and shares the hash list and batch certificate with the vehicles within the communication range. The vehicle verifies the pseudonym certificate based on the hash list shared by the edge server. Finally, the vehicle caches the batch certificate and verifies whether the Pcert is revoked based on the batch certificate.

[0040] After aggregating pseudonym certificates and batch attestations, each vehicle has a set of pseudonym certificates and batch attestations generated by CDLM. When a vehicle sends a signed message to another vehicle, the vehicle sends the message along with the signing certificate. The receiving vehicle verifies all pseudonyms received by vehicles within communication range by checking whether the pseudonym is expired, signed by a trusted PCA, and revoked.

[0041] The PCA certificate is hashed and the hash value is compared with the PCA certificate hash value recorded on the blockchain to check whether the PCA certificate is recorded in the blockchain. This ensures that the PCA's public key PK can effectively verify the pseudonymous certificate. Subsequently, each pseudonymous certificate is hashed and checked whether the hash value of the pseudonymous certificate exists in the hash list shared by the edge server. If the hash value of the pseudonymous certificate matches the hash value in the list, the pseudonymous certificate is accepted as a valid certificate. In addition, the pseudonymous certificate is cached and verified. In this embodiment, different levels of security need to be ensured. In traditional VPKI, the security of the device depends on the security of the PCA. In order to change this situation, in this embodiment, the PCA is designed to forward content between the edge server and the CDLM, and a check mechanism is introduced in the PCA and CDLM to ensure the honesty of both. In addition, the edge server is used to verify the pseudonym certificate, and the CDLM aggregates the valid and unrevoked pseudonym certificates. During the aggregation process, any party can supervise whether the CDLM has malicious behavior.

[0042] Therefore, the clients of this embodiment need to ensure honest behavior, and the CDLM needs to correctly update the ledger based on the pseudonymous certificate registration requests they receive. These checks are performed by edge servers, aggregators, trusted centers (such as ECA, PCA, and RCA), vehicles, and RSUs to observe the correctness of CDLM. Vehicles share the records of CDLM obtained through aggregators and verify them on the blockchain. Vehicles occasionally send a set of pseudonymous certificates to the aggregator to check its status, while verifying the authenticity of the aggregator and the correctness of the CDLM records. In addition, the vehicle needs to perform random verification of the log, and if the verification is correct, the entire log is verified. In short, any party can participate in supervising and identifying malicious behavior of vehicles.

[0043] When a vehicle is found to be using an unexpired pseudonym certificate and engaging in malicious behavior, especially when a vehicle is under malicious attack, the vehicle and pseudonym certificate need to be tracked, and the registration certificate needs to be associated with a group of pseudonym certificates and blacklisted. Figure 5 As shown in Figure 1, a vehicle enters an attack area from a safe area. Once the vehicle is successfully attacked by an attacker, it will become a tool for malicious attacks. Figure 6 ,To connect the registration certificate and the pseudonym certificate set of the malicious vehicle, the edge server sends the hash value to the PCA Request to map the pseudonym certificate to the PSR. In response, the SA forwards the registration certificate and the PSR hash value. The PCA further concatenates the collection of pseudonymous certificates to the PSR hash value. and forwards them to CDLM for undo operations.

[0044] In this embodiment, CDLM deletes them as follows: Compute the new list The new cumulative value of , deletes the pseudonymous certificate set belonging to the malicious vehicle in the CDLM ledger: , where: L is a list of pseudonym certificates, Is the list of pseudonymous certificates to be deleted; deleting the pseudonymous certificate from the CDLM database stops the malicious vehicle from being used and adds it to the blacklist. The SA side retains the registration certificate and the corresponding hash value The PCA only keeps the pseudonym certificate and the associated hash value. 's mapping.

[0045] Corresponding to the intelligent traffic certificate authentication and revocation method provided in the above embodiment, the present application also provides an embodiment of an intelligent traffic certificate authentication and revocation device.

[0046] See also Figure 7 The intelligent traffic certificate authentication and revocation device 20 in this embodiment includes: An information initialization module 201 is used to generate a signature certificate to initialize the vehicle and obtain a vehicle registration certificate in combination with the signature certificate and send it to the vehicle; A pseudonym certificate generating module 202 is used to generate a pseudonym certificate for the vehicle using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA, and store the pseudonym certificate and then feed it back to SA; The proof generation module 203 is used to generate confirmation information for all received pseudonym certificates, insert the received pseudonym certificates into the database in the next update, and generate proofs for all pseudonym certificates in batches; The authentication revocation module 204 is used to obtain the pseudonym certificate and its proof and share the information with the verification agency. The verification agency authenticates the certificate and proof and shares the certificate and proof with vehicles within the communication range to revoke the certificate of malicious vehicles.

[0047] The same or similar parts between the various embodiments in the present application specification can be referred to each other. In particular, for the device embodiment, since the method therein is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiment.

[0048] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0049] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for authenticating and revoking an intelligent transportation certificate, characterized in that: include: Generate a signature certificate to initialize the vehicle and obtain a vehicle registration certificate in combination with the signature certificate and send it to the vehicle; Generate a pseudonym certificate for the vehicle using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA, and store the pseudonym certificate and then feed it back to SA; Generate confirmation information for all pseudonym certificates received and insert the received pseudonym certificates into the database in the next update, and generate proofs for all pseudonym certificates in batches; Obtain a pseudonymous certificate and its proof and share the information with a verification agency, which authenticates the certificate and proof and shares the certificate and proof with vehicles within the communication range to revoke the certificate of a malicious vehicle.

2. The intelligent traffic certificate authentication and revocation method according to claim 1, characterized in that: The generating of the signature certificate to initialize the vehicle and combining the signature certificate to obtain the vehicle registration certificate and sending it to the vehicle includes: Embed the root certificate authority RCA that meets trusted security standards into the blockchain; The RCA inserts the certificates of the registered certificate authorities ECA and PCA into the blockchain, and delegates the signing authority to the said ECA and PCA; The RCA generates a signed certificate for the trusted party and records it on the blockchain, and then uses the signed certificate to initialize the vehicle; The vehicle generates a public key and sends it to ECA for signing. ECA generates a vehicle registration certificate based on the signed certificate, registers it in the distributed ledger CDLM, and sends the registration certificate to the vehicle.

3. The intelligent traffic certificate authentication and revocation method according to claim 2, characterized in that: The method of using the vehicle public key, the shuffling agency SA and the pseudonym certificate agency PCA to generate a pseudonym certificate for the vehicle, and storing the pseudonym certificate and then feeding it back to SA includes: The vehicle sends the public key to the shuffling agency SA, which generates a public key seed using the butterfly key expansion method and sends the public key seed to the pseudonymous certificate authority PCA for key signing; PCA uses the signed public key seed to generate a pseudonym certificate for the vehicle, stores the pseudonym certificate in CDLM, and sends the certificate to SA in ciphertext.

4. The intelligent traffic certificate authentication and revocation method according to claim 3 is characterized in that: The vehicle sends the public key to the shuffling agency SA, which generates a public key seed using the butterfly key expansion method and sends the public key seed to the pseudonymous certificate authority PCA for key signing, including: The vehicle generates a public key (a, Ag) and uses the (a, Ag) to generate a pseudonymous certificate signing request Forward to SA: ), where: Ecert is the vehicle's registration certificate, is the public key of the shuffling agency, is the private key of the vehicle, is a signature function, is the encryption function; The SA verifies that the vehicle's registration certificate has not been revoked and that it is the only pseudonymous certificate signing request for the vehicle, and then uses butterfly key expansion to generate n cocoon-shaped public keys; The SA mixes the extended public keys from different vehicles and sends the message Forward to PCA, , is the extended public key, is the public key of PCA, is the registration certificate, is a pseudonymous certificate signing request, is a hash function.

5. The intelligent traffic certificate authentication and revocation method according to claim 4, characterized in that: The PCA generates a pseudonym certificate for the vehicle using the signed public key seed, stores the pseudonym certificate in the CDLM, and sends the certificate to the SA in the form of ciphertext, including: PCA generates a pseudonym certificate , where metainfo is metadata, is the digital signature secret identifier, , , where: ri is a random number, g is a generator, It is a digital signature; PCA sends the signed log registration request message RegReq to CDLM. ,in: is the public key of CDLM; CDLM returns the signed timestamp of the registration request to PCA , , where: t represents the current time, is the private key of CDLM; PCA creates an encrypted packet And return to SA, ,in: yes 's public key; SA accepts the After that, bundle each vehicle , for vehicles to download; The vehicle downloads the bundled encrypted package and passes the decryption algorithm Decryption To obtain ,in: Decryption The private key of Final SA execution and algorithm to verify each pseudonym certificate and the corresponding Correctness, where Is the verification function, used to verify the digital signature.

6. The intelligent traffic certificate authentication and revocation method according to claim 5, characterized in that: The method generates confirmation information for all received pseudonym certificates, and inserts the received pseudonym certificates into the database in the next update, and generates proofs for all pseudonym certificates in batches, including: CDLM generates confirmation information for all received certificates, and inserts the received certificates into the database in the next update. The update process is as follows: Assume is a set of unexpired pseudonym certificates, then the new pseudonym certificate set is , the cumulative value is , , , , Is the private key.

7. The intelligent traffic certificate authentication and revocation method according to claim 1, characterized in that: The obtaining of the pseudonym certificate and its proof and sharing of information with the verification agency, the verification agency authenticating the certificate and proof and sharing the certificate and proof with vehicles within the communication range, and revoking the certificate of the malicious vehicle include: The aggregator downloads the newly inserted pseudonymous certificate and its proof from the blockchain and CDLM and shares that information with the edge server; The edge server verifies the batch proofs and corresponding pseudonym certificates received from vehicles within the communication range; The edge server then generates a hash list of pseudonym certificates in the communication proof and shares the hash list and batch proof with vehicles within the communication range; The vehicle verifies the pseudonym certificate against the hash list shared by the edge server; The vehicle caches the batch certificate and verifies whether the pseudonym certificate has been revoked based on the batch certificate; When a vehicle is found to be using an unexpired pseudonym certificate and engaging in malicious behavior, the vehicle and pseudonym certificate are tracked, and the registration certificate is associated with the corresponding pseudonym certificate and blacklisted.

8. The intelligent traffic certificate authentication and revocation method according to claim 7, characterized in that: The vehicle verifies the pseudonym certificate based on the hash list shared by the edge server, including: Hash the PCA certificate and compare the hash value with the PCA certificate hash value recorded on the blockchain to check whether the PCA certificate is recorded in the blockchain; Each pseudonymous certificate is then hashed and checked for the presence of its hash value in a hash list shared by the edge server; if the hash value of the pseudonymous certificate matches a hash value in the list, the pseudonymous certificate is accepted as a valid certificate.

9. The intelligent traffic certificate authentication and revocation method according to claim 7, characterized in that: When it is found that a vehicle is using an unexpired pseudonym certificate and has engaged in malicious behavior, the vehicle and pseudonym certificate are tracked, and the registration certificate is associated with the corresponding pseudonym certificate and blacklisted, including: The edge server sends the hash value to PCA Request to implement pseudonym certificate mapping to PSR; SA forwards the registration certificate and PSR hash value List of; PCA further concatenates the collection of pseudonymous certificates to the PSR hash value , and forwards them to CDLM for undo operations.

10. The intelligent traffic certificate authentication and revocation method according to claim 9, characterized in that: The PCA further concatenates the set of pseudonymous certificates to the PSR hash value , and forwards them to CDLM for undo operations, including: Compute the new list The new cumulative value of , deletes the pseudonymous certificate set belonging to the malicious vehicle in the CDLM ledger: , where: L is a list of pseudonym certificates, is a list of pseudonymous certificates to be deleted; Deleting the pseudonymous certificate from the CDLM database stops the malicious vehicle from being used and adds it to the blacklist; The SA side retains the registration certificate and the corresponding hash value records, while PCA only retains the pseudonymous certificate and the associated hash value 's mapping.

Images