JP6626228B1 - Management server, document file management system, document file management method, and document file management program - Google Patents

Abstract

An object of the present invention is to provide a management server, a document file management system, a document file management method, and a document file management program that can easily manage whether a document file has been tampered with without burdening the user with work. A hash value calculation unit calculates a hash value of a document file received from an information terminal device, and a hash value acquisition unit includes a document file ID for identifying the document file included in the received document file. And obtains a hash value corresponding to the obtained document file ID from the blockchain network 300, and the falsification determination unit 106 performs the processing based on a comparison result between the calculated hash value and the hash value obtained from the blockchain network 300. The transmitting / receiving unit 101 determines whether the document file has been tampered with, and transmits the determined result to the information terminal device 200. [Selection diagram] Fig. 1

Description

  The present invention relates to a management server, a document file management system, a document file management method, and a document file management program.

  2. Description of the Related Art In recent years, electronic documents that can be easily added, modified, and stored have been used in all cases instead of paper documents. In particular, PDF (Portable Document Format) files are widely used because they are less affected by the usage environment of an information terminal device operated by a user, and the layout is less likely to be disrupted when printed or displayed on a screen. When there are a plurality of almost identical electronic documents partially modified in such electronic documents, there is a problem that it is difficult to later confirm which part has been changed. In order to solve such a problem, a technique is disclosed in which a document file of an official version and a document file of a provisional version are compared for each paragraph, and the difference between the two is extracted by full-text comparison (see Patent Document 1).

JP 2013-045437 JP

  However, the technique described in Patent Document 1 described above has a problem in that it is necessary to perform full-text comparison of a target portion, and it takes a long processing time. In addition, the user himself / herself needs to be aware of the official version or revised version of the document file and manage the document file, and the management of the document file is complicated.

  The present invention has been made in view of the above, and has a management server, a document file management system, a document file management method, and a document file management that can manage whether a document file has been tampered with without burdening the user with work. The purpose is to provide the program.

  In order to solve the above-mentioned problem, in the present invention, a hash value of a document file received from an information terminal device is calculated, a document file ID included in the received document file, which identifies the document file, is obtained, and the obtained document file ID is obtained. A hash value corresponding to the document file ID is obtained from the blockchain network, the calculated hash value is compared with the hash value obtained from the blockchain network, and whether the document file has been tampered with based on the hash value comparison result And transmitting the determined result to the information terminal device.

  ADVANTAGE OF THE INVENTION According to this invention comprised as mentioned above, there exists an effect that the presence or absence of a falsification of a document file can be managed without burdening a user with work.

FIG. 1 is a block diagram illustrating a configuration of a document file management system 10 according to the embodiment. 6 is a flowchart illustrating a document file registration process performed by the management server 100 and the information terminal device 200. 9 is a flowchart illustrating a document file tampering confirmation processing procedure executed by the management server 100 and the information terminal device 200. 11 is a flowchart illustrating a document file version confirmation processing procedure executed by the management server 100 and the information terminal device 200. 9 is a flowchart illustrating a version determination processing procedure executed by the management server 100. FIG. 4 is an explanatory diagram illustrating an example of an image of a hash value of a document file to be verified and a hash value of a document file stored in a block of a block chain network.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description is an example of the embodiment, and the present invention is not limited to the example.

  FIG. 1 is a block diagram illustrating the configuration of the document file management system 10 according to the present embodiment. The document file management system 10 includes a management server 100, information terminal devices 200-1 to 200-n (hereinafter, referred to as information terminal devices 200), and a blockchain network 300. The management server 100, the information terminal device 200, and the blockchain network 300 are communicably connected to each other via a network N as shown in FIG. The network N is an arbitrary communication network such as the Internet, an intranet, a LAN (Local Area Network), a VPN (Virtual Private Network), a mobile communication network, or a combination thereof, and a part or all of them are wired or wireless. May be.

  The management server 100 is a server that registers information on a document file received from the information terminal device 200 in the blockchain network 300 and detects falsification of the document file using the blockchain network 300. The management server 100 includes a transmission / reception unit 101, an ID acquisition unit 102, a hash value calculation unit 103, a block chain registration unit 104, a hash value acquisition unit 105, a falsification determination unit 106, and a version determination unit 107. Prepare.

  The transmission / reception unit 101 receives the document file and the registration request transmitted from the information terminal device 200. The transmission / reception unit 101 transmits the received information on the document file to the blockchain network 300. The transmission / reception unit 101 receives the document file and the falsification confirmation request transmitted from the information terminal device 200, and transmits a falsification confirmation result to the information terminal device 200. The transmission / reception unit 101 receives the document file and the version confirmation request transmitted from the information terminal device 200, and transmits a version confirmation result to the information terminal device 200.

  The ID acquisition unit 102 acquires the document file ID if the document file received with the document registration request contains the document file ID. When the document file ID is not stored in the document file, the ID acquisition unit 102 generates a document file ID and stores the generated document file ID in the document file. The document file ID is information for uniquely identifying a document file, and may be a document name or the like as long as the document file can be identified.

  The hash value calculation unit 103 calculates a hash value of the document file. The hash value calculation unit 103 calculates a hash value from the beginning of the document file to the file size. Here, the document file is, for example, a PDF file. When the original document created first is edited, the updated content is added as an incremental update to be one document file. The document file may be a file other than the PDF file as long as the updated contents can be added to the document file. In the present embodiment, a case where the document file is a PDF file will be mainly described.

  The block chain registration unit 104 transmits the document file ID and the hash value of the document file (document file including the document file ID) for which registration has been requested to the block chain network 300, and stores the document file ID and the hash value in the blocks in the block chain network 300. Store and register the hash value.

  The hash value obtaining unit 105 obtains a hash value from the blockchain network 300 by obtaining the document file ID stored in the document file and transmitting the obtained document file ID to the blockchain network 300. The hash value acquisition unit 105 acquires the file size, version information, and other information stored in the block in addition to the hash value. The other information is, for example, a registration date and time.

  The falsification determination unit 106 determines that there is no falsification if the hash values match based on the comparison result of the hash value calculated from the document file and the hash value acquired by the hash value acquisition unit 105, and if the hash values do not match, Judge that there is tampering.

  The version determination unit 107 determines the version information of the document file to be verified, based on the hash value, the file size, and the version information, which are stored in the block of the block chain network 300 and differ for each version of one document file. It is determined whether an update not registered in network 300 has been made.

  The information terminal device 200 is a personal computer, a tablet terminal, a smartphone, or the like operated by a user who wants to manage falsification and version of the document file. The information terminal device 200 transmits various requests from the information terminal device 200 to the management server 100, and responds to the requests. Receive and display.

  The blockchain network 300 is a system using a so-called distributed ledger technology. In this embodiment, the document file ID and the hash value of the document file, the file size of the document file, version information, and other information are stored in the blockchain network 300. By transmitting to 300, it is stored in the block. By transmitting the document file ID to the blockchain network 300, the hash value of the document file stored in the block, the file size of the document file, version information, and other information are obtained.

  A document file registration process executed by the document file management system 10 configured as described above will be described. FIG. 2 is a flowchart illustrating a document file registration process performed by the management server 100 and the information terminal device 200.

  The information terminal device 200 receives registration of a document file (step S201). The information terminal device 200 transmits the document file and the document registration request to the management server 100 (Step S202).

  In the management server 100, the transmission / reception unit 101 receives the document file and the document registration request (Step S203). The ID acquisition unit 102 determines whether a document file ID is stored in the document file (Step S204). When determining that the document file ID is stored in the document file (step S204: Yes), the ID acquisition unit 102 acquires the document file ID from the document file (step S205).

  When determining that the document file ID is not stored in the document file (step S204: No), the ID acquisition unit 102 generates a document file ID (step S206). The ID acquisition unit 102 stores the document file ID in the document file (Step S207). The hash value calculation unit 103 calculates a hash value of the document file (Step S208). The transmission / reception unit 101 transmits the document file ID and the hash value of the document file to the blockchain network 300 (Step S209). Thus, the document file ID and the hash value are stored in the block of the block chain network 300. Note that, in addition to the document file ID and the hash value, file size, version information, and other information may be transmitted to the blockchain network 300 and stored in a block of the blockchain network 300. The transmission / reception unit 101 determines whether the document file ID has been generated by the ID acquisition unit 102 (step S210). If it is determined that the document file ID has not been generated (step S210: No), the process ends. When determining that the document file ID has been generated (step S210: Yes), the transmitting / receiving unit 101 transmits the document file to the information terminal device 200 (step S211).

  The information terminal device 200 receives the document file (Step S212). The information terminal device 200 stores the document file (Step S213). More specifically, the information terminal device 200 replaces the document file transmitted to the management server 100 with the document file received from the management server 100. As a result, even if the document file does not initially hold the document file ID, the information stored in the block of the blockchain network 300 and the document file stored in the information terminal device 200 can be linked by the document file ID. Can be.

  As described above, by including the document file ID in the document file and storing the information about the document file in the block of the block chain network 300 in association with the document file ID, when searching the block chain network 300 from the document file itself, Therefore, there is no need to provide a mechanism (for example, a database or the like) for associating the document file with the document file ID, and information on the document file stored in the blockchain network 300 can be obtained only with the document file. Can be referenced.

  In addition, if version information is stored as information about a document file, even if a plurality of versions exist in the document file, information about the document file can be stored in blocks of the blockchain network 300 for each version. A hash value can be stored for each version of a file.

  Next, a description will be given of a document file falsification confirmation process executed by the document file management system 10. FIG. 3 is a flowchart showing a document file falsification confirmation processing procedure executed by the management server 100 and the information terminal device 200.

  The information terminal device 200 receives the document file to be verified (step S301). For example, a document file may be accepted by selection from a list of document files. The information terminal device 200 transmits the document file and the falsification confirmation request to the management server 100 (Step S302).

  The transmission / reception unit 101 of the management server 100 receives the document file and the falsification confirmation request from the information terminal device 200 (Step S303). The hash value calculation unit 103 calculates a hash value of the received document file (Step S304). The hash value acquisition unit 105 acquires a document file ID from the document file (Step S305). The hash value acquisition unit 105 acquires a hash value corresponding to the document file ID from the blockchain network 300 (Step S306). In the falsification confirmation process, if a document file having a different version is stored in the blockchain network 300, the presence or absence of falsification can be confirmed by comparing the latest version or the hash value with the latest registration date and time. .

  The falsification determination unit 106 determines whether the document file has been falsified based on the comparison result between the hash value of the document file calculated by the hash value calculation unit 103 and the hash value obtained from the blockchain network 300 (step S307).

  More specifically, if the hash value of the document file to be verified matches the hash value of the document file stored in the blockchain network 300, the falsification determination unit 106 determines that the document file to be verified is the blockchain network 300. Is determined not to have been falsified from the document file stored in. If the hash value of the document file to be verified does not match the hash value of the document file stored in the blockchain network 300, the falsification determination unit 106 determines that the document file to be verified is the document file stored in the blockchain network 300. Is determined to have been tampered with.

  The transmission / reception unit 101 transmits the determination result regarding the falsification by the falsification determination unit 106 to the information terminal device 200 (step S308).

  The information terminal device 200 receives the determination result regarding tampering from the management server 100 (step S309). The information terminal device 200 displays the result of the determination regarding tampering on the display unit (step S310).

  As described above, by transmitting the document file obtained by the user to the management server 100, it is possible to determine whether or not the content of the document file has been falsified. In addition, since the presence or absence of falsification of the document file can be determined using the information on the document file stored in the block of the block chain network 300, the presence or absence of falsification can be determined without using an electronic signature system or the like. Although it has been described above that the updated content of the document file can be added as an incremental update, the document file to be subjected to the tampering check may be a document file to which the updated content is not added.

  By adding the registration date and time, which is the date and time stored in the block of the block chain network 300, as the information on the document file, if it is determined that the document file to be verified has not been tampered with, You can also prove it existed.

  Next, a document file version confirmation process executed by the document file management system 10 will be described. FIG. 4 is a flowchart illustrating a document file version confirmation process performed by the management server 100 and the information terminal device 200.

  The information terminal device 200 receives a document file to be verified (step S401). For example, a document file may be accepted by selection from a list of document files, and a version confirmation menu may be selected. The information terminal device 200 transmits the document file and the version confirmation request to the management server 100 (Step S402).

  The transmitting / receiving unit 101 of the management server 100 receives the document file and the version confirmation request from the information terminal device 200 (Step S403). The ID acquisition unit 102 acquires a document file ID from the document file (Step S404). The hash value acquisition unit 105 acquires a hash value, file size, and version information corresponding to the document file ID from the blockchain network 300 (Step S405). In the version confirmation processing, since it is assumed that information on a plurality of document files having different versions is stored in the blockchain network 300, a plurality of hash values, file sizes, and version information corresponding to the document file IDs are stored. Is obtained. The version determining unit 107 performs a version determining process (Step S406). Details will be described later with reference to FIG. The transmission / reception unit 101 transmits the determination result regarding the version of the document file to the information terminal device 200 (Step S407).

  The information terminal device 200 receives the determination result regarding the version of the document file from the management server 100 (step S408). The information terminal device 200 displays the result of the determination regarding the version of the document file on the display unit (step S409).

  Next, details of the version determination process executed by the management server 100 will be described. FIG. 5 is a flowchart illustrating a version determination process performed by the management server 100.

  The version determination unit 107 acquires the file size of the document file to be verified (step S501). The version determining unit 107 determines whether there is data that matches the file size of the document file among the data corresponding to the document file ID acquired from the blockchain network 300 (step S502). FIG. 6 is an explanatory diagram showing an example of an image of a hash value of a document file to be verified and a hash value of a document file stored in a block of the block chain network. In the example shown in FIG. 6, the hash value, the file size, and the version information, which are three versions of data, are obtained from the blocks stored in the blockchain network 300, and whether or not there is data with the same file size among them. Judge. In the case shown in FIG. 6, there is no matching data.

  If it is determined that there is data matching the file size of the document file (step S502: Yes), the version determination unit 107 determines whether the hash values match (step S503). If it is determined that the hash values match (step S503: Yes), the version determining unit 107 determines that the version information of the document file to be verified and the unregistered update have not been performed (step S504). The version information of the document file to be verified can be determined to be version information of data having the same file size and the same hash value, and that the file sizes of the data stored in the blockchain network 300 match. Accordingly, it can be determined that there is no additional data in the document file corresponding to the version information, that is, there is no additional content of the update content not registered in the blockchain network 300. If it is determined that the hash values do not match (step S503: No), the process proceeds to step S505.

  If it is determined that there is no data that matches the file size of the document file (step S502: No), that is, if it is determined that there is additional content to be updated that is not registered in the blockchain network 300, the version determination unit 107 The data of the next smaller file size than the file size of the file is selected (step S505). In the example shown in FIG. 6, data whose version information is “version 2” is selected.

  The hash value calculation unit 103 calculates a hash value of data from the head of the document file to the file size (Step S506). In the example shown in FIG. 6, the hash value of data from the beginning of the document file to be verified to “size 2”, which is the file size of “version 2”, that is, the original document + update 1 is calculated. The version determination unit 107 determines whether the hash value of the selected data matches the calculated hash value (step S507). If it is determined that the hash values match (step S507: Yes), the version determining unit 107 determines that the version information of the document file to be verified and the unregistered update have been performed (step S508). Since the version information of the document file to be verified can be determined to be the version information of the data having the same hash value, and the file size of the data stored in the blockchain network 300 does not match, the version information is registered in the blockchain network 300. It can be determined that there is additional update content that has not been updated.

  If it is determined that the hash values do not match (step S507: No), the version determining unit 107 determines whether there is data corresponding to the document file ID acquired from the blockchain network 300 (step S509). If it is determined that there is data (step S509: Yes), the process returns to step S505 to execute the next process. If it is determined that there is no data (step S509: No), the process ends.

  As described above, by transmitting the document file obtained by the user to the management server 100, it is confirmed whether the version information of the document file to be verified and whether the document file to be verified has not been updated. be able to. Further, since information on the document file version of the document file is stored in the block of the blockchain network 300, the version can be managed without using an electronic signature system or the like.

  By adding the registration date and time, which is the date and time stored in the blockchain network 300, it is possible to prove the date and time when the document file of each version exists.

  The hardware configuration of the management server 100 and the information terminal device 200 according to the above-described embodiment includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). This is a normal computer including a storage device, a communication control device, and the like. The CPU reads out a program stored in a ROM, a RAM, an HDD, or the like to perform the above-described configuration and functions.

  The programs that operate on the management server 100 and the information terminal device 200 are stored on a computer connected to a network such as the Internet, and are provided by being downloaded via the network, or can be installed or executed. May be recorded on a computer-readable recording medium such as a CD-ROM, DVD, USB memory, or SD card and provided. Further, a program for realizing the above-described functions and processes may be provided in a usage form such as API (Application Programming Interface), SaaS (Software as a Service), or cloud computing.

  It should be noted that the present invention is not limited to the above-described embodiments as they are, and does not necessarily need to be physically configured as illustrated. In addition, the present invention provides functional or physical division, integration, replacement, modification, or deletion of all or a part of the components described in the embodiments in arbitrary units according to various loads and usage conditions. Can be configured.

DESCRIPTION OF SYMBOLS 10 ... Document file management system, 100 ... Management server, 101 ... Transmission / reception part, 102 ... ID acquisition part, 103 ... Hash value calculation part, 104 ... Blockchain registration part, 105 ... Hash value acquisition part, 106 ... Falsification judgment part, 107: Version judging unit, 200: Information terminal device, 300: Blockchain network, N: Network

Claims (8)

A management server connected to the information terminal device via a network,
Receiving means for receiving a document file from the information terminal device;
Hash value calculation means for calculating a hash value of the document file including a document file ID for identifying the document file received by the reception means;
The document file ID included in the document file received by the receiving unit is obtained, and one or more hash values, file size, and version information corresponding to the obtained document file ID are stored in a blockchain network. Hash value obtaining means for obtaining from
Obtain the file size of the document file, determine whether there is the file size obtained by the hash value obtaining means that matches the obtained file size, if there is a matching file size, the hash The hash value corresponding to the file size obtained by the value obtaining unit is compared with the hash value of the document file. If the hash values match, the version of the document file is obtained by the hash value obtaining unit. Version determination means for determining that there is no unregistered update to the blockchain network, the version information corresponding to the file size,
The version information determined by the version determining means, and transmitting means for transmitting to the information terminal device that there is no unregistered update to the blockchain network ,
A management server, comprising:
The version determining means selects a file size smaller than the file size of the document file acquired by the hash value acquiring means when there is no file size that matches the file size of the document file, A hash value from the beginning of the file to the selected file size is calculated, and the calculated hash value is compared with a hash value corresponding to the selected file size. Is the version information corresponding to the file size, it is determined that there is an unregistered update to the blockchain network,
2. The information terminal device according to claim 1, wherein the transmitting unit transmits the version information determined by the version determining unit and a notification that there is an unregistered update to the blockchain network to the information terminal device. Management server.
The receiving means receives the document file and the document registration request from the information terminal device,
When the document file ID is stored in the document file, the document file ID is acquired from the document file. When the document file ID is not stored in the document file, the document file ID is generated. And ID acquisition means for storing the generated document file ID in the document file.
The hash value calculation means calculates a file size and version information in addition to a hash value of the document file,
3. The apparatus according to claim 1, further comprising a block chain registration unit that registers the document file ID, the hash value, the file size, and the version information in the block chain network. Management server.
The blockchain registration unit further adds a registration date and time that is a date and time when the document file ID, the hash value, the file size, and the version information are stored in the blockchain network. 4. The management server according to claim 3, wherein the management server is registered.
A document file management system, comprising: an information terminal device; and a management server connected to the information terminal device via a network,
The management server,
A hash value calculation unit that receives the document file from the information terminal device and calculates a hash value of the document file including a document file ID for identifying the document file ;
The document file ID included in the document file received from the information terminal device is acquired, and one or more hash values, file size, and version information corresponding to the acquired document file ID are blockchained. A hash value obtaining means for obtaining from a network;
Obtain the file size of the document file, determine whether there is the file size obtained by the hash value obtaining means that matches the obtained file size, if there is a matching file size, the hash The hash value corresponding to the file size obtained by the value obtaining unit is compared with the hash value of the document file. If the hash values match, the version of the document file is obtained by the hash value obtaining unit. Version determination means for determining that there is no unregistered update to the blockchain network, the version information corresponding to the file size,
Transmitting means for transmitting to the information terminal device a determination result comprising the version information determined by the version determining means, and that there is no unregistered update to the blockchain network ,
The information terminal device,
Receiving means for receiving the determination result from the management server;
Display means for displaying the determination result on a display unit;
A document file management system comprising:
A document file management method executed on a computer, comprising:
A receiving step of receiving a document file from the information terminal device;
A hash value calculating step of calculating a hash value of the document file received by the receiving step , including a document file ID for identifying the document file ;
The document file ID included in the document file received in the receiving step is obtained, and one or more hash values, file size, and version information corresponding to the obtained document file ID are stored in a blockchain network. A hash value obtaining step to obtain from
Obtain the file size of the document file, determine whether there is the file size obtained by the hash value obtaining step that matches the obtained file size, if there is a matching file size, the hash The hash value corresponding to the file size obtained in the value obtaining step is compared with the hash value of the document file. If the hash values match, the version of the document file is obtained by the hash value obtaining step. A version determination step of determining that there is no unregistered update to the blockchain network, which is the version information corresponding to the file size,
The version information determined by the version determination step, and a transmission step of transmitting to the information terminal device that there is no unregistered update to the blockchain network ,
A document file management method comprising:
The version determining step selects a file size smaller than the file size of the document file acquired by the hash value acquiring step when there is no file size that matches the file size of the document file, A hash value from the beginning of the file to the selected file size is calculated, and the calculated hash value is compared with the hash value corresponding to the selected file size. Is the version information corresponding to the file size, it is determined that there is an unregistered update to the blockchain network,
7. The information terminal device according to claim 6, wherein the transmitting step transmits the version information determined by the version determining step and a notification that there is an unregistered update to the blockchain network to the information terminal device. Document file management method.
A document file management program for causing a computer to execute the document file management method according to claim 6.

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