Blockchain-assisted conditional privacy protection method and system based on ring signcryption

Abstract

The present invention discloses a blockchain-assisted conditional privacy protection method and system based on ring signcryption, belonging to the field of blockchain technology. The method comprises: protecting the vehicle network by embedding a first blockchain and a second blockchain in a vehicle network consisting of a trusted authority (TA), a roadside unit (RSU), and vehicles equipped with an OBU. The first blockchain is used to store the identity and public key information of the vehicle user. When a vehicle engages in malicious behavior, the TA removes the malicious vehicle from the first blockchain and stores it in the second blockchain. The present invention can be used to maintain the security and data integrity of vehicle communications through blockchain. By storing traffic data on the blockchain, it can ensure that the data is not tampered with or forged, helping to prevent the spread of false information and increase the credibility of vehicle communications, thereby reducing the threat of false and malicious vehicles.

Description

Technical Field

[0001] The present invention relates to the field of blockchain technology, and in particular to a blockchain-assisted conditional privacy protection method and system based on ring signcryption. Background Art

[0002] In the vehicular ad hoc network (VANET) model, the following three main components or entities are usually involved: Trust Authority (TA), Roadside Unit (RSU) and vehicles equipped with OBU, each of which has different functions and roles.

[0003] The Trust Authority (TA) is the trust management entity in the vehicle network, responsible for ensuring security and trust within the network. Its primary functions include establishing trust, managing certificates and keys, developing security policies, and monitoring for malicious activity within the network. The TA typically maintains authentication information and trust levels for vehicles and RSUs within the network and assists in resolving security issues.

[0004] RSU: RSU is a network device located on the roadside or other dedicated locations. It is a device placed next to the road and is usually deployed by traffic management agencies. They have the following main functions: (1) Providing communication relay: RSU can be used as a communication relay station to help establish communication between vehicles or between vehicles and trusted authorities. (2) Providing network connectivity: RSU can connect vehicles to the Internet, enabling vehicles to access Internet services and cloud resources. (3) Traffic management: RSU can collect traffic data, monitor road conditions, provide traffic information and manage traffic flow.

[0005] Vehicles: Vehicles are mobile nodes in vehicular networks and have the following main functions: (1) Communication: Vehicles can communicate with other vehicles and RSUs through vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. (2) Safety warnings: Vehicles can send safety warnings, such as information about traffic accidents or road obstacles, to other vehicles to improve traffic safety. (3) Navigation and route planning: Vehicles can receive navigation information and traffic congestion information and plan the best route based on them. (4) Data sharing: Vehicles can share traffic data, road condition information, weather information, etc. to improve traffic management and road safety.

[0006] However, in existing in-vehicle networks, there is no guarantee that data will not be tampered with or forged during transmission, and the spread of false information cannot be suppressed, which makes the in-vehicle network risky during operation. Summary of the Invention

[0007] In order to solve the above problems, the purpose of the present invention is to provide a blockchain-assisted conditional privacy protection technology based on ring signcryption, which aims to ensure that data is not tampered with or forged and prevent the spread of false information.

[0008] To achieve the above technical objectives, this application provides a blockchain-assisted conditional privacy protection method based on ring signcryption, which includes the following steps:

[0009] The in-vehicle network is protected by embedding the first blockchain and the second blockchain in the in-vehicle network consisting of a trusted authority TA, a roadside unit RSU and vehicles equipped with OBU. The first blockchain is used to store the identity and public key information of the vehicle user. When the vehicle commits a malicious behavior, the TA revokes the malicious vehicle from the first blockchain and stores it in the second blockchain.

[0010] Preferably, in the process of protecting the vehicle network by building a blockchain system, TA selects two large prime numbers p, q>2 h and a group G of order q, where P is a generator of the group G;

[0011] TA randomly selects a number Among them, x is the master private key mtk, and then calculate P Pub = xP as the master public key mpk; calculate T Pub =kP as the system master tracking key mtk, H2: G×G→{0, 1} l , Among them, l represents the bit length of the message;

[0012] TA forwarding system parameters params = {p, q, G, P, P Pub , T Pub , H1, H2, H3, H4} to the vehicle equipped with OBU to complete the system establishment.

[0013] Preferably, after completing the system establishment process, the vehicle ID is obtained based on the identity encryption algorithm i Public key and private key Then store the public and private keys to the vehicle ID i The tamper-proof device TPD, at the same time TA will Insert it into the first blockchain responsible for storing vehicle identity to complete key generation.

[0014] Preferably, after completing the key generation process, the vehicle ID s A ring L = {ID1, ID2, ..., ID n}, and obtain the identity information and corresponding public key of the vehicle in the ring, where ID s Set in ring L;

[0015] Based on vehicle ID s , randomly select two values And calculate X1=x1P, X2=x2P;

[0016] Vehicle ID s The following calculation is performed, where I is the tracking flag of message m:

[0017]

[0018] Based on vehicle ID s , randomly selected Where i = 1, 2, ..., s-1, s+1, ..., n, and the following calculation is performed:

[0019]

[0020] Then introduce a timestamp TS into the ciphertext σ, vehicle ID s The complete ciphertext σ={C,I,L,X1,X2,TS,{r1,r2,...,r n},λ} is sent to the receiving vehicle ID r , complete the ring signcryption operation.

[0021] Preferably, after completing the ring signcryption operation, the vehicle ID is controlled r , by checking the condition |TS-TS cur |≤ΔTS, confirm the validity of timestamp c6, where TS cur Indicates the current time, ΔTS indicates the maximum valid time interval;

[0022] If valid, the first blockchain and the second blockchain can be searched to obtain the vehicle's identity ID r and public key Ensure that the received vehicle identity information exists in the first blockchain, but not in the second blockchain, indicating that the vehicle is currently legal and the public key registered with TA has not been revoked. Continue to operate on the received ciphertext;

[0023] If not, vehicle ID r The message is discarded and a symbol ⊥ is returned; completing the verification process.

[0024] Preferably, after completing the verification process, the vehicle ID r Perform the following calculations:

[0025]

[0026] After completing the above calculations, check the equation: If not, control the vehicle ID r Discard the message; otherwise, confirm that the message is correct and use the vehicle ID r The private key of the message m is calculated as follows: Complete the decryption process.

[0027] Preferably, during the verification process, the vehicle ID r , check the validity of TS in each message, if it exceeds the valid range, reject these messages, otherwise proceed to the next step of calculation:

[0028] By vehicle ID r , select a random vector α={a1,a2,...,a t}, at this time ID r Check the equation:

[0029]

[0030] If not, control vehicle ID r All messages will be discarded, otherwise the decryption operation will continue to complete the batch verification.

[0031] Preferably, after the decryption process is completed, the ring L = {ID1, ID2, ..., ID n}, verify the following equation: H3(C, X2)H1(ID i )P Pub =k -1 I-X2; After solving the equation, the identity of the malicious vehicle is obtained and it is punished. TA will obtain the identity information ID of the malicious vehicle. i Revoke it from the first blockchain and store it in the first blockchain to complete the malicious vehicle tracking.

[0032] Preferably, in the process of protecting the in-vehicle network, based on the first blockchain and the second blockchain, the in-vehicle network is protected through system establishment - key generation - ring signcryption - verification and decryption - batch verification - malicious vehicle tracking.

[0033] The present invention discloses a blockchain-assisted conditional privacy protection system based on ring signcryption, which is used to implement a blockchain-assisted conditional privacy protection method based on ring signcryption, including:

[0034] Data collection module, used to collect malicious messages;

[0035] Data sending module, used to send malicious messages to TA and obtain the identity of the malicious vehicle;

[0036] A revocation module is used to revoke the malicious vehicle from the first blockchain and store it in the second blockchain based on the identity of the malicious vehicle.

[0037] The present invention discloses the following technical effects:

[0038] This invention uses blockchain to maintain the security and data integrity of vehicle communications. By storing traffic data on the blockchain, it can be ensured to be tamper-proof or forged, helping to prevent the spread of false information and increase the credibility of vehicle communications. Blockchain can also be used for vehicle authentication and access control. Each vehicle can have a digital identity, and the blockchain records the access rights granted to these identities. This helps vehicles identify other vehicles and verify their legitimacy, thereby reducing the threat of fraudulent and malicious vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 This is a schematic diagram of the in-vehicle network model with blockchain described in the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0042] like Figure 1 As shown, the present invention provides an identity-based ring signcryption conditional privacy protection scheme, including the following contents:

[0043] System Initialization: TA inputs security system parameters for initialization, selects the system master private key and system master tracking key, and calculates the corresponding public key. TA passes the output public parameters to all communication entities in the system.

[0044] Key Generation: Given the vehicle identity and system public parameters, TA generates the vehicle's public key and private key and stores them in the vehicle's tamper-proof device TPD.

[0045] Ring Signcryption: To achieve anonymity, confidentiality and traceability, the sender's vehicle ID s Deliver message m to the recipient vehicle ID r When the sender first generates a ring L consisting of n vehicles including it in a self-organized or RSU-organized manner, L = {ID1, ID2, ..., ID n}, takes public parameters,m,L, sender’s private key and receiver’s public key as input, and outputs a ciphertext σ obtained by ring signcryption.

[0046] Unsigncryption: Recipient vehicle ID r After receiving the ciphertext σ, first verify its validity. If σ is confirmed to be a valid ring signcryption after verification, use your own private key to decrypt the signcryption and restore the original message m; otherwise, the vehicle ID r Returns a symbol ⊥.

[0047] Malicious Vehicle Tracking: Given public parameters, L and σ, TA takes the master tracking key, L and σ as input and returns the identity information of the malicious vehicle.

[0048] Specifically, if Figure 1 As shown in the figure, the present invention proposes a conditional privacy security solution, which is an identity-based ring signcryption technology using elliptic curves, and adds a vehicle tracking flag to it to track the true identity of malicious vehicles. The solution consists of the following six parts: 1. System establishment; 2. Key generation; 3. Ring signcryption; 4. Verification and decryption; 5. Batch verification; 6. Malicious vehicle tracking.

[0049] 1. System establishment (1 h )→(params, msk, mtk): Input security parameter h, TA selects two large prime numbers p, q>2 h and a group G of order q, where P is a generator of the group G. TA randomly selects a number Where x is the master private key mtk, then calculate P Pub = xP as the master public key mpk; calculate T Pub =kP as the system master tracking key mtk, H2:G×G→{0,1}l, The bit length of the message is defined by l. Then TA forwards the system parameters params = {p, q, G, P, P Pub , T Pub , H1, H2, H3, H4} to vehicles equipped with 0BU.

[0050] 2. Key Generation Vehicle ID i Before entering the vehicle network, you must first register with the TA. When registering, you must provide personal information such as identity information to the TA, which will then be stored in the database and the vehicle ID will be calculated using an identity-based encryption algorithm. i Public key and private key This information is then stored in the vehicle ID i The tamper-proof device TPD, at the same time TA will Inserted into the blockchain BC1 responsible for storing vehicle identity.

[0051] 3. Signcryption Sender ID s After receiving the message, it will be signed and encrypted. The specific steps are as follows:

[0052] Vehicle ID s A ring L = {ID1, ID2, ..., ID n}, and obtain the identity information and corresponding public key of the vehicle in the ring, where ID s Must be contained in the ring L.

[0053] Vehicle ID s Randomly select two values And calculate X1=x1P, X2=x2P.

[0054] Vehicle ID s The following calculation is performed, where I is the tracking flag of message m:

[0055]

[0056] Vehicle ID s Random selection Where i = 1, 2, ..., s-1, s+1, ..., n, and the following calculation is performed:

[0057]

[0058] Then introduce a timestamp TS into the ciphertext σ, vehicle ID s The complete ciphertext σ={C,I,L,X1,X2,TS,{r1,r2,...,r n},λ} is sent to the receiving vehicle ID r middle.

[0059] 4. Verify (params, σ, L) → {0, 1} and decrypt Vehicle ID r After receiving the ciphertext σ = {c1, c2, c3, c4, c5, c6, c7, c8}, perform the following calculation:

[0060] First, the vehicle ID r By checking the conditions | TS-TS cur |≤ΔTS to confirm the validity of timestamp c6, where TS cur Indicates the current time, and ΔTS indicates the maximum valid time interval. If valid, the BC1 and BC2 blockchains can be searched to obtain the vehicle's ID. r and public key Make sure the received vehicle identity information exists in BC1, not BC2, which means the vehicle is currently legal and the public key registered by TA has not been revoked, and you can continue to operate on the received ciphertext; if not, the vehicle ID r The message is discarded and a symbol ⊥ is returned.

[0061] Then, the vehicle ID r Perform the following calculations:

[0062]

[0063] After completing the above calculations, the vehicle ID r Need to check the equation: If not, ID r The message will be discarded; otherwise, ID r You can confirm that the message is correct. Then ID r The message m can be recovered by using the following calculation using your own private key:

[0064]

[0065] At this time, m' is indeed from ID s The message sent.

[0066] 5. Batch verification: When receiving multiple messages from a vehicle, a batch verification algorithm can be executed instead of verifying the validity of each message individually, which further improves the practicality of the algorithm in reality. Assume that the messages received by the receiving vehicle are σ1, σ2, ..., σ n , receive vehicle ID r The following calculations are performed to implement batch verification:

[0067] Vehicle ID rCheck the validity of TS in each message. If it exceeds the valid range, the vehicle ID r These messages will be rejected and the next calculation will be carried out instead.

[0068] Vehicle ID r Select a random vector α={a1,a2,...,a t}, at this time ID r Check the equation:

[0069]

[0070] If not, vehicle ID r All messages are discarded, otherwise the decryption operation continues.

[0071] 6. Malicious vehicle tracking: TA can also actively monitor the entire communication network. If the message is sent by a malicious vehicle, the receiving vehicle can send the malicious message to TA if the verification fails, exposing the identity of the malicious vehicle and revoking it. TA finds the ring L = {ID1, ID2, ..., D n}, we only need to verify the following equation: H3(C, X2)H1(ID i )P Pub =k -1 I-X2.

[0072] After solving the equation, the identity of the malicious vehicle can be obtained and punished. TA will obtain the identity information ID of the malicious vehicle i Revoke from BC1 and store it in blockchain BC2.

[0073] The present invention introduces Merkle trees with different structures as links between two blockchains BC1 and BC2. In the vehicle network, the system is mainly used to store different data and classify vehicles. Two blockchain structures are used. BC1 is used to store the identity and public key information of vehicle users. When a vehicle commits malicious behavior, it will be revoked from BC1 and stored in BC2, which can help the vehicle identify other vehicles and verify their legitimacy, thereby reducing the threat of false and malicious vehicles.

[0074] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0075] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0076] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A blockchain-assisted conditional privacy protection method based on ring signcryption, characterized in that: The following steps are involved: By embedding a first blockchain and a second blockchain in an in-vehicle network consisting of a trusted authority (TA), a roadside unit (RSU), and vehicles equipped with OBUs, the in-vehicle network is protected. The first blockchain is used to store the identity and public key information of the vehicle user. When a vehicle engages in malicious behavior, the TA revokes the malicious vehicle from the first blockchain and stores it in the second blockchain. In the process of protecting the in-vehicle network, based on the first blockchain and the second blockchain, the in-vehicle network is protected through system establishment - key generation - ring signcryption - verification and decryption - batch verification - malicious vehicle tracking; In the process of protecting the vehicle network by building a blockchain system, TA selects two large prime numbers p, q>2 h and a group G of order q, where P is the generator of group G and h is the security parameter; TA randomly selected Among them, x is the master private key mtk, and then calculate P Pub = xP as the master public key mpk; calculate T Pub =kP as the system master tracking key mtk, H2: G×G→{0, 1} l , Where l represents the bit length of the message; TA forwarding system parameters params = {p, q, G, P, P Pub , T Pub , H1, H2, H3, H4} to the vehicle equipped with OBU to complete the system establishment; After completing the system establishment process, the vehicle ID is obtained based on the identity encryption algorithm i Public key and private key Then store the public and private keys to the vehicle ID i The tamper-proof device TPD, at the same time TA will Inserted into the first blockchain responsible for storing vehicle identity to complete key generation; After completing the key generation process, the vehicle ID s A ring L = {ID1, ID2, ..., ID n }, and obtain the identity information and corresponding public key of the vehicle in the ring, where ID s Set in ring L; Based on vehicle ID s , randomly select two values And calculate X1=x1P, X2=x2P; Vehicle ID s The following calculation is performed, where I is the tracking flag of message m: Based on vehicle ID s , randomly selected Where i = 1, 2, ..., s-1, s+1, ..., n, and the following calculation is performed: Then introduce a timestamp TS into the ciphertext σ, vehicle ID s The complete ciphertext σ={C,I,L,X1,X2,TS,{r1,r2,...,r n },λ} is sent to the receiving vehicle ID r , complete the ring signcryption operation.

2. The blockchain-assisted conditional privacy protection method based on ring signcryption according to claim 1 is characterized by: After completing the ring signcryption process, control the vehicle ID r , by checking the condition |TS-TS cur |≤ΔTS, confirm the validity of timestamp c6, where TS cur Indicates the current time, ΔTS indicates the maximum valid time interval; If valid, the first blockchain and the second blockchain can be searched to obtain the vehicle's identity ID r and public key Ensure that the received vehicle identity information exists in the first blockchain, but not in the second blockchain, indicating that the vehicle is currently legal and the public key registered with TA has not been revoked. Continue to operate on the received ciphertext; If invalid, vehicle ID r The message is discarded and a symbol ⊥ is returned; completing the verification process.

3. The blockchain-assisted conditional privacy protection method based on ring signcryption according to claim 2 is characterized in that: After completing the verification process, control the vehicle ID r Perform the following calculations: After completing the above calculations, check the equation: If not, control the vehicle ID r Discard the message; otherwise, confirm that the message is correct and use the vehicle ID r The private key of the message m is calculated as follows: Complete the decryption process.

4. The blockchain-assisted conditional privacy protection method based on ring signcryption according to claim 3 is characterized by: After completing the verification process, pass the vehicle ID r , check the validity of TS in each message, if it exceeds the valid range, reject these messages, otherwise proceed to the next step of calculation: By vehicle ID r , select a random vector α={a1,a2,...,a t }, at this time ID r Check the equation: If invalid, control vehicle ID r All messages will be discarded, otherwise the decryption operation will continue to complete the batch verification.

5. The blockchain-assisted conditional privacy protection method based on ring signcryption according to claim 4 is characterized in that: After the decryption process is completed, the ring L = {ID1, ID2, ..., ID n }, verify the following equation: H3(C, X2)H1(ID i )P Pub =k -1 I-X2; After solving the equation, the identity of the malicious vehicle is obtained and it is punished. TA will obtain the identity information ID of the malicious vehicle. i Revoking it from the first blockchain and storing it in the second blockchain completes the malicious vehicle tracking.

6. Blockchain-assisted conditional privacy protection system based on ring signcryption, characterized by: The method for implementing the blockchain-assisted conditional privacy protection method based on ring signcryption as claimed in claim 1 comprises: Data collection module, used to collect malicious messages; A data sending module, used to send the malicious message to the TA to obtain the identity of the malicious vehicle; A revocation module is used to revoke the malicious vehicle from the first blockchain and store it in the second blockchain based on the identity of the malicious vehicle.

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