Information communication device and information communication program

Abstract

Provided is an information communication device or the like capable of sharing information using a blockchain on a network connected peer-to-peer. 【Solution means】A group information storage unit 12 that stores group information shared among members; a transaction issuing unit 18 that issues a transaction indicating that the group information has been changed to the blockchain 4 when a certain operation for changing the content of one group information is performed by one member; a transmission unit 14 that transmits the changed group information to other members; a transaction confirmation unit 20 that accesses the blockchain 4 and checks for the presence or absence of other transactions indicating that other group information has been changed when it detects the reception of other group information from other members; and an update processing unit 22 that reflects the other group information as legitimate information when there are other transactions.

Description

Technical Field

[0001] The present invention relates to an information communication system and the like that realizes highly reliable groupware using blockchain.

Background Art

[0002] A technique for synchronizing data via the Internet is disclosed in Patent Document 1. In the technique shown in Patent Document 1, the accounting data input by the accounting processing device is used as a primary accounting file. When a transmission instruction is given, the primary accounting file is used as an attached file and attached to a transmission notification email, and is stored in the primary accounting file for each consulting destination of the accounting processing device via the Internet and displayed on the screen. After the correction is completed on the accounting processing device, when a synchronization instruction operation is performed, the synchronization process between the received data of the primary accounting file and the official accounting file is performed. After the synchronization process is completed, the synchronized primary file is used as an attached file and attached to a transmission notification email, and is stored in the primary accounting file of the accounting processing device via the Internet. After receiving the email, the synchronization process between the received data of the primary accounting file and the official accounting file is performed.

[0003] In addition, the inventor has developed the technique shown in Patent Document 2 as a technique for securing the legitimate transmission and reception of electronic data using blockchain. The technique shown in Patent Document 2 includes a mail transmission unit that transmits electronic data to another computer, and a remittance control unit that generates a remittance transaction for accessing the blockchain of digital currency and broadcasts it to the blockchain. As the mail transmission unit transmits electronic data, the remittance control unit generates a remittance transaction of digital currency related to the electronic data and broadcasts it to the blockchain. It also includes a mail reception unit that receives electronic data from another computer, and a reception control unit that accesses the blockchain to confirm the deposit status of digital currency from the sender of the electronic data and determines the reception of the electronic data according to the deposit status when the data reception means receives the electronic data.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent No. 4817404 [Patent Document 2] Japanese Patent No. 6583841 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] However, in the technology disclosed in Patent Document 1, there is a problem that since the transmitted and received files cannot be authenticated, the security is vulnerable. Also, although the technology disclosed in Patent Document 2 significantly reduces the risk in terms of security through authentication, since it cannot synchronize the shared electronic data, it has a problem of being an insufficient technology as groupware.

[0006] Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide an information communication device and an information communication program that can function as groupware capable of sharing information using a blockchain on a network that is connected peer-to-peer without having a shared server. [Means for Solving the Problems]

[0007] The information communication device according to the present invention is an information communication device that constitutes an information communication system in which groupware for managing group information shared among a plurality of members without having a shared server is made to function using a blockchain, and is connected in a peer-to-peer manner. The information communication device is individually used by each of the members forming a group, and storage means having a storage area for storing the group information shared among the members for each member is provided. When a predetermined operation for changing the content of one group information in one storage area is performed by one member from one information communication device used by the one member, a transaction issuing means for issuing a transaction indicating that the predetermined operation has been performed on the one group information to the blockchain, a transmission means for transmitting the one group information after the predetermined operation to other members, and a transaction confirmation means for accessing the blockchain when detecting the reception of other group information from the other members and confirming the presence or absence of other transactions indicating that a predetermined operation for changing the content of other group information in other storage areas has been performed by the other members from other information communication devices. When it is confirmed that there is a newly issued other transaction, an updating means for reflecting the other group information transmitted from the other information communication device as legitimate information in the group information in the one storage area corresponding to the other group information is provided.

[0008] As described above, in the information communication device according to the present invention, when a predetermined operation for changing the content of the group information in the storage area secured in the storage means is performed, it is authenticated by accessing the blockchain that the group information has been changed, and on the condition that the authentication is successful, the received group information is reflected as legitimate group information. Therefore, it is possible to accurately determine whether the received group information is legitimate information by accessing the blockchain while reliably sharing and managing the group information.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] (First Embodiment of the Present Invention) The information communication device according to this embodiment will be described with reference to FIGS. 1 to 11. The information communication device according to this embodiment is a device that operates groupware capable of sharing group information among a plurality of members without providing a shared server on a network constructed by peer-to-peer connection, and ensures the security of the group information shared by using a blockchain.

[0011] In the following embodiments, examples of the shared server include a file sharing server and an authentication server for realizing a login function, and it is assumed that the mail server is not included in the shared server. Note that the configuration without a shared server includes not only a configuration without both a file sharing server and an authentication server, but also a configuration without either a file sharing server or an authentication server. Also, examples of the group information shared among a plurality of members include shared information such as shared files, shared messages, shared schedules, shared links, shared images (still images and moving images), shared tasks, and shared minutes.

[0012] Also, the terms used in the following embodiments are defined as follows. (1) Blockchain It is a type of distributed database. Data is accumulated in order in units called blocks. Each block records the hash value up to the previous block. As a result, in order to tamper with the data, it is necessary to calculate the hash value for all of the data following the block to be tampered with. Therefore, it is difficult to tamper with the data in the blockchain. (2) Digital currency It is a virtual currency realized by blockchain technology. There are digital currencies with real monetary value in reality, such as the well-known Bitcoin and Ethereum, but there are also many digital currencies without monetary value. Due to blockchain technology, it is extremely difficult to counterfeit or replicate digital currencies. (3) Wallet It is a mechanism for storing or managing digital currencies. There are various forms, from Web wallets stored online to cold wallets stored on terminals disconnected from the network. Users of digital currencies own digital currencies on wallets, and the transfer and receipt of digital currencies are carried out between wallets. (4) Wallet Account It is an ID for identifying a wallet. Each user manages digital currencies with a unique wallet account. In the above-mentioned Bitcoin and Ethereum, the hash value of the public key is used as the wallet account. (5) Transaction It is the transaction data of digital currencies recorded on the blockchain. Generally, it is data recording the transfer from one wallet account to another wallet account. The wallet account sending the digital currency signs and sends the transaction describing its own wallet account and the recipient's wallet account using its own private key, and then the transaction is issued. (6) Mining It is the work of summarizing a plurality of issued transactions into one block that can be recorded on the blockchain and recording it at the beginning of the blockchain. The wallet account performing this work is called a miner. By being recorded on the blockchain by the miner, the transaction history is determined in an unforgeable form. It takes several minutes from the issuance to the confirmation of the transaction. (7) Mail Send Coin (hereinafter referred to as MSC) A digital currency implemented in the present invention as a type of virtual currency, which is a type of digital currency that does not aim to have monetary value and can be transferred together with the sending of an email.

[0013] FIG. 1 is a system configuration diagram of an information communication system using the information communication device according to the present embodiment. In FIG. 1, the information communication system 1 includes a communication network 3 constructed by a plurality of information communication devices 10 that are individually used by each member forming a group and are connected peer-to-peer, and a blockchain 4 that accumulates transactions broadcast from each of the information communication devices 10 and functions as a distributed database.

[0014] For example, assume that one information communication device 10 (hereinafter referred to as the first information communication device 10a) and another information communication device 10 (hereinafter referred to as the second information communication device 10b) are connected peer-to-peer and both hold the same file that one has previously sent to the other (hereinafter, this file is referred to as a shared file). In the information communication system 1 of FIG. 1, since it does not have a shared server, the shared file is held as the same file in the local storage areas of the first information communication device 10a and the second information communication device 10b, respectively. At this time, when the first member using the first information communication device 10a changes the shared file, the changed file is sent to the second information communication device 10b. At the same time, the first information communication device 10a broadcasts a transaction (hereinafter referred to as a change transaction) to the blockchain 4 indicating that the shared file has been changed from the shared account of the first member of the first information communication device 10a to the shared account of the second member using the second information communication device 10b. Here, the shared account is identification information for identifying each member of the same group in groupware, and for example, an email address or an SNS ID may be used.

[0015] In the change transaction, information indicating that MSC has been transferred from the wallet account of the first member to the wallet account of the second member may be used as proof that the shared file has been changed, or the content indicating the fact that the first member has made changes to the shared file may be recorded. That is, it suffices to record the fact, time, or the content of the change (in a form in which the change content can be uniquely identified, such as a change ID) that the first member has made changes to the shared file. Specifically, for example, by sending the hash value of the shared file after the content change to the blockchain 4, it becomes possible to prove that the change content received peer-to-peer has indeed been changed by the first member.

[0016] The second information communication device 10b temporarily receives the shared file transmitted from the first information communication device 10a. Here, the temporary reception means, for example, a state where it is received as information but not displayed to the receiving member (that is, a state where the change content of the group information is not reflected as described later), or a state where only a notification indicating that the shared file has been changed (or transmitted after the change operation) is received and the shared file itself has not yet been received. When the second information communication device 10b temporarily receives the shared file, it accesses the blockchain 4 and checks for the presence of the above change transaction. If it is confirmed that the above change transaction exists on the blockchain 4, the temporarily received shared file is received as a legitimate latest shared file (when only the notification has been received, information indicating that it is possible to receive it as a legitimate shared file is transmitted to the first information communication device 10a, and the changed shared file transmitted from the first information communication device 10a that has received it is received), and overwrites the shared file stored in the local storage area of the second information communication device 10b.

[0017] Further, when the first information communication device 10a transmits the shared file, it encrypts the public key of the second member used by the second information communication device 10b that is the transmission destination, that is, the wallet account used as the public key as described above, and then transmits it in an encrypted state. When the second information communication device 10b receives the shared file transmitted in an encrypted state as a legitimate shared file, it decrypts the file using the private key of the second member itself corresponding to the public key of the second member. As a result, the transmission source of the shared file can be authenticated using the blockchain 4, and the confidentiality and security of the transmitted shared file can be ensured.

[0018] FIG. 2 is a functional block diagram showing a configuration that functions during information transmission in the information communication device according to the present embodiment. In FIG. 2, the information communication device 10 includes an operation unit 11 that executes processing according to operations performed by members on group information stored in the group information storage unit 12, an encryption processing unit 13 that encrypts target data targeted by the operation of the operation unit 11 using a public key (wallet account) stored in the public key information storage unit 16, a transmission unit 14 that transmits the encrypted target data to an account stored in the shared account information storage unit 17 using the communication network 3, and a transaction issuing unit 18 that, in response to the operation of the operation unit 11 being executed, reads out information on the wallet accounts of the members sharing the target data from the public key information storage unit 16, generates a change transaction indicating that the members have changed the group information, and signs the generated change transaction using the private key information stored in the private key information storage unit 15 and broadcasts it to the BC (blockchain) 4.

[0019] Each component will be described in detail. The group information storage unit 12 stores group information shared among members of the same group in groupware. This group information stores various shared information such as shared files and shared schedules as described above. When a member who is a user of the information communication device 10 performs an operation to make changes such as addition, update, and / or deletion to the group information stored in the group information storage unit 12 from an input device such as a keyboard, mouse, touch panel, or microphone, based on the input signal, the operation unit 11 executes change processing of the group information (including processing associated with the change of the group information (such as a transmission operation of the changed group information, etc.)). Further, in response to the operation unit 11 executing the change processing of the group information, the transaction issuing unit 18 performs issuing processing of a change transaction.

[0020] Here, the processing of the transaction issuing unit 18 will be described. FIG. 3 is a diagram showing the processing of the transaction issuing unit in the information communication device according to the present embodiment. The public key information storage unit 16 stores a wallet account, which is identification information required for accessing the blockchain 4, for each member of the same group in groupware. Since the information of this wallet account is the hash value of the public key of each member, it has a function of identifying the public key. Further, the shared account information storage unit 17 stores a shared account, which is identification information for identifying each member of the same group in groupware, for each member. And these wallet accounts and shared accounts are stored in a one-to-one correspondence. The transaction issuing unit 18 extracts the corresponding wallet account from its own shared account, and also extracts all the corresponding wallet accounts from the shared accounts of all the shared members who share the data to be changed. Using these wallet accounts, a transaction representing that MSC is transferred from the member who performed the change processing by the operation unit 11 to other shared members is created as a change transaction.

[0021] Incidentally, the user's shared account and the corresponding wallet account may be registered in advance in the public key information storage unit 16 and the shared account information storage unit 17, or a separate dedicated storage means may be provided.

[0022] Also, when the wallet accounts of the shared members are unknown, the public keys of the shared members may be requested from the blockchain 4 once, and the public key information may be obtained. The obtained public key information is stored in the public key information storage unit 16, and requests to the blockchain 4 are not required in subsequent processing.

[0023] When a change transaction is created, the created change transaction is broadcast to the blockchain 4 by signing the change transaction with the user's private key stored in the private key information storage unit 15, and the remittance information of the MSC (that is, information indicating that the modified member has performed a modification process on the target data of the group information) can be written to the blockchain 4. Since it is extremely difficult to tamper with the blockchain 4, the remittance information written here becomes highly reliable, and thus can function as highly reliable information proving that a modification process has been performed on the target data.

[0024] Returning to FIG. 2, in parallel with (or before or after) the creation of the change transaction by the transaction issuing unit 18, the encryption processing unit 13 encrypts the target data on which the change process has been performed with the public keys of the shared members stored in the public key information storage unit 16. That is, when there are multiple shared members, encryption is performed individually for each member with the corresponding public key. Then, each encrypted target data is transmitted to the accounts of the shared members by the transmission unit 14.

[0025] FIG. 4 is a functional block diagram showing a configuration that functions when information is received in the information communication device according to the present embodiment. In FIG. 4, when another shared member changes the group information stored in the group information storage unit 12 and transmits it to each shared member, the information communication device 10 receives the changed target data (the target data received here is encrypted with its own public key as described above). A temporary reception unit 19 that receives the data, a wallet account corresponding to the account of another shared member that is the transmission source is read from the public key information storage unit 16 in response to the reception of the target data by the temporary reception unit 19, and an inquiry is made to the blockchain 4. A transaction confirmation unit 20 that checks whether there is a change transaction issued by the wallet account, and when it is confirmed that there is a change transaction on the blockchain 4, the target data received by the temporary reception unit 19 is stored in the secret key information storage unit 15. A decryption processing unit 21 that decrypts with its own secret key, and an update processing unit 22 that updates the target data in the group information storage unit 12 with the decrypted target data.

[0026] Each configuration will be described in detail. The temporary reception unit 19 receives the target data after the change operation performed by another shared member on the group information. However, at this stage, it has not been confirmed that the target data is legitimate (target data guaranteed by the transmission source), so it is in a state of temporary reception. This temporary reception means, for example, that although the target data itself is received, it is stored temporarily in a storage area that cannot be accessed by the member's operation, or only a prior notice that the target data will be transmitted (for example, a message such as "The target data has been changed by XX member") is received, and the target data itself has not been transmitted yet. Or, when the target data is an e-mail, it includes a state where the e-mail remains in the receiving server.

[0027] When the temporary reception unit 19 performs the above-described temporary reception, the transaction confirmation unit 20 confirms the change transaction. FIG. 5 is a diagram showing the processing of the transaction confirmation unit in the information communication device according to the present embodiment. In FIG. 5, the transaction confirmation unit 20 extracts the corresponding wallet account from the accounts of other shared members of the transmission source of the target data temporarily received by the temporary reception unit 19, based on the public key information storage unit 16 and the shared account information storage unit 17. Also, the corresponding wallet account is extracted from its own shared account. An inquiry is made to the blockchain 4 from these extracted wallet accounts to confirm the presence or absence of a change transaction from the wallet accounts of other shared members to its own wallet account. When it is confirmed that there is a change transaction, the process proceeds to the process of the decryption processing unit 21 based on the confirmation information. When there is no change transaction, based on the confirmation information, the temporary reception unit 19 ignores the temporary reception, deletes the temporarily received target data, or makes an inquiry to the transmission source, etc.

[0028] In this case as well, its own shared account and the corresponding wallet account may be registered in advance in the public key information storage unit 16 and the shared account information storage unit 17, or dedicated storage means may be provided separately.

[0029] Also, when the wallet accounts of the shared members are unknown, the public key of the shared members may be requested from the blockchain 4 once to obtain the public key information. The obtained public key information is stored in the public key information storage unit 16, and in subsequent processing, requests to the blockchain 4 are no longer necessary.

[0030] Returning to FIG. 4, when the transaction confirmation unit 20 confirms that there is a change transaction, the decryption processing unit 21 decrypts the target data temporarily received by the temporary reception unit 19 using its own private key stored in the private key information storage unit 15, assuming that the target data temporarily received is legitimate target data on which other shared members have performed change operations. That is, as described in the block diagram of FIG. 2, the target data transmitted from other shared members is encrypted using its own public key (information of the wallet account), so it can be decrypted by using the corresponding private key.

[0031] Since the transaction confirmation unit 20 confirms that the decrypted target data is reliable data and the data has been changed by other shared members, the update processing unit 22 overwrites this target data as legitimate group information in the group information storage unit 12. Thereby, group information synchronized among members can be shared.

[0032] Next, the processing of the information communication device 10 in the above configuration will be described. FIG. 6 is a flowchart showing the transmission process of a shared file when a shared file in one's own local area is edited in the information communication device according to the present embodiment, and FIG. 7 is a flowchart showing the reception process of a shared file when a shared file in another member's local area is edited in the information communication device according to the present embodiment. In FIGS. 6 and 7, the processing flow of the processing performed between the general groupware installed in the information communication device 10, an add-in (with a shared area in the add-in) that extends the function of the groupware, the blockchain 4, and the user is shown.

[0033] First, in FIG. 6, the user specifies a file to be shared (hereinafter referred to as a shared file) using the functions of the operation unit 11 for the groupware. Or, if it is a file that has already been shared, the shared file is specified (S1). When the add-in is specified with the target shared file, the add-in acquires the shared file (S2), saves (adds) the shared file in the group information storage unit 12, which is a file sharing area within the add-in, or performs overwriting after editing on the existing shared file (S3). The transaction issuing unit 18 of the add-in detects that a predetermined operation (for example, a change operation of group information by adding or editing the shared file) has been performed on the shared file by the operation unit 11, and issues a change transaction to the blockchain 4 by the processing as described above in FIG. 3 (S4). Further, the encryption processing unit 13 of the add-in encrypts the acquired shared file by using the public key of other members who are scheduled to share (or who have already shared) the shared file (S5). The add-in returns the encrypted shared file to the groupware (S6), and the transmission unit 14 of the groupware transmits the encrypted shared file to other members who share the shared file (S7), and ends the transmission process.

[0034] When an encrypted shared file is sent from another member, the flow of FIG. 7 described below is executed. In FIG. 7, when the user operates the groupware or according to the acquisition mode of the shared information preset in the groupware, the temporary reception unit 19 of the groupware receives (temporarily receives) the shared file (S1). When the add-in acquires the shared file received by the temporary reception unit 19 (S2), the transaction confirmation unit 20 checks whether there is a change transaction for the blockchain 4 by the process as described above in FIG. 5 (S3). When it is confirmed that there is a change transaction, the decryption processing unit 21 decrypts the shared file encrypted with its own public key with its own private key (S4), and the update processing unit 22 stores (adds) or overwrites the decrypted shared file in the group information storage unit 12 which is the file sharing area in the add-in (S5). At the same time, the decrypted shared file is returned to the groupware (S6), the groupware displays the shared file (S7), and the reception process ends.

[0035] As shown in the flows of FIGS. 6 and 7, in this case, it is possible to securely and confidentially share local group information (shared files) among group members without having both a file sharing server and an authentication server.

[0036] FIG. 8 is a flowchart showing a transmission process when sharing an attached file attached to an e-mail in the information communication device according to the present embodiment, and FIG. 9 is a flowchart showing a reception process when sharing an attached file sent by e-mail in the information communication device according to the present embodiment. In FIGS. 8 and 9, general e-mail sending and receiving software (hereinafter referred to as a mailer) installed in the information communication device 10 is used as groupware, and a processing flow of processes performed among an add-in that extends the functions of the mailer, the blockchain 4, and the user is shown.

[0037] First, in FIG. 8, the user performs a transmission operation for sending an e-mail and an attached file attached to the e-mail using the function of the operation unit 11 by the mailer (S1). The add-in temporarily stops the operated transmission process (S2) and acquires the e-mail and the attached file (S3). At this time, the body of the e-mail and the attached file may be stored in the group information storage unit 12, which is a file sharing area in the add-in, as in the case shown in FIG. 6, or may be stored in an arbitrary local area by the user. In response to the transmission operation of the e-mail with the attached file being performed by the operation unit 11, the transaction issuing unit 18 of the add-in issues a change transaction to the blockchain 4 by the process as described above in FIG. 3 (S4). Further, the encryption processing unit 13 of the add-in encrypts the acquired e-mail and attached file by using the public key of the member of the transmission destination to which the e-mail is to be sent (S5). The add-in returns the encrypted e-mail and attached file to the transmission unit 14 of the mailer (S6). The transmission unit 14 transmits the encrypted e-mail and attached file to the mail server (S7) and ends the process.

[0038] Note that in FIG. 8, the case where both the e-mail and the attached file are encrypted has been described. However, if confidentiality is not required for the body of the e-mail, only the attached file may be encrypted, or if confidentiality is not required for the attached file, only the body of the e-mail may be encrypted.

[0039] When an encrypted email and attached files are sent from other members, the flow of FIG. 9 described below is executed. In FIG. 9, when the user operates the mailer or according to the setting of automatic acquisition of emails set in the mailer, the temporary reception unit 19 of the mailer checks whether there are any emails and attached files received from the mail server and temporarily receives them (S1). The temporary reception here may be in a state where the temporarily received emails and attached files are downloaded in the add-in, or may be left in the mail server. When the add-in detects the temporary reception of an email by the temporary reception unit 19 (S2), it acquires the email and attached files (S3). When the add-in acquires the email and attached files, the transaction confirmation unit 20 checks whether there is a change transaction for the blockchain by the process as described above in FIG. 5 (S4). When it is confirmed that there is a change transaction, the decryption processing unit 21 decrypts the email and attached files encrypted with its own public key, which were temporarily received by the temporary reception unit 19 or the mail server, with its own private key (S5), and the update processing unit 22 returns the decrypted email and attached files to the mailer and stores the attached files in the group information storage unit 12 (S6). The mailer displays the email and attached files (S7) and ends the reception process.

[0040] As shown in the flows of FIGS. 8 and 9, in this case as well, it is possible to share emails and attached files as group information without having both a file sharing server and an authentication server. That is, it is possible to share group information (transmission and reception of emails and attached files) securely and confidentially among members without sharing passwords in advance or performing authentication such as login.

[0041] FIG. 10 is a flowchart showing the transmission process when sharing an attachment file attached to an email in the information communication device according to the present embodiment, and FIG. 11 is a flowchart showing the reception process when sharing an attachment file sent by email in the information communication device according to the present embodiment. In FIGS. 10 and 11, the processing flow of the processing performed among the mailer installed in the information communication device 10, the add-in that extends the function of the mailer, the blockchain, the external storage, and the file sharing server that is generally provided as a service, and the user is shown.

[0042] First, in FIG. 10, the user performs a transmission operation for sending an email and an attachment file attached to the email using the function of the operation unit 11 in the mailer (S1). The add-in temporarily stops the operated transmission process (S2) and acquires the email and the attachment file (S3). At this time, the text of the email and the attachment file may be saved in the group information storage unit 12, which is a file sharing area in the add-in, in the same manner as in the case of FIG. 8, or may be saved in an arbitrary local area by the user. The transaction issuing unit 18 of the add-in issues a change transaction to the blockchain 4 by the process as described above in FIG. 3 in response to the transmission operation of the email with the attachment file attached by the operation unit 11 (S4). Further, the encryption processing unit 13 of the add-in encrypts the acquired attachment file using the public key of the member of the transmission destination of the email (S5). The upload unit (not shown in FIG. 2) of the add-in uploads the encrypted attachment file to the file sharing server (S6) and acquires the link information of the upload destination (S7). The upload unit returns the acquired link destination information and the email to the transmission unit 14 of the mailer (S8). The transmission unit 14 transmits an email in which the link information of the upload destination of the attachment file is described to the mail server (S9) and ends the process.

[0043] When an email with a link to an attached file is sent from another member, the flow of FIG. 11 described below is executed. In FIG. 11, when the user operates the mailer or according to the setting of automatic acquisition of emails set in the mailer, the temporary reception unit 19 of the mailer checks whether there is an email received from the mail server and receives an email with a link to the attached file (S1). When the add-in detects the temporary reception of the email by the temporary reception unit 19 (S2), it acquires the email with a link to the attached file (S3). The transaction confirmation unit 20 checks whether there is a change transaction for the blockchain by the above-described process (S4). When it is confirmed that there is a change transaction, the download unit (not shown in FIG. 4) of the add-in accesses the link described in the email (S5) and downloads the attached file (S6). The download unit returns the downloaded attached file to the decryption processing unit 21, and the decryption processing unit 21 decrypts the attached file encrypted with its own public key with its own private key (S7). The update processing unit 22 returns the decrypted attached file to the mailer and stores the attached file in the group information storage unit 12 (S8). The mailer displays the email and the attached file (S9) and ends the reception process.

[0044] Note that although the upload unit and the download unit are functions of the add-in, the transmission unit 14 or the temporary reception unit 19 of the mailer may also execute the functions. That is, since the mailer and the add-in function integrally, there is no need to clearly distinguish them in terms of configuration, and the transmission unit 14 may function as the upload unit or the temporary reception unit 19 may function as the download unit.

[0045] As shown in the flows of FIGS. 10 and 11, in this case, it is possible to share group information on a file sharing server without providing an authentication server. That is, since there is no need to perform authentication such as login, there is no need to share passwords in advance, and it is possible to share (send and receive attached files) group information with security and confidentiality guaranteed on a file sharing server that can be accessed by an unspecified number of people.

[0046] As described above, in the information communication device 10 according to this embodiment, a groupware for managing group information that is constructed by peer-to-peer connection and shared among a plurality of members in a state where a shared server is not provided is made to function using the blockchain 4. The information communication device 10 is an information communication device 10 that constitutes an information communication system 1. The information communication device 10 is individually used by each member forming a group, and a group information storage unit 12 having a storage area for storing group information shared among the members for each member. When a certain member performs a predetermined operation to change the content of a certain group information in a certain storage area from a certain information communication device 10 used by the certain member, a certain transaction indicating that the certain operation has been performed on the certain group information is issued to the blockchain 4 by a transaction issuing unit 18. A transmission unit 14 that transmits the certain group information after the predetermined operation to other members. When detecting the reception of other group information from other members, it accesses the blockchain 4 and a transaction confirmation unit 20 that checks for the presence of other transactions indicating that a predetermined operation has been performed to change the content of other group information in other storage areas from other information communication devices 10 by other members. When it is confirmed that there is a newly issued other transaction, an update processing unit 22 that reflects the other group information transmitted from the other information communication device 10 as legitimate information in the group information in a certain storage area corresponding to the other group information. Therefore, when a predetermined operation for changing the content of the group information is performed, it authenticates that the group information has been changed by accessing the blockchain 4, and on the condition that the authentication is successful, reflects the received group information as legitimate group information. Without providing both a file sharing server and an authentication server, it is possible to reliably share and manage group information peer-to-peer, and accurately determine whether the received group information is legitimate information by accessing the blockchain 4.

[0047] Further, if necessary, the information communication device 10 includes an encryption processing unit 13 that encrypts one group of information after a predetermined operation with a public key corresponding to the blockchain accounts of other members who share the one group of information, and a decryption processing unit 21 that decrypts the received other group of information with a private key corresponding to the blockchain account of the one member held by the one member. Therefore, by utilizing the mechanism of the blockchain 4, the transmission and reception of group information can be performed while maintaining confidentiality in the public key cryptosystem.

[0048] Furthermore, if necessary, the group information is information regarding an email and / or information of an attachment file attached to the email. When a transaction issuing unit 18 issues a transaction indicating that a transmission operation has been performed to the blockchain 4 when a member performs a transmission operation of an email and / or an attachment file, which is one group of information, to other members, a transmission unit 14 transmits the email and / or the attachment file, which is one group of information, to the email addresses of other members. When a transaction confirmation unit 20 confirms that an email and / or an attachment file has been transmitted from other members, the transaction confirmation unit 20 accesses the blockchain 4 to check for the presence or absence of other transactions indicating that other members have performed a transmission operation of an email and / or an attachment file, which is other group of information, to the one member. When an update processing unit 22 confirms that there is a newly issued other transaction, the update processing unit 22 stores and reflects the email and / or the attachment file, which is other group of information, as legitimate information in a storage area. Therefore, emails and attachment files can be transmitted and received while maintaining confidentiality, and authentication of senders and receivers can be performed by the blockchain 4.

[0049] Furthermore, if necessary, the group information is information of an attached file attached to an e-mail. When a member performs a transmission operation of transmitting an attached file, which is a piece of group information, to another member, the transaction issuing unit 18 issues a transaction indicating that the transmission operation has been performed to the blockchain 4. The transmission unit 14 uploads the attached file, which is a piece of group information, to an external storage for sharing with other members, and transmits link information indicating the storage destination of the attached file in the external storage to the e-mail addresses of other members by e-mail. When the transaction confirmation unit 20 receives the link information by e-mail from another member, it accesses the blockchain 4 and checks for the presence of other transactions indicating that another member has performed a transmission operation of transmitting an attached file, which is other group information, to a member. When it is confirmed that there is a newly issued other transaction, the update processing unit 22 accesses the external storage indicated by the link destination information received by e-mail, downloads the attached file as legitimate information to a storage area, and reflects it. As a result, it becomes possible to share group information on a peer-to-peer file sharing server without providing an authentication server, and there is no need to perform authentication such as logging in to the file sharing server. Therefore, it becomes possible to share group information with security and confidentiality on a file sharing server that can be accessed by anyone.

[0050] Furthermore, if necessary, the group information is shared information stored in a storage area secured in the local group information storage unit 12 within the information communication device 10 that each member individually uses. When the transaction issuing unit 18 performs a change operation to change the content of a piece of group information stored in a storage area, the transaction issuing unit 18 issues a transaction indicating that the change operation has been performed to the blockchain 4. The transmission unit 14 transmits the changed piece of group information to other members. When the transaction confirmation unit 20 confirms that the content of other group information stored in other storage areas has been changed by other members, the transaction confirmation unit 20 accesses the blockchain 4 and checks for the presence of other transactions indicating that other members have changed other group information. When the update processing unit 22 confirms that there is a newly issued other transaction, in order to reflect the other group information transmitted from other information communication devices 10 as legitimate information in the group information in a storage area corresponding to the other group information, it is possible to securely and confidentially share the locally stored group information among members without providing both a file sharing server and an authentication server, through a peer-to-peer manner.

Explanation of Signs

[0051] 1 Information communication system 3 Communication network 4 Blockchain (BC) 10 Information communication device 11 Operation unit 12 Group information storage unit 13 Encryption processing unit 14 Transmission unit 15 Secret key information storage unit 16 Public key information storage unit 17 Shared account storage unit 18 Transaction issuing unit 19 Temporary reception unit 20 Transaction confirmation unit 21 Decryption processing unit 22 Update processing unit

Claims

1. An information communication device that constitutes an information communication system that enables a groupware for managing group information, which is constructed by peer-to-peer connection and shared among a plurality of members, to function without a shared server using a blockchain, wherein the information communication device is individually used by each of the members forming the group, storage means having a storage area secured for storing the group information shared among the members for each member; in one information communication device used by one member, an operation unit that executes processing in response to an operation of adding, updating, and / or deleting one group information in one storage area; transaction issuing means for detecting that the processing by the operation unit has been executed when the operation unit executes the processing in response to the operation, and issuing one transaction indicating that the operation has been performed on the one group information to the blockchain; transmission means for transmitting the one group information after the operation to other members; a temporary reception unit for temporarily receiving other group information transmitted from the other members; transaction confirmation means for accessing the blockchain when the temporary reception unit temporarily receives the other group information, and confirming the presence or absence of another transaction indicating that an operation for changing the content of the other group information in another storage area from another information communication device by the other member has been performed; updating means for reflecting, as legitimate information, the other group information transmitted from the other information communication device in the group information in the one storage area corresponding to the other group information when it is confirmed by the transaction confirmation means that there is the newly issued other transaction. An information communication device characterized by comprising:

2. In the information communication device according to Claim 1, the information communication device, encryption means for encrypting the one group information after the operation with a public key corresponding to the blockchain account of other members who share the one group information; decryption means for decrypting the received other group information with a private key corresponding to the blockchain account of the one member held by the one member. An information communication device characterized by comprising:

3. In the information communication device according to Claim 1 or 2, The group information is information regarding an e-mail and / or information of an attachment file attached to the e-mail, the operation unit executes processing corresponding to a transmission operation for transmitting the e-mail and / or the attachment file as the one group information to the other members, when the operation unit executes processing corresponding to the transmission operation, the transaction issuing means issues the one transaction to the blockchain in response to receiving that the processing by the operation unit has been executed, the transmission means transmits the e-mail and / or the attachment file as the one group information to the mail addresses of the other members as destinations, the provisional reception unit provisionally receives the e-mail and / or the attachment file from the other members, when the provisional reception unit receives the e-mail and / or the attachment file, the transaction confirmation means accesses the blockchain and confirms the presence or absence of another transaction issued when the other members transmit the e-mail and / or the attachment file as the other group information to the one member, when it is confirmed by the transaction confirmation means that there is the other transaction newly issued, the update means stores and reflects the e-mail and / or the attachment file as the other group information in the one storage area as legitimate information. An information communication device characterized by this.

4. In the information communication device according to claim 1 or 2, the group information is information of an attachment file attached to an e-mail, the operation unit executes processing corresponding to a transmission operation for transmitting the attachment file as the one group information to the other members, when the operation unit executes processing corresponding to the transmission operation, the transaction issuing means issues the one transaction to the blockchain in response to receiving that the processing by the operation unit has been executed, the transmission means uploads the attachment file as the one group information to an external storage shared with the other members, and transmits, by e-mail, link information indicating the storage destination of the attachment file in the external storage to the mail addresses of the other members as destinations. The temporary reception unit receives the link information from the other member by e-mail, When the temporary reception unit receives the link information by e-mail, the transaction confirmation means accesses the blockchain, and is issued when the other member transmits the attached file as the other group information to the one member checks for the existence of other transactions, When it is confirmed by the transaction confirmation means that there is the other transaction newly issued, the update means accesses an external storage indicated by the link information received by the e-mail, and downloads and reflects the attached file as legitimate information in the one storage area. An information communication device characterized by this.

5. In the information communication device according to claim 1 or 2, the group information is shared information stored in the storage area secured in the local storage means in the information communication device used individually by the members, The operation unit executes a process corresponding to an operation of adding, updating, and / or deleting the shared information as the one group information stored in the one storage area, When the operation unit executes the process corresponding to the operation, the transaction issuing means detects that the process by the operation unit has been executed, and issues the one transaction to the blockchain, The transmission means transmits the shared information as the one group information for which the process corresponding to the operation has been performed to the other member, The temporary reception unit temporarily receives the shared information from the other member, When the temporary reception unit receives the shared information, the transaction confirmation means accesses the blockchain and checks for the existence of other transactions indicating that the other member has added, updated, and / or deleted the other group information, When it is confirmed by the transaction confirmation means that there is the other transaction newly issued, the update means reflects the other group information transmitted from the other information communication device as legitimate information in the group information in the one storage area corresponding to the other group information. An information communication device characterized by this.

6. An information communication program installed in an information communication device that constitutes an information communication system that enables groupware for managing group information constructed by peer-to-peer connection and sharable among a plurality of members without a shared server to function using a blockchain, An operation unit that executes a process in response to an operation of adding, updating, and / or deleting a piece of group information in one storage area of a storage unit in which a storage area for storing the group information is secured, A transaction issuing means that, when the operation unit executes a process corresponding to the operation, detects that the process by the operation unit has been executed, and issues a transaction indicating that the operation has been performed on the one piece of group information to the blockchain, A transmission means for transmitting the one piece of group information after the operation to other members, A temporary reception unit that temporarily receives other group information transmitted from other members, A transaction confirmation means that, when the temporary reception unit temporarily receives the other group information, accesses the blockchain and checks for the presence of another transaction indicating that an operation has been performed to change the content of the other group information in another storage area from another information communication device by the other member, An information communication program characterized by causing a computer to function as an update means for reflecting the other group information transmitted from the other information communication device as legitimate information in the group information in the one storage area corresponding to the other group information when it is confirmed by the transaction confirmation means that there is the newly issued other transaction.

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