A blockchain and password accumulator-based vehicle networking node identity authentication method

Abstract

The application discloses a kind of based on blockchain and password accumulators' vehicle networking node identity authentication method, using public-private dual-chain isolated storage architecture.Trusted authority center completes system initialization, generates RSA accumulator and Schnorr signature parameter and writes into public chain;Vehicle registration stage obtains pseudonym and membership certificate after two-way identity authentication, real identity mapping is encrypted and stored in private chain, and public identity information is stored in public chain.Authentication, roadside unit is accessed by timestamp check, Schnorr signature verification and RSA accumulator membership verification Control, support multi-node aggregation batch verification.System is refreshed accumulator by event triggering and periodic active updating two modes, realize malicious node instant revocation and controllable traceability under privacy protection.The application significantly reduces authentication calculation and communication overhead, balances vehicle communication anonymity and regulatory requirements, and is suitable for vehicle networking high-concurrency access scene.

Description

Technical Field

[0001] This invention relates to a method for authenticating the identity of vehicle network nodes based on blockchain and a cryptographic accumulator. Background Technology

[0002] Vehicle-to-everything (V2X) communication enables vehicle-to-infrastructure (V2I) collaboration, intelligent traffic management, and autonomous driving assistance through real-time information exchange between vehicles, roadside units, and the cloud. Ensuring the security of V2X communication requires establishing a trusted node authentication mechanism to prevent unauthorized node access, message tampering, and identity forgery.

[0003] The existing vehicle-to-everything (V2X) identity authentication mainly adopts the following technical solutions:

[0004] One approach is the traditional centralized identity authentication scheme. This scheme relies on a trusted authority or certificate authority to centrally manage digital certificates, with the verification end querying a centralized server to complete identity verification. However, vehicle-to-everything (V2X) nodes are highly dynamic and mobile, with stringent real-time communication requirements. The centralized authentication architecture is susceptible to single-point-of-failure risks; if the central server becomes unavailable, it will paralyze the entire network authentication process. Furthermore, centralized processing struggles to meet low-latency requirements.

[0005] The second approach is a decentralized identity authentication scheme based on blockchain. This scheme stores identity credentials in a distributed manner on the blockchain, leveraging the immutability of the blockchain to mitigate single points of failure. However, as the number of vehicle network nodes increases, each authentication requires querying and verifying the identity status stored on the blockchain. The computational overhead increases linearly with the number of nodes, leading to a significant decrease in the efficiency of secondary authentication and making it difficult to adapt to the high-concurrency, low-latency communication scenarios of vehicle networks.

[0006] Thirdly, there is the identity revocation scheme based on certificate revocation lists or blacklists. This scheme notifies the verification end which identities have expired by distributing revocation lists. In the vehicle-to-everything (V2X) environment, vehicles move at high speeds and network topology changes rapidly, resulting in a lag in the distribution of revocation information. The verification end needs to traverse a large number of revocation entries to confirm the identity status, leading to high verification overhead and poor real-time performance.

[0007] Fourthly, there are privacy protection and identity tracing solutions. While using pseudonyms or anonymity for vehicle communication can protect privacy to some extent, complete anonymity makes it impossible to trace the responsible party after malicious behavior occurs. If communication is directly linked to the real identity, there are risks of privacy leaks and behavioral tracking. Current technology struggles to strike a balance between anonymous communication and controllable traceability.

[0008] In summary, existing technologies have not yet solved the technical problems of low efficiency of secondary authentication, high on-chain query overhead, delayed identity revocation, and difficulty in balancing anonymity and traceability in vehicle-to-everything (V2X) identity authentication. There is an urgent need for a V2X identity authentication method that balances efficient authentication, low computational overhead, privacy protection, controllable traceability, and efficient revocation. Summary of the Invention

[0009] This invention provides a vehicle network node identity authentication method based on blockchain and cryptographic accumulator to solve the problems existing in the prior art.

[0010] The technical solutions adopted in this invention are as follows:

[0011] A method for authenticating the identity of vehicle network nodes based on blockchain and cryptographic accumulators includes the following steps:

[0012] S1: The trusted authority center generates RSA accumulator parameters, Schnorr signature parameters, and the key pair of the trusted authority center, calculates the initial RSA accumulator value, and writes the system public parameters into the public blockchain;

[0013] S2: The vehicle initiates a registration request to the Trusted Authority Center. The Trusted Authority Center sends a temporary credential to the vehicle. After verifying the identity of the Trusted Authority Center, the vehicle generates its own key pair and real identity identifier and sends them to the Trusted Authority Center. The Trusted Authority Center generates a pseudonym for the vehicle and generates a membership certificate for the vehicle based on the current RSA accumulator value. It stores the mapping relationship between the real identity identifier and the pseudonym in the private blockchain, stores the mapping relationship between the pseudonym and the vehicle's public key in the public blockchain, and sends the pseudonym and membership certificate to the vehicle.

[0014] S3: The vehicle generates a temporary public key point, constructs an authentication request message containing a pseudonym, temporary public key point, membership proof, timestamp, and a signature value generated based on a Schnorr signature, and broadcasts the authentication request message. The roadside unit verifies the freshness of the timestamp, queries the vehicle's public key and the current RSA accumulator value from the public blockchain, and performs dual verification.

[0015] The first layer of verification verifies the signature value to confirm the authenticity of the vehicle's identity. The second layer of verification verifies the membership certificate corresponding to the current RSA accumulator value to confirm that the vehicle's identity has not been revoked. If both verifications pass, the vehicle is allowed to access the network. If either verification fails, the vehicle is denied access.

[0016] S4: When the Trusted Authority Center determines that a vehicle is a malicious node, it queries the corresponding real identity identifier from the private blockchain based on the alias of the malicious vehicle to complete the tracing; when the Trusted Authority Center determines that a vehicle is a malicious node or receives a request for a legitimate vehicle to actively withdraw, it updates the RSA accumulator value and publishes it to the public blockchain, invalidating all old membership proofs, and regenerating membership proofs based on the updated RSA accumulator value for legitimate vehicles that have not been revoked.

[0017] Furthermore, in S1, the system common parameters include the RSA accumulator modulus, the elliptic curve parameters corresponding to the Schnorr signature, the secure one-way hash function, the valid time range of the timestamp, and the time interval for the periodic active update of the RSA accumulator.

[0018] Furthermore, in S2, the process of generating and verifying temporary credentials is as follows: the trusted authority selects a registration random number and calculates the registration elliptic curve point, calculates the registration hash value by combining its own public key with the current timestamp, generates a registration Schnorr signature value using its own private key, and sends a temporary credential containing the registration elliptic curve point, the registration Schnorr signature value, and the timestamp to the vehicle; the vehicle confirms the identity of the trusted authority by verifying the validity of the registration Schnorr signature value.

[0019] Furthermore, in S2, the pseudonym is generated by XORing the hash value of the real identity identifier and the vehicle private key; the membership proof is calculated based on the hash value of the current RSA accumulator value and the pseudonym, and all RSA accumulator-related operations are performed under the RSA accumulator modulus.

[0020] Furthermore, in S3, the temporary public key point is generated by the vehicle selecting an authentication random number and calculating based on the elliptic curve base point of the Schnorr signature; the signature value generated based on the Schnorr signature is calculated by the authentication random number, the authentication hash value and the vehicle's private key, and the authentication hash value is generated by hashing the pseudonym, the temporary public key point, the membership proof and the timestamp; and the vehicle uses different random numbers to generate different temporary public key points in different authentication sessions.

[0021] Furthermore, in S3, the first layer of verification includes the verification equation: the product of the signature value and the elliptic curve base point is equal to the sum of the products of the temporary public key point, the authentication hash value, and the vehicle public key, wherein the authentication hash value is generated by hashing the pseudonym, the temporary public key point, the membership proof, and the timestamp.

[0022] The second layer of verification includes the verification equation: the power of the pseudonym hash value of the member proof modulo the RSA accumulator modulus equals the current RSA accumulator value.

[0023] Furthermore, in S3, verifying the freshness of the timestamp includes: determining whether the difference between the timestamp and the current system time of the roadside unit is within a preset valid time range, and whether the timestamp has not been reused, in order to resist replay attacks.

[0024] Furthermore, in S4, updating the RSA accumulator value includes an event-triggered revocation mode: when the trusted authority determines that a vehicle is a malicious node or receives an active revocation request from a legitimate vehicle, the hash value of the pseudonym of the revoked vehicle is calculated, a new RSA accumulator value is calculated based on the old RSA accumulator value and the hash value, and published to the public blockchain, and membership proofs are regenerated for legitimate vehicles that have not been revoked, wherein the regenerated membership proof is equal to the multiplicative inverse power of the hash value of each legitimate vehicle's pseudonym in the new RSA accumulator value modulo the RSA accumulator modulo.

[0025] The criterion for determining a vehicle as a malicious node is: within a preset time range, the number of times the pseudonym corresponding to the vehicle is reported by different legitimate nodes reaches a preset threshold.

[0026] Furthermore, in S4, updating the RSA accumulator value also includes a periodic proactive update mode: the trusted authority center generates a random hash factor that is not bound to any vehicle at preset time intervals, calculates a new RSA accumulator value based on the old RSA accumulator value and the random hash factor, and publishes it to the public blockchain, invalidating all old membership proofs, and regenerating membership proofs for legitimate vehicles that have not been revoked, wherein the regenerated membership proof is equal to the multiplication inverse of the pseudonym hash value of each legitimate vehicle in the new RSA accumulator value modulo the RSA accumulator modulus.

[0027] Furthermore, S3 also includes a multi-node aggregation verification step:

[0028] When the roadside unit receives authentication requests from multiple vehicles at the same time, it first performs Schnorr signature verification on each request independently to filter out the legitimate requests.

[0029] Calculate the aggregate hash index and aggregate membership proof for each legitimate request corresponding to the pseudonym. Verify whether the aggregate membership proof is equal to the power of the aggregate hash index of the current RSA accumulator value modulo the RSA accumulator modulus. Complete the membership confirmation of all legitimate requests through one RSA accumulator verification.

[0030] Furthermore, the private blockchain grants write and read permissions only to a trusted authority center, and stores information including the vehicle's real identity identifier, pseudonym, vehicle private key, and the encrypted mapping relationship between the three.

[0031] The public blockchain is jointly maintained by all legitimate nodes on the network. Read and write permissions are open to all legitimate nodes. The stored content includes vehicle pseudonyms, public keys, and the current RSA accumulator value.

[0032] The present invention has the following beneficial effects:

[0033] (1) To address the problem of low efficiency in secondary authentication, this invention introduces an RSA accumulator, which transforms identity membership verification into a single modular exponentiation operation. The verification end only needs to obtain the current RSA accumulator value and complete the modular exponentiation operation locally to confirm the vehicle membership. There is no need to traverse all identity states on the chain. The computational overhead is decoupled from the number of nodes, significantly reducing the latency of secondary authentication. This is suitable for the high-concurrency and low-latency communication requirements of vehicle networks.

[0034] (2) To address the difficulty in balancing anonymity and traceability, this invention uses pseudonyms to replace real identities for daily communication, and encrypts and stores the mapping relationship between real identity identifiers and pseudonyms in a private blockchain accessible only to trusted authoritative centers. While ensuring anonymous vehicle communication, the trusted authoritative center only queries the private blockchain based on the pseudonym of the malicious vehicle to complete conditional traceability when malicious behavior occurs, thus achieving a balance between anonymity and accountability.

[0035] (3) To address the issue of delayed identity revocation, this invention maintains member status by updating the RSA accumulator value. After the update, the old member certificate automatically becomes invalid, eliminating the need to distribute a certificate revocation list. Combining event-triggered revocation with periodic proactive updates, this invention ensures both immediate response capability in the event of an emergency or malicious incident and enhances forward security of the system by periodically refreshing the accumulator value.

[0036] (4) In response to the problem of single point of failure in traditional centralized authentication, this invention uses a public blockchain to store vehicle pseudonyms, public keys and current RSA accumulator values, which are jointly maintained by all legitimate nodes in the network, reducing the dependence on a single center and improving the robustness and anti-tampering ability of the system.

[0037] (5) For batch authentication scenarios, the present invention supports aggregated verification of multiple authentication requests, compressing multiple independent membership verifications into a single aggregate operation, further reducing batch authentication overhead and improving verification throughput. Attached Figure Description

[0038] Figure 1 This diagram illustrates the system interactions between vehicles, on-site base stations, trusted authority centers, private blockchains, and public blockchains.

[0039] Figure 2 This is a schematic diagram of the registration phase process of the present invention.

[0040] Figure 3 This is a schematic diagram of a single authentication stage process according to the present invention.

[0041] Figure 4 This is a schematic diagram of the aggregation authentication phase process of the present invention.

[0042] Figure 5 This is a schematic diagram of the event-triggered cancellation process of the present invention.

[0043] Figure 6 This is a schematic diagram of the periodic proactive update process of the present invention.

[0044] Figure 7 This diagram illustrates a comparison of the computational overhead of the present invention with that of different authentication schemes.

[0045] Figure 8 This is a comparison of the total cost of a single authentication as the number of nodes changes in a multi-node scenario.

[0046] Figure 9 This is a comparison of the total overhead of secondary authentication as the number of nodes changes in a multi-node scenario.

[0047] Figure 10 This is a comparison chart of the communication overhead of the present invention and other solutions. Detailed Implementation

[0048] The invention will now be further described with reference to the accompanying drawings.

[0049] This invention discloses a vehicle-to-everything (V2X) node authentication method based on blockchain and a cryptographic accumulator, applicable to vehicle-road cooperative communication scenarios for various V2X nodes, including intelligent connected vehicles, logistics vehicles, and emergency communication vehicles. The authentication system relied upon by this method primarily comprises three core entities: a Trusted Authority Center (TA), Roadside Units (RSUs), and vehicles, and is equipped with both public and private blockchain storage nodes. The interaction relationships between these entities are as follows: Figure 1 As shown, the solid lines represent the data interaction paths of each entity during normal authentication and communication. The interaction between the vehicle and the roadside unit can effectively resist illegal attacks such as eavesdropping and identity forgery. The trusted authority center, as the root of trust of the system, is responsible for system initialization, credential generation, and identity location in malicious vehicle tracing scenarios. The separation of functions and isolation of permissions of each entity form a layered and collaborative security authentication architecture.

[0050] This method is based on elliptic curve cryptography and an RSA accumulator to build a cryptographic system, selecting elliptic curve parameters. Where E is the equation of the elliptic curve. Let be a prime number of the finite field containing the elliptic curve. , is the base point of the elliptic curve. Base point of elliptic curve The rank, Modulus The set of non-zero integers; select two distinct large prime numbers. , Calculate the modulus of the RSA accumulator In the multiplication group modulo N A generator g is randomly selected as the base of the RSA accumulator, and all RSA accumulator-related operations are performed modulo N.

[0051] The system initializes and generates keys. The trusted authority center, acting as the root of trust for the entire authentication system, performs the following operations:

[0052] Calculate the initial accumulated value ; Generate its own key pair ,in For private key, The public key is selected. A secure one-way hash function H is chosen, the valid time range of the timestamp ΔT is set, and the time interval for the RSA accumulator to be actively updated periodically is determined. Finally, the trusted authority center writes all the above system public parameters into the public blockchain for all legitimate nodes on the network to access.

[0053] When a registration node first connects to the system, it needs to complete the registration process with the trusted authority center. The overall registration process is as follows: Figure 2 As shown. The vehicle sends a registration request to the trusted authority center. Upon receiving the request, the trusted authority center first generates a temporary authentication credential for the response. The trusted authority center then randomly selects an integer. As a registration random number, calculate the registration elliptic curve point R1 = r1·G on the elliptic curve, where G is the base point of the elliptic curve.

[0054] At the same time, the trusted authority center obtains the current timestamp TS and calculates the registration hash value. Subsequently, the Trusted Authority Center used its private key skTA to calculate the registered Schnorr signature value. Finally, the trusted authority sends the message {R1, θ1, TS} to the vehicle. Upon receiving the message, the vehicle first verifies the freshness of the timestamp TS, ensuring that its difference from the current system time is within a preset valid time range ΔT, and that the timestamp has not been reused. Then, the vehicle calculates the hash value. And based on the operational relationships of points on an elliptic curve, verify the equation. Is the authentication valid? If valid, it proves that the identity of the trusted authority center is genuine and the message has not been tampered with, and the vehicle has completed the authentication of the trusted authority center.

[0055] After successful verification, the vehicle generates its own long-term key pair. The vehicle randomly selects a secret value. Use it as the private key, and calculate the corresponding public key pk. j =sk j ·G.

[0056] At the same time, the vehicle constructs its Real Identity Identifier (RID). j To ensure secure transmission, the vehicle employs an elliptic curve integrated encryption scheme for (sk)j RID j Encryption is performed by first generating a temporary key pair (r, R) and then calculating the shared key K = r·pk. TA Then calculate the symmetric encryption key key=H(K); use this key pair (sk j RID j The authentication encryption is performed to obtain the ciphertext; the temporary public key R and the above ciphertext are concatenated to form a new ciphertext C. j The vehicle will C j It is sent to a trusted authority center. After receiving it, the trusted authority center uses its own private key sk TA Calculate the shared key ， ,because The trusted and authoritative center calculates the same And decrypt and recover (sk) j RID j ).

[0057] Upon receiving the above message, the trusted authority center performs the registration data generation and storage operations. First, the trusted authority center generates a pseudonym for the vehicle. ,in This indicates a bitwise XOR operation; the pseudonym will replace the real identity in subsequent communications to protect vehicle privacy. Next, the trusted authority center will use the current system's global accumulator value... Calculate the hash value of the pseudonym Then, a member certificate is generated for the vehicle. ， This allows the verifier to confirm that the vehicle belongs to a legitimate member through a single modular exponentiation operation.

[0058] The trusted and authoritative center will identify the true identity of the vehicle. With kana Mapping relationship, vehicle private key The master key is stored in a private blockchain using symmetric encryption (such as AES). This private blockchain can only be queried by a trusted authority when necessary, enabling conditional traceability. Simultaneously, the trusted authority will publicly disclose its public key. With kana The identity credentials are stored in a public blockchain and can be read in real time by all verification nodes. Finally, the trusted authority center will... The information is sent to the registered vehicle, which then saves it in its local anti-tamper module, thus completing the registration process.

[0059] Any node within the system can act as either a sender or a authenticator. The sender (e.g., a vehicle) performs the following operations to initiate an authentication; the process for a single authentication phase is as follows: Figure 3 As shown.

[0060] The vehicle is randomly selected for authentication. Calculate temporary public key points Subsequently, the vehicle obtains the current timestamp TS and constructs an authentication hash value. This hash binds the pseudonym, temporary public key, membership proof, and timestamp together. Next, the vehicle uses its private key to calculate the Schnorr signature value. Ultimately, the vehicle broadcast authentication tuple... Upon receiving a single authentication request, the verification end (e.g., a roadside unit) executes the following verification process.

[0061] First, the freshness of the timestamp TS is verified by checking whether the difference between the timestamp and the current system time is within a preset valid time range ΔT, and whether the timestamp has been reused to prevent replay attacks. Then, the roadside unit queries the current accumulator value from the public blockchain. ,pseudonym and its public key Next, we will perform two-factor authentication:

[0062] The first layer is Schnorr signature verification, followed by roadside unit calculation. And verify the equation. Whether this equation holds true depends on the elliptic curve discrete logarithm problem. If it holds, it proves that the sender possesses the public key pk. j The corresponding private key sk j Furthermore, the message content was not altered.

[0063] The second layer is RSA accumulator membership verification, where the roadside unit calculates the hash value of the pseudonym. And verify the equation. Whether the equation holds true is determined by the strong RSA assumption of the RSA accumulator, which confirms that the vehicle identity corresponding to the pseudonym has not been revoked. If both verifications pass, authentication is successful, the roadside unit accepts the node's identity, and allows it to access the network or exchange data; if either verification fails, authentication fails, and the roadside unit rejects the node's access.

[0064] When a roadside unit receives authentication requests from multiple vehicles simultaneously, aggregated verification can be performed to improve processing efficiency. The process of the aggregated authentication phase is as follows: Figure 4 As shown. When the roadside unit simultaneously receives authentication requests from m vehicles. First, each request is individually verified for signature validity. Only requests that pass signature verification are allowed to enter the aggregation queue. Assume a total of m requests pass signature verification. Then, the roadside unit performs an aggregation operation on these requests, calculating the hash value of each valid pseudonym. Next, calculate the aggregate hash index. Simultaneously calculate aggregate membership proofs This aggregation step compresses m independent membership validation conditions into a linear relationship.

[0065] Finally, the roadside unit utilizes the aggregated value H and the current global accumulator value obtained from the blockchain. Verify the equation Does the equation hold true? If it does, it means that all m vehicles are currently legitimate members that have not been revoked. Through aggregation verification, the roadside unit compresses the independent verification that originally required m modular exponentiation operations into one aggregation operation and one modular exponentiation operation, significantly reducing computational overhead.

[0066] The system maintains member status by updating accumulator values. The update operation is triggered by a trusted authority center and includes two modes: event-triggered reversal and periodic proactive update.

[0067] The process of event-triggered undo is as follows: Figure 5 As shown. When the number of valid reports against a vehicle reaches a preset threshold, the Trusted Authority Center determines that the vehicle is a malicious node and triggers the event revocation process; when the Trusted Authority Center receives a legitimate vehicle's voluntary withdrawal request, it directly triggers the event revocation process without determining that the vehicle is a malicious node. In both of these scenarios, the Trusted Authority Center performs the following operations:

[0068] The trusted authority center first calculates the hash value of the malicious pseudonym. Then calculate the new accumulator value. The credible and authoritative center will The data is published to a public blockchain, overwriting the old value. Subsequently, a trusted authority center regenerates membership certificates for all legitimate vehicles that have not been revoked. And distribute them to the corresponding vehicles.

[0069] The process of periodic proactive updates is as follows: Figure 6 As shown, to enhance the system's forward security and periodically refresh credentials, the system sets a timer to automatically trigger updates periodically at preset time intervals.

[0070] The trusted authority center generates two random numbers. Calculate the random hash factor This hash factor is not tied to any actual vehicle; its sole purpose is to introduce a random factor that replaces the old accumulator value. The trusted authority then calculates the new accumulator value. This renders the proofs of all original members invalid. The Trusted Authority Center will... The data is published to a public blockchain, overwriting the old value. Subsequently, a trusted authority center regenerates membership certificates for all legitimate vehicles that have not been revoked. The data is then distributed to the corresponding vehicles. These two driving mechanisms work together to ensure both immediate response capabilities in the event of an emergency or malicious incident and to enhance the system's long-term security through periodic updates.

[0071] When a vehicle is identified as a malicious node, the Trusted Authority Center is responsible for performing privacy-protected tracing. The Trusted Authority Center obtains the alias of the malicious vehicle from the report message or system logs. Because the private blockchain stores an encrypted mapping between pseudonyms and real identities, the trusted authority uses its own master key to decrypt this mapping table and retrieve the corresponding information. Corresponding real identity identifier This allows for the identification and liability determination of malicious vehicles. Throughout the tracing process, the trusted authority center only accesses the mapping entries of malicious nodes, without involving the privacy information of any legitimate vehicles, thus achieving the privacy protection goal of "accurate tracing only when necessary."

[0072] Vehicles use different authentication random numbers to generate different temporary public key points in different authentication sessions, making it impossible for attackers to associate multiple authentication requests with the same vehicle, thus enhancing the anonymity of vehicle communication. When a vehicle moves from the coverage area of ​​one roadside unit to the coverage area of ​​another, the target roadside unit synchronizes the current RSA accumulator value from the public blockchain. The vehicle only needs to resend the authentication request message to complete cross-domain re-authentication, without having to re-register with a trusted authority.

[0073] To verify the feasibility and applicability of the proposed efficient identity authentication method for vehicle network nodes based on blockchain and cryptographic accumulators, a theoretical performance analysis and comparative evaluation were conducted. The analysis mainly focuses on computational overhead and compares the method with other existing solutions under the same assumptions.

[0074] like Figure 7 The computational overhead of this method compared to different schemes in a single-node scenario is shown. The single-authentication overhead of this invention is 3.4ms, and the secondary authentication overhead is 1.2ms, both significantly lower than the corresponding values ​​of the compared schemes, representing reductions of approximately 53% and 83%, respectively. Furthermore, the secondary authentication overhead of this invention is approximately 65% ​​lower than the single-authentication overhead. Figure 8 The paper presents a comparison of the total overhead of a single authentication operation as the number of nodes changes in a multi-node scenario. When the number of nodes increases to 500, the total overhead of this invention for a single authentication operation is approximately 1401.8 ms, while the overhead of other solutions is as high as 4600 ms, 3600 ms, and 5150 ms, respectively. The computational overhead of this invention for a single authentication operation increases the most gradually, demonstrating a significant efficiency advantage in scenarios with large-scale concurrent node access. Figure 9The paper presents a comparison of the total overhead of secondary authentication in a multi-node scenario as the number of nodes changes. When the number of nodes increases to 500, the total overhead of secondary authentication in this invention is approximately 301.8 ms, while the overhead of other solutions is as high as 4600 ms, 3600 ms, and 5150 ms, respectively. Thanks to the aggregation verification mechanism, the overhead growth of this invention is extremely gradual, far superior to existing solutions. Figure 10 To compare the communication overhead of this invention with other solutions, the additional information transmitted during the authentication process of this invention is 40 bytes, while the communication overhead of the comparative solutions is 64 bytes, 44 bytes and 60 bytes respectively. This invention effectively reduces the transmission load while ensuring the integrity of the authentication information, and is suitable for the bandwidth-constrained vehicle network communication environment.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A method for authenticating the identity of vehicle network nodes based on blockchain and cryptographic accumulator, characterized in that: Includes the following steps: S1: The trusted authority center generates RSA accumulator parameters, Schnorr signature parameters, and the key pair of the trusted authority center, calculates the initial RSA accumulator value, and writes the system public parameters into the public blockchain; S2: The vehicle initiates a registration request to the Trusted Authority Center. The Trusted Authority Center sends a temporary credential to the vehicle. After verifying the identity of the Trusted Authority Center, the vehicle generates its own key pair and real identity identifier and sends them to the Trusted Authority Center. The trusted authority center generates a pseudonym for the vehicle and generates a membership certificate for the vehicle based on the current RSA accumulator value. The mapping relationship between the real identity identifier and the pseudonym is stored in the private blockchain, and the mapping relationship between the pseudonym and the vehicle's public key is stored in the public blockchain. The pseudonym and membership certificate are then sent to the vehicle. S3: The vehicle generates a temporary public key point, constructs an authentication request message containing a pseudonym, temporary public key point, membership proof, timestamp, and a signature value generated based on a Schnorr signature, and broadcasts the authentication request message. The roadside unit verifies the freshness of the timestamp, queries the vehicle's public key and the current RSA accumulator value from the public blockchain, and performs dual verification. The first layer of verification verifies the signature value to confirm the authenticity of the vehicle's identity. The second layer of verification verifies the membership certificate corresponding to the current RSA accumulator value to confirm that the vehicle's identity has not been revoked. If both verifications pass, the vehicle is allowed to access the network. If either verification fails, the vehicle is denied access. S4: When the Trusted Authority Center determines that a vehicle is a malicious node, it queries the corresponding real identity identifier from the private blockchain based on the alias of the malicious vehicle to complete the tracing; when the Trusted Authority Center determines that a vehicle is a malicious node or receives a request for a legitimate vehicle to actively withdraw, it updates the RSA accumulator value and publishes it to the public blockchain, invalidating all old membership proofs, and regenerating membership proofs based on the updated RSA accumulator value for legitimate vehicles that have not been revoked.

2. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S1, the system common parameters include the RSA accumulator modulus, the elliptic curve parameters corresponding to the Schnorr signature, the secure one-way hash function, the valid time range of the timestamp, and the time interval for the periodic active update of the RSA accumulator.

3. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S2, the process of generating and verifying temporary credentials is as follows: The trusted authority selects a registration random number and calculates the registration elliptic curve point. It then combines the registration elliptic curve point, its own public key, and the current timestamp to calculate the registration hash value. Using its own private key, it generates a registration Schnorr signature value and sends a temporary credential containing the registration elliptic curve point, the registration Schnorr signature value, and the timestamp to the vehicle. The vehicle verifies the validity of the registration Schnorr signature value to confirm the identity of the trusted authority.

4. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S2, the pseudonym is generated by XORing the hash value of the real identity identifier and the vehicle private key; the membership proof is calculated based on the hash value of the current RSA accumulator value and the pseudonym, and all RSA accumulator-related operations are performed under the RSA accumulator modulus.

5. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S3, the temporary public key point is generated by the vehicle selecting an authentication random number and calculating the elliptic curve base point based on the Schnorr signature; the signature value generated based on the Schnorr signature is calculated by the authentication random number, the authentication hash value and the vehicle's private key. The authentication hash value is generated by hashing the pseudonym, the temporary public key point, the membership proof and the timestamp; and the vehicle uses different random numbers to generate different temporary public key points in different authentication sessions.

6. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 5, characterized in that: In S3, the first layer of verification includes the verification equation: the product of the signature value and the elliptic curve base point is equal to the sum of the product of the temporary public key point, the authentication hash value, and the vehicle public key, wherein the authentication hash value is generated by hashing the pseudonym, the temporary public key point, the membership proof, and the timestamp. The second layer of verification includes the verification equation: the power of the pseudonym hash value of the member proof modulo the RSA accumulator modulus equals the current RSA accumulator value.

7. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S3, verifying the freshness of the timestamp includes: determining whether the difference between the timestamp and the current system time of the roadside unit is within a preset valid time range, and whether the timestamp has not been reused, in order to resist replay attacks.

8. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S4, updating the RSA accumulator value includes an event-triggered revocation mode: when the trusted authority determines that a vehicle is a malicious node or receives an active revocation request from a legitimate vehicle, the hash value of the pseudonym of the revoked vehicle is calculated, a new RSA accumulator value is calculated based on the old RSA accumulator value and the hash value, and published to the public blockchain. Membership proofs are regenerated for legitimate vehicles that have not been revoked, where the regenerated membership proof is equal to the multiplicative inverse power of the hash value of each legitimate vehicle's pseudonym in the new RSA accumulator value modulo the RSA accumulator modulo. The criterion for determining a vehicle as a malicious node is: within a preset time range, the number of times the pseudonym corresponding to the vehicle is reported by different legitimate nodes reaches a preset threshold.

9. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: In S4, updating the RSA accumulator value also includes a periodic proactive update mode: the trusted authority center generates a random hash factor that is not bound to any vehicle at preset time intervals, calculates a new RSA accumulator value based on the old RSA accumulator value and the random hash factor, and publishes it to the public blockchain, invalidating all old membership proofs, and regenerating membership proofs for legitimate vehicles that have not been revoked, wherein the regenerated membership proof is equal to the multiplication inverse of the pseudonym hash value of each legitimate vehicle in the new RSA accumulator value modulo the RSA accumulator modulo.

10. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: S3 also includes a multi-node aggregation verification step: When the roadside unit receives authentication requests from multiple vehicles at the same time, it first performs Schnorr signature verification on each request independently to filter out the legitimate requests. Calculate the aggregate hash index and aggregate membership proof for each legitimate request corresponding to the pseudonym. Verify whether the aggregate membership proof is equal to the power of the aggregate hash index of the current RSA accumulator value modulo the RSA accumulator modulus. Complete the membership confirmation of all legitimate requests through one RSA accumulator verification.

11. The vehicle network node identity authentication method based on blockchain and cryptographic accumulator as described in claim 1, characterized in that: The private blockchain grants write and read permissions only to a trusted authority center, and stores information including the vehicle's real identity identifier, pseudonym, vehicle private key, and the encrypted mapping relationship between the three. The public blockchain is jointly maintained by all legitimate nodes on the network. Read and write permissions are open to all legitimate nodes. The stored content includes vehicle pseudonyms, public keys, and the current RSA accumulator value.

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