CN103873473A - Method for authenticating anonymity groups of power-driven automobiles by charging station - Google Patents

Abstract

The invention discloses an anonymous group authentication method for an electric vehicle by a charging station, which relates to the technical field of information security and comprises the following steps: 1. The electric vehicle requests to connect to a power grid; 2. A central aggregator issues a network access license for the electric vehicle; 3. The electric vehicle requests to join a charging station in a certain area; 4. The local aggregator verifies the legitimacy of the electric vehicle network access certificate; 5. The local aggregator assigns the group to which the electric vehicle belongs and issues a certificate; 6. The electric vehicle requests access Charging station; 7. Charging station verifies whether electric vehicles are allowed to access; 8. Charging station assigns an actually available charging socket to verified electric vehicles; 9. Information and energy interaction between electric vehicles and charging stations. The invention realizes the anonymous authentication of the vehicle by the charging station, can track malicious users and give certain punishments, and at the same time improves the efficiency of group authentication.

Description

Anonymous group authentication method for electric vehicles at charging stations

technical field

The invention belongs to the technical field of communication, and further relates to an anonymous group authentication method for an electric vehicle by a charging station in the technical field of information security. The present invention can be used in the scene where the electric vehicle needs to be charged or powered and connected to the power grid to realize the anonymous authentication of the vehicle user by the charging station, thereby protecting the privacy of the vehicle user.

Background technique

Electric vehicles connected to the grid (V2G) combines electric vehicles with smart grids, which not only solves the problem of charging pressure caused by the large-scale development of electric vehicles, but also connects electric vehicles to the grid as mobile and distributed energy storage units. However, the mobility of electric vehicles is strong, and frequent data exchange satisfies real-time management and at the same time brings the risk of user sensitive information leakage. Therefore, the V2G charging station (ST _i ) needs to design an anonymous group authentication scheme, which supports dynamic joining of members and identity revocation with low overhead.

Binod Vaidya et al. proposed a comprehensive decentralized authentication method for electric vehicle charging in the article "Efficient Authentication Mechanism for PEVCharging Infrastructure" (In: Communications (ICC), 2011 IEEE International Conference on). The specific implementation steps of this method are: _first , initialization, the server of the charging station obtains a certificate from the registration authority; parameters, write these parameters into the smart card, and send the smart card to user UD _i . Third, in the authentication stage, when user UD _i wants to access the charging device, user UD _i must enter his identity and login password into the smart card, and the smart card verifies whether the login password is valid. If not, the login request is rejected; otherwise, the smart card generates a certificate, and send the certificate to the server of the charging station. The server verifies the validity of the certificate. Fourth, if the user UD _i wants to update the login password, it needs to reset the password. Fifth, when a user's valid registration expires, all parameters need to be updated. Although this method has a mutual authentication function and protects the user's identity privacy. However, the disadvantage of this method is that when a malicious user disturbs the order of the power grid, the identity of the malicious user cannot be verified, so that the malicious user cannot be punished.

In the article "A Secure and Privacy-Preserving Communication Protocol for V2G Networks" (In: Communications, 2012 IEEE Wireless Communications and Networking Conference), Huei-Ru Tseng et al proposed one of the electric vehicles to join the grid (Vehical-to-Grid, V2G) Secure, privacy-preserving communication methods. The specific implementation steps of the method are: first, the key center initializes system parameters, and distributes public and private keys for the electric vehicle, the local aggregator and the central aggregator. Second, electric vehicles must register with the central aggregator before joining the network composed of electric vehicles and the grid. The electric vehicle sends its identity and generated parameters to the central aggregator. After the central aggregator verifies that the identity is legal, it generates a certificate. , and issue the certificate to the electric vehicle. Third, when an electric vehicle is connected to the grid (Vehical-to-Grid, V2G), the electric vehicle will send the pseudonym and the certificate to the local aggregator, and the local aggregator will verify the validity of the certificate. Fourth, after confirming the validity of the certificate, the electric vehicle sends its state information to the local aggregator, and the local aggregator aggregates all the received information and sends the aggregation result to the central aggregator. The method adopts pseudonyms to realize the privacy protection of user identities. The pseudonyms are generated and distributed to different users by the central aggregator, which needs to store these pseudonyms. Every time an electric vehicle joins a V2G network, it needs to use a different pseudonym, and the number of users is relatively large. This brings the problem of management and maintenance of pseudonyms to the central aggregator.

State Grid Corporation of China proposed an electric vehicle in its patent application "Safety Data Exchange Method and System for Electric Vehicles and Charging Stations" (application date: October 15, 2010, application number: 201010508362.3, publication number: CN102045340A). A safe data exchange method between the car and the charging and swapping station. The implementation method of this method is: first, the electric vehicle sends its own integrity information through digital signature to the charging and swapping station, and obtains the integrity information of the other party to submit to the safety information management center; second, the charging and swapping station sends the safety information The management center submits the integrity information sent by the electric vehicle, and submits the digitally signed integrity information to the electric vehicle; third, the safety information management center authenticates the integrity information and feeds back the certification results; fourth, the certification results are in line with , the connection between the electric vehicle and the charging and swapping station is established for data exchange. Although the patent application has achieved the safety verification of the equipment status of electric vehicles and charging and swapping stations through the verification of equipment integrity information. However, this method still has shortcomings in that: the legality of the user identity is not authenticated, and when a malicious user appears, the malicious user cannot be tracked.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, and propose an anonymous group authentication method for electric vehicles by charging stations for electric vehicles joining the power grid. The invention realizes the anonymous authentication of the electric vehicle by the charging station, and at the same time can track malicious users and give certain punishments, which greatly improves the stability of the power grid system.

To achieve the above object, the concrete steps of the present invention are as follows:

1. A method for anonymous group authentication of electric vehicles by a charging station, comprising the following steps:

(1) Request access to the grid:

(1a) The user sends the real identity of the user and the real identity of the electric vehicle license plate to be connected to the central aggregator for registration, and the central aggregator issues an ID card for the electric vehicle to be connected to the network, and records the ID card to the central aggregator in the database;

(1b) The electric vehicle to be connected to the network sends the network connection request information to the central aggregator, requesting to connect to the charging station;

(2) Issuing a license certificate:

The central aggregator checks whether its database stores the ID card of the electric vehicle to be connected to the network. If it is stored but the network access permit has not been issued, the central aggregator uses its own private key to sign the identity and public key of the electric vehicle to generate a network access permit. , issue the license certificate to the electric vehicle to be connected to the network; if not stored, perform step (1);

(3) Request to join the zone:

The electric vehicle sends the request information of the area to be joined to the local aggregator;

(4) Verify that the certificate is legal:

(4a) The local aggregator uses the public key of the central aggregator to verify whether the network access certificate is legal, if the network access certificate is not legal, then perform step (1); otherwise, perform step (4b);

(4b) The local aggregator verifies whether the time of receiving the network access permit is within the valid date range, if it exceeds the valid date, then execute step (1), otherwise execute step (5);

(5) Establish group parameters and issue certificates:

(5a) The local aggregator sends the message that the electric vehicle is allowed to join the group where the charging station is located to the electric vehicle;

(5b) The electric vehicle generates an electric vehicle number according to the number generation method, and sends the electric vehicle number to the local aggregator;

(5c) After the local aggregator receives the electric vehicle number sent from the electric vehicle, it checks whether the record table in the current database contains the electric vehicle number, and if so, executes step (5b); otherwise, allocates A charging location and corresponding charging location identifier;

(5d) The local aggregator sends the relevant information of the group it belongs to and the signature certificate for accessing the charging station to the electric vehicle;

(5e) Electric vehicles generate group member certificates according to the following formula:

C=(I,X,num,σ)

Among them, C represents the group member certificate, I represents the electric vehicle charging location identifier, X represents the number of the electric vehicle, num represents the path code of the electric vehicle, and σ represents the number of the electric vehicle with the system private key signed by the local aggregator with structure protection Structure-protected signatures with path coding for EVs;

(6) Request access to the charging station:

The electric vehicle sends a request message to be connected to the charging station to the charging station;

(7) Verify whether electric vehicle access is allowed:

(7a) The charging station uses the public key of the local aggregator to verify the legitimacy of the signature certificate of the electric vehicle. If the signature certificate is not legal, then execute step (5), otherwise execute step (7b);

(7b) The charging station verifies whether the time of receiving the signed certificate is within the valid date of the signed certificate, if it exceeds the valid date, then execute step (5), otherwise execute step (8);

(8) The charging station assigns an actually available charging socket to the electric vehicle;

(9) Information and energy interaction:

(9a) After the electric vehicle is connected to the charging station, it conducts key negotiation with the charging station, and negotiates a session key;

(9b) The electric vehicle proves itself to be a legitimate group member through the subset division method and the vector commitment method;

(9c) The electric vehicle uses the private key of the group to sign its own application message and send the signature result to the charging station;

(9d) After the charging station receives the message from the electric vehicle, it uses the group public key to verify the signature. If the verification is passed, the charging station will exchange energy and information with the electric vehicle according to the application and the grid demand; Otherwise, execute step (9e);

(9e) The charging station sends the group signature message sent by the electric vehicle to the local aggregator;

(9f) After receiving the signed message sent from the charging station, the local aggregator tracks the electric vehicle that sent the wrong message according to the group member tracking method.

Compared with the prior art, the present invention has the following advantages:

First, since the present invention uses revocable group member signatures during information interaction between electric vehicles and charging stations, it overcomes the disadvantage of untraceable malicious users in the prior art, making the present invention traceable to malicious users , can punish malicious users and improve the stability of the power grid system.

Second, because the invention adopts the subset division method and the vector commitment method when the electric vehicle anonymously proves the legality of the identity to the charging station, it overcomes the disadvantages of high management and maintenance complexity in the prior art that uses pseudonyms to realize anonymous authentication , so that the present invention realizes the simplification of management and maintenance.

Third, since the present invention adopts a structure-protected signature when the group member certificate is formed, it overcomes the shortcoming that the group member certificate needs to be continuously updated when updating the member state list in the prior art, so that the present invention realizes There is no need to update group member certificates when listing, which reduces computing overhead and improves group authentication efficiency.

Description of drawings

Fig. 1 is a flowchart of the present invention;

Fig. 2 is a schematic diagram of the relationship and functions of the central aggregator, local aggregator, and charging station of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

Referring to accompanying drawing 2, the relation and function of central aggregator, local aggregator and charging station involved in the present invention are as follows:

The central aggregator is the highest-level processor in the Vehical-to-Grid (V2G) of electric vehicles. Due to the strong computing and storage capabilities of the central aggregator, it is mainly responsible for the registration of electric vehicles. Issue network access license certificates for electric vehicles and save detailed identity information of all registered users, including multiple local aggregators.

The local aggregator is the next-level processor of the central aggregator. Since the computing and storage capabilities of the local aggregator are weaker than that of the central aggregator, it is mainly responsible for assigning groups to electric vehicles and issuing certificates.

The charging station is the next level of the local aggregator and acts as the interface for electric vehicles to the grid. Information and energy are exchanged between EVs and charging stations, and charging stations and local aggregators jointly maintain a revocable list.

With reference to accompanying drawing 1, the realization step of the present invention is as follows.

Step 1, request to connect to the grid.

The user sends the real identity of the user and the real identity of the electric vehicle license plate to be connected to the central aggregator for registration, and the central aggregator issues an ID card for the electric vehicle to be connected to the network, and records the ID card in the database of the central aggregator .

The electric vehicle to be connected to the network sends the network access request information to the central aggregator. The request information is the result of encrypting the ID card of the electric vehicle with the public key of the central aggregator.

Step 2, issuing license certificates.

After receiving the request information, the central aggregator decrypts it with its private key to obtain the ID card of the electric vehicle. Then, the central aggregator checks whether the ID card of the electric vehicle to be connected to the network is stored in its database. If it is stored, but the network access license certificate has not been issued, the central aggregator uses its own private key to sign the identity and public key of the electric vehicle to obtain the network access License certificate, issue the license certificate to the electric vehicle to be connected to the network; if it is not stored, go to step 1.

Step 3, request to join the zone.

The electric vehicle will send the request information to the local aggregator to the local aggregator. The request information is the identity of the electric vehicle, the public key of the electric vehicle, the identity of the central aggregator, the charging station the electric vehicle wants to join, the central aggregator The result of encrypting the network access certificate issued to the electric vehicle with the public key of the local aggregator.

Step 4, verify whether the certificate is legal.

In the first step, the local aggregator uses the public key of the central aggregator to verify whether the network access license is legal according to the following steps. If the network access license is not valid, perform step 1; otherwise, perform the first step of step 4.

After the local aggregator receives the request message sent by the electric vehicle, it decrypts the request message with the private key of the local aggregator, and obtains the identity of the electric vehicle, the public key of the electric vehicle, the identity of the central aggregator, and the user the electric vehicle wants to join. Network access certificates issued by charging stations and central aggregators to electric vehicles.

According to the identity of the central aggregator, the local aggregator searches the public key list and obtains the public key of the central aggregator.

The local aggregator uses the public key of the central aggregator to verify whether the signature of the central aggregator is valid. If it is valid, it means that the network access license is legal; otherwise, the network access license is invalid.

In the second step, the local aggregator verifies whether the time of receiving the network access permit is within the valid date range. If it exceeds the valid date, go to step 1, otherwise go to step 5.

Step 5, establish group parameters and issue certificates.

In the first step, the local aggregator assigns the group to which the electric vehicle belongs according to the charging station it wants to join, and sends information about the group it belongs to to the electric vehicle.

In the second step, the electric vehicle calculates an electric vehicle number according to the following formula, and sends the electric vehicle number to the local aggregator:

X=g ^x

Among them, X represents the serial number of the electric vehicle, x represents the group private key of the electric vehicle, and g represents the generator of the group G.

In the third step, after the local aggregator receives the electric vehicle number sent from the electric vehicle, it checks whether the record table in the current database contains the electric vehicle number, and if so, executes the second step of step 5; if not , assign a charging location and a corresponding charging location identifier to the electric vehicle, and record the number in its database.

In the fourth step, the local aggregator uses its own private key to sign the serial number and public key of the electric vehicle to obtain a signature certificate for the electric vehicle to connect to the charging station, and sends the signature certificate to the electric vehicle. The validity period of this signature certificate is short, and generally for a day.

In the fifth step, the electric vehicle obtains the group member certificate according to the following formula:

C=(I,X,num,σ)

Among them, C represents the group member certificate, I represents the electric vehicle charging location identifier, X represents the number of the electric vehicle, num represents the path code of the electric vehicle, and σ represents the number of the electric vehicle with the system private key signed by the local aggregator with structure protection Structure-protected signatures performed with path coding for EVs.

Step 6, request access to the charging station.

The electric vehicle will send a request message to the charging station to connect to the charging station. This request message is the number of the electric vehicle, the public key of the electric vehicle, the identity of the local aggregator, and the certificate issued by the local aggregator to the electric vehicle. The result of encrypting the private key of the charging station.

Step 7, verify whether electric vehicles are allowed to access.

In the first step, the charging station uses the public key of the local aggregator to verify the legitimacy of the electric vehicle signature certificate according to the following steps. If the signature certificate is invalid, go to step 5, otherwise go to step 2 of step 7.

After receiving the request message from the electric vehicle, the charging station decrypts the request message with the private key of the charging station, and obtains the number of the electric vehicle, the public key of the electric vehicle, the identity of the local aggregator, and the certificate issued by the local aggregator to the electric vehicle. Issue a certificate.

According to the identity of the local aggregator, the charging station searches the public key list and obtains the public key of the local aggregator.

The charging station uses the public key of the local aggregator to verify whether the signature of the local aggregator is valid. If it is valid, it means that the issued certificate is legal; otherwise, it means that the issued certificate is illegal.

In the second step, the charging station verifies whether the time of receiving the signed certificate is within the valid date of the signed certificate. If it exceeds the valid date, go to step 5, otherwise go to step 8.

Step 8, assign charging sockets.

The charging station assigns the electric vehicle a physically available charging socket.

Step 9, information and energy interaction.

In the first step, after the electric vehicle connects to the charging station, it conducts key negotiation with the charging station to negotiate a session key.

In the second step, using the subset partition method and the vector commitment method respectively, the electric vehicle anonymously proves to the charging station that it is a legitimate group member.

In the third step, the electric vehicle uses the group private key to sign its own charging application message, and sends the signature result to the charging station. The signature method used here is a revocable group signature.

Step 4: After the charging station receives the message from the electric vehicle, it uses the group public key to verify the signature. If the verification is passed, the charging station will exchange energy and information with the electric vehicle according to the application and the grid demand. ; Otherwise, go to Step 5 of Step 9.

In the fifth step, the charging station sends the group signature message sent by the electric vehicle to the local aggregator.

Step 6: After receiving the signed message from the charging station, the local aggregator uses the group member tracking method to track the electric vehicle that sent the wrong message and impose certain penalties according to the following steps.

The local aggregator uses the group signature to open the private key and obtain an EV number.

Check the relevant information records of the numbered electric vehicle in the database of the local aggregator, and send the relevant information of the numbered electric vehicle to the central aggregator.

The central aggregator finds out the real identity of the electric vehicle in the database according to the received electric vehicle-related information sent by the local aggregator, and imposes certain penalties.

Claims (7)

1. A method for anonymous group authentication of electric vehicles by a charging station, comprising the following steps: (1) Request access to the grid: (1a) The user sends the real identity of the user and the real identity of the electric vehicle license plate to be connected to the central aggregator for registration, and the central aggregator issues an ID card for the electric vehicle to be connected to the network, and records the ID card to the central aggregator in the database; (1b) The electric vehicle to be connected to the network sends the network connection request information to the central aggregator, requesting to connect to the charging station; (2) Issuing a license certificate: The central aggregator checks whether its database stores the ID card of the electric vehicle to be connected to the network. If it is stored but the network access permit has not been issued, the central aggregator uses its own private key to sign the identity and public key of the electric vehicle to generate a network access permit. , issue the license certificate to the electric vehicle to be connected to the network; if not stored, perform step (1); (3) Request to join the zone: The electric vehicle sends the request information of the area to be joined to the local aggregator; (4) Verify that the certificate is legal: (4a) The local aggregator uses the public key of the central aggregator to verify whether the network access certificate is legal, if the network access certificate is not legal, then perform step (1); otherwise, perform step (4b); (4b) The local aggregator verifies whether the time of receiving the network access permit is within the valid date range, if it exceeds the valid date, then execute step (1), otherwise execute step (5); (5) Establish group parameters and issue certificates: (5a) The local aggregator sends the message that the electric vehicle is allowed to join the group where the charging station is located to the electric vehicle; (5b) The electric vehicle generates an electric vehicle number according to the number generation method, and sends the electric vehicle number to the local aggregator; (5c) After the local aggregator receives the electric vehicle number sent from the electric vehicle, it checks whether the record table in the current database contains the electric vehicle number, and if so, executes step (5b); otherwise, allocates A charging location and corresponding charging location identifier; (5d) The local aggregator sends the relevant information of the group it belongs to and the signature certificate for accessing the charging station to the electric vehicle; (5e) Electric vehicles generate group member certificates according to the following formula: C=(I,X,num,σ) Among them, C represents the group member certificate, I represents the electric vehicle charging location identifier, X represents the number of the electric vehicle, num represents the path code of the electric vehicle, and σ represents the number of the electric vehicle with the system private key signed by the local aggregator with structure protection Structure-protected signatures with path coding for EVs; (6) Request access to the charging station: The electric vehicle sends a request message to be connected to the charging station to the charging station; (7) Verify whether electric vehicle access is allowed: (7a) The charging station uses the public key of the local aggregator to verify the legitimacy of the signature certificate of the electric vehicle. If the signature certificate is not legal, then execute step (5), otherwise execute step (7b); (7b) The charging station verifies whether the time of receiving the signed certificate is within the valid date of the signed certificate, if it exceeds the valid date, then execute step (5), otherwise execute step (8); (8) The charging station assigns an actually available charging socket to the electric vehicle; (9) Information and energy interaction: (9a) After the electric vehicle is connected to the charging station, it conducts key negotiation with the charging station, and negotiates a session key; (9b) The electric vehicle proves itself to be a legitimate group member through the subset division method and the vector commitment method; (9c) The electric vehicle uses the private key of the group to sign its own application message and send the signature result to the charging station; (9d) After the charging station receives the message from the electric vehicle, it uses the group public key to verify the signature. If the verification is passed, the charging station will exchange energy and information with the electric vehicle according to the application and the grid demand; Otherwise, execute step (9e); (9e) The charging station sends the group signature message sent by the electric vehicle to the local aggregator; (9f) After receiving the signed message sent from the charging station, the local aggregator tracks the electric vehicle that sent the wrong message according to the group member tracking method. 2. The charging station according to claim 1 is characterized in that, whether the verification network access certificate described in step (4a) is legal, is carried out according to the following steps: In the first step, after receiving the request message from the electric vehicle, the local aggregator decrypts the request message with the private key of the local aggregator to obtain the identity of the electric vehicle, the public key of the electric vehicle, the identity of the central aggregator, the The charging station that wants to join, the network access license certificate issued by the central aggregator to the electric vehicle; In the second step, the local aggregator searches the public key list according to the identity of the central aggregator, and obtains the public key of the central aggregator; In the third step, the local aggregator uses the public key of the central aggregator to verify whether the signature of the central aggregator is valid. If it is valid, it means that the network access license certificate is legal; otherwise, it means that the network access license is not legal. 3. The charging station according to claim 1 is characterized in that the number generation method described in step (5b) refers to obtaining the electric vehicle number according to the following formula: X=g ^x Among them, X represents the serial number of the electric vehicle, x represents the group private key of the electric vehicle, and g represents the generator of the group G. 4. charging station according to claim 1 to the anonymous group authentication method of electric vehicle, it is characterized in that, whether the verification signature certificate described in step (7a) is legal, is carried out according to the following steps: In the first step, after receiving the request message from the electric vehicle, the charging station decrypts the request message with the private key of the charging station, and obtains the serial number of the electric vehicle, the public key of the electric vehicle, the identity of the local aggregator, and the Certificate of issuance issued by electric vehicles; In the second step, the charging station searches the public key list according to the identity of the local aggregator, and obtains the public key of the local aggregator; In the third step, the charging station uses the public key of the local aggregator to verify whether the signature of the local aggregator is valid. If it is valid, it means that the issued certificate is legal; otherwise, it means that the issued certificate is not legal. 5. The charging station according to claim 1 is characterized in that the subset division method described in step (9b) is carried out as follows: In the first step, the local aggregator divides the non-revoked group members into several disjoint sets; In the second step, the local aggregator encodes the disjoint sets to obtain the path encodings of unrevoked group members. 6. The charging station according to claim 1 is characterized in that the vector commitment method described in step (9b) is carried out as follows: In the first step, after the electric vehicle makes a commitment to the message vector that can prove that it is a legitimate user, it sends the commitment value to the charging station; In the second step, the charging station uses the vector commitment key to open the commitment and obtain the message vector. 7. The charging station according to claim 1 is characterized in that the group member tracking method described in step (9f) is carried out according to the following steps: In the first step, the local aggregator uses the group signature to open the private key and obtain an electric vehicle number; The second step is to check the relevant information records of the numbered electric vehicle in the database of the local aggregator, and send the relevant information of the numbered electric vehicle to the central aggregator; In the third step, the central aggregator finds out the real identity of the electric vehicle in the database according to the received information about the electric vehicle sent by the local aggregator.

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