Management device, management device control method, and program

Abstract

A management device according to an embodiment of the present invention is designed to manage electronic signatures for electronic content, said device comprising: an indication acquisition unit that acquires an indication of signature for electronic content and signature content information that indicates the content of the signature; a signature generation unit that generates an electronic signature on the basis of the indication; an addition unit that adds the generated electronic signature to the electronic content; an electronic certificate generation unit that generates an electronic certificate which pertains to the electronic signature and which includes the signature content information; and a storage that stores the electronic certificate in a prescribed storage unit.

Description

[Technical Field]

[0001] The present disclosure relates to a management device, a control method for the management device, and a program. [Background technology]

[0002] It is known that digital signatures are used to prove that digital content such as digital documents has not been altered. For example, a digital signature management system has been proposed that digitally signs data to be signed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-067807 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the signature value generated by the digital signature management system of Patent Document 1 cannot include, for example, information arbitrarily entered by the signer, making it difficult to understand the intentions of the parties when signing a digital document.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned conventional situation, and aims to provide a management device, a control method for the management device, and a program that can confirm the intention of the signer's electronic signature. [Means for solving the problem]

[0006] A management device according to an embodiment of the present invention is a management device for managing electronic signatures for electronic content, and includes an instruction acquisition unit that acquires instructions for signing the electronic content and signature content information, which is information indicating the content of the signature, a signature generation unit that generates an electronic signature in accordance with the instructions, an assignment unit that assigns the generated electronic signature to the electronic content, an electronic certificate generation unit that generates an electronic certificate related to the electronic signature, the electronic certificate including the signature content information, and a storage unit that stores the electronic certificate in a specified memory unit.

[0007] As a result, when a digital signature is applied to digital content in response to a signature instruction, a digital certificate including signature content information, which is information indicating the content of the signature for the digital content, is stored in a predetermined storage unit. As the signature content information is recorded in the digital certificate, it is possible to confirm the intention of the signer in applying the digital signature by checking the digital certificate. [Effects of the Invention]

[0008] According to the present invention, it is possible to confirm the intention of the signer in signing an electronic signature. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an overview of an electronic signature management system 100 using a management device 1 according to an embodiment. [Figure 2] 1 is a schematic diagram showing an electronic document D to which a digital signature S generated by a management device 1 according to an embodiment has been attached. [Figure 3] 1 is a block diagram showing a configuration of a management device 1 according to an embodiment. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of a data structure of a digital certificate according to the embodiment. [Figure 5] FIG. 2 is a block diagram showing the configuration of a user terminal 4 according to the embodiment. [Figure 6A] FIG. 2 is a sequence diagram showing an example of an operation process executed by the digital signature management system 100 according to the embodiment. [Figure 6B]FIG. 10 is a sequence diagram showing another example of the operation process executed by the digital signature management system 100 according to the embodiment. [Figure 6C] FIG. 10 is a sequence diagram showing yet another example of the operation process executed by the digital signature management system 100 according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A preferred embodiment of the present invention will be described with reference to the accompanying drawings. (Note that in each drawing, components with the same reference numerals have the same or similar configurations.)

[0011] (1) Overview FIG. 1 is a schematic diagram showing an overview of an electronic signature management system 100 using a management device 1 according to an embodiment.

[0012] 1, the digital signature management system 100 includes, for example, a management device 1, an electronic content database 2, an electronic certificate database 3, and multiple user terminals 4. The management device 1 is connected to each of the electronic content database 2 and the electronic certificate database 3 so as to be able to manage (store, delete, change, etc.) the information stored in these databases. The management device 1 is also connected to multiple user terminals via a communication network N such as the Internet so as to be able to send and receive information to and from each other.

[0013] In this embodiment, the users include, for example, an order-receiving company that receives an order for the provision of goods and services, an ordering company that orders goods and services from the order-receiving company, a factoring company that factors receivables related to orders between the order-receiving company and the ordering company, and a collection agency company that collects the transfer fees for factoring. Furthermore, for example, the multiple user terminals 4 include a user terminal 4A used by the order-receiving company, a user terminal 4B used by the ordering company, a user terminal 4C used by the factoring company, and a user terminal 4D used by a person in charge of the collection agency company.

[0014] The management device 1 is, for example, a computer (information processing device) such as a server, and has a processing unit such as a CPU and a storage unit such as a memory. The management device 1 is a device that generates a digital signature S for digital content D such as a user's contract. The digital content D is stored, for example, in an digital content database 2. That is, the management device 1 is a device that has a function of generating a digital signature S to be attached to the user's digital content D. The management device 1 may, for example, create digital content D that indicates consent to the digital content D by attaching the digital signature S to the digital content D in a visible manner.

[0015] In the following embodiments, "electronic content" may include "electronic documents" or "electronic images." An "electronic document" refers to any document, such as a contract, estimate, application, purchase order, delivery note, invoice, receipt, invoice, minutes, approval request, application, or signature list, and may include an electronically created document. An "electronic image" may be a still image or a moving image (video) consisting of a chronological sequence of multiple still images. Video may be combined with audio. An "electronic signature" may include a process of electronically stamping a paper contract or the like on electronic content D. An "electronic certificate" may be a certificate for certifying matters related to an electronic signature, and may include, for example, an electromagnetic record created to certify that matters used to confirm that a user has signed an electronic signature belong to that user.

[0016] As shown in FIG. 1, the management device 1 is connected to a digital certificate database 3. The management device 1 creates a digital certificate for digital content D to which a digital signature S has been attached. The management device 1 stores the created digital certificate for digital content D in the digital certificate database 3. The digital certificate database 3 may be configured, for example, from multiple node computers that store a blockchain. The format of the blockchain is not particularly limited, but may be configured, for example, as a consortium-type private blockchain. The management device 1 stores, for example, a digital certificate in the digital certificate database 3 configured as the blockchain or the like.

[0017] FIG. 2 is a schematic diagram showing an electronic document D to which a digital signature S generated by the management device 1 according to an embodiment is attached. In particular, the management device 1 may attach a visible digital signature S to the electronic document D as shown in FIG. 2. The management device 1 may, for example, attach a visible digital signature S corresponding to an individual user. The management device 1 may, for example, attach a digital signature S shown as a QR code (registered trademark) to electronic content D. When attaching a digital signature S to an electronic image as electronic content, the management device 1 may superimpose the digital signature S on a part of at least one of the still images included in the electronic image, or may attach the digital signature S to metadata held by the electronic image.

[0018] As shown in FIG. 1, the user terminal 4 is configured as, for example, a device different from the management device 1. The user terminal 4 is, for example, a computer (information processing device) such as a smartphone, tablet terminal, or personal computer with an imaging function, and has a processing unit such as a CPU and a storage unit such as a memory. The user terminal 4 acquires information contained in the electronic certificate stored in the electronic certificate database 3 based on the electronic signature S generated by the management device 1, and performs processing to verify the authenticity of the electronic content D based on the acquired information. The user terminal 4 also performs processing to display various information based on the information contained in the acquired electronic certificate. In particular, the user terminal 4 displays a URL for identifying the storage area in the electronic content database 2 where the electronic content D is stored. When the user selects the URL, the user terminal 4 acquires the electronic content D from the electronic content database 2 and displays it. This allows the content of the electronic content D to be confirmed in an environment where the authenticity of the electronic content D is guaranteed. Furthermore, since the content of the electronic content D can be confirmed from the electronic signature S, the user can maintain the evidential force (supported by the information on the electronic certificate) by storing a paper printout of the electronic content D rather than a file of the electronic content D.

[0019] (2) Composition (2-1) Management device 1 3 is a block diagram showing the configuration of a management device 1 according to an embodiment. The management device 1 includes a document management unit 11, an instruction acquisition unit 12, a user information acquisition unit 13, a signature generation unit 14, an assignment unit 15, a digital certificate generation unit 16, a digital certificate storage unit 17, and a transmission / reception unit 18. These various functional units are realized by the operation of a processing unit such as a CPU included in the management device 1.

[0020] The document management unit 11 is realized, for example, by the operation of a CPU. The document management unit 11 creates, acquires, modifies, and stores in a memory unit electronic content D that is the subject of an electronic signature. The document management unit 11 acquires electronic content D, for example, from the electronic content database 2 or the user terminal 4. The electronic content D may be electronic data created using word processing software or image processing software, or may be data obtained by scanning printed matter such as paper. The document management unit 11 may also create and modify electronic content based on instructions acquired from the user terminal 4. The document management unit 11 may also store the electronic content in the electronic content database 2.

[0021] The instruction acquisition unit 12 acquires an instruction (signature instruction) to sign the acquired electronic content to be signed. The instruction acquisition unit 12 acquires the signature instruction from the user terminal 4, for example.

[0022] The user information acquisition unit 13 acquires user information as user information. In addition, in this embodiment, the user information acquisition unit 13 acquires a user ID and a user name issued in advance to the user. Here, the user information acquisition unit 13 acquires the user IDs and user names of the contractors (users) as the user information. In addition, in this embodiment, the user information acquisition unit 13 acquires user information from each of the two corporate users when generating the electronic signature S. The user information may include any information specific to the user that is managed by the user.

[0023] The signature generation unit 14 generates a digital signature in which a digital certificate identifier, which is an identifier of a digital certificate, is coded. The signature generation unit 14 may include a unique character string in the digital certificate identifier. The character string may be unique for each digital signature S, for example. The digital certificate identifier is generated (numbered) by, for example, assigning the digital signature S to the digital content D.

[0024] The attaching unit 15 attaches the generated digital signature S to the digital content D. For example, the attaching unit 15 may attach the digital signature S to the digital content D in a visible manner. This makes it easy to identify that the digital signature S has been attached to the digital content D. For example, as shown in FIG. 2, the attaching unit 15 may attach the generated digital signature S to a position where it is displayed alongside the corporate name and the name of the representative, which are user information written in the digital content D. For example, the attaching unit 15 may attach the digital signature S to a position in the digital content D where it is clear that the digital signature S corresponds to the written user information. In this embodiment, the attaching unit 15 may write the user's name included in the acquired user information alongside the digital signature S. For example, as shown in FIG. 2, the attaching unit 15 writes the user's name alongside the corresponding user's digital signature S (QR code) below the display surface of the digital content D (digital document). This makes it clear which user's digital signature S belongs to the coded digital signature S. Furthermore, by adding the code to the coded electronic signature S, the code can be treated like a seal impression, which creates a visual effect similar to that of a seal being stamped on paper.

[0025] The digital certificate generating unit 16 generates various digital certificates related to the digital signature S. The digital certificates are stored in the digital certificate database 3, for example.

[0026] The digital certificate storage unit 17 stores the generated digital certificate in the digital certificate database 3.

[0027] Fig. 4 is a schematic diagram showing an example of the data structure of digital certificates stored in the digital certificate database 3. Each row shown in Fig. 4 corresponds to one digital certificate. For example, each time a digital signature is assigned to digital content, a digital certificate is added to the digital certificate database 3 one by one.

[0028] The electronic certificate may include, for example, the issuer name, issue number, issue date and time, expiration date, series ID, branch number, user ID, organization to which the user belongs, user position, user name, signature content, original text hash value, pre-signature hash value, post-signature hash value, URL for publishing electronic content, and password.

[0029] The issuer name is the name of the issuer of the electronic certificate, and may be, for example, the name of the administrator of the management device 1. The issue number is an electronic certificate identifier (an identifier for identifying an electronic certificate) issued by the management device 1. The issue date and time is the date and time when the electronic certificate was issued, and may be the time information of the signature. The issue date and time is an example of ranking information indicating the ranking of an electronic signature (information indicating, each time an electronic signature is granted, the ranking of the electronic signature among a series of electronic signatures). The validity period expiration date is the date on which the validity period of the electronic certificate expires.

[0030] The series ID is an example of lineage identification information, which is identification information for identifying the lineage of electronic content D. The series ID may be identification information unique to the electronic content D (lineage) that does not change even if one or more digital signatures S are assigned to the electronic content D. In other words, the series ID is identification information assigned to the content (which may include modified content) represented by the electronic content D. This makes it possible, when digital signatures S are assigned consecutively to the electronic content D, to manage the digital content D and the series of digital signatures S as a series, and to confirm which digital signature S among the series of digital signatures S is the latest, or whether the digital signature S assigned to the digital content D in one's possession is the latest, etc.

[0031] The branch number is an example of ranking information indicating the ranking of the electronic signature S (information indicating, each time an electronic signature S is assigned, the ranking of the electronic signature S among a series of electronic signatures S). In the example shown in Fig. 4, natural numbers such as 1, 2, and 3 are used as the branch numbers, but the branch numbers (ranking information) may be arbitrarily configured using symbols, signs, etc., as long as they can indicate the ranking.

[0032] The user ID is identification information for the user. The user organization is information indicating the organization to which the user belongs. The user job title is information indicating the user's job title in the organization. The user name is the user's name (the name of the person in charge at each company).

[0033] The signature content is information accompanying the digital signature S, and may be text data arbitrarily entered by the user. The signature content may be, for example, a statement of the user's intention accompanying the digital signature, or, if the digital content to be signed has been modified, information indicating that the modification has been made and the details of the modification. This makes it possible to confirm the user's intention regarding the digital signature, whether or not the digital content has been modified and the details of the modification, by verifying the digital certificate.

[0034] The original hash value, pre-signature hash value, and post-signature hash value are used, for example, in a process of verifying the integrity of digital content D. The integrity verification process will be described later. The original hash value is the hash value of digital content D (original) that does not include any digital signatures. The pre-signature hash value is the hash value of digital content D immediately before the latest digital signature S is added (digital content D that includes a digital signature S that is earlier in order than the digital signature S). The post-signature hash value is the hash value of digital content D to which the latest digital signature S has been added.

[0035] The digital content publishing URL may be a URL for identifying the storage area in which the digital content D is saved (for example, the URL of the digital content D in the digital content database 2). An expiration date may be set for the digital content publishing URL. The password may be a password required to access the file publishing URL and view the digital content D, and may be arbitrary or assigned by the system.

[0036] The above-mentioned electronic certificate is merely an example, and the electronic certificate in this embodiment may not include any of the above-mentioned items, or may include items other than the above-mentioned items.

[0037] The transmitting / receiving unit 18 transmits and receives various information to and from the user terminal 4. For example, the transmitting / receiving unit 18 receives a signature instruction for the electronic content D from the user terminal 4. Furthermore, the transmitting / receiving unit 18 transmits, for example, the electronic content D (including the content to which the digital signature S has been added) to the user terminal 4.

[0038] Each component included in the management device 1 can be realized by hardware, software, or a combination of these. "Implemented by software" here means that the program is implemented by a computer reading and executing it. The program can be stored and provided to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, programmable ROMs (PROMs), erasable PROMs (EPROMs), flash ROMs, and random access memories (RAMs)). The display program may also be provided to a computer by various types of transitory computer-readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire or an optical fiber, or via a wireless communication path.

[0039] (2-2) User terminal 4 5 is a block diagram showing the configuration of a user terminal 4 according to an embodiment. The user terminal 4 includes an imaging unit 41, an identifier acquisition unit 42, a retained information acquisition unit 43, a hash value calculation unit 44, a consistency verification unit 45, an output unit 46, and an operation reception unit 47. These various functional units are realized by the operation of a processing unit such as a CPU included in the user terminal 4.

[0040] The imaging unit 41 is an imaging mechanism including a so-called camera. The imaging unit 41 captures, for example, an arbitrary digital signature S attached to the digital content D. The imaging unit 41 captures, for example, an arbitrary digital signature S included in the digital content D displayed on a display unit (not shown) of another terminal.

[0041] The identifier acquisition unit 42 acquires the digital certificate identifier included in the digital signature S (QR code) by capturing an image of the digital signature S.

[0042] The hash value calculation unit 44 calculates various hash values ​​based on the electronic content D. For example, the hash value calculation unit 44 may calculate a hash value (post-signature hash value) of the electronic content D including the latest digital signature S. Alternatively, the hash value calculation unit 44 may calculate a hash value (pre-signature hash value) of the electronic content D that does not include the latest digital signature S. Alternatively, the hash value calculation unit 44 may calculate a hash (original text hash value) of the electronic content D as the original text that does not include any digital signature S.

[0043] The integrity checking unit 45 executes a process for checking the integrity of the electronic content D based on the digital certificate stored in the management device 1. The process for checking the integrity of the electronic content D makes it possible to determine whether the electronic content D is authentic. For example, the integrity checking unit 45 acquires a digital certificate from the management device 1 based on a digital certificate identifier acquired by capturing an image of any digital signature S included in the digital content D, and then checks the integrity of hash values ​​(original text hash value, pre-signature hash value, and / or post-signature hash value) included in the acquired digital certificate with hash values ​​(original text hash value, pre-signature hash value, and / or post-signature hash value) calculated from the digital content D by the hash value calculation unit 44. The integrity checking unit 45 may determine whether the original text hash value obtained from the target digital content D matches the original text hash value included in the digital certificate, thereby determining whether the original text has been altered. Furthermore, the integrity verification unit 45 may determine whether the electronic content D has been altered during the period from when the previous electronic signature S was created to when the latest electronic signature S was created, for example, by determining whether a pre-signature hash value (a hash value calculated based on the electronic content obtained excluding only the latest electronic signature) obtained from the target electronic content D matches a post-signature hash value included in the immediately preceding electronic certificate. A specific operation example is as follows. That is, a user can access the electronic content D (original) stored in the management device 1 (such as the electronic content database 2) and display the electronic content D on the user terminal 4 by, for example, capturing an image of the electronic signature S of the electronic content D printed on paper (such as handed over or delivered) with the user terminal 4. The management device 1 may calculate a hash value for the accessed electronic content D and determine whether the electronic content D is authentic by comparing the calculated hash value with the hash values ​​(original hash value, pre-signature hash value, and post-signature hash value) stored in the digital certificate database 3.With regard to the electronic content D that has been handed over or delivered to the user, the user can confirm whether the electronic content D is authentic by, for example, visually comparing the handed over or delivered electronic content D with the electronic content D stored in the management device 1 displayed on the user terminal 4. Furthermore, whether the electronic content D stored in the management device 1 is authentic may be determined, for example, by querying the digital certificate database 3.

[0044] The output unit 46 outputs various types of information related to the electronic content D. For example, the output unit 46 outputs information on various types of digital certificates acquired from the digital certificate database 3. Furthermore, for example, the output unit 46 outputs the result of the consistency check performed by the consistency check unit 45.

[0045] The operation accepting unit 47 accepts various operations from the user. For example, the operation accepting unit 47 accepts a selection to perform a consistency check process for the electronic content D. The operation accepting unit 47 also accepts, for example, transitions between various screens that display information about the electronic content D, link selections, and the like.

[0046] The transmitting / receiving unit 48 transmits and receives various types of information between the management device 1 and other user terminals 4. For example, the transmitting / receiving unit 48 transmits a signature instruction for electronic content to the management device 1. The transmitting / receiving unit 48 also receives, for example, electronic content D (including that to which a digital signature S has been attached) and a digital certificate from the management device 1.

[0047] (3) Example of operation 6A to 6C are sequence diagrams illustrating an example of operational processing executed by the digital signature management system 100 according to the embodiment. In the following description, it is assumed that an ordering company has placed an order for goods or services provided by the receiving company with an order-receiving company, and a person in charge at the receiving company has created an electronic document D0 as an invoice for the goods or services. The digital document D0 may be created by the user terminal 4A using an electronic document creation service provided by the management device 1, or it may be created using general document creation software without using such a creation service. The created digital document D0 may be stored in the digital document database 2 by the management device 1, or it may be stored in a memory accessible by the user terminal 4A. While the sequence diagram illustrates an example in which the digital signature management system 100 according to the embodiment handles digital documents as digital content, the present invention is applicable not only to digital documents but also to other digital content such as digital images.

[0048] (3-1) Acquisition of claims 6A is a sequence diagram for generating a claim. When a user terminal 4A used by a person in charge of an order-receiving company accepts an operation by the person in charge of the order-receiving company to instruct the person in charge of the order-receiving company to sign electronic document D0, the user terminal 4A transmits the instruction to sign electronic document D0 to management device 1 (S101). Management device 1 receives the instruction to sign electronic document D0 from user terminal 4A (S102).

[0049] The signature instructions for the electronic document D0 may include, for example, the data of the electronic document D0 itself, or may include information (such as a series ID) for identifying the electronic document D0 stored in the electronic document database 2 or a storage unit accessible by the user terminal 4A. The signature instructions may also include, for example, any item recorded in the digital certificate database 3 (such as an item related to the person in charge at the order-receiving company). The signature instructions may also include, for example, the signature content entered by the person in charge at the order-receiving company. In the example shown in FIG. 4, the signature content "claim" entered by the person in charge at the order-receiving company is shown.

[0050] Based on the signing instructions, the management device 1 generates a digital signature S1 by the person in charge at the order-receiving company, and also generates a digital certificate (S103). Regarding the generation of the digital certificate, the management device 1 generates a hash value of the digital document D0 immediately before the digital signature S1 is added, and includes this in the digital certificate as a pre-signature hash value. The management device 1 also generates a hash value of the digital document D1 after the digital signature S1 is added, and includes this in the digital certificate as a post-signature hash value. The management device 1 also generates a hash value of the digital document D0 that does not include any digital signatures S, and includes this in the digital certificate as an original text hash value. The management device 1 stores the generated digital certificate (for example, the digital certificate in the first row shown in FIG. 4) in the digital certificate database 3 (S104).

[0051] The management device 1 generates an electronic document D1 by adding the generated digital signature S1 to the electronic document D0. Then, the management device 1 transmits the generated electronic document D1 to the user terminal 4A (S105). The user terminal 4A may store the received electronic document D1 in a storage unit accessible by the user terminal 4A.

[0052] In response to an operation by a person in charge of the receiving company, user terminal 4A transmits electronic document D1 to user terminal 4B used by a person in charge of the ordering company (S106). Note that transmission of electronic document D1 to user terminal 4B may be performed via management device 1. User terminal 4B receives electronic document D1 (S107). User terminal 4B may store the received electronic document D1 in a storage unit accessible by user terminal 4B.

[0053] The person in charge of the ordering company appropriately checks the contents of the received electronic document D1 (the contents of the invoice) and then performs an operation to instruct the person in charge of the ordering company to sign electronic document D1. Upon receiving this operation, user terminal 4B transmits the instruction to sign electronic document D1 to management device 1 (S108). Management device 1 receives the instruction to sign electronic document D1 from user terminal 4B (S109).

[0054] The signature instructions for the electronic document D1 may include, for example, the data of the electronic document D1 itself, or may include information (such as a series ID) for identifying the electronic document D1 stored in the electronic document database 2 or a storage unit accessible by the user terminal 4B. The signature instructions may also include, for example, any item recorded in the digital certificate database 3 (such as an item related to the person in charge of the ordering company). The signature instructions may also include, for example, the signature content entered by the person in charge of the ordering company. In the example shown in Figure 4, the signature content entered by the person in charge of the ordering company is shown as "I will pay as invoiced."

[0055] Based on the signing instructions, the management device 1 generates a digital signature S2 from the person in charge of the ordering company, and also generates a digital certificate (S110). Regarding the generation of the digital certificate, the management device 1 generates a hash value of the digital document D1 immediately before the digital signature S2 is added, and includes this in the digital certificate as a pre-signature hash value. The management device 1 also generates a hash value of the digital document D2 after the digital signature S2 has been added, and includes this in the digital certificate as a post-signature hash value. The management device 1 also generates a hash value of the digital document D0 that does not include any digital signatures S, and includes this in the digital certificate as an original text hash value. The management device 1 stores the generated digital certificate (for example, the digital certificate in the second row shown in FIG. 4) in the digital certificate database 3 (S111).

[0056] The management device 1 may determine whether the content of the electronic document D1 has been altered. That is, the management device 1 may determine whether the content of the electronic document D1 to which the electronic signature S2 is to be applied has been altered from the content of the electronic document D1 immediately after the previous electronic signature S1 was applied. For example, the management device 1 compares the post-signature hash value of the electronic certificate in the first line shown in FIG. 4 with the pre-signature hash value of the electronic certificate in the second line. If the two values ​​match, the management device 1 determines that the electronic document D1 has not been altered. If the two values ​​do not match, the management device 1 may output the determination result by transmitting it to the user terminal 4B, for example. This allows the person in charge at the ordering company to confirm the continuity of the content of the electronic document D1 to be applied when applying the electronic signature S2.

[0057] The management device 1 generates an electronic document D2 by adding the generated digital signature S2 to the electronic document D1. The management device 1 then transmits the generated electronic document D2 to the user terminal 4B (S112). The user terminal 4B may store the received electronic document D2 in a storage unit accessible by the user terminal 4B.

[0058] In response to an operation by a person in charge of the ordering company, user terminal 4B transmits electronic document D2 to user terminal 4A used by a person in charge of the order-receiving company (S113). Note that transmission of electronic document D2 to user terminal 4A may be performed via management device 1. User terminal 4A receives electronic document D2 (S114). Note that a notification of payment acceptance may be transmitted from user terminal 4B to user terminal 4A, with or without the intervention of management device 1. User terminal 4A may store the received electronic document D2 in a storage unit accessible to user terminal 4A.

[0059] (3-2) Assignment of claims FIG. 6B is a sequence diagram for the assignment of receivables. The user terminal 4A used by the person in charge of the order-receiving company accepts the operation of inputting the assignment conditions for the receivables indicated in the electronic document D2 by the person in charge of the order-receiving company (S201). The content of the assignment conditions is not particularly limited and may include any item related to the receivables (such as amount and due date). The input assignment conditions are sent from the user terminal 4A to the management device 1, which then records them in the electronic document database 2 in a searchable manner.

[0060] The user terminal 4C used by the factoring company's staff executes a search process for receivables in response to an operation by the factoring company's staff (S202). For example, the user terminal 4C sends a search request including transfer conditions such as the amount entered by the factoring company's staff to the management device 1. In response to the search request received from the user terminal 4C, the management device 1 searches for receivables using the transfer conditions included in the search request as a key, and sends the search results to the user terminal 4C.

[0061] In this example, it is assumed that electronic document D2 is found in the search results, and information about electronic document D2 is sent from management device 1 to user terminal 4C. After confirming the information about electronic document D2, the factoring company's staff decides to purchase the receivables related to electronic document D2, and inputs a purchase request for the receivables into user terminal 4C. User terminal 4C then transmits the purchase request to user terminal 4A used by the staff of the order-receiving company, which is the original creditor (S203). Note that this transmission process may be executed via management device 1.

[0062] The person in charge at the order-receiving company, which is the original creditor, checks the purchase application made by the person in charge at the factoring company, and if he or she decides to transfer the credit, inputs a signature instruction for electronic document D2 to user terminal 4A to consent to the transfer of the credit. In response to this operation, user terminal 4A transmits the signature instruction for electronic document D2 to management device 1 (S204). Management device 1 receives the signature instruction for electronic document D2 from user terminal 4A (S205).

[0063] The signature instructions for the electronic document D2 may include, for example, the data of the electronic document D2 itself, or may include information (such as a series ID) for identifying the electronic document D2 stored in the electronic document database 2 or a storage unit accessible by the user terminal 4A. The signature instructions may also include, for example, any item recorded in the digital certificate database 3 (such as an item related to the person in charge at the order-receiving company). The signature instructions may also include, for example, the signature content entered by the person in charge at the order-receiving company. The example shown in FIG. 4 shows the signature content entered by the person in charge at the order-receiving company: "The claim rights set forth in this invoice have been assigned."

[0064] Based on the signing instructions, the management device 1 generates a digital signature S3 by the person in charge at the order-receiving company, and also generates a digital certificate (S206). Regarding the generation of the digital certificate data, the management device 1 generates a hash value of the digital document D2 immediately before the digital signature S3 is added, and includes this in the digital certificate as a pre-signature hash value. The management device 1 also generates a hash value of the digital document D3 after the digital signature S3 is added, and includes this in the digital certificate as a post-signature hash value. The management device 1 also generates a hash value of the digital document D0 that does not include any digital signatures S, and includes this in the digital certificate as an original text hash value. The management device 1 stores the generated digital certificate (for example, the digital certificate in the third row shown in FIG. 4) in the digital certificate database 3 (S207).

[0065] The management device 1 may determine whether the content of the electronic document D2 has been altered. That is, the management device 1 may determine whether the content of the electronic document D2 to which the electronic signature S3 is to be applied has been altered from the content of the electronic document D2 immediately after the previous electronic signature S2 was applied. For example, the management device 1 compares the post-signature hash value of the electronic certificate in the second line shown in FIG. 4 with the pre-signature hash value of the electronic certificate in the third line. If the two values ​​match, the management device 1 determines that the electronic document D2 has not been altered. If the two values ​​do not match, the management device 1 may output the determination result by transmitting it to the user terminal 4A, for example. This allows the person in charge at the order-receiving company to confirm the continuity of the content of the electronic document D2 to be applied when applying the electronic signature S3.

[0066] The management device 1 generates an electronic document D3 by adding the generated digital signature S3 to the electronic document D2. The management device 1 then transmits the generated digital document D3 to the user terminal 4C (S208). The user terminal 4C may store the received digital document D3 in a storage unit accessible by the user terminal 4C.

[0067] User terminal 4C displays electronic document D3, and the person in charge at the factoring company confirms the contents of electronic document D3 (S209). When the person in charge at the factoring company performs a deposit operation for the transfer fee, user terminal 4C accepts the operation and executes a deposit process for the transfer fee (S210). By performing the deposit process for the transfer fee, for example, the transfer fee is transferred from the account of the factoring company to the account of the collection agency company. User terminal 4D used by the person in charge at the collection agency company executes a deposit confirmation process for the transfer fee accepted from user terminal 4C in accordance with the operation of the person in charge at the collection agency company (S211).

[0068] The person in charge at the factoring company, which is the new creditor, confirms the payment and receipt of the transfer price, and then inputs a signature instruction for registering the transfer of the credit to the electronic document D3 into the user terminal 4C. In response to this operation, the user terminal 4C sends the signature instruction for the electronic document D3 to the management device. The management device 1 then sends the signature instruction for the electronic document D3 to the user terminal 4C (S212). The management device 1 then receives the signature instruction for the electronic document D3 from the user terminal 4C (S213).

[0069] The signature instructions for the electronic document D3 may include, for example, the data of the electronic document D3 itself, or may include information (such as a series ID) for identifying the electronic document D3 stored in the electronic document database 2 or the like. The signature instructions may also include, for example, any item recorded in the digital certificate database 3 (such as an item related to the person in charge at the order-receiving company). The signature instructions may also include, for example, the signature content entered by the person in charge at the factoring company. In the example shown in Figure 4, the signature content reads, "I have accepted the claim described in this invoice."

[0070] Based on the signing instructions, the management device 1 generates a digital signature S4 from the person in charge at the order-receiving company, and also generates a digital certificate (S214). Regarding the generation of the digital certificate, the management device 1 generates a hash value of the digital document D3 immediately before the digital signature S4 is added, and includes this in the digital certificate as a pre-signature hash value. The management device 1 also generates a hash value of the digital document D4 after the digital signature S4 is added, and includes this in the digital certificate as a post-signature hash value. The management device 1 also generates a hash value of the digital document D0 that does not include any digital signatures S, and includes this in the digital certificate as an original text hash value. The management device 1 stores the generated digital certificate (for example, the digital certificate in the fourth row shown in FIG. 4) in the digital certificate database 3 (S215).

[0071] The management device 1 may determine whether the content of the electronic document D3 has been altered. That is, the management device 1 may determine whether the content of the electronic document D3 to which the electronic signature S4 is to be applied has been altered from the content of the electronic document D3 immediately after the previous electronic signature S3 was applied. For example, the management device 1 compares the post-signature hash value of the electronic certificate on the third line in FIG. 4 with the pre-signature hash value of the electronic certificate on the fourth line. If the two values ​​match, the management device 1 determines that the electronic document D3 has not been altered. If the two values ​​do not match, the management device 1 may output the determination result by transmitting it to the user terminal 4C, for example. This allows the person in charge at the factoring company to confirm the continuity of the content of the electronic document D3 to be applied when applying the electronic signature S4.

[0072] The management device 1 generates an electronic document D4 by adding the generated digital signature S4 to the electronic document D3, and then transmits the generated electronic document D4 to the user terminal 4C (S216).

[0073] The user terminal 4C displays the electronic document D4, which the factoring company's staff member confirms (S217). When the factoring company's staff member performs an operation to request payment of the transfer fee, the user terminal 4C accepts the operation and sends a transfer fee payment request to the user terminal 4D used by the collection agency company's staff member (S218). When the user terminal 4D used by the collection agency company's staff member receives the transfer fee payment request from the user terminal 4C, it executes a transfer fee payment process in accordance with the operation by the collection agency company's staff member (S219). Through the transfer fee payment process, for example, the transfer fee is deposited from the collection agency company's account to the order-receiving company's account. The user terminal 4A used by the order-receiving company's staff member executes a payment confirmation process for the transfer fee received from the user terminal 4D in accordance with the operation by the order-receiving company's staff member (S220).

[0074] (3-3) Extinguishment of claims FIG. 6C is a sequence diagram related to the extinguishment of a claim. User terminal 4B used by a person in charge of the ordering company executes payment processing for the accounts payable related to electronic document D4 in response to an operation by the person in charge of the ordering company (S301). Through the accounts payable payment processing, for example, the accounts payable are transferred from the account of the ordering company to the account of the collection agency company. User terminal 4D used by a person in charge of the collection agency company executes payment confirmation processing for the accounts payable received from user terminal 4B in response to an operation by the person in charge of the collection agency company (S302). User terminal 4D used by a person in charge of the collection agency company executes payment processing for the accounts payable in response to an operation by the person in charge of the collection agency company (S303). Through the accounts payable payment processing, for example, the accounts payable are deposited from the account of the collection agency company to the account of the factoring company. User terminal 4C used by a person in charge of the factoring company executes payment confirmation processing for the accounts payable received from user terminal 4D in response to an operation by the person in charge of the factoring company (S304).

[0075] After confirming the payment of the accounts payable, the person in charge at the factoring company, which is the new creditor, inputs a signature instruction for registering the extinguishment of the credit to electronic document D4 into user terminal 4C. In response to this operation, user terminal 4C transmits the signature instruction for electronic document D4 to management device 1 (S305). Management device 1 receives the signature instruction for electronic document D4 from user terminal 4C (S306).

[0076] The signature instructions for the electronic document D4 may include, for example, the data of the electronic document D4 itself, or may include information (such as a series ID) for identifying the electronic document D4 stored in the electronic document database 2 or the like. The signature instructions may also include, for example, any item recorded in the digital certificate database 3 (such as an item related to the factoring company's staff member). The signature instructions may also include, for example, the signature content entered by the factoring company's staff member. In the example shown in Figure 4, the signature content reads, "Payment was made as invoiced."

[0077] Based on the signing instructions, the management device 1 generates an electronic signature S5 by the factoring company's employee and also generates an electronic certificate (S307). Regarding the generation of the electronic certificate, the management device 1 generates a hash value of the electronic document D4 immediately before the digital signature S5 is applied, and includes this in the electronic certificate as a pre-signature hash value. The management device 1 also generates a hash value of the electronic document D5 after the digital signature S5 is applied, and includes this in the electronic certificate as a post-signature hash value. The management device 1 also generates a hash value of the electronic document D0 that does not include any digital signatures S, and includes this in the electronic certificate as an original text hash value. The management device 1 stores the generated electronic certificate (for example, the digital certificate in the fifth row shown in FIG. 4) in the digital certificate database 3 (S308).

[0078] The management device 1 may determine whether the content of the electronic document D4 has been altered. That is, the management device 1 may determine whether the content of the electronic document D4 to which the electronic signature S5 is to be applied has been altered from the content of the electronic document D4 immediately after the previous electronic signature S4 was applied. For example, the management device 1 compares the post-signature hash value of the electronic certificate on the fourth line in FIG. 4 with the pre-signature hash value of the electronic certificate on the fifth line. If the two values ​​match, the management device 1 determines that the electronic document D4 has not been altered. If the two values ​​do not match, the management device 1 determines that the electronic document D4 has been altered. The management device 1 may output the determination result to the user terminal 4C, for example. This allows the factoring company's staff member to confirm the continuity of the content of the electronic document D4 to be applied when applying the electronic signature S5.

[0079] The management device 1 generates electronic document D5 by adding the generated digital signature S5 to electronic document D4. Then, the management device 1 transmits the generated electronic document D5 to the user terminal 4C (S309). The user terminal 4C displays electronic document D5, and the factoring company's staff member confirms it (S310).

[0080] (4) Supplementary notes In the above-described embodiment, the process of determining whether an electronic document (electronic content) has been altered is performed when an electronic signature is generated in response to a signing instruction (steps S110, S206, S214, and S307). However, the process of determining whether an electronic document (electronic content) has been altered is not limited to these timings and may be performed, for example, when a user requests a determination from the management device 1 via the user terminal 4 at any timing. In this case, the user terminal 4 may, for example, accept information about an electronic signature designated by the user as the target of the determination process and include that information in the request for determination and send it to the management device 1. The management device 1 may compare the pre-signature hash value of the designated electronic signature with the post-signature hash value of the electronic signature immediately preceding the designated electronic signature, and if the pre-signature hash value matches, determine that the electronic document (electronic content) has not been altered at the time of the designated electronic signature. If the pre-signature hash value does not match, determine that the electronic document (electronic content) has been altered at the time of the designated electronic signature.

[0081] The above-described digital signature management system 100 can also be applied when a user modifies the contents of a contract after it has been concluded. For example, when the user needs to modify the contents (delivery date, price, etc.) of an concluded contract, the user first performs an operation to acquire the target digital document on the user terminal 4. As a result, the user terminal 4 acquires the target digital document from the digital document database 2 via the management device 1. Next, the user terminal 4 modifies the digital document as appropriate in accordance with the user's operation. Then, the user terminal 4 transmits a signature instruction for the modified digital document (modified digital document) to the management device 1 in accordance with the user's operation. The management device 1 generates a digital signature for the modified digital document and assigns it to the modified digital document.

[0082] The amended electronic document with the digital signature may be transmitted from the management device 1 to a user terminal 4 used by another user (e.g., the other party to a contract). The other user then confirms the contents of the amended electronic document displayed on the user terminal 4 and applies a digital signature to the amended electronic document via the user terminal 4. The user terminal 4 transmits a signature instruction to the management device 1, which then generates the other user's digital signature and further affixes it to the amended electronic document (to which the user's digital signature has been affixed). This allows, for example, amendments to the contract content within the same electronic document file without the need for an amendment memorandum. With conventional digital signatures, changes to the contents of the electronic document or the hash value based on the contents can render the original digital signature invalid. In contrast, the digital signature management system 100 according to this embodiment allows for the identification of a series of digital signatures associated with each other using a series ID (series identification information) even if the hash value of the electronic document changes due to the digital signature. This facilitates the management of amendments to the contract content.

[0083] The above-mentioned digital signature management system 100 can verify a series of digital signatures that are associated with each other using a series ID (series identification information) even if the hash value of the digital content changes due to the digital signature, and therefore can be applied to any digital content that is expected to be continuously signed, not just contracts. For example, the digital signature management system 100 can be applied to cases such as signature campaigns in political activities, where multiple signers sequentially sign digital documents on a signature book. [Explanation of symbols]

[0084] 1...management device, 2...electronic content database, 3...electronic certificate database, 4, 4A, 4B, 4C, 4D...user terminal, 11...document management unit, 12...instruction acquisition unit, 13...user information acquisition unit, 14...signature generation unit, 15...assignment unit, 16...electronic certificate generation unit, 17...electronic certificate storage unit, 18...transmission / reception unit, 41...imaging unit, 42...identifier acquisition unit, 43...retained information acquisition unit, 44...hash value calculation unit, 45...integrity verification unit, 46...output unit, 47...operation acceptance unit, 48...transmission / reception unit, N...communication network, S...electronic signature, D...electronic content, D0, D1, D2, D3, D4, D5...electronic document

Claims

1. A management device for managing digital signatures for digital content, comprising: an acquisition unit that acquires an instruction to sign the electronic content and signature content information that is information indicating the content of the signature; a signature generation unit that generates an electronic signature in response to the instruction; an attaching unit that attaches the generated digital signature to the digital content; an electronic certificate generating unit that generates an electronic certificate related to the electronic signature, the electronic certificate including the signature content information, a pre-signature hash value that is a hash value of the electronic content before the electronic signature is added, a post-signature hash value that is a hash value of the electronic content after the electronic signature is added, and ranking information that indicates the ranking of the electronic signature; a storage unit that stores the digital certificate in a predetermined storage unit; a comparison unit that compares the post-signature hash value included in one of the digital certificates with the pre-signature hash value included in another digital certificate that includes ranking information next to the ranking information included in the one of the digital certificates; an output unit that outputs the comparison result of the comparison unit; A management device comprising:

2. The management device according to claim 1 , wherein the digital signature includes an encoded identifier for identifying the digital certificate.

3. The management device according to claim 1 , wherein the adding unit adds the digital signature to the digital content in a visible manner.

4. The management device according to claim 1 , wherein the digital certificate generating unit further includes, in the generated digital certificate, an original hash value that is a hash value of the digital content that does not include any of the digital signatures.

5. The management device according to claim 1 , wherein the electronic content is an electronic document or an image.

6. 1. A method for controlling a management device for managing digital signatures for digital content, comprising: acquiring an instruction to sign the electronic content and signature content information that is information indicating the content of the signature; generating a digital signature in response to the instructions; adding the generated digital signature to the digital content; generating a digital certificate relating to the digital signature, the digital certificate including the signature content information, a pre-signature hash value which is a hash value of the digital content before the digital signature is added, a post-signature hash value which is a hash value of the digital content after the digital signature is added, and ranking information which indicates the ranking of the digital signature; storing the digital certificate in a predetermined storage unit; generating a comparison result by comparing the post-signature hash value included in one of the digital certificates with the pre-signature hash value included in another digital certificate that includes ranking information next to the ranking information included in the one of the digital certificates; outputting the comparison result; A control method comprising:

7. A program for causing an information processing device to function as a management device for managing digital signatures for digital content, The management device an acquisition unit that acquires an instruction to sign the electronic content and signature content information that is information indicating the content of the signature; a signature generation unit that generates an electronic signature in response to the instruction; an attaching unit that attaches the generated digital signature to the digital content; an electronic certificate generating unit that generates an electronic certificate related to the electronic signature, the electronic certificate including the signature content information, a pre-signature hash value that is a hash value of the electronic content before the electronic signature is added, a post-signature hash value that is a hash value of the electronic content after the electronic signature is added, and ranking information that indicates the ranking of the electronic signature; a storage unit that stores the digital certificate in a predetermined storage unit; a comparison unit that compares the post-signature hash value included in one of the digital certificates with the pre-signature hash value included in another digital certificate that includes ranking information next to the ranking information included in the one of the digital certificates; an output unit that outputs the comparison result of the comparison unit; A program to function as a

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