KR102314573B1 - Method of contract management based on block cahin - Google Patents

Abstract

A method for a contract management server to manage a contract using a block chain, comprising the steps of receiving information on a contract product from a block chain network, and providing the received information to a purchaser terminal, from the purchaser terminal to the contract product receiving a purchase request for the purchase request, requesting a digital signature for non-repudiation of the purchase request, and if the signature is valid, conclude a purchase contract between the seller and the buyer according to the smart contract, and recall the contents of the contract and storing it on a blockchain network.

Description

Blockchain-based contract management method {METHOD OF CONTRACT MANAGEMENT BASED ON BLOCK CAHIN}

The present invention relates to a blockchain-based contract management method.

The electronic contract-based contract management method stores all contract processes in an electronic form, allows multiple people to collaborate based on the stored content, and improves work efficiency by minimizing unnecessary processes.

However, due to the centrally managed nature, the system operator can easily manipulate the contents, the system is not transparently disclosed, so the reliability is lowered, the service may be stopped in the event of a system failure due to a disaster, etc. Since various types of certificates such as certificates, private certificates, and personal certificates are used, central management is difficult. In addition, it requires the configuration of servers, certificates, electronic contract systems, and customer programs.

A contract management method using block chain and smart contract is required to solve the service accessibility problems caused by the performance degradation of the centralized contract management system, weak security, the possibility of errors in data input, and the initial cost burden.
(Patent Document 1) KR10-2018-0113140 A
(Patent Document 2) KR10-2019-0019004 A

The task to be solved is to provide a contract management server that includes an authentication procedure for non-repudiation of contract conclusions based on the blockchain network and manages the process from the conclusion of the contract to the execution of the contract using the smart contract.

A method for a contract management server to manage a contract using a block chain according to an embodiment, the method comprising: receiving information on a contract target product from a block chain network, and providing the received information to a purchaser terminal; receiving a purchase request for the contracted product, requesting a digital signature for non-repudiation of the purchase request, and if the signature is valid, signing a purchase contract between the seller and the buyer according to the smart contract, and storing the contents of the contract in the blockchain network.

Before the step of providing, receiving the information of the contract target product from the seller terminal, requesting the digital signature for identification and non-repudiation from the seller terminal, the public key and the original of the signature from the seller terminal The method may further include the steps of receiving the included data, determining the validity of the received signature using the public key, and if the signature is valid, storing the information on the contract product in the block chain network. have.

The seller terminal and the purchaser terminal may be authenticated by registering identification information of each terminal, receiving the registered identification information from each terminal, and authentication or OTP authentication method.

After the step of storing, receiving the execution details of the concluded contract from the seller terminal, comparing the execution details with the contents of the contract stored in the block chain network and, if they match, pay the down payment to the seller virtual wallet The method may further include the step of paying, and storing the implementation details and down payment details in the block chain network.

As a method for a contract management server according to another embodiment to manage a contract using a block chain, requesting bidding information including a proposal request stored in a block chain network, a smart contract including a successful bid condition, and a plurality of bid proposals Step, receiving the bid information from the block chain network, selecting a successful bidder according to the successful bid conditions, requesting the successful bidder terminal and the requester terminal to write a contract and to sign the contract for non-repudiation, and to sign a signature from each terminal, respectively receiving, and when all of the signatures are valid, signing a contract between the successful bidder and the requester, and storing the contract including the successful bidder's signature and the requester's signature in the blockchain network.

The receiving of the signature may include requesting and receiving securities information of the successful bidder.

The proposal request form and the successful bid condition are generated by receiving the proposal request form and the successful bid condition from the requestor terminal, and performing an authentication procedure using a digital signature of the requester terminal, and the plurality of bid proposals are, a plurality of bidder terminals Bidding proposals are received from the bidders, and may be generated through an authentication procedure using a digital signature for each bidder terminal.

After the storing step, receiving the execution details of the written contract from the successful bidder terminal, comparing the execution details with the contents of the contract stored in the blockchain network and paying the down payment to the successful bidder virtual wallet if they match and storing the implementation details and down payment details in a block chain network.

As a method for a contract management server to manage a contract using a block chain according to another embodiment, receiving contract-related information from a first terminal, data including a public key and an original signature, using the public key determining the validity of the received signature of the first terminal, and when the signature of the first terminal is valid, writing the contract-related information including the signature of the first terminal as a smart contract and storing it in a blockchain network receiving a contract conclusion request according to the contract-related information from a second terminal, performing digital signatures for non-repudiation of the first terminal and the second terminal, and when all digital signatures are valid, the Concluding a contract according to the smart contract, and storing the contract including all the digital signatures in the blockchain network.

The first terminal and the second terminal may be authenticated by registering identification information of each terminal and receiving the registered identification information from each terminal, or may be authenticated by any one of OTP authentication methods.

After the step of storing the contract in the blockchain network, receiving the execution details of the signed contract from the first terminal or the second terminal, and the execution details and the contract stored in the blockchain network The method may further include the step of storing the implementation details in the blockchain network if they are matched by comparison.

According to the present invention, as a service based on blockchain and distributed ledger, contract-related information can be safely managed and the operator's forgery or falsification of contract contents can be blocked, thereby enhancing security.

In addition, according to the present invention, it is possible to increase the reliability of the contract participants by including a digital signature procedure for non-repudiation of the contract participants at each stage of the contract process and the process of verifying the validity of related documents.

In addition, according to the present invention, it is possible to enjoy the effect of using a single management system by allowing only the contract participants to share data on the entire process, such as user authentication, contract conclusion, and contract fulfillment confirmation.

1 is a configuration diagram of a contract management system according to an embodiment.
2 is a flowchart of a contract conclusion process according to an exemplary embodiment.
3 is a flowchart of a method for a contract management server to authenticate a user terminal according to an embodiment.
4 is a flowchart of a process in which a seller registers a contract product according to an exemplary embodiment.
5 is a flowchart of a process in which a buyer purchases a contract product according to an exemplary embodiment.
6 is an exemplary diagram of a contract ledger included in a smart contract according to an embodiment.
7 is a flowchart of a process of registering a proposal request and a bid proposal according to an exemplary embodiment.
8 is a flowchart illustrating a process of selecting a successful bidder and concluding a contract according to an exemplary embodiment.
9 is a flowchart of a process of managing execution details of a contract according to an exemplary embodiment.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

In the present specification, the contract is concluded in such a way that the seller uploads the product or service that is the target of the transaction in advance to the contract management server 300 and the buyer selects it and the contract is concluded, or the buyer wants one of a plurality of sellers. A bidding may be made to determine the seller, and the bidding method may be performed to determine the seller to be contracted with. For convenience, the former is referred to as a commodity type and the latter as a bidding type.

Meanwhile, the contract management server 300 may manage general contracts as well as contracts by sale or bidding, and the types of contracts that can be managed are not limited to any one. In addition, the type of bidding may be limited competition, general competition, nomination competition, etc., but is not limited to any one.

In this specification, the down payment or the price of goods may be paid in coins or tokens, which are virtual currency based on block chain technology. A token means a means to be issued as an economic reward tool to promote the cooperation of each role in the ecosystem when a blockchain project is first opened. For example, it may be an Ethereum Request for Comment 20 (ERC20) issued on the Ethereum blockchain network.

1 is a configuration diagram of a contract management system according to an embodiment.

Referring to FIG. 1 , the contract management system 1000 includes a seller terminal 100 , a buyer terminal 200 , a contract management server 300 , a block chain network 400 , and a financial institution server 500 .

The seller terminal 100 and the buyer terminal 200 refer to devices capable of installing applications such as computers, smart phones, and tablets, and having a built-in web browser to access the Internet. 1 shows the terminals and the block chain network 400 separated for convenience, the terminals may be nodes constituting the block chain network 400 .

The seller terminal 100 means a terminal of a seller who wants to upload a contract product to the contract management server 300 . When a contract is made in a bidding type, it may play a role in participating in the bidding.

The purchaser terminal 200 refers to a terminal of a purchaser who intends to purchase a contract product registered in the contract management server 300 . When a contract is made in a bidding type, it may mean a terminal of a person who makes a bid.

The contract management server 300 provides the contract product uploaded by the seller terminal 100 to the buyer terminal 200 to mediate the establishment of the contract, and to verify the identity of the seller and the buyer in the process of the contract being concluded and to guarantee performance. Proceed with non-repudiation digital signatures. In addition, the contents of the established contract are stored in the block chain network 400, and the payment of the down payment is managed according to whether the contract is fulfilled.

Meanwhile, the contract management server 300 includes a seller virtual wallet 310 , a buyer virtual wallet 320 , and a down payment account 330 .

The seller virtual wallet 310 is a kind of virtual ledger issued to the seller by the contract management server 300 , and the seller can receive the price of the sold product through the virtual wallet. If the contract is concluded in the form of bidding, you can receive a down payment based on a bid proposal or contract in a virtual wallet.

On the other hand, the down payment or product price is paid to the seller through the contract management server 300 , and the seller can use the down payment or the product price by receiving a registered prepaid card connected to the account of the seller virtual wallet 310 .

The buyer virtual wallet 320 means a kind of virtual book issued by the contract management server 300 to the buyer. The buyer charges the buyer virtual wallet 320 in advance, and the contract management server 300 may pay the purchase price to the seller by recording the transmission details from the buyer virtual wallet 320 to the seller virtual wallet 310 . In addition, the payment of the down payment to the successful bidder may also be made in the virtual currency of the virtual wallet.

The down payment account 330 is an account in which the down payment or the price of goods actually deposited from the buyer is managed. Also, since it is connected to the financial institution server 500 , when a seller or a successful bidder uses the down payment of their respective virtual wallets, the amount in the down payment account 330 is transferred to the financial institution server 500 .

The blockchain network 400 is a kind of distributed database composed of a plurality of blocks, and stores and manages seller and buyer information, contract information including contract details, and contract conclusion or cancellation details. In addition, smart contract code including contract details is stored, and the code can be executed by member nodes constituting the block chain network 400 .

Since contract-related information is recorded and stored in the block chain network 400, the seller, buyer, or third party with authority to access the contract management server 300 or the block chain network 400 can verify the authenticity of the stored information. can be verified.

The financial institution server 500 issues a virtual account connected to the down payment account 330 or a virtual account connected to the prepaid card paid to the seller, and when the seller uses the prepaid card, the payment is paid to the card use place. On the other hand, the seller's use of the prepaid card may be limited to the place specified in the contract depending on the nature of the contract, which will be described in detail with reference to FIG. 9 .

Hereinafter, a method in which the contract management server 300 manages the process from information exchange between the seller and the buyer to the conclusion of the contract will be described. Fig. 2 describes the process of entering into a general contract, Figs. 4 to 5 describe a commodity-type contract, Figs. 6 to 8 describe a bidding-type contract, and Fig. 9 is a down payment management according to whether the contract is fulfilled explain about

2 is a flowchart of a contract conclusion process according to an exemplary embodiment.

Referring to FIG. 2 , the seller terminal 100 transmits a contract creation request including a written contract to the contract management server 300 ( S101 ).

The contract management server 300 requests a digital signature for confirming the identity of the seller from the seller terminal 100 (S102).

The seller terminal 100 performs a digital signature using a public key encryption algorithm (S103). Specifically, a digital signature consists of a signing key generation step, a signature step, and a signature verification step. The seller terminal 100 generates a public key and a private key, generates a hash value by hashing the original signature, and generates an electronic signature by hashing the hash value with a private key for signature. On the other hand, an electronic signature is also called a digital signature. The hash function used to generate the hash value may be a known function such as SHA256.

The seller terminal 100 transmits the original signature, the electronic signature, and the generated public key to the contract management server 300 (S104).

The contract management server 300 decrypts the electronic signature using the public key received from the seller terminal 100, and compares it with a hash value obtained by hashing the original signature to confirm that the digital signature is not forged or forged. (S105).

The contract management server 300 determines the validity of the signature by comparing whether the decrypted value and the hash value are the same (S106). If the signature is valid, proceed to the next step S107, and if it is confirmed that the signature is forged or falsified, return to step S102 and request a digital signature from the seller terminal 100.

When the contract management server 300 confirms that the signature is valid, the contract before signing written by the seller is written as a smart contract and transmitted to the blockchain network 400 (S107).

Specifically, a smart contract on the blockchain network 400 is a contract protocol written in the form of program code executable by a computing device, and the code is stored in the nodes constituting the blockchain network 400, and the code is can be executed When the code is executed, a predetermined procedure is performed if certain predetermined conditions are satisfied.

As an example, the obligations to be fulfilled by the seller and the buyer at the time of the contract, the contract details, the contract termination conditions, etc. are written as the conditions of the smart contract, and if the conditions are satisfied, the contract may be established or terminated.

The blockchain network 400 creates a contract ledger in each node constituting the network (S108). The data stored in the block shared by each node cannot be manipulated because it is very difficult to change due to the nature of the distributed ledger. Therefore, the blockchain-based contract management server 300 can provide reliability and transparency.

The contract management server 300 proceeds with the electronic signature for non-repudiation of the seller and the electronic signature for identification and non-repudiation of the purchaser (S109). In this case, the contract management server 300 may transmit the identity information of the seller confirmed through step P11 to the purchaser terminal 200 . Since the digital signature proceeding step is the same procedure as described in P11, a detailed description thereof will be omitted.

When the contract management server 300 confirms that the signatures of the seller and the buyer are valid, a signed contract including the seller's signature and the buyer's signature is created as a smart contract and transmitted to the block chain network 400 (S110).

The blockchain network 400 generates a contract ledger including the seller's signature and the buyer's signature in each node (S111).

Thereafter, the seller and the buyer, who are contract parties, can access the block chain network 400 through the contract management server 300 to view the contract details.

3 is a flowchart of a method for a contract management server to authenticate a user terminal according to an embodiment.

Referring to FIG. 3 , the contract management server 300 registers the seller terminal 100 or the buyer terminal 200 , and checks whether the registered device is used when the seller or the buyer accesses the contract management server 300 .

Since the contract management server 300 determines whether the terminal is a registered terminal using the information used by the seller or the buyer for registration, it checks what information is used for registration (S201). The seller or the buyer may select the MAC address, location information, or OTP of the terminal as information for registering their terminal with the contract management server 300 .

For example, a seller or a buyer who intends to register the terminal with location information receives the GPS information of the terminal from a specific application of the terminal. And it is possible to store the encrypted hash value obtained from the latitude and longitude in the blockchain network (400).

The contract management server 300 requests and receives the input of the MAC address of the terminal when the seller terminal 100 or the buyer terminal 200 is registered using the MAC address, and when registered using the location information, the terminal's It requests and receives location information input (S202).

For example, when a terminal is registered with location information, GPS information is received from a specific application of the terminal again at the time of authentication, and latitude and longitude values are generated as hash values.

The contract management server 300 compares the received information with the information input during registration (S203). In the above example, the contract management server 300 checks whether the hash value generated at the time of authentication and the hash value generated when registering the terminal and stored in the blockchain network 400 are the same.

The contract management server 300 determines whether the two pieces of information are the same (S204), and if they are the same, completes authentication of the terminal and allows access (S205).

If the information is not the same, the contract management server 300 performs authentication two more times and blocks the connection of the terminal when authentication fails three or more times (S208) (S209). Meanwhile, in the present specification, the number of authentication attempts is limited to three, but the number of authentication attempts is merely an example and may be changed by the contract management server 300 or the server administrator.

On the other hand, when the seller terminal 100 or the buyer terminal 200 is registered as a one-time password (OTP) method, the contract management server 300 receives the OTP from the terminal and transmits it to the authentication server (S206) .

The contract management server 300 receives whether or not authentication is successful from the authentication server (S207), and if the authentication is successful, completes the authentication of the terminal and allows access (S205).

When the OTP authentication fails three or more times (S208), the contract management server 300 blocks access to the terminal as in the case of registration using a MAC address or location information (S209).

Hereinafter, a method for concluding a commodity-type contract through FIGS. 4 to 5 and a method for concluding a bid-type contract with reference to FIGS. 6 to 8 will be described.

4 is a flowchart of a process in which a seller registers a contract product according to an exemplary embodiment.

Referring to FIG. 4 , the seller terminal 100 transmits contract product information to the contract management server 300 and requests contract product registration (S301). In this case, the contract product may mean a product or service to be traded.

The contract management server 300 requests a non-repudiation signature from the seller terminal 100 (S302). The non-repudiation signature is performed in a digital signature method, and steps S302 to S306 are the same as P11 of FIG. 2 , so a detailed description thereof will be omitted.

If the signature is valid, the contract management server 300 creates the contract product information as a smart contract and transmits it to the block chain network 400 (S307).

The blockchain network 400 stores the smart contract in the member node (S308). That is, the contents of the contract product are written in a smart contract and recorded in the blockchain network 400 in a distributed ledger method, in which case the blockchain network 400 may be of a private type.

5 is a flowchart of a process in which a buyer purchases a contract product according to an embodiment, and FIG. 6 is an exemplary diagram of a contract ledger included in a smart contract according to an embodiment.

Referring to FIG. 5 , the purchaser terminal 200 requests to view the registered contract products with the contract management server 300 ( S401 ).

The contract management server 300 requests to view the contract products registered in the block chain network 400 (S402), and receives information on the contract products (S403).

The contract management server 300 provides the received contract product information to the purchaser terminal 200 (S404).

The purchaser terminal 200 transmits a purchase request written by the purchaser to the contract management server 300 (S405). The form or content of the purchase requisition may vary depending on the nature of the contract product.

The contract management server 300 determines whether items to be described in the purchase request are omitted, and determines the suitability of the purchase request (S406).

Purchase requisition form must include buyer information (company name, contact number, e-mail, fax, etc.), desired item to be purchased, product name, model name, quantity, desired unit price, total individual amount, and total total. When at least one of the above items is omitted, the contract management server 300 may receive a purchase request from the purchaser terminal 200 again.

The contract management server 300 requests the purchaser's electronic signature for non-repudiation to the purchaser terminal 200 (S407). Since the electronic signature or digital signature process is the same as that described with reference to P11 of FIG. 2 , the following description will be omitted.

Thereafter, the contract management server 300 requests the seller terminal 200 to write an agreement (S408). Agreement means that if the buyer fills out a purchase request form and signs the non-repudiation, and then places an order for the product, the seller expresses his/her intention to deliver the product.

In a transaction through a sales contract, it is generally considered that the intention of the contract is included, but depending on the characteristics of the contracted product, only buyers who satisfy certain conditions can possess or purchase the product. management may be required.

Accordingly, the contract management server 300 requests that the seller confirm the conditions of the buyer and write an agreement stating that the sale of the product is accepted.

The seller terminal 100 requests the contract management server 300 to conclude a contract together with the written agreement (S409).

Meanwhile, steps S408 to S409 may be performed in step S301 of FIG. 4 in which the seller registers the contract product, and may be omitted depending on the characteristics of the product or service to be contracted.

When the purchaser's signature in step S407 is valid, the contract management server 300 notifies the seller terminal 100 and the purchaser terminal 200 that the contract has been pre-concluded, respectively (S410).

Thereafter, the purchaser determines whether to purchase the product through the purchaser terminal 200 (S411).

When the buyer confirms the purchase, the buyer pays the seller for the product, and transmits the purchase decision details to the contract management server 300 through the buyer terminal 200 (S412). Meanwhile, the price may be paid in the virtual currency of the buyer virtual wallet 320 to the seller virtual wallet 310 .

The contract management server 300 concludes a contract according to the smart contract, and transmits the content that the contract is concluded to the block chain network 400 (S413). In this case, the contract ledger of FIG. 6 may be included in the smart contract. The contract ledger includes, but is not limited to, the essential conditions stated in the purchase requisition;

Thereafter, the blockchain network 400 stores the contract conclusion in each node (S414).

Meanwhile, when the purchaser rejects the purchase in step S411 , the purchaser transmits a purchase rejection intention to the seller terminal 100 through the purchaser terminal 200 ( S415 ).

The seller terminal 100 transmits the fact that the contract has been canceled due to the buyer's intention to refuse to the contract management server 300 (S416).

The contract management server 300 transmits the contents of the contract termination to the block chain network 400 (S417).

The blockchain network 400 stores the contract cancellation details in each node (S418).

7 is a flowchart of a process of registering a proposal request and a bid proposal according to an exemplary embodiment.

Referring to FIG. 7 , the buyer prepares a proposal request form and successful bid conditions and transmits them to the contract management server 300 through the buyer terminal 200 ( S501 ). In this case, the buyer may write a request for proposal including information on whether the type of bid is a competitive bid or a limited bid.

The contract management server 300 proceeds with an electronic signature to prevent the buyer from denying it (S502). Since the electronic signature process is the same as described with reference to P11 of FIG. 2 , a description thereof will be omitted.

If the signature is valid, the contract management server 300 writes the proposal request and the successful bid condition as a smart contract and transmits it to the block chain network 400 (S503).

Accordingly, when a seller who satisfies the conditions for successful bids set according to the nature of each contract appears, the contract is established at the same time as the conditions are satisfied. For example, the type of contract is a subcontract contract, and the buyer is a request for a proposal to recruit a service company and a condition for a successful bid. and the like. When the above conditions are included in the code of the smart contract and a bid proposal that satisfies the conditions is received, the code is executed and the contract can be concluded.

The blockchain network 400 stores the smart contract code received in each node (S504).

Thereafter, the seller requests to read the buyer's proposal request to the contract management server 300 through the seller terminal 100 (S505).

The contract management server 300 requests and receives the proposal request from the block chain network 400 (S506, S507), and transmits it to the seller terminal 100 again (S508). Meanwhile, according to the type of bid, the contract management server 300 may deliver the proposal request only to the seller terminal 100 that satisfies a predetermined condition.

The seller terminal 100 transmits a bid proposal prepared according to the content of the proposal request to the contract management server 300 (S509).

The contract management server 300 determines whether the bid proposal prepared by the seller is appropriate (S510). If it is inappropriate, the bid proposal is received again from the seller terminal 100 .

If appropriate, the contract management server 300 proceeds with the electronic signature for non-repudiation through the seller terminal 100 (S511). This process is the same as step P11 in FIG. 2 .

If the signature is valid, the contract management server 300 transmits a bid proposal to the block chain network 400 (S512).

The blockchain network 400 stores the bid proposal in each node (S513). Thereafter, the purchaser terminal 200 may view the stored bid proposal through the contract management server 300 .

8 is a flowchart illustrating a process of selecting a successful bidder and concluding a contract according to an exemplary embodiment.

Referring to FIG. 8 , the contract management server 300 requests the block chain network 400 for a proposal request form, successful bid conditions, and information on bid proposers ( S601 ).

The blockchain network 400 provides the requested information to the contract management server 300 (S602).

The contract management server 300 selects a successful bidder that meets the successful bid conditions from among the bid proposers according to the smart contract (S603).

The contract management server 300 requests the purchaser terminal 200 to write a contract (S604).

The contract management server 300 receives the contract written from the purchaser terminal 200 (S605), and determines whether the contract is appropriate (S606). If it does not fit, request a rewrite and, if appropriate, proceed to the next step.

When the contract is properly written, the contract management server 300 proceeds with the same electronic signature as in step P11 for non-repudiation of the buyer (S607).

Thereafter, the contract management server 300 requests the seller terminal 100 to write a contract (S608).

The contract management server 300 receives the written contract from the seller terminal 100 (S609), and determines whether the contract is appropriate (S610). If it does not fit, request a rewrite and, if appropriate, proceed to the next step.

When the contract is properly written from the seller, the contract management server 300 proceeds with an electronic signature for the seller's non-repudiation (S611).

Meanwhile, in the present specification, it has been described that the purchaser prepares the contract first, but the order of writing the contract between the buyer and the seller is irrelevant to the effect of the contract.

The contract management server 300 requests the seller terminal 100 for registration of securities in the seller's name in order to guarantee the seller's contract execution (S612).

Securities in the name of the seller means securities in the form of performance guarantee insurance. For example, it may mean any one of contract performance guarantee insurance, advance payment performance guarantee, and defect performance guarantee insurance issued by SGI Seoul Guarantee. Seller may obtain the above policies by paying a fee to the Guarantee Insurance Agency.

The seller terminal 100 transmits the seller's securities information to the contract management server 300 (S613). For example, it is possible to transmit commonly used contract performance guarantee insurance policy information.

The contract management server 300 determines whether the seller's stock information is valid (S614), and if not valid, requests the information again, and if valid, proceeds to the next step.

The contract management server 300 transmits a contract including the seller's signature and the buyer's signature to the block chain network 400 (S615).

The blockchain network 400 creates a contract ledger in each member node (S616).

After the contract between the seller and the buyer is established, the contract management server 300 manages whether each contract party performs the contract and the payment of the down payment. Hereinafter, a contract execution management process of the contract management server 300 will be described.

9 is a flowchart of a process of managing execution details of a contract according to an exemplary embodiment.

Referring to FIG. 9 , after the contract is concluded in an arbitrary manner, the contract management server 300 checks whether the seller has fulfilled the contract, and pays a down payment or payment to the seller or refunds the buyer depending on whether the contract is fulfilled. In this case, the down payment or payment may be deposited into the virtual wallets of the contracting parties.

The seller terminal 100 transmits the contents of fulfilling the matters described in the contract to the contract management server 300 (S701). For example, in the case of a sales contract, delivery of goods or provision of services to the buyer may be transmitted.

The contract management server 300 requests the contract ledger for the contract transmitted by the seller to the blockchain network 400 (S702). The contract ledger may include seller information, buyer information, unit price, delivery deadline, purchase agreement, etc. shown in FIG. 6 .

The blockchain network 400 transmits the contract ledger to the contract management server 300 (S703).

The contract management server 300 compares the implementation details received from the seller terminal 100 with the matters described in the contract ledger (S704).

If they match (S705), that is, when the seller fulfills all the items described in the contract ledger, the contract management server 300 pays a down payment or payment from the down payment account 330 to the seller virtual wallet 310 (S706).

On the other hand, the contract management server 300 may limit the use of the paid down payment after paying the down payment to the seller. For example, if the buyer is a government and the seller is a successful bidder who has entered into a contract to perform an arbitrary task with the government, the place where the seller uses the down payment, that is, the task performance fee, may be limited only to the matters specified in the contract. Specifically, when there is a payment request from a place other than the permitted use from the financial institution server 500 by allowing only deposits to the account connected with the wages of the personnel participating in the task or project, and the operating expenses of the project, the contract management server ( 300) may reject the payment.

Returning to FIG. 9 again, when the fulfillment information received from the seller terminal 100 and the items described in the contract ledger do not match (S705), the contract management server 300 stores the purchaser virtual wallet 320 from the down payment account 330. to refund the down payment or the amount (S707).

The contract management server 300 stores the changed details of the seller virtual wallet 310 or the buyer virtual wallet 320 in the blockchain network 400 (S708).

According to the present invention, since it is a blockchain and distributed ledger-based service, contract-related information can be safely managed, and the operator's forgery or falsification of contract contents can be blocked, thereby enhancing security.

In addition, according to the present invention, it is possible to increase the reliability of the contract participants, including the process of verifying the validity of the electronic signature procedure and related documents for non-repudiation of the contract participants at each stage of the contract process.

In addition, according to the present invention, it is possible to enjoy the effect of using a single management system by allowing only the contract participants to share data on the entire process, such as user authentication, contract conclusion, contract execution, and down payment.

The embodiment of the present invention described above is not implemented only through the apparatus and method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium in which the program is recorded.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improved forms of the present invention are also provided by those skilled in the art using the basic concept of the present invention as defined in the following claims. is within the scope of the right.

Claims (11)

A method for a contract management server to manage a contract using a blockchain, comprising:
Receiving the information of the contract target product from the seller terminal;
requesting a digital signature for identification and non-repudiation from the seller terminal;
receiving data including a public key and an original of the seller's signature from the seller terminal, and determining the validity of the received seller's signature using the public key; and
If the seller's signature is valid, writing the contract product information into a smart contract and storing it in a blockchain network;
receiving information on the contract product from the block chain network, and providing the received information to a purchaser terminal;
receiving a purchase request for the contract target product from the purchaser terminal, and determining suitability of the purchase request;
if the purchase request is appropriate, requesting a non-repudiation purchaser signature for the purchase request;
If the buyer's signature is valid, transmitting a consent form including an expression of intention to deliver the product according to the purchase request to the seller terminal;
receiving a contract conclusion request together with the consent form from the seller terminal;
Concluding a purchase contract between the seller and the buyer according to the contract details included in the smart contract, and storing the contents of the concluded contract in the block chain network;
receiving the execution details of the concluded contract from the seller terminal;
Comparing the execution details with the contract contents stored in the blockchain network and recording the amount paid from the buyer virtual wallet to the seller virtual wallet as payment details,
storing the fulfillment details and the payment details in the blockchain network; and
Restricting the usage of the amount paid to the merchant virtual wallet, and rejecting the payment request when receiving a payment request for an unauthorized usage from a financial institution server,
The amount paid by the buyer to the seller is managed in the down payment account connected to the financial institution server, and when the seller uses the amount paid from the buyer virtual wallet to the seller virtual wallet, the amount in the down payment account is transferred to the financial institution server. delete In claim 1,
The seller terminal and the buyer terminal,
A contract management method that registers identification information of each terminal, receives the registered identification information from each terminal, and is authenticated or authenticated by any one of the OTP authentication methods. delete A method for a contract management server to manage a contract using a blockchain, comprising:
Receiving a proposal request form and a successful bid condition from the requester terminal;
requesting the requester's signature for identification and non-repudiation from the requestor's terminal, and if the requester's signature is valid, writing the proposal request and the successful bid condition into a smart contract and storing it in a blockchain network;
transmitting the proposal request to each of the at least one bidder terminal requesting the proposal request, and receiving a bid proposal for the proposal request;
requesting a seller's signature for identification and non-repudiation from the bidder terminal, and if the signature of the bidder terminal is valid, storing the bid proposal in the blockchain network;
requesting bidding information including the smart contract stored in the blockchain network and a plurality of bidding proposals;
receiving the bid information from the blockchain network and selecting a successful bidder from among the plurality of bid proposals according to the successful bid conditions included in the smart contract;
requesting the successful bidder terminal and the requester terminal to prepare a contract and to sign a non-repudiation of the contract, and receiving signatures from each terminal,
When all the signatures on the contract are valid, signing a contract between the successful bidder and the requester, and storing the contract including the signature of the successful bidder terminal and the signature of the requester terminal in the block chain network;
receiving the execution details of the written contract from the successful bidder terminal;
Comparing the implementation details with the contents of the contract stored in the blockchain network and recording the amount paid from the requester virtual wallet to the successful bidder virtual wallet as payment details;
storing the fulfillment details and the payment details in a blockchain network; and
restricting the use of the amount paid to the successful bidder's virtual wallet, and rejecting the payment request when receiving a payment request for an unauthorized use from a financial institution server,
The amount paid by the requester to the successful bidder is managed in a down payment account connected to the financial institution server, and when the successful bidder uses the amount paid from the requester virtual wallet to the successful bidder virtual wallet, the amount in the down payment account is transferred to the financial institution server. delete In claim 5,
The request for proposal and the conditions for the successful bid are:
Receives the proposal request form and the successful bid condition from the requestor terminal, and is generated through an authentication procedure using a digital signature of the requester terminal;
The plurality of bid proposals,
A contract management method that receives bid proposals from a plurality of bidder terminals and is generated through an authentication procedure using a digital signature for each bidder terminal. delete delete delete delete

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