JP2023019673A - Electronic contract method, electronic contract system, and program - Google Patents

Abstract

To implement a system which stores a block chain relating to a contract more easily.SOLUTION: There is disclosed an electronic contract method to be executed in an electronic contract system which is connected to a block chain system which stores a transaction into a block chain. The electronic contract method includes a contract processing step and a storage control step. The contract processing step receives from first and second contractors each agreement instruction for a contract having been concluded between the first and second contractors. The storage control step transmits to the block chain system an instruction to store into the block chain a first transaction indicating that the first contractor has agreed to the contract, and an instruction to store into the block chain a second transaction indicating that the second contractor has agreed to the contract.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to an electronic contract method, an electronic contract system and a program.

A contract agreement system has been proposed that stores transactions related to agreed contracts on a blockchain. Blockchain is a mechanism in which multiple devices that make up a distributed network synchronize transactions and connect them like a chain to store them.

For example, there is a technology in which multiple terminals used by multiple contractors each have a storage unit that stores a block chain, and a transaction including a trail of whether or not to agree to a contract is stored in the storage unit of the own terminal. Proposed.

JP 2017-220710 A WO2017/010455

However, with conventional technology, there were cases where it was not possible to easily build a system for storing blockchains related to contracts. For example, in the above conventional technology, each terminal is configured to store a block chain. Therefore, when adding a contractor, a terminal equipped with a storage unit for storing the block chain is provided for each additional contractor. need to prepare. Also, all terminals corresponding to each of a plurality of subscribers need to store transactions for contracts unrelated to the corresponding subscriber.

An electronic contract method of an embodiment is an electronic contract method executed in an electronic contract system connected to a blockchain system that stores transactions in a blockchain. The electronic contract method includes a contract processing step and a storage control step. The contract processing step receives from each of the first contractor and the second contractor an instruction to agree to a contract concluded between the first contractor and the second contractor. The storage control step stores in the blockchain an instruction to store in the blockchain a first transaction indicating that the first contractor has agreed to the contract, and a second transaction that indicates that the second contractor has agreed to the contract in the blockchain. Send instructions to the blockchain system.

FIG. 1 is a block diagram showing an example of the configuration of the electronic contract system of this embodiment. FIG. 2 is a diagram illustrating an example of the data structure of correspondence information. FIG. 3 is a sequence diagram showing an example of pre-registration processing in this embodiment. FIG. 4 is a sequence diagram showing an example of electronic bidding/electronic contract processing in this embodiment. FIG. 5 is a diagram showing an example of the flow of electronic bidding/electronic contract processing. FIG. 6 is a diagram showing an example of a contract content input screen. FIG. 7 is a diagram showing an example of a contract output screen. FIG. 8 is a diagram showing an example of an electronic contract screen. FIG. 9 is a diagram showing an example of the electronic contract flow on the successful bidder side. FIG. 10 is a diagram showing an example of the electronic contract flow on the orderer side. FIG. 11 is a diagram showing an example of the data structure of transaction information. FIG. 12 is an explanatory diagram showing a hardware configuration example of the apparatus according to this embodiment.

Preferred embodiments of the electronic contract method, electronic contract system and program according to the present invention will be described in detail below with reference to the accompanying drawings.

In the following, an example will be described in which an electronic contract system is realized as a system for managing electronic bidding and making contracts for electronic bidding. Applicable systems are not limited to electronic bidding systems.

In the conventional technology described above, a plurality of terminals used by a plurality of contractors each have a storage unit that stores blockchains. In other words, in the prior art, each terminal is configured to be a user terminal used for agreement of contracts and at the same time to store the blockchain.

If such a configuration is applied to an electronic contract system for electronic bidding, for example, a bidder (a business operator equivalent to a contractor who agrees to a contract, a corporation, etc.) will have a block chain on their terminal It is configured to perform memory as well. Transactions for all contracts are stored on the blockchain, so bidders can choose contracts that are unrelated to themselves for potentially large numbers of contracts (e.g., thousands to tens of thousands of contracts per year). Even if it is, it is necessary to store it all in the terminal of the company.

The electronic contract system according to the present embodiment does not include a storage unit for storing blockchain therein, and instructs a blockchain system having a storage unit for storing blockchain to store transactions.

The blockchain system is configured to store the blockchain in an internal storage unit according to instructions from an external system including the electronic contract system of this embodiment. A blockchain system is composed of, for example, a plurality of distributed servers (blockchain peers). Each server is operated, for example, by a plurality of traders who are not related to the parties to the electronic contract.

The electronic contract system, for example, uses a private key to apply an electronic signature to a transaction (a packet containing the transaction) and transmits the transaction to the blockchain system. After that, the blockchain system executes the processing related to the blockchain.

In this way, the electronic contract system only needs to have functions (programs, etc.) for creating transactions, electronic signatures, and sending transactions, and does not need to have a storage unit for storing blockchains inside. . When a contractor is added, it is sufficient, for example, to make the above function available from the terminal used by the contractor, or to add a terminal capable of using the above function. In this way, it becomes possible to more easily build a system that stores blockchains related to contracts.

FIG. 1 is a block diagram showing an example of the configuration of an electronic contract system 100 of this embodiment. As shown in FIG. 1, the electronic contract system 100 is connected to certificate authorities 201 and 202, an orderer terminal 301, a bidder terminal 302, and a blockchain system 400 via a network 10.

Network 10 is, for example, the Internet, but may be any other type of network. The network 10 may be a wired network, a wireless network, or a mixed network of wired and wired networks.

Certificate authorities 201 and 202 are organizations that issue electronic certificates used in various systems. For example, the certificate authorities 201 and 202 issue private keys and public key certificates in authentication technology based on Public Key Infrastructure (PKI).

The certification authority 201 is, for example, a ministry certification authority recognized by GPKI (Government Public Key Infrastructure), or an organizational certification authority recognized by LGPKI (Local Government Public Key Infrastructure). There may be. A ministry certification authority is, for example, a certification authority that issues a government position certificate of an orderer. The Organizational CA is the CA that issues the Employer's Occupational Certificate. Certificate authority 202 may be, for example, a commercial certificate authority that issues job certificates for bidders.

Certificate authorities 201, 202 need not be distinct and may be replaced by a single certificate authority that issues electronic certificates to both the ordering party and the bidder. Also, the electronic contract system 100 may be connected to three or more certificate authorities.

The certificate authorities 201 and 202 may be configured to issue IC (Integrated Circuit) cards that store private keys and public key certificates.

The orderer terminal 301 is a terminal used by an orderer of electronic bidding. Although one orderer terminal 301 is shown in FIG. 1 , the electronic contract system 100 may be connected to two or more orderer terminals 301 .

A bidder terminal 302 is a terminal used by a bidder for electronic bidding. Although one bidder terminal 302 is shown in FIG. 1 , the electronic contract system 100 may be connected to two or more bidder terminals 302 .

Each terminal (orderer terminal 301 and bidder terminal 302) can be configured by a general computer such as a personal computer. Also, each terminal uses each function of the electronic contract system 100 via various screens provided by the electronic contract system 100 . For example, each terminal can be configured to use each function of the electronic contract system 100 through a browser, web application, or the like.

Blockchain system 400 is a system configured to store a blockchain in an internal storage unit according to instructions from an external system, as described above.

Blockchain system 400 includes communication control unit 411 , smart contract processing unit 412 , management unit 413 , and blockchain storage unit 421 . Blockchain system 400 includes a plurality of servers (blockchain peers) that are multiplexed and distributed so that each of these units is provided. Each server may be built on a cloud environment.

The blockchain storage unit 421 is a storage unit that stores blockchains. For example, the blockchain storage unit 421 stores transactions in the blockchain according to smart contracts executed by the smart contract processing unit 412 .

The communication control unit 411 controls communication with external systems such as the electronic contract system 100 . For example, the communication control unit 411 receives an instruction to store a transaction in the blockchain storage unit 421 (such as a smart contract execution instruction) transmitted from the electronic contract system 100 . In addition, the communication control unit 411 transmits the processing execution result (such as the return value of the instructed smart contract) to the processing request source (such as the electronic contract system 100).

The smart contract processing unit 412 executes the smart contract whose execution has been instructed. For example, the smart contract processing unit 412 executes an instructed smart contract among a plurality of smart contracts each defining processing for each type of transaction, and stores the transaction in the blockchain. The plurality of smart contracts includes an electronic contract smart contract that stores contracts by electronic contract system 100 .

A smart contract may be written in a general-purpose language such as JavaScript (registered trademark). An external system such as the electronic contract system 100 can execute a desired smart contract using a web application or the like that uses an API that calls the smart contract.

Execution of a smart contract can also be interpreted as a transaction. A log (transaction log) that indicates the execution state of a transaction is stored in the blockchain. The transaction log includes, for example, information identifying the called smart contract, arguments of the smart contract, date and time, caller, and the like.

Smart contracts may be able to be added and modified. The management unit 413 manages the smart contract, manages the state of the system, and manages users. For example, the management unit 413 causes the administrator's terminal to display a management screen for smart contract correction, test execution, and the like. The management unit 413 also displays a screen for confirming the state of the blockchain system 400 and a screen for changing user authority.

Modifications to smart contracts and other administrative actions (system configuration changes, user authority changes, etc.) may also be stored on the blockchain as transactions. Thereby, a more reliable system can be realized.

A smart contract may have the ability to call other smart contracts. For example, an electronic contract smart contract may be configured to call a smart contract to perform payment processing. If it is realized as a smart contract, the transaction log can be stored in the blockchain as described above, so compared to the method of realizing payment processing outside the blockchain system 400, a more reliable system can be realized. can.

The electronic contract system 100 includes a registration processing unit 111, a contract management unit 112, a bid processing unit 113, a contract processing unit 114, a storage control unit 115, an authentication unit 116, and a storage unit 121. .

The registration processing unit 111 performs registration processing of a user (first user) of the electronic contract system 100 . A user corresponds to a contractor who makes an electronic contract using the electronic contract system 100 . For example, the registration processing unit 111 examines the qualifications of traders who conduct electronic bidding, and executes trader registration processing for registering traders certified by the examination as users. In the vendor registration process, the vendor information such as the name of the vendor, the name of the representative, the location, the e-mail address, and the registration number issued at the time of certification is stored in the storage unit 121, for example.

In addition, the registration processing unit 111 executes use registration processing for allowing registered traders to use the electronic contract system 100 . The usage registration process includes, for example, a process of registering information on an IC card that has been assigned to the vendor in advance. Before the use registration process, the dealer requests the certificate authorities 201 and 202 to issue an IC card, and obtains the IC card. The IC card is used, for example, for login processing to the electronic contract system 100 (personal identification using IC card information, or personal identification using a user ID and password), and for electronic documents handled in electronic bidding processing. Can be used for signatures.

The private key and public key certificate stored in the IC card may be used for electronic signatures of transactions stored in the blockchain system 400 . The key information used for the electronic signature of the transaction is not limited to the key information stored in the IC card issued for using the electronic contract system 100 .

For example, instead of the IC card, a secret key assigned to the user (business operator) by another method (any method is acceptable) may be used for the electronic signature of the transaction. Wallets that store private and public keys may be used instead of IC cards.

Two or more pieces of key information (IC card, wallet) may be assigned to one trader. For example, different key information may be assigned to one trader for each type of electronic bidding. Also, different key information may be assigned to each individual belonging to one trader.

In such a case, the registration processing unit 111 may execute processing (association processing) that associates the user (second user) of the blockchain system 400 with a plurality of pieces of key information. For example, the registration processing unit 111 executes a process of associating one or more public keys assigned to users of the electronic contract system 100 with users of the blockchain system. A wallet address generated from a public key may be used instead of the public key.

The association process enables the user of the electronic contract system 100 to store in the blockchain system 400 the transaction of the electronic contract with the electronic signature by the private key assigned to the user.

The contract management unit 112 manages contracts related to electronic bidding. For example, the contract management unit 112 registers items to be subjected to electronic bidding, manages successful bidders through electronic bidding, and manages contract details with successful bidders.

The bid processing unit 113 executes processing related to electronic bidding. For example, the bid processing unit 113 allows bidders to display or search for items registered by the contract management unit 112 as electronic bidding targets. The bid processing unit 113 also receives bid applications from bidders and information indicating the determined successful bidders.

The contract processing unit 114 executes processing related to electronic contracts. For example, the contract processing unit 114 concludes a contract between a contractor (first contractor) corresponding to the orderer of the electronic bidding and a contractor (second contractor) corresponding to the successful bidder of the electronic bidding. accepts instructions to agree to contracts that have been signed. Then, the contract processing unit 114 uses the storage control unit 115 to perform processing for storing in the block chain a transaction indicating that the contract has been agreed.

Note that the functions of the contract processing unit 114 may be integrated into the contract management unit 112 . When adding a function to digitize a contract (electronic contract function) to an existing system (such as an electronic bidding system), the contract processing unit 114 that realizes the electronic contract function is added as in the present embodiment. , a configuration that is provided independently of the contract management unit 112 can be employed. This makes it possible to more easily add an electronic contract function, that is, a function of storing a contract in the blockchain system 400, to an existing system.

The storage control unit 115 controls processing for storing transactions in the blockchain storage unit 421 . For example, the storage control unit 115 instructs the block chain to store a transaction (first transaction) indicating that the orderer has agreed to the contract, and a transaction (second transaction) that indicates that the successful bidder has agreed to the contract. An instruction to be stored in the blockchain is sent to the blockchain system 400 .

When the above electronic contract smart contract is prepared, the storage control unit 115 uses the electronic contract smart contract, that is, by calling the electronic contract smart contract, to send a transaction indicating agreement to the contract to the blockchain. can be instructed to be stored in

When the registration processing unit 111 executes the association processing, the storage control unit 115 stores a transaction indicating the association processing, for example, one or more public keys (or wallet addresses) assigned to the user of the electronic contract system 100 and , and the user of the blockchain system may be stored in the blockchain (third transaction). This makes it possible to verify that the electronic contract was stored by the correct user.

The authentication unit 116 authenticates users of the electronic contract system 100 . For example, the authentication unit 116 authenticates the user using a user ID, which is user identification information, and authentication information including a password. The authentication method is not limited to this, and any method may be used. For example, an authentication method using a PIN (Personal Identification Number) number stored in an IC card may be used.

The storage unit 121 stores various information used in the electronic contract system 100 . For example, the storage unit 121 stores vendor information obtained by the vendor registration processing by the registration processing unit 111 . Further, the storage unit 121 stores correspondence information obtained by the association processing by the registration processing unit 111 .

FIG. 2 is a diagram illustrating an example of the data structure of correspondence information. As shown in FIG. 2, the correspondence information has a structure in which a blockchain user ID and key information are associated with each other. A blockchain user ID is identification information of a user of the blockchain system 400 . The key information is information specifying a key assigned to a user (such as a trader) of the electronic contract system 100 corresponding to the user identified by the blockchain user ID. For example, information specifying a key is a public key included in an IC card or wallet, or a unique value calculated from this public key.

Each unit described above (registration processing unit 111, contract management unit 112, bidding processing unit 113, contract processing unit 114, storage control unit 115, and authentication unit 116) is implemented by, for example, one or a plurality of processors. For example, each of the above units may be realized by causing a processor such as a CPU (Central Processing Unit) to execute a program, that is, by software. Each of the above units may be implemented by a processor such as a dedicated IC, that is, by hardware. Each of the above units may be implemented using both software and hardware. When multiple processors are used, each processor may implement one of the units, or may implement two or more of the units.

Each of the above storage units (storage unit 121 and blockchain storage unit 421) is generally used such as flash memory, memory card, RAM (Random Access Memory), HDD (Hard Disk Drive), and optical disc. Any storage medium can be used.

The electronic contract system 100 may be built on a cloud environment, or, like the block chain system 400, may be composed of a plurality of distributed servers.

Next, pre-registration processing by the electronic contract system 100 configured in this way will be described. Pre-registration processing is processing performed before executing an electronic contract, and includes the above-described vendor registration processing and usage registration processing. FIG. 3 is a sequence diagram showing an example of pre-registration processing in this embodiment.

A bidder transmits a qualification application to the electronic contract system 100 using the bidder terminal 302 (step S101). For example, a screen for qualification application provided by the electronic contract system 100 is displayed on the browser of the bidder terminal 302 . Bidders use this screen to submit their qualification applications.

The registration processing unit 111 of the electronic contract system 100 receives the transmitted qualification application and executes a vendor registration process for registering the certified bidder (step S102).

A review of eligibility may be carried out by a reviewer reviewing the application documents. In such a case, the vendor registration process may be executed when the examination by the person in charge of examination is completed and the person in charge of examination designates to the electronic contract system 100 that the bidder has been certified.

The registration processing unit 111 transmits the screening result to the bidder terminal 302 (step S103). The examination result is sent by e-mail, for example, but may be sent by any other method.

If the bidder is certified as a result of the qualification application, the bidder uses the bidder terminal 302 to request the certificate authority 202 to issue an IC card for use registration processing (step S104). The certificate authority 202 sends the issued IC card to the requesting bidder (step S105).

The bidder who received the IC card uses the bidder terminal 302 to transmit a usage registration application to the electronic contract system 100 (step S106). For example, the electronic contract system 100 (registration processing unit 111) displays a screen for inputting the registration number and password of the bidder, which is notified when the qualification application is sent or as a result of the qualification examination, to the bidder terminal. 302. When the bidder enters the registration number and password on this screen, the registration processing unit 111 displays a screen for registering user information. The user information includes, for example, the company information of the bidder (dealer), the person in charge, and the e-mail address of the contact. When the bidder inputs user information on this screen and instructs registration, a use registration application including the user information is transmitted to the electronic contract system 100 .

The registration processing unit 111 executes a usage registration process according to the transmitted usage registration application (step S107). For example, the registration processing unit 111 stores the user information included in the usage registration application in the storage unit 121 or the like.

The registration processing unit 111 may execute matching processing (step S108). The registration processing unit 111 stores the correspondence information obtained by the association processing in the storage unit 121 . Further, the registration processing unit 111 causes the blockchain system 400 (blockchain storage unit 421) to store the transaction indicating the association processing via the storage control unit 115 (step S109).

Next, electronic bidding/electronic contract processing by the electronic contract system 100 configured as described above will be described. The electronic bidding/electronic contract processing includes processing related to electronic bidding (steps S201 to S210) and processing to store the contract concluded as a result of the electronic bidding in the block chain (steps S211 to S217). FIG. 4 is a sequence diagram showing an example of electronic bidding/electronic contract processing in this embodiment.

Steps S201 to S204 correspond to login processing to the electronic contract system 100 of the orderer and the bidder.

For example, the orderer uses the authentication screen displayed on the orderer terminal 301 to enter the orderer's authentication information (for example, user ID, password), and sends the authentication information to the electronic contract system 100 (authentication unit 116). Send (step S201). The authentication unit 116 performs authentication using the authentication information, and transmits the authentication result to the orderer terminal 301 (step S202).

Similarly, the bidder uses the authentication screen displayed on the bidder terminal 302 to enter the bidder's authentication information, and transmits the authentication information to the electronic contract system 100 (authentication unit 116) (step S203). ). The authentication unit 116 performs authentication using the authentication information, and transmits the authentication result to the bidder terminal 302 (step S204).

If the login is successful, the orderer uses the item registration screen displayed on the orderer terminal 301, for example, to enter information (item information) regarding the item to be subjected to electronic bidding, and instruct registration. . The orderer terminal 301 transmits an instruction to register the item information to the electronic contract system 100 (contract management unit 112) in response to the instruction (step S205).

In accordance with the received item information, the contract management unit 112 performs processing such as registering the item as an object of electronic bidding. The registered items are displayed, for example, on the electronic bidding screen, or can be searched on the electronic bidding screen.

When successfully logged in, the bidder uses, for example, an electronic bidding screen displayed on the bidder terminal 302 to enter bidding information including bidding conditions for the desired item and instruct transmission. . The bidder terminal 302 transmits the bid information to the electronic contract system 100 (bid processor 113) according to the instruction (step S206).

The orderer refers to the bid information sent from each bidder to determine the successful bidder. The orderer uses, for example, a successful bidder registration screen displayed on the orderer terminal 301 to input successful bidder information indicating the determined successful bidder and instruct transmission. The orderer terminal 301 transmits successful bidder information to the electronic contract system 100 (bid processor 113) in response to the instruction (step S207).

The bid processing unit 113 transmits the transmitted successful bidder information to the contract management unit 112 (step S208). As a result, the contract management unit 112 can manage that the successful bidder for the item has been determined.

Further, the orderer inputs the details of the contract to be concluded with the winning bidder using, for example, a contract details registration screen displayed on the orderer terminal 301, and instructs transmission. The orderer terminal 301 transmits the contract content to the electronic contract system 100 (contract management unit 112) according to the instruction (step S209).

The contract management unit 112 generates contract information corresponding to electronic data of the contract in accordance with the received contract details (step S210).

In the case of a system that does not execute an electronic contract, for example, generated contract information is printed on a paper medium, and a contract using the paper medium is executed. In this embodiment, an electronic contract using the electronic data of the contract is executed in steps S211 to S217 below.

The contract processing unit 114 transmits the contract information to the bidder terminal 302 used by the bidder who is the successful bidder (step S211). The contract information may include not only the contract but also electronic data of other related documents (related books) (details will be described later).

A bidder (successful bidder) uses, for example, a consensus building screen displayed on the bidder terminal 302 to input information indicating agreement to the contract and instruct transmission. The bidder terminal 302 transmits information indicating contract agreement to the electronic contract system 100 (contract processing unit 114) in response to the instruction (step S212).

Upon receiving the contract agreement instruction, the contract processing unit 114 instructs the storage control unit 115 to store the transaction information including the information indicating the contract agreement as a transaction in the blockchain system 400 (step S213). For example, the contract processing unit 114 instructs to store a transaction indicating agreement to a contract using an electronic contract smart contract.

The storage control unit 115 stores the transaction information as a transaction in the blockchain system 400 (blockchain storage unit 421) according to the instruction (step S214). For example, the storage control unit 115 stores transactions by calling an electronic contract smart contract.

A similar process is executed on the orderer side. For example, the orderer uses a consensus building screen displayed on the orderer terminal 301 to enter information indicating that he or she agrees to the contract, and instruct transmission. The orderer terminal 301 transmits information indicating contract agreement to the electronic contract system 100 (contract processing unit 114) in response to the instruction (step S215).

Since steps S216 and S217 are the same as steps S213 and S214, description thereof is omitted.

In FIG. 4, the bidder (successful bidder) first stores the contract agreement transaction, and then the orderer stores the contract agreement transaction. good too.

In addition, although FIG. 4 shows an example of consensus building for a contract between two parties (orderer, successful bidder), the same procedure can be applied to consensus building among three or more contractors. In this case, the blockchain stores multiple transactions that indicate consensus building by multiple contractors.

Next, the details of the electronic bidding/electronic contract processing will be further described. FIG. 5 is a diagram showing an example of the flow of electronic bidding/electronic contract processing.

In FIG. 5, the contract processing unit 114 has an "electronic contract" function that creates contract document information for an electronic contract, a "contract APL (application)" function that stores contract transactions in the blockchain, and a contractor's It is described separately from the “login processing” function that performs identity verification.

The vendor information obtained by the qualification application and vendor registration processing by the registration processing unit 111 is stored in the storage unit 121 or the like and referred to by the contract management unit 112 (step S301). The contract management unit 112 registers the transmitted item information according to the orderer's instruction (step S302). The registered item is sent to the bid processing unit 113 as an object for electronic bidding (step S303).

The bid processing unit 113 receives the bid information transmitted from the bidder (step S304). The bid processing unit 113 notifies the successful bidder among the bidders of the successful bid according to the successful bidder information determined by the orderer (step S305). The bid processing unit 113 also transmits the successful bid result to the contract management unit 112 (step S306).

The contract management unit 112 receives the contract details input by the orderer (step S307). FIG. 6 is a diagram showing an example of a contract details input screen used for entering contract details. The contract details input screen includes a function of searching for a target case, a function of deleting a contract, a function of updating a contract, and a function of registering the entered contract details.

Returning to FIG. 5, the contract management unit 112 transmits the contract information generated based on the contract content entered through the contract content input screen of FIG. 6 or the like to the contract processing unit 114 (step S308).

The contract information may be output to the contract processing unit 114 when the orderer designates output. FIG. 7 is a diagram showing an example of a contract output screen for designating output of contract information. The contract output screen includes functions such as a function of searching for a target project and a function of outputting contract information corresponding to contract details.

Returning to FIG. 5, information specifying the successful bidder (eg, identification information such as a user ID) is transmitted from the bid processing unit 113 to the contract processing unit 114, for example (step S309).

As described above, the contract information may include electronic data of documents related to the contract. For example, the contract processing unit 114 causes the orderer terminal 301 to display a screen for specifying related books, and receives information indicating the related books specified by the orderer using this screen (step S310). The contract processing unit 114 may store and manage the related books in the storage unit 121 or the like (book management in FIG. 5).

In generating the contract transaction, the identification information of the contractor (step S311) and the hash value of the contractor information (step S312) are used.

The contract processing unit 114 transmits the contract information to the bidder terminal 302 used by the successful bidder (step S313). If the successful bidder instructs to agree to the contract, information indicating the agreement to the contract is transmitted to the contract processing unit 114 (step S314). The contract processing unit 114 causes the block chain system 400 to store transaction information including information indicating that the successful bidder has agreed to a contract as a transaction.

When the orderer instructs to agree to the contract (step S315), the contract processing unit 114 causes the block chain system 400 to store transaction information including information indicating that the orderer has agreed to the contract as a transaction.

The contract processing unit 114 transmits information indicating the contract result to the contract management unit 112 (steps S316 and S317).

As described above, according to the present embodiment, electronic contract function (contract processing unit 114) can be realized.

FIG. 8 is a diagram showing an example of an electronic contract screen that can be used in various processes by the contract processing unit 114. As shown in FIG. The electronic contract screen includes an add related book button 801 , a send contract document button 802 , a contract agreement button 803 and an end button 804 .

When the related document add button 801 is pressed, for example, a screen for designating the related document to be added to the contract is displayed. The contractor can add related books on this screen.

When the contract document transmission button 802 is pressed, the contract document information is transmitted to the successful bidder (bidder terminal 302). This function corresponds to step S313 in FIG.

When the contract agreement button 803 is pressed, transaction information including information indicating that the contract has been agreed is stored in the blockchain system 400 as a transaction. This function corresponds to steps S314 and S315 in FIG.

When the end button 804 is pressed, the processing by the contract processing unit 114 ends. At this time, information indicating the contract result may be transmitted to the contract management unit 112 (step S317 in FIG. 5).

FIG. 9 is a diagram showing an example of the electronic contract flow on the successful bidder side. The successful bidder is authenticated by the login processing function of the contract processing unit 114, for example. The contract APL function of the contract processing unit 114 makes it possible to search for projects to be electronically contracted and to download contract information. Note that the contract set corresponds to the downloaded contract information (which may include related documents).

The successful bidder can further designate a contract agreement using the contract APL function of the contract processing unit 114 and store it in the blockchain system 400 as a transaction indicating the contract agreement.

FIG. 10 is a diagram showing an example of the electronic contract flow on the orderer side. The orderer is authenticated by the login processing function of the contract processing unit 114, for example. The orderer can input the contract content to be included in the contract through the contract management unit 112 (“contract management” in FIG. 10). Further, the contract APL function of the contract processing unit 114 enables addition of related books and retrieval of other past contracts.

The orderer can further designate a contract agreement using the contract APL function of the contract processing unit 114 and store it in the blockchain system 400 as a transaction indicating the contract agreement.

FIG. 11 is a diagram showing an example of the data structure of transaction information (transaction). The electronic document in FIG. 11 corresponds to electronic data of a contract, for example. A and B correspond to, for example, a successful bidder and an orderer.

As shown in FIG. 11, the transaction information includes information obtained by electronically signing the hash value of the electronic document, the address of the public key, and information indicating transaction behavior.

A hash value may be calculated by any method. For example, a method of calculation using a hash function such as SHA-256 (Secure Hash Algorithm 256-bit) can be applied. SHA-256 calculates a hash value that summarizes data of any length into 256 bits.

The information indicating transaction behavior corresponds to, for example, information indicating contractual agreement. In addition, if it is designated not to agree to the contract, information indicating not to agree to the contract may be stored as information indicating the transaction action.

Thus, in this embodiment, the electronic document itself is not stored in the blockchain, but only the fact of the transaction (contract agreement) is stored. In addition, in this embodiment, for example, after storing the agreement of Party A (successful bidder) in the blockchain storage unit 421, Party B (orderer) can form a consensus on the same electronic document. In other words, it is possible to store in the blockchain the fact that multiple contractors (A and B) have agreed to a single contract electronic data.

Transactions stored on the blockchain can be validated by a third party. The third party is, for example, an individual (auditor, etc.) other than the contractor (successful bidder) who belongs to the trader, a loan officer for the trader, and a resident related to the contracted project.

In the present embodiment, the case where the electronic document stored in the blockchain is an electronic bidding contract has been described as an example. Electronic bidding, as described above, may only be permitted to bidders who have been accredited by qualification screening and have been issued an IC card by a certification authority. For this reason, the electronic bidding contract may correspond to only a part of the documents handled by the organization to which the bidder belongs.

However, since the electronic document storage method of the present embodiment is a method in which the electronic document itself is not signed, the target electronic document need not be limited to the electronic bidding contract. In other words, the electronic document stored in the blockchain is not limited to the electronic bidding contract, and may be any electronic document.

For example, the target document can be extended to the following documents. Even when the target document is expanded in this way, the technique of this embodiment can be applied without modification.
・Contracts for free contracts ・Contract-related documents (application notifications, drawings, books, etc.)
・Other general documents

As described above, the electronic contract system according to the present embodiment does not include a storage unit that internally stores a blockchain, and stores transactions related to electronic documents to a blockchain system that includes a storage unit that stores a blockchain. instruct. Therefore, it becomes possible to more easily build a system that stores blockchains related to contracts.

Also, even if there is an existing system (such as an electronic bidding system), simply adding a function (contract processing part) that cooperates with the blockchain system will store transactions related to electronic documents in the blockchain. be able to.

If an existing system has a linkage function for additional functions, for example, a single sign-on function, the electronic contract system can be realized more easily by using such a linkage function.

In addition, when key information such as an IC card is used in an existing system, this key information can also be used for electronic signatures of transactions stored in the blockchain system 400 . Therefore, management of key information can be simplified.

Next, the hardware configuration of the device (orderer terminal 301, bidder terminal 302) according to this embodiment will be described with reference to FIG. FIG. 12 is an explanatory diagram showing a hardware configuration example of the apparatus according to this embodiment.

The device according to the present embodiment includes a control device such as a CPU 51, a storage device such as a ROM (Read Only Memory) 52 and a RAM (Random Access Memory) 53, a communication I / F 54 that connects to a network and performs communication, A bus 61 is provided to connect each part.

A program executed by the electronic contract system according to the present embodiment is preinstalled in the ROM 52 or the like and provided.

The program executed by the electronic contract system according to the present embodiment is an installable format or executable format file, CD-ROM (Compact Disk Read Only Memory), flexible disk (FD), CD-R (Compact Disk) Recordable), DVD (Digital Versatile Disk), or other computer-readable recording medium, and provided as a computer program product.

Furthermore, the program executed by the electronic contract system according to this embodiment may be stored on a computer connected to a network such as the Internet, and provided by being downloaded via the network. Also, the program executed by the electronic contract system according to this embodiment may be configured to be provided or distributed via a network such as the Internet.

A program executed by the electronic contract system according to this embodiment can cause a computer to function as each part of the electronic contract system described above. In this computer, a CPU can read a program from a computer-readable storage medium into a main memory and execute the program.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

100 Electronic contract system 111 Registration processing unit 112 Contract management unit 113 Bid processing unit 114 Contract processing unit 115 Storage control unit 116 Authentication unit 121 Storage unit 201 Certification authority 202 Certification authority 301 Orderer terminal 302 Bidder terminal 400 Block chain system 411 Communication Control unit 412 Smart contract processing unit 413 Management unit 421 Block chain storage unit

Claims (12)

An electronic contract method executed in an electronic contract system connected to a blockchain system that stores transactions on a blockchain,
a contract processing step of receiving, from each of the first contractor and the second contractor, an instruction to agree to a contract concluded between the first contractor and the second contractor;
an instruction to store in the blockchain a first transaction indicating that the first contractor has agreed to the contract; and a second transaction that indicates that the second contractor has agreed to the contract in the blockchain. a storage control step of sending an instruction to store to the blockchain system;
Electronic contract methods including; The blockchain system is configured to store the transaction in the blockchain according to an instructed smart contract among a plurality of smart contracts that respectively define processing for each type of the transaction;
The plurality of smart contracts includes an electronic contract smart contract that stores contracts by the electronic contract system,
The storage control step uses the electronic contract smart contract to send an instruction to store the first transaction in the blockchain and an instruction to store the second transaction in the blockchain.
The electronic contract method according to claim 1. A process of associating one or more public keys or wallet addresses assigned to a first user who is either the first contractor or the second contractor with a second user who is a user of the blockchain system. a registration processing step that performs
a second storage control step of sending an instruction to the blockchain system to store a third transaction indicating that the public key or wallet address and the second user are associated with each other;
The electronic contract method according to claim 1. The storage control step includes an instruction to store, in the blockchain, the first transaction electronically signed by a first private key assigned to the first contractor; sending an instruction to the blockchain system to store the second transaction electronically signed by a second private key on the blockchain;
The electronic contract method according to claim 1. The first contractor is an orderer of electronic bidding,
The second contractor is the successful bidder of the electronic bidding,
the contract indicates a contract for the electronic bidding;
The first secret key is a key assigned to the first contractor for processing the electronic bidding,
The second secret key is a key assigned to the second contractor for processing the electronic bidding,
The electronic contract method according to claim 4. The first contractor is an orderer of electronic bidding,
The second contractor is the successful bidder of the electronic bidding,
the contract indicates a contract for the electronic bidding;
The second secret key is a key assigned to electronically sign a transaction stored in the blockchain to the second contractor to whom a secret key is not assigned for processing the electronic bidding. ,
The electronic contract method according to claim 4. The first secret key is a key assigned to the first contractor for processing the electronic bidding,
The electronic contract method according to claim 6. The first secret key is a key assigned for electronic signature of a transaction stored in the blockchain to the first contractor to whom a secret key is not assigned for the processing of the electronic bidding. ,
The electronic contract method according to claim 6. The first transaction includes information indicating that the first contractor has agreed to the contract and a hash value of an electronic document related to the contract,
the second transaction includes information indicating that the second contractor has agreed to the contract and a hash value of the electronic document;
The electronic contract method according to claim 1. the contract processing step receives from each of the plurality of contractors an instruction to agree to a contract concluded between the plurality of contractors including the first contractor and the second contractor;
The storage control step transmits a plurality of instructions to the blockchain system to store a plurality of transactions in the blockchain indicating that each of the plurality of contractors has agreed to the contract.
The electronic contract method according to claim 1. An electronic contract system connected to a blockchain system that stores transactions on the blockchain,
a contract processing unit that receives, from each of the first contractor and the second contractor, an instruction to agree to a contract concluded between the first contractor and the second contractor;
an instruction to store in the blockchain a first transaction indicating that the first contractor has agreed to the contract; and a second transaction that indicates that the second contractor has agreed to the contract in the blockchain. a storage control unit that transmits an instruction to store to the blockchain system;
An electronic contract system with A computer equipped with an electronic contract system connected to a blockchain system that stores transactions on a blockchain,
a contract processing step of receiving, from each of the first contractor and the second contractor, an instruction to agree to a contract concluded between the first contractor and the second contractor;
an instruction to store in the blockchain a first transaction indicating that the first contractor has agreed to the contract; and a second transaction that indicates that the second contractor has agreed to the contract in the blockchain. a storage control step of sending an instruction to store to the blockchain system;
program to run the

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