Service providing system, service providing method, and program

Abstract

The present disclosure provides a service provision system that provides a service to the user terminal of a user, the service provision system comprising: a reception unit that receives, from a prescribed user terminal of a prescribed user, a second electronic certificate that includes a first electronic certificate indicating information pertaining to the prescribed user and indicates a use application for the service; a verification unit that verifies the validity of the first electronic certificate and the validity of the second electronic certificate, with or without revocation of the first electronic certificate, by using a distributed database; a service providing unit that provides a prescribed service to the prescribed user terminal when the first electronic certificate and the second electronic certificate are valid without revocation of the first electronic certificate; and a billing unit that charges a service fee of the prescribed service to a prescribed issuer who has issued the first electronic certificate.

Description

Service provision system, service provision method and program

[0001] The present disclosure relates to a service providing system, a service providing method, and a program.

[0002] Self-Sovereign Identity (SSI) has been attracting attention in recent years. SSI is an identity management concept (idea) that aims to enable users to manage their own identifiers and identities themselves, without relying on centralized identity providers (ID providers), and to present only information selected at the users' own discretion to recipients such as service providers (Non-Patent Documents 1 and 2).

[0003] Here, the verification mechanism using SSI will be briefly explained using Fig. 8. Fig. 8 is a schematic diagram showing the verification mechanism using SSI. In the world of SSI, there are three parties: Holder, Issuer, and Verifier.

[0004] A Holder is a user such as a student or working adult who creates and holds a decentralized identifier such as their own DID (Decentralized DIDentifier) ​​and registers it in a decentralized DB (Data Base) 110 such as a distributed repository or blockchain network.

[0005] An Issuer is an issuer of digital certificates for schools, hospitals, government institutions, etc., and issues digital certificates such as Verifiable Credentials (VCs) that include the user's distributed identifier, etc., obtained from the user, registers them in a DB, and presents them to the user. In this case, the Issuer, for example, certifies attribute information such as the user's name (name, age, address, etc.) and qualification information such as the name of the company to which the user belongs (being an employee of a certain company, being a member of a service provided by a certain company, etc.), and then issues a digital certificate (for example, a VC) that includes the attribute information and qualification information.

[0006] The Verifier is a service provider such as a company, and uses the distributed DB 110 to verify the attributes and qualifications of the Holder based on the digital certificate presented by the Holder, and determines whether or not to provide the service to the Holder.

[0007] There are various services available, such as video streaming, storage usage, and communication. Until now, service providers have charged users for services based on the amount of usage or conditions of usage, such as the amount of time used, the amount of usage, and the number of times used.

[0008] W3C DID (https: / / www.w3.org / TR / DID-core / )W3C VC (https: / / www.w3.org / TR / VC-data-model / )

[0009] However, for example, students who take video streaming classes at school not only have to pay tuition fees to the school, but also communication fees to service providers such as telecommunications carriers, which creates a heavy burden for the students. If students did not take video streaming classes, they could use a low-quality, inexpensive communication service, but in order to take video streaming classes, they must sign up for a high-quality, expensive communication service.

[0010] Another option is for the service provider to issue high-quality SIM (Subscriber Identity Module) cards to schools, which then lend the cards to students. However, because issuing and lending cards takes time and effort, it would be difficult to complete everything before the start of video-streamed classes.

[0011] The present disclosure has been made in consideration of the above circumstances, and aims to reduce the financial burden on users while minimizing the time and effort required.

[0012] In order to solve the above problem, the present disclosure provides a service provision system having a receiving unit that receives, from a specified user terminal of a specified user, a second electronic certificate that includes a first electronic certificate indicating information about the specified user and indicates an application to use the service; a verification unit that uses a distributed database to verify whether the first electronic certificate has expired, the validity of the first electronic certificate, and the validity of the second electronic certificate; a service provision unit that provides a specified service to the specified user terminal if the first electronic certificate has not expired and the first electronic certificate and the second electronic certificate are valid; and a billing unit that bills a service fee for the specified service to a specified issuer that issued the first electronic certificate.

[0013] As described above, the present disclosure has the effect of reducing the financial burden on users while minimizing time and effort.

[0014] FIG. 1 is a schematic diagram of a communication system according to the present embodiment. FIG. 2 is an electrical hardware configuration diagram of a service providing system. FIG. 3 is a functional configuration diagram of a service providing system according to a first embodiment. FIG. 4 is a conceptual diagram of a service content management table. FIG. 5 is a sequence diagram showing a registration process in a service content management DB according to the first embodiment. FIG. 6 is a sequence diagram showing a service usage application process. FIG. 7 is a sequence diagram showing a service provision process. FIG. 8 is a functional configuration diagram of a service providing system and nodes according to a second embodiment. FIG. 9 is a sequence diagram showing a registration process in a service content management DB according to the second embodiment. FIG. 10 is a schematic diagram showing a verification mechanism using SSI.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present invention. Since the drawings are intended to conceptually explain the present invention, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0016] [Outline of System of Embodiment] First, an outline of the configuration of a communication system of this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of a communication system according to this embodiment.

[0017] As shown in Figure 1, the communication system 1 of this embodiment utilizes an existing verification mechanism using SSI as shown in Figure 11, and is constructed with at least a service providing system 2, an issuer terminal 6, and a user terminal 8.

[0018] The service providing system 2 is constructed by one or more computers, and provides services such as communication services, storage usage services, video distribution services, EC (Electronic Commerce) sites, corporate job application sites, community sites, etc. The service providing system 2 is managed and operated by a service provider S acting as a verifier.

[0019] The issuer terminal 6 is a computer and a communication terminal used by issuer A as an issuer. Issuer A is an organization such as a school, government, local government, or company. The issuer terminal 6 can also be referred to as an organization terminal.

[0020] The user terminal 8 is a computer and a communication terminal used by User B as Holder. User B is a student, staff member, employee, executive, etc., who belongs to an organization as Issuer A or is a member of a service provided by such an organization.

[0021] The issuer terminal 6 and the user terminal 8 are a node PC, a desktop PC, a tablet terminal, a smartphone, etc. There are a plurality (many) of issuer terminals 6 and user terminals 8, but for convenience of explanation, only one of each is shown in FIG.

[0022] Furthermore, the wallet (storage area (Digital IDentity Wallet)) of the issuer terminal 6 stores issuer identification information such as a DID, which is a distributed identifier of issuer A created by issuer A itself. Similarly, the wallet of the user terminal 8 stores user identification information such as a DID, which is a distributed identifier created by user B himself.

[0023] Note that the issuer terminal 6 and the user terminal 8 do not necessarily have to be terminals that are in the hands of each user; for example, the terminal functions may be provided on a cloud platform, and the user may operate them via remote access.

[0024] Furthermore, in response to a request from the user terminal 8, the issuer terminal 6 issues a user-related certificate, which is an electronic (digital) certificate such as a VC, and provides it to the user terminal 8. In this case, the issuer terminal 6 stores the issued user-related certificate within its own terminal (issuer terminal 6), and reads it out and provides it when providing it to the user terminal 8. Note that the issuer terminal 6 may store the issued user-related certificate in a cloud server using a cloud service contracted by issuer A, and the cloud server may provide the user-related certificate to the user terminal 8.

[0025] Here, the user-related certificate includes a certificate ID for identifying the user-related certificate, information about user B (attribute information, qualification information), the issuer DID of issuer A, and the issuer's electronic (digital) signature encrypted with a private key (an example of a first private key). The user-related certificate is an example of a first electronic certificate.

[0026] The user attribute information indicates the user's attributes such as User B's name, age, address, etc. The user qualification information indicates the user's qualification indicating that the user is related to an organization such as a specific company. This "related to an organization" includes the fact that User B belongs to the organization, or that User B is a member of a specific service provided by the organization, etc.

[0027] Meanwhile, the user terminal 8 creates a service use application form, which is an electronic (digital) certificate such as a VP (Verifiable Presentation) including the user-related certificate acquired from the issuer terminal 6, and provides it to the service providing system 2. In this case, the user terminal 8 stores the created service use application form within its own terminal (user terminal 8), and reads and provides it when providing it to the service providing system 2. Note that the user terminal 8 may store the created service use application form in a cloud server using a cloud service subscribed to by user B, and the cloud server may provide the service use application form to the service providing system 2.

[0028] Here, the service application form indicates an application to use a specific service provided by the service provider S. This service application form includes a user-related certificate obtained from the issuer A, the user DID of the user B, and the issuer's electronic (digital) signature encrypted with a private key (an example of a second private key). The service application form is an example of a second electronic certificate.

[0029] The service providing system 2, the issuer terminal 6, and the user terminal 8 can communicate with each other via a communication network 100 such as the Internet or a LAN (Local Area Network). The connection form of the communication network 100 may be either wireless or wired. As shown in FIG. 11, the service providing system 2, the issuer terminal 6, and the user terminal 8 can access a distributed DB (database) 110 such as a distributed repository or a blockchain network.

[0030] In the distributed DB 110, issuer A manages, in association with each other, a certificate ID for identifying a user-related certificate and information indicating whether the user-related certificate has been revoked. In addition, issuer A manages, in association with each other, the issuer DID of issuer A and the issuer's digital signature encrypted with a private key (an example of a first private key). In addition, user B manages, in association with each other, the user DID of user B and the user's digital signature encrypted with a private key (an example of a second private key).

[0031] [Hardware Configuration] Next, the electrical hardware configuration of the service providing system 2 will be described with reference to Fig. 2. Fig. 2 is a diagram showing the electrical hardware configuration of the service providing system.

[0032] As shown in Figure 2, the service providing system 2 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a processor 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, etc., all of which are interconnected by a bus 1010.

[0033] The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via the communication network 100. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0034] When an instruction to start a program is received, the memory device 1003 reads the program from the auxiliary storage device 1002 and stores it. The processor 1004 realizes functions related to the device in accordance with the program stored in the memory device 1003. The processor 1004 may include not only a CPU (Central Processing Unit) but also a GPU (Graphics Processing Unit).

[0035] The interface device 1005 is used as an interface for connecting to a communication network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to a program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the calculation results to an external device such as a printer or an external display.

[0036] The issuer terminal 6 and the user terminal 8 have the same hardware configuration as the service providing system 2, and therefore a description thereof will be omitted.

[0037] [Functional Configuration of Service Providing System] Next, the functional configuration of the service providing system 2a will be described with reference to Fig. 3. Fig. 3 is a functional configuration diagram of the service providing system in the embodiment. Note that the service providing system 2a is an example of the service providing system 2 shown in Fig. 1.

[0038] 3, the service providing system 2a includes a communication unit 21, a registration unit 23, a verification unit 25, a service providing unit 27, and a billing unit 29. Each of these units has a function realized by an instruction from the processor 1004 in FIG. 2 based on a program.

[0039] 2 implements the storage unit 20. In this storage unit 20, a service content management DB d1 is constructed.

[0040] 3, the verification unit 25, the service providing unit 27, and the billing unit 29 may be independent devices, and the service providing system 2a may have the verification device, the service providing device, and the billing device. In this case, the service content management DB d1 may be built in the verification device, the service providing device, or the billing device. Alternatively, the service content management DB d1 may be built in a DB server or the like separate from the service providing system 2a (see FIG. 9).

[0041] <Service Content Management> Fig. 4 is a conceptual diagram of a service content management table. The service content management DB d1 is configured by the service content management table shown in Fig. 4. In the service content management table, user classifications and service contents are managed in association with each other.

[0042] "User Classification" indicates the classification of the user related to User B's organization (Publisher A). For example, if Issuer A is a school, the user classification of User B, who is a student, indicates the name of the video-streamed lesson that the user has acquired. If Issuer A is a company, the user classification of User B, who is an employee, indicates the name of the e-learning course that the user has signed up for.

[0043] For example, when the service providing system 2a provides a communication service, the "service content" includes communication quality, communication volume, and communication destinations.

[0044] The service providing system 2a provides the user B with service content according to the user classification of the user B.

[0045] <Functional Configuration> Next, each functional configuration of the service providing system 2a will be described with reference to FIG.

[0046] The communication unit 21 transmits and receives data (information) to and from the service providing system 2 a and the user terminal 10 via the communication network 100 .

[0047] The registration unit 23 registers data (information) in the service content management DB d1 stored in the storage unit 20, etc.

[0048] The verification unit 25 performs a variety of verification processes, which will be described in detail later with reference to FIG.

[0049] The service providing unit 27 provides services such as a communication service, a storage usage service, a video distribution service, an e-commerce site, a company's job application site, or a community site.

[0050] The billing unit 29 bills the service fee for the service provided to user B not to user B but to an organization with which user B is associated (an organization to which user B belongs or an organization of which user B is a member).

[0051] [Processing or Operation of First Embodiment] Next, the processing or operation of this embodiment will be described with reference to Fig. 5 to Fig. 8. In the following, an example will be described in which issuer A is a university, user B is a student, and service provider S is a telecommunications carrier.

[0052] <Registration Process in Service Content Management DB> First, the registration process in the service content management DB d1 will be described. Fig. 5 is a sequence diagram showing the registration process in the service content management DB according to the first embodiment.

[0053] S1: Issuer A operates the issuer terminal 6 to transmit to the service providing system 2a the user classification and service content managed by issuer A. As a result, the communication unit 21 of the service providing system 2a receives the user classification and service content.

[0054] S2: In the service providing system 2a, the registration unit 23 registers the user class and service content received in step S1 to d1.

[0055] <Service Use Application Processing> S11: The user terminal 8 sends a request for a user-related certificate to the issuer terminal 6. This user certificate contains user identification information (e.g., student ID number) for identifying the user. As a result, the issuer terminal 6 receives the request for the user-related certificate.

[0056] S12: The issuer terminal 6 issues a user-related certificate based on the user identification information included in step S11. This user-related certificate includes the certificate ID of this user-related certificate, user information, issuer DID, and the issuer's digital signature encrypted with a private key.

[0057] The certificate ID is managed in the distributed DB 110 together with information indicating whether or not the student associated with this certificate ID is enrolled at the university. The certificate ID is not the student's student number or name, but a unique value randomly assigned by issuer A, which is the university. Therefore, even if a third party searches the distributed DB 110, they will not be able to identify User B from this certificate ID.

[0058] The user information includes user attribute information (such as name, age, and address) and user qualification information (such as university name, faculty name, department name, and year of study). Furthermore, the user information includes the above-mentioned user classification (such as class name).

[0059] S13: The issuer terminal 6 transmits the data of the user-related certificate issued in step S12 to the user terminal 8. As a result, the user terminal 8 receives the data of the user-related certificate.

[0060] S14: The user terminal 8 uses the user-related certificate acquired in process S13 to create a service usage application to be sent to the service provider S. This service usage application includes the user-related certificate received in process S13, the user DID issued by user B, and the user's digital signature encrypted with a private key.

[0061] S15: The user terminal 8 transmits the data of the service use application created in step S15 to the service providing system 2a, whereby the service providing system 2a receives the data of the service use application.

[0062] <Service Provision Processing> S21: The service providing system 2a performs verification processing using the service use application form received in processing S15. Here, the verification processing will be described in detail with reference to FIG.

[0063] (Verification Process) S41: The verification unit 25 searches the distributed DB 110 using the certificate ID included in the user-related certificate received in process S15 to obtain information indicating whether the user is enrolled in a university corresponding to the certificate ID. The verification unit 25 then verifies whether the user-related certificate has been revoked based on the user's enrollment status. Specifically, if the user is enrolled in a university, the verification unit 25 determines that the user-related certificate has not been revoked. If the user is not enrolled in a university, the verification unit 25 determines that the user-related certificate has been revoked. For example, if user B obtained a user-related certificate from the university he or she was enrolled in in process S13, then withdrew from the university and submitted a service use application form in process S15 after withdrawing, the verification unit 25 determines that the user-related certificate has been revoked.

[0064] S42: The verification unit 25 uses the issuer DID received in step S15 to search the distributed DB 110 to obtain a public key corresponding to the issuer DID. The verification unit 25 then uses this public key to decrypt the issuer's digital signature, thereby verifying the legitimacy of the user-related certificate (issuer).

[0065] S43: The verification unit 25 uses the user DID received in step S15 to search the distributed DB 110 to obtain a public key corresponding to the user DID. The verification unit 25 then uses this public key to decrypt the user's digital signature, thereby verifying the validity of the service usage application (user).

[0066] S44: The verification unit 25 determines whether the certificate is not revoked in step S41 and is valid in steps S42 and S43. If the certificate is revoked in step S41 or is invalid in either step S42 or S43 (NO), the verification process ends without performing step S45.

[0067] S45: In process S44, if all the verification results are valid, i.e., the certificate has not been revoked in process S41, and both processes S42 and S43 are valid (YES), the verification unit 25 sends permission to provide the service to the service providing unit 27. Then, the service providing unit 27 uses the predetermined user classification included in the user-related certificate received in process S15 to search the service content management DB d1, thereby reading out the predetermined service content corresponding to the predetermined user classification.

[0068] This completes the description of the verification process. Next, we return to FIG.

[0069] S22: If all the results in process S44 are valid (YES), the service providing unit 27 provides a service to the requesting user terminal 8 via the communication unit 21 within the scope of the service content read out in process S45. For example, the service providing unit 27 provides a high-quality communication service for video streaming lessons. If the verification result of at least one of processes S41 to S43 is invalid (NO), the service providing unit 27 sends a notification to the requesting user terminal 8 via the communication unit 21 indicating that the requested service is not available.

[0070] S23: The billing unit 29 sends a service fee bill to the issuer terminal 6 of the university via the communication unit 21 based on the service provided in process S22. As a result, the issuer terminal 6 receives the service fee bill. That is, the service providing system 2a changes the billing destination from User B, who actually receives the service, to Issuer A, which is the university to which User B belongs. Note that the billing unit 29 may send the service fee bill to a terminal other than Issuer A's, rather than to Issuer terminal 6, as long as it bills Issuer A.

[0071] S24: At the end of the month or the like, the issuer terminal 6 pays the service fees in response to the bills of step S23 to the service providing system 2a via a financial institution or the like.

[0072] [Major Effects of the Embodiments] As described above, according to each embodiment, the service providing system 2 bills the service usage fee not to the user B, who is the service recipient, but to the issuer A, which is the organization with which the user B is associated (the organization to which the user B belongs or the organization of which the user B is a member), thereby achieving the effect of reducing the financial burden on users such as students with as little time and effort as possible.

[0073] Furthermore, if there are no restrictions on the use of the service, User B, such as a student, can also receive communications other than video streaming classes (for example, personal communications services related to User B's hobbies, etc.). Therefore, the service providing system 2 can provide a service that limits the service content read out in process S45 shown in Figure 8, thereby preventing financial disadvantages from occurring on the side of Issuer A, such as a school.

[0074] Second Embodiment Next, a second embodiment will be described with reference to Figures 9 and 10. In the second embodiment, a service providing system 2b will be described, which is another example of the service providing system 2a shown in Figure 3. In the second embodiment, a service content management DB d1 is managed in node 5 of the distributed DB 110.

[0075] [Functional Configuration of Service Providing System] Fig. 9 is a functional configuration diagram of a service providing system and nodes in the second embodiment. Note that in Fig. 9, the same components as those in Fig. 3 are denoted by the same reference numerals, and description thereof will be omitted.

[0076] 9, the service providing system 2b is managed and operated by a service provider S. The service providing system 2b is constructed by a verification device 3 and a service providing device 4. The electrical hardware configurations of the verification device 3 and the service providing device 4 are similar to the configurations shown in FIG. 2, and therefore, description thereof will be omitted.

[0077] The verification device 3 has a communication unit 31 that also functions as a registration unit, and a verification unit 35. These have the same functions as the communication unit 21, the registration unit 23, and the verification unit 25 in FIG.

[0078] The service providing device 4 also has a communication unit 41, a service providing unit 47, and a billing unit 49. These have the same functions as the communication unit 21, the service providing unit 24, and the billing unit 29 in Fig. 3. The verification unit 35 of the verification device 3 notifies the service providing unit 47 of permission to provide the service via the communication units 31 and 41.

[0079] The distributed DB 110 also includes a node 5. The node 5 has a communication unit 51 and a registration / readout unit 53. The node 5 also has a service content management DB d1. The communication unit 51 has the same function as the communication unit 21 shown in Fig. 3. The registration / readout unit 53 has the same function as the registration unit 23 shown in Fig. 3, and in addition has the function of reading out corresponding predetermined service content from the service content management DB d1 based on a predetermined service classification.

[0080] The verification unit 35 of the verification device 3 requests the registration and reading unit 53 via the communication unit 31 and the communication unit 51 to search for and read out predetermined service content corresponding to a predetermined service category.

[0081] [Processing or Operation of Second Embodiment] The processing or operation of the second embodiment is basically the same as that of the first embodiment. However, in the second embodiment, the registration process to the service content management DB d1 is different from that described in Fig. 5, and therefore will be described using Fig. 10.

[0082] S101: The issuer terminal 6 transmits the user class and the service content to the service providing system 2b, whereby the communication unit 31 or the communication unit 41 of the service providing system 2b receives the user class and the service content.

[0083] S102: The communication unit 31 or the communication unit 41 of the service providing system 2b transmits the user class and service content received in step S101 to the node 5. As a result, the communication unit 51 of the node 5 receives the user class and service content.

[0084] S103: In the node 5, the registering and reading unit 53 associates the user class and the service content with each other and registers them as one record in the service content management DB d1.

[0085] This concludes the description of the registration process in the service content management DB d1 in this embodiment.

[0086] The second embodiment has the same effects as the first embodiment.

[0087] [Supplementary Note] The present invention is not limited to the above-described embodiment, and may have the following configurations or processes (operations).

[0088] (1) The service providing system 2 can be realized by a computer and a program, but this program can also be recorded on a (non-transitory) recording medium or provided via the communication network 100.

[0089] (2) The processor 1004 shown in FIG. 2 as hardware may be a single processor or may be multiple processors.

[0090] DESCRIPTION OF SYMBOLS 1 Communication system 2, 2a, 2b Service provision system 3 Verification device 4 Service provision device 6 Issuer terminal (organization terminal) 8 User terminal 20 Storage unit 21 Communication unit (transmission unit, reception unit) 23 Registration unit 25 Verification unit 27 Service provision unit 29 Billing unit 31 Communication unit (transmission unit, reception unit) 35 Verification unit 41 Communication unit (transmission unit, reception unit) 47 Service provision unit 49 Billing unit d1 Service content management DB (an example of a service content management unit) 100 Communication network 110 Distributed DB

Claims

1. A service provision system for providing a service to a user terminal of a user, comprising: a receiving unit that receives, from a predetermined user terminal of a predetermined user, a second electronic certificate that includes a first electronic certificate indicating information about the predetermined user and indicates an application to use the service; a verifying unit that uses a distributed database to verify whether the first electronic certificate has expired, the validity of the first electronic certificate, and the validity of the second electronic certificate; a service providing unit that provides the predetermined service to the predetermined user terminal if the first electronic certificate has not expired and the first electronic certificate and the second electronic certificate are valid; and a billing unit that bills the predetermined issuer that issued the first electronic certificate for a service fee for the predetermined service.

2. The service provision system of claim 1, wherein the first electronic certificate includes a predetermined user classification indicating the classification of the predetermined user associated with the predetermined issuer, and the service provision unit provides the predetermined service to the predetermined user terminal in accordance with the predetermined service content corresponding to the predetermined user classification in a service content management unit that associates and manages the user classification indicating the classification of the user associated with the issuer of the electronic certificate and the service content to be provided to the user.

3. A service provision method executed by a service provision system that provides services to user terminals of users, comprising: a receiving process that receives, from a predetermined user terminal of a predetermined user, a second electronic certificate that includes a first electronic certificate indicating information about the predetermined user and indicates an application to use the service; a verification process that uses a distributed database to verify whether the first electronic certificate has expired, the validity of the first electronic certificate, and the validity of the second electronic certificate; a service provision process that provides a predetermined service to the predetermined user terminal if the first electronic certificate has not expired and the first electronic certificate and the second electronic certificate are valid; and a billing process that bills the predetermined issuer that issued the first electronic certificate for the service fee.

4. A program for causing a computer to execute the method according to claim 3.

Images