Electric vehicle charging method, apparatus, and storage medium based on linkable ring signatures

Abstract

This invention relates to the field of electric vehicle charging authentication technology, and provides an electric vehicle charging method, device, and storage medium based on a linkable ring signature. The method includes: an electric vehicle generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy; and sending a charging request and the charging request ring signature to a charging pile. The charging pile verifies the charging request ring signature based on the public parameter set, user identity list, charging request message, message timestamp, system timestamp, and event identifier in the sent charging request. When the verification is successful, the user authentication of the electric vehicle is confirmed, and charging of the electric vehicle begins. The ring signature of this invention is generated based on a distributed key protocol and threshold cryptography, thereby achieving anonymity through the ring member identity list, effectively protecting the privacy of electric vehicle user charging information.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle charging authentication technology, and particularly relates to an electric vehicle charging method, device and storage medium based on a linkable ring signature. Background Technology

[0002] With the deepening of global energy structure transformation and the pursuit of carbon neutrality, electric vehicles (EVs) and their supporting charging infrastructure have entered a critical stage of large-scale development. According to the latest report from the International Energy Agency (IEA), the global EV fleet is projected to exceed 80 million units by 2025, corresponding to a surge in demand for public charging stations. In EV charging scenarios, directly applying traditional Public Key Infrastructure (PKI) authentication schemes (i.e., EVs using a single digital identity certificate to prove their identity to charging stations) can lead to the leakage of user charging information privacy, such as driving routes, charging times, charging locations, and charging bills.

[0003] Existing technologies can protect the privacy of electric vehicle charging behavior, such as digital signature authentication methods. However, directly applying current digital signature authentication methods to the dynamic, open, and resource-constrained IoT environment of electric vehicle charging still faces challenges. First, during the authentication process, the charging operation center needs to maintain a constantly growing list of used signatures (i.e., status) in its storage space. Verifying signature duplication requires querying this list, resulting in an excessive storage and computational burden. Second, if the private key of a digital signature is leaked, attackers can calculate the corresponding private key and scan the charging operation center's database to find all of the user's historical charging records, posing a privacy risk. Third, existing charging authentication schemes are mostly one-way authentications, which cannot support the complex interaction protocols between electric vehicles, charging piles, and the charging operation center. Finally, the lack of a tracking mechanism in current digital signatures makes it impossible to trace the user's true identity. If a user skips out on payment or charges repeatedly after charging, the charging operation center cannot identify the unpaid user, creating a regulatory challenge for the charging operation center. Summary of the Invention

[0004] The purpose of this invention is to provide an electric vehicle charging method, apparatus, and storage medium based on a linkable ring signature, aiming to solve the problem of electric vehicle user privacy leakage caused by the inability of existing technologies to provide a safe and effective electric vehicle charging method.

[0005] On one hand, the present invention provides a method for charging electric vehicles based on a linkable ring signature, the method comprising the following steps: The electric vehicle generates a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, and sends a charging request and the charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp, and an event identifier. The charging pile verifies the ring signature of the charging request based on the common parameter set, the user identity list, the charging request message, the first message timestamp, the first system timestamp, and the event identifier in the sent charging request. When the verification is successful, it authorizes the charging of the electric vehicle.

[0006] In some embodiments, the steps of an electric vehicle generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, and sending a charging request and the charging request ring signature to a charging pile include: The electric vehicle generates the event identifier based on the charging request identifier, the charging strategy, and the first message timestamp; generates a temporary private key based on the master private key share; generates a linkable tag based on the event identifier and the temporary private key; and generates a ring member hash value and a first message identity list hash value based on the user identity list, the first message timestamp, the first system timestamp, and the charging request message. The electric vehicle generates the charging request ring signature based on the linkable tag, the ring member hash value, the first message identity list hash value, and the public parameter set, and sends the charging request and the charging request ring signature to the charging pile.

[0007] In some embodiments, the step of the charging pile verifying the ring signature of the charging request based on the common parameter set, the user identity list, the charging request message, the first message timestamp, the first system timestamp, and the event identifier in the sent charging request includes: The charging pile verifies the time validity of the charging request ring signature based on the first message timestamp and the first system timestamp. If the verification is successful, it calculates the second ring member hash value and the second message identity list hash value based on the public parameter set, the user identity list, the charging request message, the first message timestamp, and the first system timestamp. The charging pile verifies the first balance value of the charging request ring signature based on the public parameter set, the user identity list, the charging request message, the first message timestamp, the first system timestamp, the event identifier, the second ring member hash value, and the second message identity list hash value, and verifies the linkable tags based on the used tag list.

[0008] In some embodiments, before the step of generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, the method further includes: The operation center obtains the minimum number of cooperating nodes and the number of charging operation center nodes. Based on the minimum number of cooperating nodes and the number of charging operation center nodes, it generates a preset number of master private key shares based on the distributed key generation protocol. Based on the master private key shares and bilinear pairings, it generates a preset number of master public key shares. Based on the preset number of master public key shares, it aggregates to generate a master public key. The operation center generates the common parameter set based on the bilinear pair, the elliptic curve group and target group of the bilinear pair, the generator of the elliptic curve group, security parameters, and several hash functions.

[0009] In some embodiments, after the step of authorizing the charging of the electric vehicle, the method further includes: The operation center generates a master private key based on a preset number of master private key shares, and determines the electric vehicle identity information based on the master private key, the charging request ring signature, the public parameter set, the user identity list, the event identifier, the first message timestamp, and the first system timestamp.

[0010] In some embodiments, before the step of generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, the method further includes: The operation center generates an identity certificate for the electric vehicle based on the electric vehicle's identity information, the second system timestamp, and the second message timestamp, and then issues the identity certificate to the electric vehicle.

[0011] In some embodiments, after the step of authorizing the charging of the electric vehicle, the method further includes: The electric vehicle generates a first monitoring parameter based on a first random number and a prime base, and sends the first monitoring parameter to the charging pile; The charging pile generates a second monitoring parameter based on a second random number and the prime base, and sends the second monitoring parameter to the electric vehicle; The electric vehicle generates an electric vehicle session key based on the second monitoring parameter and the first random number. Based on the first monitoring parameter, the second monitoring parameter, the charging pile identity identifier, the prime number base, and the charging timestamp, it generates an electric vehicle message authentication code using a message authentication function and sends it to the charging pile. The charging pile generates a charging pile session key based on the first monitoring parameter and the second random number, and generates a charging pile message authentication code based on the first monitoring parameter, the second monitoring parameter, the electric vehicle identification, the prime number base, and the charging timestamp using the message authentication function and sends it to the electric vehicle. The charging pile and the electric vehicle determine a two-way session key based on the charging pile message authentication code, the electric vehicle message authentication code, the charging pile session key, and the electric vehicle session key.

[0012] On the other hand, the present invention provides an electric vehicle charging device based on a linkable ring signature, the device comprising: The ring signature generation module is used to generate a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, and to send a charging request and the charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp, and an event identifier. The ring signature authentication module is used to verify the ring signature of the charging request based on the public parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, the module authorizes the charging of the electric vehicle.

[0013] In some embodiments, the ring signature generation module includes: The parameter generation module is used for the electric vehicle to generate the event identifier based on the charging request identifier, the charging strategy, and the first message timestamp; generate a temporary private key based on the pre-acquired master private key share; generate a linkable tag based on the event identifier and the temporary private key; and generate a first ring member hash value and a first message identity list hash value based on the user identity list, the first message timestamp, the first system timestamp, and the charging request message. The signature sending module is used for the electric vehicle to generate the charging request ring signature based on the linkable tag, the hash value of the first ring member, the hash value of the first message identity list, and the public parameter set, and to send the charging request and the charging request ring signature to the charging pile.

[0014] On the other hand, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method described above.

[0015] In this embodiment of the invention, when charging an electric vehicle, the electric vehicle generates a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy. The electric vehicle then sends a charging request and the charging request ring signature to the charging pile. The charging pile verifies the charging request ring signature based on the public parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, the charging pile authorizes the electric vehicle to charge. In this way, the electric vehicle generates a charging request ring signature based on the public parameter set, user identity list, charging request message, and charging strategy. This charging request ring signature effectively prevents malicious attackers from locking the signer through the signature or spying on the user's charging history information by forging historical signatures, thereby achieving the goal of protecting the privacy of electric vehicle user charging information. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the electric vehicle charging method based on a linkable ring signature provided in Embodiment 1 of the present invention. Figure 2 This is a flowchart illustrating the implementation of step S101 in the electric vehicle charging method based on a linkable ring signature provided in Embodiment 1 of the present invention. Figure 3 This is a flowchart illustrating the implementation of step S102 in the electric vehicle charging method based on a linkable ring signature provided in Embodiment 1 of the present invention. Figure 4 This is a flowchart illustrating the implementation of the electric vehicle charging method based on a linkable ring signature provided in Embodiment 4 of the present invention. Figure 5 This is a flowchart illustrating the implementation of the electric vehicle charging method based on a linkable ring signature provided in Embodiment 4 of the present invention. Figure 6 This is a flowchart illustrating the implementation of the electric vehicle charging method based on a linkable ring signature provided in Embodiment 4 of the present invention. Figure 7 This is a schematic diagram of the structure of an electric vehicle charging device based on a linkable ring signature provided in Embodiment 5 of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. Furthermore, the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification, unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" are intended to include the plural forms. The terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships, which may change accordingly when the absolute position of the described object changes.

[0019] To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of some known functions and known components are omitted in this specification.

[0020] The specific implementation of the present invention will be described in detail below with reference to specific embodiments: Example 1: Figure 1 The flowchart of the electric vehicle charging method based on linkable ring signatures provided in Embodiment 1 of the present invention is shown. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below: In step S101, the electric vehicle generates a charging request ring signature based on the public parameter set, user identity list, charging request message, and charging strategy, and sends the charging request and charging request ring signature to the charging pile.

[0021] In this embodiment of the invention, the public parameter set includes several public parameters for generating the charging request ring signature, which are obtained in advance by the electric vehicle from the operation center. These parameters may include, for example, several hash functions, bilinear pairs, security parameters, charging strategies, etc. The user identity list (ring member identity list) refers to multiple legitimate electric vehicles registered with the operation center, used to hide the identity information of the electric vehicle currently requesting charging. The charging request message typically refers to the specific content of the charging request sent by the electric vehicle to the charging pile, which may include the current charging time, charging power, target capacity, and charging duration, etc. The charging strategy typically refers to the rules and constraints of the charging pile, which may include charging rate, time scheme, and cost scheme, etc. The first message timestamp is the specific time when the electric vehicle sends the charging request, such as a specific moment on a certain day. The first system timestamp is the (system) version of the operation center corresponding to when the electric vehicle registers its identity with the operation center. The event identifier is the identifier of the charging request. After generating the charging request ring signature based on the public parameter set, user identity list, charging request message, and charging strategy, the electric vehicle sends the charging request ring signature and charging request to the charging pile. The charging request includes the first message timestamp, the first system timestamp, and the event identifier.

[0022] In step S102, the charging pile verifies the ring signature of the charging request based on the common parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, it authorizes the charging of the electric vehicle.

[0023] In this embodiment of the invention, the charging pile verification verifies the first message timestamp and the first system timestamp based on a common parameter set, and verifies whether the user identity list, charging request message, and event identifier have been tampered with, thereby determining the validity of the charging request ring signature.

[0024] In this invention, during the electric vehicle charging process, digital authentication is achieved through a charging request ring signature. The charging station can verify that the electric vehicle belongs to a legitimate user in the user identity list, enabling anonymous authentication of the electric vehicle user. However, neither the charging station nor an attacker can pinpoint the specific electric vehicle, thus protecting the user's privacy and resolving the issue of electric vehicle charging privacy leakage. Simultaneously, the charging request ring signature is bound to the charging request message, charging strategy, and user identity list. This ensures the unforgeability of the charging request ring signature when an attacker attempts to forge it. Furthermore, the charging request ring signature is also bound to an event identifier, preventing electric vehicles from using expired charging request ring signatures to request charging and evade payment, thus resolving the problem of repeated charging fraud.

[0025] Example 2: Figure 2The implementation flow of step S101 in the electric vehicle charging method based on linkable ring signatures provided in Embodiment 1 of the present invention is shown. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below: In step S201, an event identifier is generated based on the charging request identifier, the charging strategy, and the first message timestamp, and a temporary private key is generated based on the master private key share.

[0026] In this embodiment of the invention, the charging request identifier can be a fixed string constant used to identify the charging request message and distinguish it from other request messages.

[0027] In some embodiments, specifically, the event identifier can be generated using the following formula: .

[0028] in, This represents the hash value of the charging strategy. Indicates the charging strategy. This represents the fourth hash function. Indicates the event identifier, Indicates a charging request identifier. The first message timestamp is represented by the first hash function, and the fourth hash function is obtained by the electric vehicle from the charging station's operation center.

[0029] In some embodiments, when generating a temporary private key based on a master private key share, specifically, a long-term private key is generated based on a preset number of master private key shares using a bilinear pairing and Lagrange interpolation algorithm. A temporary private key is then derived from the long-term private key, which serves as a short-term key for daily signing of the electric vehicle. The master private key shares are obtained by the electric vehicle from the charging station's operation center.

[0030] In step S202, a linkable tag is generated based on the event identifier and the temporary private key.

[0031] In this embodiment of the invention, after obtaining the event identifier and temporary private key, the electric vehicle generates a linkable tag based on the event identifier and temporary private key. The linkable tag is used to prevent the same electric vehicle user from initiating multiple charging requests within the same time window. Specifically, the linkable tag can be calculated using the following formula: .

[0032] in, The hash value representing the event identifier. This represents the third hash function. Indicates a linkable tag. Indicates a bilinear pair. This indicates that the temporary private key, the third hash function, and the bilinear pair are obtained by the electric vehicle from the operations center.

[0033] In step S203, the hash value of the first ring member and the hash value of the first message identity list are generated based on the user identity list, the first message timestamp, the first system timestamp, and the charging request message.

[0034] In this embodiment of the invention, a first ring member hash value is generated based on the user identity list, the first message timestamp, and the first system timestamp, and a first message identity list hash value is generated based on the user identity list and the charging request message.

[0035] In some embodiments, the hash values ​​of the first ring members and the first message identity list can be calculated using the following formulas: , .

[0036] in, This represents the hash value of the first ring member. This represents the second hash function. This indicates the identity information of the ring members. Indicates the first system timestamp. This represents the hash value of the first message's identity list. This indicates a charging request message. The number of ring members is represented by the second hash function. The identity information of the ring members and the number of ring members are obtained by the electric vehicle from the operation center.

[0037] In step S204, a charging request ring signature is generated based on the linkable tag, the hash value of the first ring member, the hash value of the first message identity list, and the common parameter set. The electric vehicle sends a charging request and the charging request ring signature to the charging pile.

[0038] In this embodiment of the invention, when generating a charging request ring signature based on a linkable tag, a first ring member hash value, a first message identity list hash value, and a public parameter set, the following steps can be taken: (1) Multiplication group in prime number field Select random parameters In the elliptic group of bilinear pairs Select random parameters .

[0039] (2) The first verification point and first verification value of non-signers and signers in the differential calculation ring members.

[0040] In this embodiment of the invention, the first verification point is an elliptic curve point calculated by the electric vehicle for each ring member when the charging request ring signature is generated, used to calculate the first balance value. The first verification value is a hash value calculated by the electric vehicle for each ring member when the charging request signature is generated, also used to calculate the first balance value. The signer refers to the electric vehicle currently requesting charging, and the non-signer refers to other electric vehicles in the user identity list (i.e., the ring member identity list).

[0041] In some embodiments, the signer's first verification point and first verification value can be calculated using the following formula: , .

[0042] in, This indicates the first verification point for the signer. , Both represent the multiplication group in the prime field. The selected random parameter, Let represent the generators of the elliptic curve group. This indicates the selection of random parameters within the elliptic curve group. This represents the sum of the hash values ​​of all members of the first ring. Represents the signer's hash value. This represents the signer's first verification value. Indicates the master public key, Indicates a linkable tag. The generator, the second hash function, and the prime field multiplication group are obtained by the electric vehicle from the operation center.

[0043] In some embodiments, the first verification point and the first verification value of the non-signer in the ring member can be calculated using the following formula: , .

[0044] in, This indicates the first verification point for the signer. Represents the multiplication group in the prime field The selected random parameter, and In the elliptic curve group Choose random parameters. This represents the hash value of the first ring member. This represents the signer's first verification value. This indicates a linkable tag.

[0045] (3) Based on random parameters and random parameters The second verification point can be calculated using the following formula: , + .

[0046] in, This represents the second verification point for the signer. This represents the second verification point for non-signers. The second verification point is a transportable form of the first verification point and is used to reconstruct the first verification point.

[0047] (4) Calculate the challenge value and response value.

[0048] In some embodiments, the challenge value and response value can be calculated using the following formula: , .

[0049] in, Indicates the challenge value. This represents the sum of all second verification points, including those of signers and non-signers. This represents the sum of all response values, which are generated by random numbers. Assignment, i.e. , Represents the multiplication group of prime fields Random numbers on the screen This represents the response value. Challenge value. It could be a random question posed by the charging station (verifier) ​​to the electric vehicle (signer), and the response value would be... It can be the signer's cryptographic response to the challenge value.

[0050] (5) Calculate the first balance value based on the challenge value, response value, linkable tag, first message ring member hash value, first verification point, first verification value, event identifier and ring member hash value, and obtain the charging request ring signature based on the first balance value, challenge value, response value, linkable tag, second verification point, ring member response value and charging strategy hash value.

[0051] In this embodiment of the invention, the first balance value is used to ensure the integrity of the charging request ring signature. Specifically, the first balance value can be calculated using the following formula: .

[0052] in, This represents the first equilibrium value. Indicates a linkable tag. This represents the hash value of the electric vehicle. Indicates the event identifier, This represents the first verification point for all ring members, including both signers and non-signers. This represents the first verification value for all ring members, including the first verification values ​​for signers and non-signers. This represents the sum of the hash values ​​of all members of the first ring.

[0053] Then, the charging request ring signature is obtained using the following formula: .

[0054] in, This indicates the ring signature for the charging request. Represents the sum of the second verification points of the ring members. This represents the sum of the response values ​​of the ring members.

[0055] In the charging request ring signature generation process, this invention employs random numbers to construct the calculation formulas for the first verification point and the first verification value for both the signer and non-signer. This makes the formula outputs of the non-signer and the signer indistinguishable, thereby hiding the electric vehicle's identity in the ring member identity list. This effectively protects sensitive privacy information such as the electric vehicle's travel mode and charging habits, achieving unconditional anonymity. The event identifier contains a charging policy hash value; any tampering with the charging policy will cause the event identifier to change, leading to charging request verification failure. The hash values ​​of the first ring members and the first message identity list ensure that the charging request has not been tampered with, guaranteeing its integrity and timeliness. The charging request ring signature uses a temporary private key instead of a long-term private key. The temporary private key serves as a short-term key for daily signing of the electric vehicle, and different temporary private keys are used for different first message timestamps. Even if the temporary private key corresponding to a certain first message timestamp is leaked, attackers cannot deduce the long-term private key or forge historical charging request ring signatures, ensuring the security of the long-term private key.

[0056] Example 3: Figure 3 The implementation flow of step S102 in the electric vehicle charging method based on linkable ring signatures provided in Embodiment 1 of the present invention is shown. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below: In step S301, the charging pile verifies the time validity of the charging request ring signature based on the first message timestamp and the first system timestamp.

[0057] In this embodiment of the invention, when the charging pile verifies the first message timestamp and the first system timestamp in the charging request, specifically, the charging pile divides a day into several time windows with a preset time length, and presets different cycle lengths to represent different versions of the operation center. When the version of the operation center is upgraded, the old charging request ring signature is automatically invalidated. Specifically, it verifies whether the first message timestamp in the charging request is within the time window corresponding to the current moment, and whether the first system timestamp in the charging request matches the version of the operation center corresponding to the current moment. The preset time length and the cycle length are obtained by the charging pile from the operation center.

[0058] In step S302, if the verification in step S301 is successful, the hash value of the second ring member and the hash value of the second message identity list are calculated based on the public parameter set, the user identity list, the charging request message, the first message timestamp, and the first system timestamp.

[0059] In this embodiment of the invention, specifically, the charging pile calculates the second ring member hash value based on the electric vehicle's identity information, the first message timestamp, and the first system timestamp, and calculates the second message identity list hash value based on the user identity list (i.e., the ring member identity list) and the charging request message in the charging request.

[0060] In this embodiment of the invention, the hash value of the second ring member and the hash value of the second message identity list can be calculated using the following formula: , .

[0061] in, This represents the hash value of the second ring member. This indicates the identity information of the ring members. Indicates the first system timestamp. This represents the hash value of the second message identity list. The list of user identities, the second hash function, the identity information of the ring members, and the number of ring members are obtained by the electric vehicle from the operation center.

[0062] In step S303, the charging pile verifies the first balance value of the charging request ring signature based on the public parameter set, user identity list, charging request message, first message timestamp, first system timestamp, event identifier, second ring member hash value, and second message identity list hash value, and verifies the linkable tags based on the used tag list.

[0063] In this embodiment of the invention, when verifying the first balance value of the charging request ring signature based on the public parameter set, user identity list, charging request message, first message timestamp, first system timestamp, event identifier, second ring member hash value, and second message identity list hash value, the specific steps include: (1) Generate the third verification point and the third verification value based on the response value, challenge value, master public key, linkable tag and second ring member hash value.

[0064] In this embodiment of the invention, the charging pile calculates the response value and challenge value of the electric vehicle charging request ring signature, and reconstructs the third verification point and the third verification value based on the master public key, the linkable tag, the second verification point of the ring member and the hash value of the second ring member. If the third verification point is equal to the first verification point and the third verification value is equal to the first verification value, then continue to step (2).

[0065] In this embodiment of the invention, the third verification point and the third verification value can be calculated using the following formula: .

[0066] in, This indicates the third verification point. This indicates the second verification point. This represents the third verification value. This represents the second hash function. Indicates a linkable tag. This represents the hash value of the second ring member. The second hash function and the master public key are obtained by the charging station from the operations center.

[0067] (2) The charging pile calculates the second balance value based on the event identifier, the third verification point, the third verification value, the hash value of the second ring member, the hash value of the second message identity list, the response value, the challenge value, and the linkable tag. When the first balance value is equal to the second balance value, the verification is successful.

[0068] In this embodiment of the invention, the second equilibrium value can be calculated using the following formula: .

[0069] in, This represents the second equilibrium value. Indicates a linkable tag. This represents the third verification value, which can be linked to a tag obtained from the electric vehicle by the charging station.

[0070] (3) Validate the linkable tags based on the list of used tags.

[0071] In this embodiment of the invention, when verifying the ring signature of a charging request, it is verified whether the linkable tag already exists in the list of used tags. If it exists, it indicates that the electric vehicle has repeatedly initiated a charging request, and the verification fails; otherwise, the verification passes. The list of used tags includes the linkable tags of electric vehicles that have submitted charging requests to the charging station and is stored in the charging station.

[0072] In step S304, when the first message timestamp, the first system timestamp, the first ring member hash value, the first message identity list hash value, the first balance value, and the linkable tag verification pass, the electric vehicle is authorized to be charged.

[0073] The embodiments of the present invention have the following beneficial effects: 1. During the verification process of the charging request ring signature, the charging pile performs time validity verification on the received charging request ring signature to prevent electric vehicles from requesting charging from the charging pile using expired charging request ring signatures.

[0074] 2. By calculating the second balance value and verifying whether the first balance value is equal to the second balance value, the charging pile confirms the integrity of the charging request ring signature, ensuring that the ring member identity list and charging request message at the time of generating the charging request ring signature have not been tampered with, thus enhancing the unforgeability of the charging request ring signature.

[0075] 3. Verify whether the linkable tag of the charging pile is in the list of used tags to further verify the time validity of the charging request ring signature, prevent electric vehicles from using the same linkable tag to initiate charging requests, and ensure the revenue of the operation center and the fairness of charging.

[0076] Example 4: Figure 4 The implementation flow of the electric vehicle charging method based on linkable ring signatures provided in Embodiment 4 of the present invention is illustrated. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below: In step S401, the operation center obtains the minimum number of cooperating nodes and the number of charging operation center nodes. Based on the minimum number of cooperating nodes and the number of charging operation center nodes, it generates a preset number of master private key shares based on the distributed key generation protocol. Based on the master private key shares and bilinear pairs, it generates a preset number of master public key shares. Based on the preset number of master public key shares, it aggregates to generate a master public key. Based on the bilinear pairs, the elliptic curve group and target group of the bilinear pairs, the generator of the elliptic curve group, security parameters, and several hash functions, it generates a common parameter set.

[0077] In this embodiment of the invention, the common parameter set is determined by the operation center during system initialization. The common parameter set includes bilinear pairs, generators of the elliptic curve group, security parameters, prime order, a first hash function, a second hash function, a third hash function, a fourth hash function, the number of operation center nodes, a third message timestamp, a third system timestamp, and a minimum number of collaborating nodes. The third system timestamp represents the current version of the operation center, and the third message timestamp is a preset time window used to determine the length of the list of used tags stored in the charging pile storage.

[0078] In one embodiment of the present invention, the generation of the master public key can be achieved by the following steps: (1) Through Secret sharing scheme, generated by each operations center node The polynomial of degree [degree] can be generated using the following formula to generate the polynomial of the operations center node: .

[0079] in, The polynomial representing the operation center node, It is the share of the master private key. These are random numbers, used as coefficients of the polynomial. Used for counting, Let integers represent the independent variables of the polynomial, where Obtained from the charging station's operation center.

[0080] (2) Calculate the commitment value of the operation center node and broadcast it.

[0081] In this embodiment of the invention, the commitment value can be calculated using the following formula: .

[0082] in, Indicates the commitment value. Represents a random number. Used for counting, ≤ The commitment value is used to verify the correctness of the polynomial share and prevent the operation center node from cheating.

[0083] In this embodiment of the invention, broadcasting the commitment value specifically involves the current operation center node sending polynomial shares to other operation center nodes. The broadcasting of the commitment value can be represented by the following formula: .

[0084] in, Indicates the operation center node To the Operations Center Node Send polynomial shares.

[0085] (3) Verify the polynomial share of the operation center node.

[0086] In this embodiment of the invention, the polynomial share of the operation center node can be verified using the following formula: .

[0087] in, Represents a node To the node Send polynomial shares, Represents a node The Each commitment value. If the formula holds, it means the node... To the node Sending polynomial shares and commitment values Equal, nodes If there is no cheating, the multinomial share verification of the operation center node will pass; otherwise, the verification will fail.

[0088] (4) After the polynomial share of the operation center node is verified, the master public key is calculated based on the master private key share of the operation center node.

[0089] In this embodiment of the invention, the master public key can be calculated using the following formula: .

[0090] in, Indicates the operation center node The share of the master public key, This represents the share of the master private key.

[0091] In this embodiment of the invention, a distributed architecture is adopted during the electric vehicle charging process, in which several operation center nodes jointly participate in the generation of the master private key. The complete master private key is divided into multiple master private key shares and stored separately. No single operation center node can obtain the complete master private key. Even if some operation center nodes are attacked or offline, as long as the number of malicious operation center nodes does not exceed the preset number, the complete master private key cannot be generated. This effectively eliminates the single point of failure and single point of malicious activity risk of a single identity certificate authority in traditional public key infrastructure.

[0092] In step S402, the operation center generates an identity certificate for the electric vehicle based on the electric vehicle's identity information, the second system timestamp, and the second message timestamp, and issues the identity certificate to the electric vehicle.

[0093] In this embodiment of the invention, the operation center generates an identity certificate for the electric vehicle based on the electric vehicle's identity information, the second system timestamp, and the second message timestamp, specifically including the following steps: (1) The operation center verifies the validity of the electric vehicle identity information based on the identity verification function.

[0094] (2) After the electric vehicle's identity information is verified, the long-term private key of the electric vehicle is calculated based on the pre-obtained master private key share and sent to the electric vehicle. The long-term private key can be calculated using the following formula: .

[0095] in, , , It is the hash value of the electric vehicle's identity information that is requesting charging. This indicates the electric vehicle's identity information. This represents the second system timestamp, indicating the version of the operation center corresponding to the electric vehicle at the time of registration. This indicates the second message timestamp, which is the specific moment the electric vehicle was registered; The first one indicates electric vehicles A long-term private key share is generated from the minimum number of long-term private key shares through collaboration, using the Lagrange algorithm. Let Lagrange's coefficients be represented as . This indicates the long-term private key for the electric vehicle. This represents the complete master private key.

[0096] (3) After receiving the long-term private key, the electric vehicle calculates the temporary private key using the long-term private key. The temporary private key can be calculated using the following formula: .

[0097] in This represents the temporary private key for the electric vehicle. This indicates the long-term private key for the electric vehicle. This indicates the timestamp of the second message.

[0098] (4) The operation center generates an identity certificate based on the electric vehicle's identity information, the second system timestamp, the second message timestamp, and the operation center's signature private key, and issues it to the electric vehicle. The identity certificate can be generated using the following formula: in, , This indicates a message awaiting signature, consisting of the electric vehicle's identity information and a timestamp from the second system. Second message timestamp constitute, This indicates that the operation center's private key is used to generate the signature value for signing messages. The identity certificate consists of a signature value and a message to be signed. The operations center sends the identity certificate to the electric vehicle.

[0099] In step S403, the electric vehicle generates a charging request ring signature based on the public parameter set, user identity list, charging request message and charging strategy, and sends the charging request and charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp and an event identifier.

[0100] In step S404, the charging pile verifies the ring signature of the charging request based on the common parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, it authorizes the charging of the electric vehicle.

[0101] In this embodiment of the invention, the specific implementation of steps S403 to S404 can be referred to the description of the foregoing embodiments, and will not be repeated here.

[0102] In this embodiment of the invention, the long-term private key of the electric vehicle is jointly generated by at least a preset number of operation center nodes. Each operation center node calculates its share of the long-term private key and sends it to the electric vehicle. The electric vehicle then recovers the complete long-term private key through Lagrange interpolation. This process does not require any single operation center node to know the complete master private key or the long-term private key of the electric vehicle, effectively preventing single-point malicious attacks and key leakage risks, and achieving decentralized key distribution. Temporary private keys are derived from the long-term private key and bound to message timestamps. Different message timestamps generate different temporary private keys. Even if the temporary private key corresponding to a certain message timestamp is leaked, attackers cannot reverse engineer the long-term private key or any previously generated temporary private keys, ensuring the security of the ring signature for past charging requests and achieving forward security and key isolation.

[0103] Example 5: Figure 5 The implementation flow of the electric vehicle charging method based on linkable ring signatures provided in Embodiment 5 of the present invention is illustrated. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below: In step S501, the electric vehicle generates a charging request ring signature based on the public parameter set, user identity list, charging request message and charging strategy, and sends the charging request and charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp and an event identifier.

[0104] In step S502, the charging pile verifies the ring signature of the charging request based on the common parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, it authorizes the charging of the electric vehicle.

[0105] In the embodiments of the present invention, the specific implementation of steps S501 to S502 can be referred to the description of the foregoing embodiments one to three, and will not be repeated here.

[0106] In step S503, the operation center generates a master private key based on a preset number of master private key shares. The operation center determines the electric vehicle identity information based on the master private key, the charging request ring signature, the public parameter set, the user identity list, the event identifier, the first message timestamp, and the first system timestamp.

[0107] In this embodiment of the invention, when an unpaid bill for electric vehicle charging is detected, the operation center can generate a master private key based on a preset number of master private key shares. The operation center determines the electric vehicle's identity information based on the master private key, the charging request ring signature, the public parameter set, the user identity list, the event identifier, the first message timestamp, and the first system timestamp.

[0108] Specifically, if, during the charging process, a charging station claims that the electric vehicle has not completed payment, the operations center needs to trace the identity of the person who signed for the electric vehicle to clarify responsibility. In some embodiments, determining the identity information of the electric vehicle can be achieved through the following steps: (1) The operation center extracts linkable tags from the charging request ring signature of electric vehicles. The extraction of linkable tags can be expressed by the following formula: 。

[0109] in, This represents the ring signature for the electric vehicle's charging request. This indicates the linkable tag field in the charging request ring signature. This indicates the linkable tag extracted from the ring signature of the charging request corresponding to the electric vehicle for which payment has not been completed; the first message timestamp, the first system timestamp, and the event identifier are obtained by the operation center from the charging records stored in the charging pile.

[0110] (2) The operation center receives at least Authorization of each operation center node, and based on The master private key share of each operation center node is used to recover the master private key using the Lagrange interpolation algorithm. The operation center node selected for generating the master private key can be represented by the following formula: (5) The operation center uses the public parameter set and the master private key to traverse the user identity list and lock the specific identity of the electric vehicle.

[0111] In some embodiments, the operation center traverses the user identity list based on a public parameter set and the master private key to pinpoint the specific identity of the electric vehicle, which includes the following steps: (5-1) The long-term private key of each ring member can be calculated using the following formula: .

[0112] in, Indicates the first The long-term private key of each ring member.

[0113] (5-2) The temporary private key of each ring member can be calculated using the following formula: .

[0114] in, Indicates the first Temporary private key of each ring member.

[0115] (5-3) The first linkable tag of each ring member can be calculated using the following formula: .

[0116] in, Indicates the event identifier, The hash representing the event identifier. Indicates the first The first linkable tag of each ring member.

[0117] (5-4) Based on the principle that the charging request ring signatures generated by the same signer in the same event and time have the same linkable label, check whether the first linkable label of the calculated ring member is the same as the linkable label extracted from the charging request ring signature of the electric vehicle. If they are the same, the ring member corresponding to the first linkable label is the electric vehicle.

[0118] In this embodiment of the invention, when an electric vehicle is detected to deny charging or maliciously default on payments, the operation center, after obtaining authorization, traverses the ring member list and calculates the hash value of the first ring member, the long-term private key, the temporary private key, and the linkable tag when the charging request ring signature is generated. Only when the charging request ring tag generated by the charging pile is completely equal to the linkable tag in the charging request ring signature of the electric vehicle, does it indicate that the electric vehicle is an unpaid electric vehicle tracked by the operation center. This provides traceable technical support for handling and legally auditing the problem of electric vehicle fare evasion while protecting user privacy.

[0119] Example 6: Figure 6 The implementation flow of the electric vehicle charging method based on linkable ring signatures provided in Embodiment Six of the present invention is illustrated. For ease of explanation, only the parts related to the embodiments of the present invention are shown, and are described in detail below: In step S601, the electric vehicle generates a charging request ring signature based on the public parameter set, user identity list, charging request message and charging strategy, and sends the charging request and charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp and an event identifier.

[0120] In step S602, the charging pile verifies the ring signature of the charging request based on the common parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, it authorizes the charging of the electric vehicle.

[0121] In the embodiments of the present invention, the specific implementation of steps S601 to 602 can be referred to the description of the foregoing embodiments one to three, and will not be repeated here.

[0122] In step S603, the electric vehicle generates a first monitoring parameter based on a first random number and a prime base, and sends the first monitoring parameter to the charging pile.

[0123] In this embodiment of the invention, when either the charging pile or the electric vehicle requests a charging status session, steps 603 to S607 are used to negotiate a two-way session key between the charging pile and the electric vehicle, which is then used to exchange information such as the current battery level and time.

[0124] The electric vehicle generates first monitoring parameters based on a first random number and a prime base, and sends these first monitoring parameters to the charging station. Specifically, the first monitoring parameters can be calculated using the following formula: , .

[0125] in, Represent the base of a prime number , Represent the base of a prime number The reverse of the model, , Modulus of integer The multiplication group, containing from arrive integers, Represents the first random number , This indicates the first monitoring parameter.

[0126] In step S604, the charging pile generates a second monitoring parameter based on a second random number and a prime base, and sends the second monitoring parameter to the electric vehicle.

[0127] In this embodiment of the invention, the charging pile generates a second monitoring parameter based on a second random number and a prime base, and sends the second monitoring parameter to the electric vehicle. Specifically, the second monitoring parameter can be calculated using the following formula: in, This indicates the second monitoring parameter. Represents the second random number .

[0128] In step S605, the electric vehicle generates an electric vehicle session key based on the second monitoring parameter and the first random number, and generates an electric vehicle message authentication code based on the first monitoring parameter, the second monitoring parameter, the charging pile identity identifier, the prime number base, and the charging timestamp using a message authentication function and sends it to the charging pile.

[0129] In this embodiment of the invention, the electric vehicle session key can be calculated using the following formula: .in, This represents the session key for the electric vehicle.

[0130] In this embodiment of the invention, the electric vehicle message authentication code can be calculated using a MAC function, and the calculation formula is as follows: .

[0131] in, This indicates the electric vehicle message authentication code. This indicates the identity of the charging station. This indicates the charging timestamp.

[0132] In step S606, the charging pile generates a charging pile session key based on the first monitoring parameter and the second random number, and generates a charging pile message authentication code based on the first monitoring parameter, the second monitoring parameter, the electric vehicle identification, the prime number base, and the charging timestamp using a message authentication function and sends it to the electric vehicle.

[0133] In this embodiment of the invention, the charging pile generates a charging pile session key based on the first monitoring parameter and the second random number, and generates a charging pile message authentication code based on the first monitoring parameter, the second monitoring parameter, the electric vehicle identification, the prime number base, and the charging timestamp using a message authentication function and sends it to the electric vehicle.

[0134] The charging station session key can be calculated using the following formula: .in This indicates the charging station session key.

[0135] In this embodiment of the invention, the charging pile message authentication code can be calculated using a MAC function, and the following formula can be used to calculate the charging pile message authentication code: .

[0136] in, This indicates the authentication code for the charging pile message. This indicates the identification of an electric vehicle.

[0137] In step S607, the charging pile and the electric vehicle determine a two-way session key based on the charging pile message authentication code, the electric vehicle message authentication code, the charging pile session key, and the electric vehicle session key.

[0138] In this embodiment of the invention, it is verified whether the values ​​of the electric vehicle session key and the charging pile session key are the same. When the values ​​of the electric vehicle message authentication code and the charging pile message authentication code are the same, it indicates that the two-way authentication is successful. At this time, the electric vehicle session key or the charging pile session key is determined as the two-way session key.

[0139] In this embodiment of the invention, the two-way session key is never directly transmitted in the channel during the negotiation process. Both parties independently calculate the same key using their respective random numbers. Even if an attacker intercepts all the publicly available parameters, they cannot deduce the key. Furthermore, the negotiation process only involves elliptic curve multiplication, modular inverse, and hash operations, resulting in low computational complexity and fewer communication rounds, making it suitable for charging piles and vehicle-mounted units with limited computing resources.

[0140] Example 7: Figure 7 The structure of an electric vehicle charging device based on a linkable ring signature provided in Embodiment 7 of the present invention is shown. For ease of explanation, only the parts related to the embodiments of the present invention are shown, including: The ring signature generation module 71 is used to generate a charging request ring signature based on the public parameter set, user identity list, charging request message and charging strategy, and send the charging request and charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp and an event identifier. The ring signature authentication module 72 is used to verify the ring signature of the charging request based on the public parameter set, user identity list, charging request message, message timestamp, system timestamp, and event identifier in the sent charging request. When the verification is successful, the electric vehicle is authorized to charge.

[0141] In some embodiments, the ring signature generation module 71 may include: The parameter generation module is used for electric vehicles to generate event identifiers based on charging request identifiers, charging strategies, and first message timestamps; generate temporary private keys based on pre-acquired master private key shares; generate linkable tags based on event identifiers and temporary private keys; and generate first ring member hash values ​​and first message identity list hash values ​​based on user identity lists, first message timestamps, first system timestamps, and charging request messages. The signature sending module is used by electric vehicles to generate a charging request ring signature based on the hash value of the first ring member of the linkable tag, the hash value of the first message identity list, and the common parameter set, and to send the charging request and the charging request ring signature to the charging pile.

[0142] In this embodiment of the invention, for the sake of convenience and brevity, only the division of the above-described functional units and modules is used as an example. In practical applications, the above functions can be allocated to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to achieve all or part of the functions described above. Each unit and module of the device can be implemented by corresponding hardware or software units. Each unit and module can be an independent hardware or software unit, or it can be integrated into a single hardware or software unit, which is not intended to limit the invention. In addition, the specific names of each functional unit and module are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the device can be referred to the corresponding description in the foregoing method embodiments, and will not be repeated here.

[0143] Example 8: In this embodiment of the invention, a computer-readable storage medium is provided, which stores a computer program. When executed by a processor, the computer program implements the steps described in the above-described embodiment of the electric vehicle charging method based on a linkable ring signature. For example... Figure 1 The steps S101 to S102 are shown. Alternatively, when the computer program is executed by the processor, it implements the functions of each unit in the above-described device embodiments, for example... Figure 7 The functions of units 71 to 72 shown.

[0144] The computer-readable storage medium of this invention can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EEPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this invention, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0145] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the scope of disclosure involved in the above embodiments is not limited to technical solutions formed by specific combinations of the above technical features, but should also cover other technical solutions formed by arbitrary combinations of the above technical features or their equivalent features without departing from the above-disclosed concept. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0146] Furthermore, while the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in sequential order. In certain circumstances, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of the invention. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

Claims

1. A method for charging electric vehicles based on linked ring signatures, characterized in that, The method includes: The electric vehicle generates a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, and sends a charging request and the charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp, and an event identifier. The charging pile verifies the ring signature of the charging request based on the common parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, it authorizes the charging of the electric vehicle.

2. The method of claim 1, wherein, The steps of an electric vehicle generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, and sending the charging request and the charging request ring signature to the charging pile include: The electric vehicle generates the event identifier based on the charging request identifier, the charging strategy, and the first message timestamp; generates a temporary private key based on the pre-acquired master private key share; generates a linkable tag based on the event identifier and the temporary private key; and generates a first ring member hash value and a first message identity list hash value based on the user identity list, the first message timestamp, the first system timestamp, and the charging request message. The electric vehicle generates the charging request ring signature based on the linkable tag, the hash value of the first ring member, the hash value of the first message identity list, and the public parameter set, and sends the charging request and the charging request ring signature to the charging pile.

3. The method of claim 2, wherein, The step of verifying the ring signature of the charging request based on the common parameter set, the user identity list, the charging request message, the first message timestamp, the first system timestamp, and the event identifier in the sent charging request includes: The charging pile verifies the time validity of the charging request ring signature based on the first message timestamp and the first system timestamp. If the verification is successful, it calculates the second ring member hash value and the second message identity list hash value based on the public parameter set, the user identity list, the charging request message, the first message timestamp, and the first system timestamp. The charging pile verifies the first balance value of the charging request ring signature based on the public parameter set, the user identity list, the charging request message, the first message timestamp, the first system timestamp, the event identifier, the second ring member hash value, and the second message identity list hash value, and verifies the linkable tags based on the used tag list.

4. The method of claim 2, wherein, Before the step of generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, the electric vehicle also includes: The operation center obtains the minimum number of cooperating nodes and the number of charging operation center nodes. Based on the minimum number of cooperating nodes and the number of charging operation center nodes, it generates a preset number of master private key shares based on the distributed key generation protocol. Based on the master private key shares and bilinear pairings, it generates a preset number of master public key shares. Based on the preset number of master public key shares, it aggregates to generate a master public key. The operation center generates the common parameter set based on the bilinear pair, the elliptic curve group and target group of the bilinear pair, the generator of the elliptic curve group, security parameters, and several hash functions.

5. The method of claim 2, wherein, Following the step of authorizing the charging of the electric vehicle, the method further includes: The operation center generates a master private key based on a preset number of master private key shares, and determines the electric vehicle identity information based on the master private key, the charging request ring signature, the public parameter set, the user identity list, the event identifier, the first message timestamp, and the first system timestamp.

6. The method of claim 1, wherein, Before the step of generating a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, the electric vehicle also includes: The operation center generates an identity certificate for the electric vehicle based on the electric vehicle's identity information, the second system timestamp, and the second message timestamp, and then issues the identity certificate to the electric vehicle.

7. The method of claim 1, wherein, Following the step of authorizing the charging of the electric vehicle, the method further includes: The electric vehicle generates a first monitoring parameter based on a first random number and a prime base, and sends the first monitoring parameter to the charging pile; The charging pile generates a second monitoring parameter based on a second random number and the prime base, and sends the second monitoring parameter to the electric vehicle; The electric vehicle generates an electric vehicle session key based on the second monitoring parameter and the first random number. Based on the first monitoring parameter, the second monitoring parameter, the charging pile identity identifier, the prime number base, and the charging timestamp, it generates an electric vehicle message authentication code using a message authentication function and sends it to the charging pile. The charging pile generates a charging pile session key based on the first monitoring parameter and the second random number, and generates a charging pile message authentication code based on the first monitoring parameter, the second monitoring parameter, the electric vehicle identification, the prime number base, and the charging timestamp using the message authentication function and sends it to the electric vehicle. The charging pile and the electric vehicle determine a two-way session key based on the charging pile message authentication code, the electric vehicle message authentication code, the charging pile session key, and the electric vehicle session key.

8. An electric vehicle charging device based on linkable ring signature, characterized in that, The device includes: The ring signature generation module is used to generate a charging request ring signature based on a public parameter set, a user identity list, a charging request message, and a charging strategy, and to send a charging request and the charging request ring signature to the charging pile. The charging request includes a first message timestamp, a first system timestamp, and an event identifier. The ring signature authentication module is used to verify the ring signature of the charging request based on the public parameter set, user identity list, charging request message, first message timestamp, first system timestamp, and event identifier in the sent charging request. When the verification is successful, the module authorizes the charging of the electric vehicle.

9. The apparatus of claim 8, wherein, The ring signature generation module includes: The parameter generation module is used for the electric vehicle to generate the event identifier based on the charging request identifier, the charging strategy, and the first message timestamp; generate a temporary private key based on the pre-acquired master private key share; generate a linkable tag based on the event identifier and the temporary private key; and generate a first ring member hash value and a first message identity list hash value based on the user identity list, the first message timestamp, the first system timestamp, and the charging request message. The signature sending module is used for the electric vehicle to generate the charging request ring signature based on the linkable tag, the hash value of the first ring member, the hash value of the first message identity list, and the public parameter set, and to send the charging request and the charging request ring signature to the charging pile.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

Images