A signcryption method with dynamic key update function for V2G scenario

Abstract

The application relates to a signing and encrypting method with a dynamic key updating function for a V2G scene, which comprises the following steps: a trusted authority (TA) and a key generation center initialize their secret values; after an electric vehicle accesses a charging interface, a pseudonym set required for communication is dynamically and autonomously generated according to time change and a random value; when the electric vehicle accesses a charging column of a charging station, registration is completed to the TA; the TA allocates and issues a domain key to all entities; the key generation center generates a partial private key for the registered electric vehicle based on the pseudonym of the electric vehicle; a complete public and private key pair is generated; the domain key is dynamically updated in response to the electric vehicle joining or exiting; after the entity receives the domain key broadcast by the TA, the domain key is restored through the Chinese remainder theorem; the signing and encrypting method encrypts information, calculates a hash value and performs signature processing based on the domain key and a time stamp, and constructs a signing and encrypting text; the verifying and decrypting method receives the signing and encrypting text, and verifies the signature validity by calculating a hash value based on the public key of the signing and encrypting method and the domain key.

Description

Technical Field

[0001] This invention relates to the field of network security technology, and in particular to a signature method with dynamic key update function for V2G scenarios. Background Technology

[0002] With the rapid development of new energy technologies, electric vehicles have become a global focus and are seen as an important solution to environmental and energy problems. Vehicle-to-grid (V2G) technology refers to the technology of electric vehicles supplying electricity to the grid. Its core idea is to utilize the energy storage capacity of electric vehicles as a buffer between the grid and renewable energy sources. V2G technology is receiving widespread attention because it can significantly alleviate grid inefficiencies and the volatility of renewable energy sources, while also generating revenue for electric vehicle users.

[0003] However, current research has not considered the issues of identity authentication and key distribution in V2G scenarios, such as multiple vehicles frequently entering and exiting charging stations. Therefore, how to efficiently authenticate frequently entering and exiting users on infrastructure with limited computing resources is an urgent technical problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a signature method with dynamic key update function for V2G scenarios, so as to solve or partially solve the problems of complex identity authentication and key distribution and high resource consumption in infrastructure scenarios such as multiple vehicles frequently entering and exiting charging stations in V2G scenarios.

[0005] The objective of this invention can be achieved through the following technical solutions: This invention provides a signature method with dynamic key update function for V2G scenarios, comprising the following steps: Trusted authoritative institutions and key generation centers initialize their own secret values ​​and public parameters; After the electric vehicle is connected to the charging interface, the electric vehicle dynamically and autonomously generates the set of pseudo-names required for communication based on time changes and random values. When an electric vehicle connects to a charging station's charging pile, it completes registration with the aforementioned trusted authority. The trusted authority assigns and distributes domain keys to all entities; The key generation center generates partial private keys for registered electric vehicles based on the pseudonyms of the electric vehicles. After receiving the partial private key, the electric vehicle generates a complete public-private key pair; The domain key is dynamically updated in response to the joining or leaving of an electric vehicle. After receiving the domain key broadcast by a trusted authority, the entity recovers the domain key using the Chinese Remainder Theorem. The signature formula encrypts information, calculates hash values, and performs signature processing based on domain keys and timestamps to construct signed ciphertext; The authentication method receives the signed ciphertext and verifies the validity of the signature by calculating a hash value based on the authentication method's public key and domain key.

[0006] As a preferred technical solution, the process by which trusted authoritative institutions and key generation centers initialize their own secret values ​​and public parameters includes the following steps: A credible and authoritative institution randomly selects a cyclic additive group G of order q, where P is the generator of the group, and then selects a multiplicative group modulo q. Randomly select a value Calculate public parameters , where ・ denotes scalar multiplication of elliptic curves; The key generation center starts from the modulo q multiplication group Randomly select a value s2 and calculate the public parameters. ; Trusted and authoritative institutions publish system parameters ,in This is a hash function.

[0007] As a preferred technical solution, the process of generating the pseudonym set includes the following steps: electric vehicles From the multiplication group modulo p Randomly select a value Calculate the first part of the pseudonym ,in Public parameters; set up To determine the validity period of the pseudonym, calculate the second part of the pseudonym. ,in for True identity identifier, This represents the XOR operation. For hash functions; electric vehicles Generate a set of pseudo-names Each pseudonym n is The total number of pseudonyms.

[0008] As a preferred technical solution, the process of completing registration with the trusted authority includes the following steps: electric vehicles From the multiplication group modulo p Randomly select values ,calculate ,Will The registration request information is sent to a trusted authority, among which... Public parameters; Charging column from Randomly select values ,calculate ,Will Send to a trusted and authoritative organization, among which for Identity identifier; Trusted and authoritative institutions receive and After obtaining the registration information, calculate the hash value. ,in For hash functions, s 1 represents a publicly available parameter; A trusted and authoritative organization collects information on all registered electric vehicles. Value, calculation and for each electric vehicle calculate ; For each Solve for the condition that satisfies of ; Calculation by a trusted authoritative institution ,get ; A trusted authority broadcasts to the entire V2G network.

[0009] As a preferred technical solution, the process by which a trusted authority allocates and distributes domain keys to all entities includes the following steps: Trustworthy authoritative institutions from the multiplication group modulo q Random selection As a domain key, calculate ; Credible and authoritative institutions Sign it and get Where || represents string concatenation. This is the current timestamp. For signature algorithms; Trusted authorities will use domain keys Distribute to all electric vehicles and charging stations.

[0010] As a preferred technical solution, the process of generating a partial private key for a registered electric vehicle includes the following steps: Key generation center receives electric vehicles Sending pseudonym Then, from the multiplication group modulo p Random selection ,calculate ,in Public parameters; Calculate hash value ,in, It is a pseudonym. For hash functions, Public parameters; Calculate part of the private key ,in Public parameters; The key generation center will distribute a portion of the private key. Return to electric vehicles and publicly .

[0011] As a preferred technical solution, the process of generating a complete public-private key pair includes the following steps: electric vehicles From the multiplication group modulo p Randomly select secret value Calculate the public key ,in Public parameters; electric vehicles Full private key The public key is , This is a partial private key.

[0012] As a preferred technical solution, the process of dynamically updating the domain key includes: When electric vehicles are added, the newly added electric vehicles from Selected from ,calculate ,Will Send to a trusted authority, which selects the new domain key. ,calculate ,renew ,calculate Trusted authoritative institutions broadcast to the internet ,in Public parameters; When electric vehicles are phased out, a trusted and authoritative organization removes the corresponding information for the phased-out vehicles. Select a new domain key ,renew ,calculate Trusted authoritative institutions broadcast to the internet .

[0013] As a preferred technical solution, the process of recovering the domain key using the Chinese Remainder Theorem includes the following steps: Entity verification signature The effectiveness; electric vehicles Calculate hash value ; electric vehicles The domain key is computed using the Chinese Remainder Theorem. .

[0014] As a preferred technical solution, the signature stage includes the following steps: sender Obtain the domain key Then, calculate ,in Public parameters; Based on the current timestamp Regarding the message Encryption is performed to obtain the encrypted message. Based on encrypted messages Calculate two different hash values , ; Based on hash value , The encryption result is signed using modulo q operations. ; sender Based on encrypted messages and signature Constructing a secret document And send it to the recipient. The authentication phase includes the following steps: The receiver obtains the sender's information. public key and domain key ,calculate ,in Public parameters; Calculate the hash value and verify the signature validity. If the signature verification passes, decrypt to obtain the original message.

[0015] Compared with the prior art, the present invention has at least one of the following beneficial effects: (1) Improved real-time response speed of the power grid to vehicle access and exit: This invention sets up a Trusted Authority (TA) as the global controller and designs a dynamic domain key update mechanism based on the Chinese Remainder Theorem. When a vehicle joins or leaves the network, the operation type is identified and only the global parameters and the new domain key are updated. After binding, the signature is broadcast, and the new domain key is quickly restored locally on the network device without the need for re-registration and distribution of keys across the entire network. This solves the problem of efficient authentication of multi-user messages for resource-constrained devices, reduces the waste of communication resources during the key update process, improves the real-time response speed of the power grid to vehicle access and exit, adapts to the actual application needs of frequent vehicle entry and exit in V2G scenarios, and improves the user experience.

[0016] (2) Achieved forward and backward security for V2G communication: The newly updated domain key is completely independent of the historical domain key, and the old key automatically becomes invalid after the domain key is updated; When a vehicle leaves the network, the TA permanently removes its corresponding key component from the global parameters, so that it can no longer obtain the new domain key or decrypt subsequent communication messages, thus achieving forward and backward security for V2G communication. Even if the domain key is leaked at a certain moment, it will not affect the security of past and future communication, eliminating the risk of decryption of communication data caused by zombie vehicles and ensuring the confidentiality of information interaction in the V2G scenario.

[0017] (3) Privacy Protection: This invention enables electric vehicles to autonomously generate a set of pseudonyms locally. These pseudonyms are only valid for a short set period and are automatically replaced upon expiration. Other participants cannot link and track vehicle messages. During the domain key update process, the TA completes the binding and broadcasting of the new domain key through the Chinese Remainder Theorem. On-network vehicles and charging stations can quickly recover the new domain key locally without relying on external link reconstruction. This effectively protects the identity privacy of electric vehicles, avoids the problem of vehicles being maliciously tracked, and ensures the continuous operation of services such as charging scheduling, energy trading, and data reporting in V2G scenarios, thus guaranteeing the stability of energy interaction and information transmission. Attached Figure Description

[0018] Figure 1 This is a flowchart of a signature method with dynamic key update function for a V2G scenario in the embodiment. Figure 2 This is a schematic diagram of a signature system with dynamic key update function for V2G scenarios in the embodiment. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] Example 1 To address the problems existing in the prior art, this embodiment provides a signature method with dynamic key update functionality for V2G scenarios, see [link to documentation]. Figure 1 The method includes the following steps: Step S1: System initialization phase.

[0021] Once the Trusted Authority (TA) and Key Generation Center (KGC) receive the security parameters, they perform the following steps: A trusted authority (TA) randomly selects a cyclic additive group G of order q, where P is the generator of the group; TA then selects a multiplicative group modulo q. Randomly select a value Calculate public parameters (Where “・” represents scalar multiplication of elliptic curves).

[0022] Key Generation Center (KGC) from modulo q multiplication group Randomly select a value s2 and calculate the public parameters. .

[0023] TA randomly selects four hash functions, which are defined as follows: H1: ; H2: ; H3: ; H4: .

[0024] TA publishes system parameters Meanwhile, TA secretly kept KGC Secret Preservation .

[0025] Step S2, kana generation stage.

[0026] When electric vehicles After connecting to the charging interface, you need to manually generate the set of pseudonyms required for communication. The steps are as follows: electric vehicles From the multiplication group modulo p Randomly select a value Calculate the first part of the pseudonym ; set up To determine the validity period of this pseudonym, calculate the second part of the pseudonym. ,in for True identity identifier, " indicates the XOR operation; electric vehicles Generate a set of pseudo-names Each pseudonym n is The total number of pseudonyms; pseudonym Electric vehicles Based on time changes and random values Dynamically generated, without relying on a Key Generation Center (KGC).

[0027] Step S3, registration phase.

[0028] When electric vehicles Charging poles connected to charging stations At this time, you need to complete the registration with a trusted authority (TA). The steps are as follows: electric vehicles From the multiplication group modulo p Randomly select values ,calculate ,Will Send the registration request information to TA; Charging column Perform similar operations: from Randomly select values ,calculate ,Will ( for Send the identity identifier to TA; TA receives and After obtaining the registration information, calculate the hash value. ; TA collects all registered electric vehicles Value, calculation and for each electric vehicle calculate ; For each Solve for the condition that satisfies of ; TA calculation , and then calculate ; TA broadcasts X to the entire V2G network.

[0029] Step S4, security domain key calculation stage.

[0030] A trusted authority (TA) assigns and distributes domain keys to all entities within the system (electric vehicles, charging stations, etc.) in the following steps: TA from the multiplication group modulo q Random selection As a domain key, calculate ; TA to Sign it and get The symbol "||" represents string concatenation. This is the current timestamp. For signature algorithms; TA will use the key Distribute to all electric vehicles and charging stations.

[0031] Step S5, Partial Key Generation Stage.

[0032] Key Generation Center (KGC) for registered electric vehicles Generate a partial private key The steps are as follows: KGC receives electric vehicles Sending pseudonym Then, from the multiplication group modulo p Random selection ,calculate ; Calculate hash value ,in ; Calculate part of the private key ; KGC will use part of the private key Return to electric vehicles and publicly .

[0033] Step S6, Key Generation and Update Stage.

[0034] 1. Key generation stage.

[0035] electric vehicles After receiving a portion of the private key, generate the complete public-private key pair using the following steps: electric vehicles From the multiplication group modulo p Randomly select secret value Calculate the public key ; electric vehicles Full private key The public key is .

[0036] 2. Key update phase.

[0037] Scenario 1: Electric vehicles join Newly added electric vehicles from Selected from ,calculate ,Will Send to TA; TA selects new domain key ,calculate (Calculation method is the same as in the registration stage) ),renew , and then calculate ;TA broadcasts to the network .

[0038] Scenario 2: Electric vehicles exiting the market TA removes the vehicle corresponding to the exit. Select a new domain key ,renew ,calculate ;TA broadcasts to the network .

[0039] Step S7, Domain Key Recovery Phase.

[0040] All entities within the system (electric vehicles, charging stations) receive the TA broadcast. Then, recover the domain key, following these steps: Entity (with electric vehicles) (For example) First, verify the signature. The effectiveness of ensuring It has not been tampered with; electric vehicles Calculate hash value ; electric vehicles The domain key is computed using the Chinese Remainder Theorem. .

[0041] Step S8, the signature and deseal stage.

[0042] Signature stage: sender Obtain the domain key Then, calculate ; set up For the current timestamp, the message Encrypt: ; Calculate the two hash values: Sign the encryption result: (Modal-q operation); sender Constructing a secret document And send it to the recipient.

[0043] Deciphering the secret: The receiver obtains the sender's information. public key and domain key ,calculate ; Calculate the three hash values: Verify signature validity: Check ; If signature verification passes, decrypt to retrieve the original message: .

[0044] The following example illustrates the method using the deployment and implementation of secure communication at a V2G charging station in a city center. This embodiment targets a large public charging station in a city center. The power grid company deploys TA and KGC as the core of security management. The electric vehicles include various types such as private cars and ride-hailing vehicles. It is necessary to achieve secure communication requirements such as charging dispatch command transmission, battery status data reporting, and energy trading information exchange, while also adapting to resource-constrained devices such as on-board units (OBUs) and charging station edge gateways.

[0045] The TA and KGC are deployed on the power grid company's private cloud server, supporting parameter calculation and global broadcast; the charging station edge gateway uses industrial-grade embedded devices to handle signature aggregation and message forwarding; the electric vehicle on-board OBUs all support the SECP256k1 elliptic curve algorithm and have local key storage and hash operation capabilities.

[0046] The system security parameters are preset to elliptic curve order q (256 bits), generator P, and TA and KGC pre-configured with dedicated private keys, using SHA-256 series hash functions as the default hash function. - This ensures a balance between computational efficiency and security.

[0047] When the TA and KGC services are started, the TA automatically generates the core private key and public parameters. KGC synchronously generates a unique private key and public parameters. Both parties verify the validity of the parameters through an encrypted channel, and after confirming that they are correct, integrate them into the publicly available parameters of the system. The system broadcasts to charging stations and electric vehicles in the area via a dedicated power grid network. After initialization, the system enters a "ready state".

[0048] After the driver pulls the electric vehicle into the charging station and connects to the charging pile, the on-board unit (OBU) automatically triggers pseudonym generation: locally randomly generated parameters, combined with the vehicle's unique identifier and a 30-minute validity period, generate three pseudonyms through a hash XOR operation. Enabled by default To conduct communication.

[0049] The OBU automatically initiates a registration request to the TA and uploads the necessary files. The request, along with the locally calculated exclusive parameters, is forwarded via the charging station edge gateway. The TA performs information verification (confirming the uniqueness of the pseudonym and the validity of the parameter format) and calculates the corresponding parameters for the vehicle. The component updates the global aggregation parameter X and broadcasts it to the entire network. Upon successful registration, feedback is sent to the vehicle's OBU, and the charging station submits its own identity and parameters to the TA.

[0050] After the electric vehicle registration is approved, it sends a partial private key request to the KGC. After the KGC verifies the legality of the pseudonym, it generates a partial private key PPK and distributes it. After receiving it, the OBU supplements the secret value locally to generate a complete public-private key pair. The key configuration is completed, the vehicle has the ability to sign and decrypt, and the system switches to "running status".

[0051] When an electric vehicle joins a charging station, the system automatically triggers a key update: the key recognition unit (TA) identifies the "vehicle joining" operation and calculates the new vehicle's key information. The system updates the global parameter X', generates a new domain key, binds it using the Chinese Remainder Theorem, signs it, and broadcasts it to all networked devices. The networked electric vehicles and the charging station edge gateway complete the recovery of the new domain key. During this process, the ongoing charging scheduling message communication is not interrupted, and the key update does not affect business continuity.

[0052] In summary, this method has the following characteristics: (1) Support for flexible vehicle access and exit: When a vehicle joins or leaves the charging station communication domain, the TA dynamically updates the domain key through the Chinese Remainder Theorem, without having to re-register or distribute keys to all vehicles on the network. This avoids the waste of communication resources caused by vehicle-by-vehicle registration in the traditional scheme and improves the real-time response speed of the power grid to vehicle access.

[0053] (2) Achieve forward and backward security: During the key update process, the new domain key is completely independent of the historical key. Even if the key is leaked at a certain moment, it will not affect the security of past or future communication. At the same time, after the vehicle leaves, its corresponding key component is removed and cannot be decrypted for subsequent communication data, thus eliminating the security risks caused by zombie vehicles.

[0054] Example 2 Based on Example 1, see Figure 2 This embodiment provides a signature system with dynamic key update function for V2G scenarios, used to execute the signature method of Embodiment 1. Figure 2 In the diagram, the light blue rectangle represents the energy interaction between the EV and CS in the V2G scenario; the light gray rectangle represents the information interaction between the EV, CS, and other auxiliary facilities.

[0055] Before initialization is complete, the system is in a "not ready state." In this state, only the Trusted Authority (TA) and Key Generation Center (KGC) can perform parameter configuration operations. Electric vehicles and charging stations cannot access the network for communication or energy exchange. Once the TA completes system parameter publishing and the KGC completes initial key component configuration, the system enters a "ready state," allowing electric vehicles and charging stations to initiate registration requests. When the first electric vehicle completes registration and obtains a complete key, the system switches to a "running state." If all registered devices (electric vehicles and charging stations) exit the network, the system automatically reverts to the "ready state," retaining the core configuration parameters of the TA and KGC without requiring re-initialization.

[0056] The system comprises four core participants, each with independent permissions and no risk of unauthorized access. The four core participants are: Trusted Authority (TA), Key Generation Center (KGC), Charging Station (CS), and Electric Vehicle (EV). The TA is the highest-authority role in the system and exists exclusively. It is responsible for system initialization, domain key generation and updates, device registration verification, and global parameter broadcasting. It also secretly stores the core private key but does not participate in the signing or decryption of specific messages. The TA's permissions are non-transferable; it only supports modifying core system parameters through hardware encryption modules, and all modifications are fully logged. The KGC is a semi-trusted role, responsible only for generating partial private keys for registered devices. It does not possess the complete private key of any device and cannot decrypt communication messages. The KGC secretly stores the private key and only responds to partial private key requests from devices that have passed TA registration verification. It has no right to modify system parameters or domain keys. The CS is a communication relay and energy interaction role, capable of connecting multiple electric vehicles simultaneously. The primary communication unit (PCU) is responsible for forwarding registration requests, transmitting domain keys, and aggregating signature messages from multiple vehicles. It does not generate its own domain keys and can only use the domain keys issued by the primary communication unit (TA) to verify message validity. It has no right to modify or distribute keys to unregistered vehicles. The electric vehicle (EV) acts as the terminal communication unit, possessing the authority to independently generate pseudonyms, initiate registration, sign messages, and decrypt legitimate messages. EVs only possess their own complete private key and cannot obtain key information from other vehicles or charging stations. Pseudonym updates and key storage are all performed locally, without relying on external institutions.

[0057] During system initialization, the TA and KGC respectively complete key and public parameter configuration, select a suitable hash function to integrate into the system's public parameters, and broadcast them to the entire network after mutual verification of parameter validity to ensure that the initial configuration is vulnerability-free. After an electric vehicle connects to a charging station, it automatically generates a set of pseudo-names locally and sends a registration request to the TA in combination with its unique parameters. When the charging station registers, it submits its own identity identifier and corresponding parameters. The TA quickly completes the information verification. If successful, it updates the global aggregate parameters and broadcasts the information; if unsuccessful, it sends an error message, and the device needs to re-initiate the request. After the electric vehicle passes the registration review, it requests a partial private key from the KGC, supplements the secret value locally after receiving it, and generates a complete public-private key pair to complete the key configuration. When a vehicle joins or leaves the network, the TA automatically identifies the operation type, updates the global parameters and the new domain key, binds them using the Chinese Remainder Theorem, signs and broadcasts the result. The key update process does not interrupt existing communication, and vehicles already in the network quickly recover the new domain key locally. When an electric vehicle sends a message, it first processes the message using the local domain key, completes encryption and signing, and then constructs a signed ciphertext for transmission. The receiver verifies the signature validity upon receipt and decrypts the message to obtain the original message.

[0058] When parties interact in the system, the pseudonym of the electric vehicle is only valid for a short period of time. When it expires, it will be automatically replaced with a new pseudonym, and other participants will not be able to link to its messages. After the domain key is updated, the old key will automatically become invalid. When the vehicle leaves the network, its corresponding key component will be removed from the global parameters, and it will be impossible to obtain the new domain key or decrypt subsequent messages.

[0059] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A signature method with dynamic key update function for V2G scenarios, characterized in that, Includes the following steps: Trusted authoritative institutions and key generation centers initialize their own secret values ​​and public parameters; After the electric vehicle is connected to the charging interface, the electric vehicle dynamically and autonomously generates the set of pseudo-names required for communication based on time changes and random values. When an electric vehicle connects to a charging station's charging pile, it completes registration with the aforementioned trusted authority. The trusted authority assigns and distributes domain keys to all entities; The key generation center generates partial private keys for registered electric vehicles based on the pseudonyms of the electric vehicles. After receiving the partial private key, the electric vehicle generates a complete public-private key pair; The domain key is dynamically updated in response to the joining or leaving of an electric vehicle. After receiving the domain key broadcast by a trusted authority, the entity recovers the domain key using the Chinese Remainder Theorem. The signature formula encrypts information, calculates hash values, and performs signature processing based on domain keys and timestamps to construct signed ciphertext; The authentication method receives the signed ciphertext and verifies the validity of the signature by calculating a hash value based on the authentication method's public key and domain key.

2. The signcryption method with dynamic key update function for V2G scenario according to claim 1, characterized in that, The process by which trusted authorities and key generation centers initialize their own secret values ​​and public parameters includes the following steps: A trusted authority randomly selects a cyclic additive group G of order q, and P is the generator of the group. A number a is randomly selected from the multiplicative group Zq The public parameters are calculated as follows where represents the scalar multiplication operation of the elliptic curve.​ The key generation center randomly selects a value s2 from the multiplicative group of modulo q and calculates the public parameter ; Trusted authority discloses system parameters wherein is a hash function. 3.The signcryption method with dynamic key update function for V2G scene of claim 1, wherein, The process of generating the pseudonym set includes the following steps: electric vehicles From the multiplication group modulo p Randomly select a value Calculate the first part of the pseudonym ,in Public parameters; set up To determine the validity period of the pseudonym, calculate the second part of the pseudonym. ,in for True identity identifier, This represents the XOR operation. For hash functions; electric vehicles Generate a set of pseudo-names Each pseudonym n is The total number of pseudonyms.

4. The signature method with dynamic key update function for V2G scenarios according to claim 1, characterized in that, The process of completing registration with the aforementioned trusted authority includes the following steps: electric vehicles From the multiplication group modulo p Randomly select values ,calculate ,Will The registration request information is sent to a trusted authority, among which... Public parameters; Charging column from Randomly select values ,calculate ,Will Send to a trusted and authoritative organization, among which for Identity identifier; The trusted authority receives and registration information, calculates a hash value wherein is a hash function, s 1 is a public parameter; A trusted and authoritative organization collects information on all registered electric vehicles. Value, calculation and for each electric vehicle calculate ; For each Solve for the condition that satisfies of ; Calculation by a trusted authoritative institution ,get ; A trusted authority broadcasts to the entire V2G network.

5. The signcryption method with dynamic key update function for V2G scenario according to claim 1, characterized in that, The process by which a trusted authority assigns and distributes domain keys to all entities includes the following steps: A trusted authority randomly selects from the multiplicative group of the modulus q As the domain key, compute ;​ A trusted authority signs to obtain where || denotes the string concatenation operation, is the current timestamp, is the signature algorithm; A trusted authority issues domain keys to all electric vehicles and charging pillars.

6. The signcryption method with dynamic key update function for V2G scenario according to claim 1, characterized in that, The process of generating a partial private key for a registered electric vehicle includes the following steps: Key generation center receives electric car Pseudonym transmitted After, the multiplicative group of modulo p Randomly selected from , Calculate Where Is a public parameter; Computing a hash value wherein, is a pseudonym, is a hash function, is a public parameter; Computing a partial private key wherein are public parameters; The key generation center will distribute a portion of the private key. Return to electric vehicles and publicly .

7. A signature method with dynamic key update function for V2G scenarios according to claim 1, characterized in that, The process of generating a complete public-private key pair includes the following steps: Electric vehicle From the multiplicative group of a modulus p Randomly select a secret value , calculate the public key where is a public parameter; Electric vehicle complete private key , the public key is , partial private key.

8. The signcryption method with dynamic key update function for V2G scenario according to claim 1, characterized in that, The process of dynamically updating the domain key includes: When electric vehicles are added, the newly added electric vehicles from Selected from ,calculate ,Will Send to a trusted authority, which selects the new domain key. ,calculate ,renew ,calculate Trusted authoritative institutions broadcast to the internet ,in Public parameters; When electric vehicles are phased out, a trusted and authoritative organization removes the corresponding information for the phased-out vehicles. Select a new domain key ,renew ,calculate Trusted authoritative institutions broadcast to the internet .

9. The signcryption method with dynamic key update function for V2G scenario according to claim 8, characterized in that, The process of recovering the domain key using the Chinese Remainder Theorem includes the following steps: entity verification signature validity; electric vehicles Calculate hash value ; electric vehicles The domain key is computed using the Chinese Remainder Theorem. .

10. The signcryption method with dynamic key update function for V2G scenario according to claim 1, characterized in that, The signature process includes the following steps: Sender Obtain domain key Then, calculate Where is a public parameter; based on a current timestamp encrypting the message ​ Based on encrypted messages Computing two different hash values , ; Based on hash value , , signature of encryption result by modulo q operation ; Sender based on an encrypted message and a signature constructs a signcrypted message and sends it to the receiver, The authentication phase includes the following steps: The receiver obtains the sender's information. public key and domain key ,calculate ,in Public parameters; Calculate the hash value and verify the signature validity. If the signature verification passes, decrypt to obtain the original message.

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