JP6511017B2 - Contract agreement method, agreement verification method, contract agreement device and agreement verification device - Google Patents

Description

  The present invention relates to a technique for agreeing a contract using a block chain mechanism, in particular, a technique for leaving a trail of agreed contracts.

  Electronic signature is a technology for guaranteeing the origin of information. At present, the most widespread mechanism for realizing digital signatures is based on public key cryptography. Also, in order to indicate that the electronic key used in the digitally signed information is indeed that of the information sender, a trusted third party will usually be used. Centralized management by a trusted third party secures reliability by linking information on the key with the individual.

  On the other hand, a system capable of securing credibility is spreading, centering on digital virtual currency, without requiring centralized management as described above. In this scheme called block chain, the reliability of the information exchanged is secured by the process of consensus building in the network formed by all participants, and the whole system is protected against frauds such as falsification and double use. In this way, the soundness is maintained (Non-Patent Document 1). In addition, application of the block chain mechanism to various transactions has been studied (Non-Patent Document 2).

Saito, "Bitcoin-Digital Giant Stone Money without Humans", WIDE Technical-Report in 2013, WIDE Project, December 31, 2013 H. Watanabe, S. Fujimura, A. Nakadaira, Y. Miyazaki, A. Akutsu, J. Kishigami, “Blockchain contract: A complete consumption using blockchain”, 2015 IEEE 4th Global Conference on Consumer Electronics (GCCE), 2015, pp 577 -578

  The block chain functions as a huge ledger, in which transaction information of virtual currency between participants is grouped as a transaction in one unit called a block, and shared by all the participants in a P2P (Peer to Peer) network. For example, the transaction "Mr. A has handed three coins to Mr. B" is shared by all members. If this block chain is regarded as one ledger recording the contents of all participants' transactions, it can be applied to various transactions other than currency.

  Therefore, in the present invention, the block chain is applied as a trail when contracts are made between a plurality of parties. A contract (contract) refers to a sales contract, a transfer certificate, an application, a license, etc., and is document data indicating the contents of a contract made by an individual or an organization between two or more parties. At that time, leaving a trail as to how two or more parties have reached agreement is a public proof of claiming the right.

  Here, in the case of the virtual currency described above, for example, the hash value of the previous transaction, the address of the remittance source, the address of the remittance destination, the payment amount, and the electronic signature of the remittance source are included in one transaction. They allow all participants who share the blockchain to publicly confirm the content of the transaction. Therefore, the same effect is expected by adding information on the contract to the transaction to apply this to the trail of contract agreement. The above-mentioned address refers to the hash value of the public key for digital signature in the block chain technology.

  Here, in the case of applying a blockchain as a virtual currency to a trail of contract agreement, the issue is how to prove that the contents of the agreement have been agreed between two or more parties. The electronic signature scheme adopted in the block chain of virtual currency is made up of only the electronic signature of the remittance source as described above, and the electronic signature of the remittance destination is not required. On the other hand, when two or more parties conclude a contract, the issuance of a one-sided contract does not hold a contract, and an agreement between all parties who are contract parties is required. However, since only one sender's digital signature is included in one transaction forming a block chain, a trail of contract agreement by the recipient will not remain in the transaction.

  As a simple solution to the above problem, for example, a method can be considered in which the electronic signatures of all the parties are included in one transaction. A mechanism called multi-signature is adopted for the virtual currency, and it is possible to create an address where the transaction is not approved unless there is a certain number or more of electronic signatures. However, in one transaction, multiple electronic data such as which electronic signature is required in advance, how to share the transaction before approval between the parties, where to collect multiple private keys and perform signature The process of including a signature is cumbersome.

  In addition, Non-Patent Document 2 proposes a method of achieving an agreement by dividing and chaining two types of transactions, the transaction of the issuer and the transaction showing an agreement, to the above problem. However, although this method can be applied to a small number of people, it is inefficient when leaving a trail of many people at the same time, for example, when many users agree on the service terms of service of a company .

  The present invention has been made in view of the above circumstances, and while maintaining the form of one electronic signature in one transaction, the present invention can be efficiently performed even by a large number of people while obtaining agreement among parties involved in a contract. The purpose is to leave a trail of contracts on the blockchain.

  In order to achieve the above object, the present invention is a contract agreement method performed between a plurality of devices connected to a distributed network sharing a block chain, wherein each of the plurality of devices is broadcast to the network. Step of storing the block chain including the transaction in the storage unit, and whether or not the block chain stored in the storage unit includes the transaction addressed to the shared contract address corresponding to the agreement subject to agreement. Monitoring the transaction address, and detecting a transaction addressed to the contract address, the transaction addressed to the contract address including a trail of whether or not to agree on the contract, and the electronic signature of the user of the self apparatus Generating and broadcasting to the network.

  Here, in the transaction described in the present invention, in addition to the original data itself of the transaction originally issued by the user, data obtained by extracting a part of the data from the original data and data summarized by hashing are also represented as transactions.

  The present invention is an agreement verification method for verifying agreement agreement made by a plurality of devices connected to a distributed network sharing a block chain, the block chain including transactions broadcast to the network. Control step of storing in the storage unit, and a transaction addressed to the shared contract address corresponding to the contract to be verified is retrieved from the storage unit and set in the transaction based on the trail of the agreement on the agreement Performing an agreement verification step of verifying the agreement of the agreementr whose agreement on the agreement is required.

  The present invention is a contract agreement apparatus which agrees a contract with another apparatus connected to a distributed network sharing a block chain, and stores the block chain including a transaction broadcast to the network. A control unit stored in the storage unit, a monitoring unit monitoring whether or not the block chain stored in the storage unit includes a transaction addressed to a shared contract address corresponding to a contract to be agreed; When a transaction addressed to an address is detected, a generation unit that generates a transaction addressed to the contract address including a trail of whether or not to agree on the contract, and the electronic signature of the user of the own device, and broadcasts to the network And.

  The present invention is an agreement verification device for verifying agreement agreement made by a plurality of devices connected to a distributed network sharing a block chain, the block chain including transactions broadcast to the network. And a control unit for storing in the storage unit and a transaction addressed to a shared contract address corresponding to a contract to be verified from the storage unit, and set in the transaction based on a trail of an agreement on the agreement. And an agreement verification unit for verifying the agreement of the agreementr for whom the agreement on the agreement is required.

  According to the present invention, while keeping the form of one electronic signature in one transaction, a trail of contracts can be efficiently left in a block chain, even with many people, while obtaining agreement among contract parties. Can.

It is a conceptual diagram which shows the concept of the contract agreement of this embodiment. It is a whole block diagram of the contract agreement system of this embodiment. It is a figure which shows the example of a transaction. It is a block diagram which shows the structure of a contract agent part. It is a flowchart which shows formation operation of a block chain. It is a figure for demonstrating the operation | movement of a contract agent part. It is a figure for demonstrating the modification of operation | movement of a contract agent part. It is a figure which shows the operation | movement which leaves the trail of contract agreement on a block chain. It is a block diagram which shows the structure of a consensus verification terminal.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In this embodiment, the existing block chain technology is used as a trail of contract agreement. Specifically, it is realized by utilizing the existing block chain technology protocol and describing the status of the agreement regarding the contract inside the transaction to be issued. The following description shows one mode of the invention when a contract is concluded between certain parties using a block chain, using the present invention, in which a contract is concluded with the parties to make a trail. It shall be divided into the "issuer" of the contract to be left and the "agreeter" of the contract. In addition, although an issuer is one person, two or more consenters may be set.

  FIG. 1 is a diagram showing the concept of a contract in the present embodiment. As shown in FIG. 1A, first, the issuer issues a transaction for requesting agreement on a contract to the contract address (S1). The contract address is not an address associated with a specific "person", but is a shared address set for each contract to be agreed upon.

  The contract agent confirms the transaction addressed to the contract address issued in S1 (S2), and notifies the agreementr (S3). The agreementr transmits a transaction indicating an agreement to the transaction issued in S1 to the contract address (S4), and the contract agent acquires the transaction transmitted in S4.

  Fig. 1 (b) is an image diagram of the case where the flow of contract agreement between the issuer and the agreer shown in Fig. 1 (a) is expanded to a large number of agreers (in the example shown, agreeers A to C). is there. The issuer simply issues a transaction to the contract address to request agreement on the contract (S1), and the contract agent confirms the transaction (S2), and sends it to each of a number of contractors A to C. To notify (S3), and receive a transaction indicating an agreement from each of a large number of agreers A to C (S4).

  That is, since each agreer simply sends a transaction indicating an agreement to the issuer's transaction without considering the other consenter's agreement status, the order of the agreement, etc. Even if it increases, processing does not become complicated.

  Thus, in the present embodiment, by sending transactions to the shared contract address, the issuer and the contractor can efficiently leave a trail of contracts in the block chain via the contract agent. .

  FIG. 2 is an overall configuration diagram of a contract agreement system in the present embodiment. In this embodiment, the total number of parties involved in the contract is, for example, 3. The person who intends to conclude the contract and leave a trail of the contract agreement is the issuer of the contract, and the person who received the request is the person who agreed the contract. I assume.

  As shown in FIG. 2, the contract agreement system includes an issuer terminal 1 used by the issuer of the contract, and two agreer terminals 3a and 3b used by two agreers A and B, respectively. All terminals are terminals that are autonomously connected in a distributed manner by a P2P network 50 (distributed network) sharing a block chain, and agree a contract with other devices. The issuer terminal 1 and the agreer terminals 3a and 3b are also referred to as contract agreement devices.

  Each terminal includes a block chain storage unit 11, a block chain control unit 12, a transaction generation unit 13, and a contract agent unit 14.

  The block chain storage unit 11 stores a block chain including a transaction broadcast to the P2P network 50. Here, a block chain refers to a chain of blocks including a transaction indicating a trail of agreement on a contract to be agreed.

  The block chain control unit 12 cooperates with the block chain control units of the other terminals in an autonomous distributed manner, and always holds the latest block chain in the block chain storage unit 11. Further, the block chain is acquired from the block chain storage unit 11 and provided to the transaction generation unit 13 or the like.

  When the legitimacy or the like for the immediately preceding transaction is confirmed, the transaction generation unit 13 generates a transaction regarding the user of the own terminal and broadcasts it to the P2P network 50. Specifically, when a transaction addressed to the contract address is detected, the transaction generation unit 13 generates a transaction addressed to the contract address including a trail of whether or not to agree on the contract, and broadcasts to the P2P network 50. Do.

  The transaction generation unit 13 includes a data holding unit (not shown). The data holding unit holds various data required to generate a transaction. Each terminal has a unique address, and holds, for example, a hash value of a public key paired with a secret key necessary for the electronic signature as an address, as in a virtual currency scheme. Also, it holds contract data (for example, a hash value of a contract) for identifying a contract to be agreed (a contract). By using the hash value of the contract as contract data, matching with the target contract becomes possible.

  FIG. 3 is a diagram showing an example of a transaction (transaction for contract) according to the present embodiment. The transaction of the present embodiment is a transaction for leaving a trail of contracts. The illustrated transaction includes the sender's public key, the sender's address, the receiver's address (here, the contract address), the sender's electronic signature. In addition, the issuer and the agreer generate a key pair for electronic signature in advance, hold the public key in the terminal used by the self, and use the hash value of the public key as the address of each person.

  Further, the transaction of the present embodiment identifies the contract subject to the agreement and records contract data for identifying the contract subject to the agreement, and the status of the agreement, in order to record the agreement of the parties concerned with the contract. Including. For example, the contract data may be in any form, as long as it can identify the target contract, such as a hash value of a contract document and a key for decrypting an encrypted contract, in addition to data of the contract content itself. That is, the transaction used in the present embodiment further includes contract data to be agreed and information on the agreement of the parties regarding the agreement, and refers to the evidence data of the contract agreement to which the sender's digital signature is given. This makes it possible to record the presence or absence of an agreement on a contract while maintaining the form of one electronic signature in one transaction.

  FIG. 4 is a block diagram showing the configuration of the contract agent unit 14. The contract agent unit monitors whether or not the block chain stored in the block chain storage unit 11 includes a transaction addressed to a shared contract address corresponding to a contract to be agreed. When the contract agent unit 14 finds a transaction addressed to a contract address, the contract agent unit 14 notifies the own terminal.

  The illustrated contract agent unit 14 includes a contract address storage unit 141 and a contract confirmation script 142.

  The contract address storage unit 141 stores a contract address shared by parties (issuer and agreer) of the contract. The contract address is not an address associated with a specific person, but a special address set so as to be identifiable for each contract to be agreed. When the contract agent unit 14 detects that the transaction addressed to the contract address stored in the contract address storage unit 141 is included in the block chain, the contract agent unit 14 notifies the own terminal.

  The contract confirmation script 142 is a script (program) for determining whether the transaction addressed to the contract address is valid. Specifically, the contract confirmation script 142 is a script for confirming (verifying, checking) the contract according to a predetermined procedure between parties concerned with the contract. When the contract confirmation script 142 receives a transaction including contract data, the contract confirmation script 142 confirms whether the contract data is included in a predetermined format. For example, the contract confirmation script 142 confirms the length of the contract data (hash value of the contract), whether the contract data is in the correct format, and the like.

  In addition, the contract confirmation script 142 transmits whether the address of the sender (issuer) of the transaction is the correct address previously determined by the contract confirmation script 142, and whether the agreed party has made an agreement in the correct procedure. It may be confirmed whether the electronic signature of the hand is correct or not.

  The contract confirmation script 142 may be published on the network so that at least the parties concerned can acquire and verify the transaction, or it is included in the block chain and anyone can acquire and validate the transaction. It may be published so as to be verifiable.

  Further, in the present embodiment, it is assumed that the contract address section 141 of the contract targeted for the agreement and the contract confirmation script 142 have already been acquired in the contract agent unit 14 of each terminal used by the issuer and the agreer.

  The above is a function with which each terminal (contract agreement terminal) 1, 3a, 3b of a contract agreement system is provided. Although not shown in FIG. 2, in order to maintain the block chain system, an approval terminal for chaining the block chain through the transaction approval work exists on the P2P network 50 as in the case of the virtual currency.

  Next, the operation of the contract agreement system will be described. First, the operation of forming a block chain will be described.

  FIG. 5 illustrates an operation in which the sender generates a transaction and the approval terminal performs block chain approval work. This operation is used not only for this embodiment but also for trading of virtual currency using a block chain.

  First, the sender's terminal generates a transaction with an electronic signature that specifies addressing from the sender's address to the receiver's address (step S101), and broadcasts it on the P2P network (step S102).

  Next, the approval terminal on the P2P network collects the transactions broadcasted on the network, and collectively performs approval work in units of blocks (step S103). With regard to this approval work, in virtual currency, a method of performing a complex hash calculation called proof of work, a method of consuming coin years called a proof of stake, and the like have been proposed. In this embodiment, regardless of those methods, an approval operation is performed, and a transaction is incorporated into the block chain. Here, in the approval work, the previous transaction is passed from the valid sender by verifying the electronic signature of the transaction using the sender's public key and checking the hash value. It includes the task of verifying whether it is a legitimate transaction or not. This verification method can be implemented by known techniques, and is described, for example, in Non-Patent Document 1. In the above manner, transactions are synchronized at all terminals after being included in the block chain.

  Next, the operation of the contract agent unit 14 will be described using FIG.

  FIG. 6 is a diagram showing the operation of the contract agent unit 14. As illustrated, the contract agent unit 14 monitors transactions included in the latest block chain stored in the block chain storage unit 11 of the own terminal (S201). When the contract agent unit 14 finds a transaction addressed to the shared contract address stored in the contract address storage unit 141, it indicates that the transaction addressed to the contract address is included in the block chain, as the own terminal. The relevant party (issuer or consenter) who uses F. is notified (S202). For example, the contract agent unit 14 notifies a person concerned by outputting a predetermined message (text, image, voice or the like) to an output device (display, speaker or the like) included in the terminal.

  Also, when the contract agent unit 14 finds a transaction addressed to a contract address, it uses the contract confirmation script 142 to determine whether the transaction is valid or not, and also uses the own terminal together with the determination result. Are notified to the person (S202).

  The relevant person confirms the notification from the contract agent unit 14 (the result of finding the transaction and the determination of the legitimacy), and acquires and confirms the content of the transaction held in the block chain storage unit 11 as necessary. Then, according to the confirmation result, an instruction to generate a transaction is input to the terminal (S203).

  For example, in the case where the relevant party is the agreer, if the status of the agreement included in the transaction is "on request" and the transaction is determined to be valid, the agreementr instructs the generation of the transaction indicating the trail of the agreement. Are input to the transaction generation unit 13. The transaction generation unit 13 receives the transaction generation instruction, and generates a transaction indicating a trail of agreement of the contract addressed to the contract address.

  On the other hand, in the case where the relevant party is the issuer, and the status of the agreement included in the transaction is, for example, "non-agreement", the issuer does not input a transaction generation instruction to the transaction generation unit 13.

  As a modification of the operation of the contract agent unit 14 shown in FIG. 6, as shown in FIG. 7, a transaction automation unit 15 instead indicates a trail of agreement agreement, without involving persons (people). The generation instruction of may be sent to the transaction generation unit 13. The transaction generation unit 13 receives the transaction generation instruction sent by the contract automation unit 15 and generates a transaction indicating a trail of agreement agreement.

  FIG. 7 is a diagram showing the operation of the contract agent unit 14 of the modification. In the modification shown, the terminal is different from the issuer terminal 1 and the agreer terminals 3a and 3b of FIG. 2 in that the terminal includes the contract automation unit 15, and the other is similar to the terminals 1, 3a and 3b of FIG. is there.

  The contract automation unit 15 receives a notification from the contract agent unit 14 that the transaction addressed to the contract address is included in the block chain and the notification of the determination result of the legitimacy of the transaction in S202A.

  When the contract automation unit 15 receives notification of the determination result that the transaction is valid, the contract automation unit 15 acquires the transaction from the block chain storage unit 11, and the contents of the transaction (for example, the status of the agreement, the sender address, etc.) To determine whether to generate a transaction that indicates a trail of agreement agreement. Then, if it is determined that the transaction is to be generated, the contract automation unit 15 sends a transaction generation instruction to the transaction generation unit 13 (S203A).

  For example, when the transaction is valid and the self terminal is the agreer terminal and the status of the agreement included in the transaction is "on request", the contract automation unit 15 sends the transaction generation instruction to the transaction generation unit 13. .

  On the other hand, when the transaction automation unit 15 determines that the transaction is not valid or does not generate a transaction indicating the contract agreement trail from the contents of the transaction, the contract automation unit 15 indicates a contract agreement trail. Do not send out transaction creation instructions. In addition, since S201 of FIG. 7 is the same as S201 of FIG. 6, description is abbreviate | omitted here.

  Next, with reference to FIG. 8, when using the contract agreement system, transition of transactions included in each block of the block chain will be described.

  FIG. 8 shows the process of entering into a contract between the issuer of the contract and the contractor A and the contractor B, and leaving a trail of the agreement in the block chain. It is assumed that all the terminals receive the block chain including the transaction through the approval work at the approval terminal as described in FIG. 5, and always hold the latest block chain.

  In addition, all parties concerned (issuer, agreer A and agreer B) have in advance the same electronic contract to be agreed, and the hash value obtained by hashing the contract is used as contract data. It shall be held in advance in the terminal. The hashing of the contract has the purpose of preventing tampering in the middle and the purpose of concealing the contents of the contract from a third party, and the contents of the contract indicated by the transaction can be compared with the contract to be agreed upon .

  First, an issuer terminal that wants to conclude a contract generates and issues a transaction for a contract addressed to the contract address (S301). This transaction is broadcasted on the P2P network, put into blocks by the approval terminal, added to the block chain, and synchronized with other terminals, as described above. Also, this process is performed each time a transaction is broadcast. Hereinafter, the description is omitted.

  The transaction issued by the issuer terminal is added to the block chain as block # 101 in FIG. In the transaction of block # 101 shown in the figure, the address of the issuer terminal is the address of the sender (sender), the address of the contract (the address of the receiver), and the contract address is the hash value of the contract. , The status of the agreement is set to Requesting. The states of the agreement may be set as Boolean values or specific values corresponding to the respective states.

  The block chain control unit 12 of the agreer A terminal synchronizes the block chain to which the transaction of block # 101 is added with the block chain storage unit 11 of the own terminal. In addition, the contract agent unit 14 of the terminal A of the agreementr A monitors the synchronized block chain of the block chain storage unit 11 (S302).

  Upon detecting that the transaction addressed to the contract address is included in the block chain, the contract agent unit 14 of the agreementr A terminal determines the legitimacy of the transaction and finds that the transaction is found together with the determination result. It notifies the contractor A or the contract automation unit 15 in its own terminal (see FIGS. 6 and 7).

  The contractor A or the contract automation unit 15 extracts the transaction (block # 101) addressed to the contract address from the latest block chain, and according to the contents of the transaction, instructs the transaction generation instruction including the trail of the agreement, It is sent to the generation unit 13. When receiving the generation instruction, the transaction generation unit 13 generates a transaction including the trail of the agreement and broadcasts it (S303). Specifically, the transaction generation unit 13 generates a transaction addressed to the contract address, including the contract data and the status of the agreement as a proof that the contract has been agreed.

  The transaction issued by the agreer A terminal is added to the block chain as block # 102 in FIG. In the transaction of block # 102 shown in the figure, the sender address is the address of the agreementr A terminal, the destination is the contract address, the contract data is the hash value of the contract, and the agreement state is the agreement. It is done.

  The terminal B also monitors the block chain as in the terminal A, generates a transaction, and broadcasts it (S304, S305). The transaction issued by the agreer B terminal is added to the block chain as block # 103 in FIG.

  Further, the contract agent unit 14 of the issuer terminal also monitors the synchronized block chains of the block chain storage unit 11 as in the case of the agreementr A terminal and the agreementr B terminal (S306). Therefore, when the contract agent unit 14 of the issuer terminal detects that the transaction (here, blocks # 102 and # 103) addressed to the contract address is included in the block chain, it determines the validity of the transaction. And notifies the issuer or the contract automation unit 15 in the own terminal that the transaction has been found together with the determination result.

  Thereby, the issuer can grasp the state of the agreement between the agreer A and the agreer B by acquiring the transaction notified from the block chain storage unit 11. In addition, the issuer or contract automation unit 15 can also instruct the transaction generation unit 13 to generate a transaction according to the state of the agreement of each agreer.

  According to the process described above, the issuer's transaction (block # 101) and the trail of agreement between consenter A and agreement B according to the transaction (block # 102, block # 103) are recorded in the block chain. Becomes possible.

  Finally, the agreement verification terminal (agreement verification device) will be described. The trail of contract agreements left on the block chain can be easily verified from any terminal or device on the P2P network as long as the block chain system exists. Also, after verification, it is also possible to issue a transaction (for example, money transfer, etc.) automatically according to the agreement agreement in cooperation with the automatic execution program. Therefore, the agreement verification terminal used to verify the agreement will be described.

  FIG. 9 shows the configuration of two types of agreement verification terminals 8 and 9. The first agreement verification terminal 8 is a terminal in the case where the agreement verification is performed according to the instruction of the verifier. The verifier may be the issuer of the contract, the contractor of the contract, or a third party. When the verifier is an issuer or a consenter, the contract agreement terminal (issuer terminal, agreementr terminal) shown in FIG. 2 may have the function of the first agreement verification terminal 8.

  The first agreement verification terminal 8 includes a block chain storage unit 81, a block chain control unit 82, a data holding unit 83, and an agreement verification unit 84.

  The block chain storage unit 81 and the block chain control unit 82 are the same as the block chain storage unit 11 and the block chain control unit 12 described in FIG. That is, the block chain control unit 12 stores the block chain including the transaction broadcast to the P2P network 50 in the block chain storage unit 81.

  The agreement verification unit 84 extracts a transaction addressed to the shared contract address corresponding to the contract to be verified from the block chain storage unit 81, and based on the trail of the agreement on the agreement set in the extracted transaction, Verify the agreement of each of the consenters for which an agreement is required. Specifically, when the agreement verification unit 84 receives an instruction from the verifier, the agreement verification unit 84 uses the data stored in the data storage unit 83 to perform verification from the block chain storage unit 81 via the block chain control unit 82. Retrieve the transaction for the contract of.

  The data holding unit 83 holds data (for example, a contract address, contract data (hash value of contract), and the like) for specifying a contract to be verified. The agreement verification unit 84 uses the contract address, the contract data, or both the contract address and the contract data to extract the transaction regarding the contract to be verified.

  Depending on the type of block chain, the contents of the transaction may be reprinted and held in another data area in the block chain for efficient search. In this case, the agreement verification unit 84 may retrieve data reprinted from the transaction instead of the transaction itself.

  The agreement verification unit 84 verifies that the agreementr has issued a transaction indicating an agreement or non-agreement with respect to the transaction requiring the contract agreement issued by the issuer, and presents the verification result to the verifier. . Specifically, in the case of the block chain shown in FIG. 8, the agreement verification unit 84 takes out transactions of blocks # 101 to # 103, and among them, for each transaction of # 102 and # 103 of the agreeers A and B, the transmission source is Present the status of the agreement as a verification result. In this case, the agreement verification unit 84 outputs “agreement A: agreement (true), agreement B: agreement (true)” to an output device such as a display and presents it to the verifier.

  In addition, the agreement verification unit 84 may present the verification results of all the consenters (for example, the consenters A and B), or the specific consenter (for example, the consenter A instructed by the verifier) Only the verification results may be presented.

  Subsequently, the operation of the first agreement verification terminal 8 will be described.

  First, when the agreement verification unit 84 receives a verification instruction from the verifier (S401), the agreement verification unit 84 acquires the contract address or contract data of the contract to be verified from the data holding unit 83, and the corresponding transaction is received by the block chain control unit 82. Through the block chain storage unit 81 (S402).

  Then, the agreement verification unit 84 verifies the agreement of each of the consenters who are requested to agree to the contract based on the status of the agreement on the contract (a trail of agreement) set in the extracted transaction (S403). The verification result is displayed (S404). That is, the state (agreement, non-agreement) of each consenter's agreement is displayed.

  Next, the second agreement verification terminal 9 will be described.

  The second agreement verification terminal 9 is a terminal in which the agreement verification unit 95 automatically generates a predetermined transaction in cooperation with the execution automation unit 96 without intervention of a verifier (person). According to the second agreement verification terminal 9, for example, when it is detected that a contract has been concluded between the issuer and the agreer A, it automatically transmits a fund transfer transaction to the block chain network to execute payment. Such usage is possible. The verifier using the second agreement verification terminal 9 may be the issuer of the contract, the contractor of the contract, or a third party. When the verifier is an issuer or a consenter, the contract agreement terminal (issuer terminal, agreementr terminal) shown in FIG. 2 may have the function of the second agreement verification terminal 9.

  The second agreement verification terminal 9 includes a block chain storage unit 91, a block chain control unit 92, a transaction generation unit 93, a contract agent unit 94, an agreement verification unit 95, and an execution automation unit 96. The block chain storage unit 91, the block chain control unit 92, and the transaction generation unit 93 are the same as the block chain storage unit 11 shown in FIG. 2, the block chain control unit 12, and the transaction generation unit 13.

  The contract agent unit 94 is the same as the contract agent unit 14 shown in FIG. 4 and monitors the latest block chain in the block chain storage unit 91, and determines the transaction addressed to the contract address stored in the contract address storage unit. If it is detected, it instructs the agreement verification unit 95 to verify the agreement.

  Similar to the agreement verification unit 84 of the first agreement verification terminal 8, the agreement verification unit 95 extracts the transaction regarding the corresponding contract from the block chain and carries out the verification of the agreement. Then, the agreement verification unit 95 notifies the enforcement automation unit 96 of the verification result.

  The execution automation unit 96 instructs generation of a transaction according to the verification result. For example, in the case where the verification result is “agreement A: agreement (true), agreementr B: nonagreement (false), agreementr C: agreement (true)”, the enforcement automation unit 96 determines the agreement A of the state of agreement. And an instruction to issue a transaction for transferring the copyright, for example, to the transaction generation unit 93. The transaction generation unit 93 generates a transaction according to the instruction of the execution automation unit 96 and broadcasts it to the P2P network.

  Subsequently, the operation of the second agreement verification terminal 9 will be described.

  The contract agent unit 94 monitors the latest block chain in the block chain storage unit 91 (S501), and when detecting a transaction addressed to a contract address to be verified, instructs the agreement verification unit 95 to verify the agreement (S502). ).

  The agreement verification unit 95 receives a verification instruction from the contract agent unit 94, and takes out the transaction of the contract address of the contract to be verified from the block chain storage unit 91 via the block chain control unit 92 (S503).

  Then, the agreement verification unit 95 verifies the agreement of a plurality of consenters who are required to agree on the contract, based on the status (a trail of agreement) of the agreement on the contract set in the extracted transaction (S504) The verification result is sent to the execution automation unit 96 (S505).

  The execution automation unit 96 instructs the transaction generation unit 93 to generate a transaction according to the verification result (S506). The transaction generation unit 93 generates a transaction according to the instruction of the execution automation unit 96, and broadcasts it to the P2P network (S507).

  As a result, the second agreement verification terminal 9 can automatically generate a new transaction for the agreed party. The content of the transaction depends on the content of the operation to be executed regarding the contract. For example, there is a transaction of money transfer.

  As mentioned above, in this embodiment, the contract address shared among the parties concerned of the contract is used. Then, when the transaction addressed to the contract address is included in the block chain, the contract agent unit confirms the contract data (hash value of the contract) included in the transaction according to the contract confirmation script and confirms the confirmation result of the contract. Notify the contractor (or contract automation department). The contractor (or the contract automation unit) of the contract instructs the generation of a transaction addressed to the contract address indicating the agreement according to the confirmation result. When a transaction indicating an agreement is incorporated into the block chain, the contract agent of the issuer terminal detects this and notifies the issuer as described above.

  Thus, in the present embodiment, a trail of contracts between two or more parties is efficiently recorded on a block chain without complicated procedures via a contract agent linked to the shared contract address between the issuer and the agreementr. As well as being able to do so, the issuer and the agreer can know that the trail of each other's contract has been included in the blockchain. Also, by referring to the transaction addressed to the contract address, it is possible to easily confirm the trail of the agreement.

  That is, in the present embodiment, a trail of contract agreement between two or more parties can be recorded on a block chain by a simpler method without performing a complicated procedure. Further, in the present embodiment, since the agreement trail of the contract is maintained on the autonomous distributed network without using a centralized mechanism, even if the trail of the agreement is lost in some devices, this is applicable. The trail can be held permanently as long as there is a block chain system.

  The present invention is not limited to the above embodiment, and various modifications are possible within the scope of the invention. For example, although the P2P network is described as an example in the above embodiment, it is not necessary to use a literally pure peer-to-peer network. In recent bitcoins, for example, there are nodes that become hubs, and in general, they may be distributed networks that share block chains.

  Finally, the issuer terminal 1, the agreer terminals 3a and 3b, and the agreement verification terminals 8 and 9 described in the present embodiment include, for example, a CPU, a memory, an external storage device such as a hard disk, and an input device. A general purpose computer system provided with an output device can be used. In this computer system, each function of each device is realized by the CPU executing a predetermined program loaded on the memory. For example, in the case of a program for the issuer terminal 1, each function of the issuer terminal 1, the agreementr terminals 3a and 3b, and the agreement verification terminals 8 and 9 is for the CPU of the agreementr terminal 3a or 3b In the case of the above program, the CPUs of the consenter terminals 3a and 3b are implemented, and in the case of the programs for the agreement verification terminals 8 and 9, the CPUs of the agreement verification terminals 8 and 9 respectively execute. The programs of the issuer terminal 1, the agreer terminals 3a and 3b, and the agreement verification terminals 8 and 9 are stored in a computer readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD-ROM. Can also be distributed via a network.

DESCRIPTION OF SYMBOLS 1 ... Issuer terminal 3a, 3b ... Agreeer terminal 11 ... Block chain storage part 12 ... Block chain control part 13 ... Transaction generation part 14 ... Contract agent part 141 ... Contract address storage part 142 ... Contract confirmation script 15 ... Contract automation Sections 8, 9 ... Agreement verification terminal 81, 91 ... Block chain storage unit 82, 92 ... Block chain control unit 83 ... Data holding unit 84, 95 ... Agreement verification unit 94 ... Contract agent unit 96 ... Execution automation unit 50 ... P2P network

Claims (8)

A contract agreement method between a plurality of devices connected to a distributed network sharing a block chain, comprising:
Each of the plurality of devices is
Storing, in a storage unit, a block chain including a transaction broadcast to the network;
A monitoring step of monitoring whether or not the block chain stored in the storage unit includes a transaction addressed to a shared contract address corresponding to a contract to be agreed;
When a transaction addressed to the contract address is detected, a transaction addressed to the contract address including the trail of whether or not to agree on the contract and the electronic signature of the user of the own device is generated and broadcast to the network And a contract agreement method characterized by: generating steps. A contract agreement method according to claim 1, wherein
A contract agreement method comprising performing a notification step of notifying the user of the own device when a transaction addressed to the contract address is detected. The contract agreement method according to claim 2, wherein
When a transaction addressed to the contract address is detected, a determination step of determining whether the transaction is valid or not is performed;
The contract agreement method, wherein the notification step notifies the user of the own device of the determination result of the determination step. A contract agreement method according to claim 1, wherein
A determination step of determining whether the transaction is valid if a transaction addressed to the contract address is detected;
A contract agreement method comprising: a determination step of determining generation of a transaction addressed to the contract address based on the determination result of the determination step and the content of the transaction. An agreement verification method for verifying agreement of a contract made by a plurality of devices connected to a distributed network sharing a block chain, comprising:
Storing, in a storage unit, a block chain including a transaction broadcast to the network;
An issuer transaction that refers to the block chain and requests a contract agreement issued by the issuer of the contract, and an agreementr transaction that indicates whether the contractor of the agreement agrees on the issuer transaction. And an agreement verification step to verify
The issuer transaction and the agreement's transaction, Ri transaction der of the contract for the address of the share corresponding to the contract,
A monitoring step of monitoring whether or not the block chain stored in the storage unit includes a transaction addressed to the contract address, and when a transaction addressed to the contract address is detected, instructing verification of an agreement; An agreement verification method characterized by further performing . A contract agreement device for agreeing a contract with another device connected to a distributed network sharing a block chain,
A control unit that stores, in a storage unit, a block chain including a transaction broadcast to the network;
A monitoring unit configured to monitor whether or not the block chain stored in the storage unit includes a transaction addressed to a shared contract address corresponding to a contract to be agreed;
When a transaction addressed to the contract address is detected, a transaction addressed to the contract address including the trail of whether or not to agree on the contract and the electronic signature of the user of the own device is generated and broadcast to the network A contract agreement apparatus comprising: a generation unit. An agreement verification device for verifying agreement agreement made by a plurality of devices connected to a distributed network sharing a block chain, the agreement verification device comprising:
A control unit that stores, in a storage unit, a block chain including a transaction broadcast to the network;
An issuer transaction that refers to the block chain and requests a contract agreement issued by the issuer of the contract, and an agreementr transaction that indicates whether the contractor of the agreement agrees on the issuer transaction. And an agreement verification unit to verify
The issuer transaction and the agreement's transaction, Ri transaction der of the contract for the address of the share corresponding to the contract,
It monitors whether or not the block chain stored in the storage unit contains a transaction addressed to the contract address, and when a transaction addressed to the contract address is detected, instructs the agreement verification unit to verify the agreement. An agreement verification apparatus , further comprising a monitoring unit . The agreement verification apparatus according to claim 7, wherein
And executive unit for instructing the generation of the transaction in accordance with the verification result of the agreement verification unit,
An agreement verification apparatus comprising: a generation unit that generates a transaction based on an instruction of the executive unit and broadcasts the transaction to the network.

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