KR102782457B1 - Real estate transaction system using block chain and the method of real estate transaction - Google Patents

Abstract

The real estate transaction method using the blockchain of the present invention is composed of four systems, namely, the Real Estate Brokerage Association System, the Korean Association of Legal Scriveners (Registry Office) System, the Banking System, and the City, County, and District Office Real Estate Integrated System, and, in the real estate transaction method using Hyperledger Fabric, which does not use cryptocurrencies such as Bitcoin or Ethereum among the blockchains capable of smart contracts, comprises the steps of: a seller (landlord) and a buyer (tenant) connecting to a peer of the Real Estate Brokerage Association System through a personal PC or mobile application; a step in which both the seller (landlord) and the buyer (tenant) verify their identities using a digital certificate authority (CA); a step in which a transaction is created for a real estate sale product and a step in which a real estate transaction is guaranteed; a step in which a simulation is performed for writing and signing a sales contract (Read/Write set) and a confirmation step is performed using a digital certificate; a step in which a block is created for the real estate sale and purchase and a step in which the latest block of the created blocks is verified; It includes the distributed ledger recording and update stages, the stages of payment of purchase price and completion of registration transfer, and the stages of payment of acquisition tax and reporting of actual transactions.

Description

{Real estate transaction system using block chain and the method of real estate transaction}

The present invention relates to a real estate transaction system and a real estate transaction method using blockchain technology. More specifically, the present invention relates to a real estate transaction system and a real estate transaction method using blockchain technology that can prevent forgery and alteration of contracts, enable sellers and buyers to conduct transactions directly online during real estate transactions, and reduce transaction fees due to the absence of brokers.

Representative real estates include income-generating real estate such as officetels and knowledge industry centers. Most investors who want to invest in income-generating real estate often make wrong investment decisions based only on the advice from sales consultants, such as increased premiums or guaranteed safe monthly rental income. Recently, as the use of real estate transaction information via the Internet has increased, various real estate transaction management services that mediate matches between real estate sellers and buyers have emerged. Recently, blockchain technology is a technology in which all nodes connected to the network share the same ledger, so if a hacker tries to tamper with the transaction history recorded in the ledger, he or she has to tamper with all the shared ledgers, making tampering almost impossible. Therefore, data recorded in the blockchain is trustworthy.

By recording the distribution history of content on this trustworthy blockchain ledger, it is possible to build an ecosystem where all entities participating in content distribution can trust each other and share profits. Therefore, it has the effect of allowing content creators to obtain fair profits.

Recently, blockchain technology has been widely used to ensure the integrity of certain data by organizing it into chained blocks and storing it in distributed manners on nodes rather than a central server.

Republic of Korea Patent No. 10-2052629 (Announcement date: December 5, 2019) “Data management system and method for distribution of digital content files” was disclosed.

The above invention is based on an on-off hybrid blockchain network, processes a large amount of data transaction history in an off-blockchain network, and records only the total result at once in an on-blockchain network, thereby increasing the number of transactions that can be processed per second, thereby enabling the distribution of large amounts of data. In addition, it provides a distribution structure in which anyone can participate as a transmitter and obtain profits through it by enabling compensation according to transmission contribution.

Korean Patent Registration No. 10-2322983 (Publication Date: November 9, 2021) "Asset Trading Platform Server and its Operating Method for Enabling Trading of Spot Assets Based on Blockchain" has been disclosed. The asset trading platform server and its operating method can store and manage data related to spot asset trading information based on blockchain, thereby supporting sellers and buyers of spot assets to easily search for spot asset information and conduct transactions online.

Republic of Korea Patent Publication No. 10-2052629 Republic of Korea Patent Publication No. 10-2322983 Republic of Korea Patent Publication No. 10-2302954 Republic of Korea Patent Publication No. 10-2022-0122418

The purpose of the present invention is to provide a real estate transaction system using blockchain, which allows the seller and buyer of real estate to safely conduct direct transactions without a broker and to conclude contracts online, thereby reducing the loss of documents and records and increasing security by decentralizing information, preventing forgery and falsification of contracts by using blockchain technology, and reducing transaction fees due to the absence of brokers.

Another purpose of the present invention is to provide a real estate transaction method using blockchain that enables transparent and safe transactions by providing a safe and scientific real estate transaction platform.

The real estate transaction system using blockchain of the present invention separates real estate transaction sales into channel 1 and real estate transaction rentals into channel 2, and configures each channel separately, and in the real estate transaction system using Hyperledger Fabric, which does not use cryptocurrencies such as Bitcoin or Ethereum among blockchains capable of smart contracts, the real estate transaction system is composed of four systems: the Association of Certified Real Estate Brokers system, the Korean Association of Legal Scriveners (registry office) system, the banking system, and the city, county, and district office real estate comprehensive system; each of the systems is configured based on a private method so that the concept of cryptocurrency is not necessary; and users and nodes within each stakeholder are independently managed;

In order to process a large number of transactions at a high speed and operate in parallel, the above nodes execute only some of the chaincode; the above users can execute the above chaincode installed on the peer network through a distributed application, and it is divided into two types of functions: read (query) and write (write/update); the chaincode executed according to the transaction request can read and write the state DB or inquire past recorded history, and the above chaincode (System chaincode)

QSCC (Query System ChainCode) used when reading data stored in a block,

It is characterized by the ESCC (Endorsement System ChainCode) that is responsible for the guarantee policy, the VSCC (Validation System ChainCode) that is used when verifying blocks, the CSCC (Configuration System ChainCode) that is used when setting up channels, and the LSCC (Lifecycle System ChainCode) that performs everything from chaincode installation to application.

In addition, in the real estate transaction system using the blockchain of the present invention, the real estate transaction of the channel 1 includes the Certified Real Estate Brokerage Association system, the Korean Association of Legal Scriveners (Registrar's Office) system, the banking system, and the city/county/district office real estate comprehensive system;

The above real estate transaction rental of the above channel 2 is characterized by including the above real estate agent association system and the city/county/district office real estate comprehensive system.

In addition, in the real estate transaction system using the blockchain of the present invention, the QSCC, the CSCC, and the LSCC among the chaincodes (system chaincode) are characterized in that they are executed by the user as CLI commands; and the ESCC and the VSCC are characterized in that they are executed by the Endorsing peer responsible for guaranteeing the transaction and the Committing peer responsible for verifying the block.

The real estate transaction method using the blockchain of the present invention is composed of four systems: the Certified Real Estate Brokers Association system, the Korean Association of Legal Scriveners (registration office) system, the banking system, and the city, county, and district office real estate comprehensive system. In order to limit access to data provided by a specific system among the four systems so that it can be called only by the relevant organization, each system configures a Peer for connection with other systems, a CA for identity verification, an MSP for calling related data, and a DApp for data storage; In the real estate transaction method using Hyperledger Fabric, which does not use cryptocurrencies such as Bitcoin or Ethereum among the blockchains capable of smart contracts,

A step for the seller (landlord) and the buyer (tenant) to connect to the peer of the above-mentioned Real Estate Brokerage Association system through a personal PC or mobile application; a step for both the seller (landlord) and the buyer (tenant) to verify their identity using a digital certificate authority (CA); a step for creating a transaction for a real estate sale product, a step for guaranteeing a real estate transaction; a step for simulating the writing and signing of a sales contract (Read/Write set) and a step for confirmation using a digital certificate;

It is characterized by including a block generation step for the above real estate transaction, a latest block verification step of the generated blocks, a distributed ledger recording and update step, a purchase price payment and registration transfer completion step, and an acquisition tax payment and actual transaction report step.

Also, in a real estate transaction method using blockchain, in the step of creating a transaction for the real estate sale product, the step of guaranteeing the real estate transaction, and the step of simulating the writing and signing of the contract and the step of confirming it using a digital certificate, a filter is used for the clarity and overall sharpening and background of images such as the contract (Read/Write set), identification card, photo, and fingerprint; and the method of constructing four systems, the Certified Real Estate Brokerage Association System, the Korean Association of Legal Scriveners (Registry Office) System, the banking system, and the city/county/district real estate comprehensive system, is characterized by including the steps of installing Docker using a Linux package manager (apt-get); installing Curl, Node.js, and Go languages; installing Hyperledger fabric; installing a Docker image, and installing a client.

According to the present invention, rather than centralizing information management through a third party, which was a shortcoming of the current real estate electronic contract system, decentralization of information is achieved, thereby reducing the loss of documents and records and increasing security.

Additionally, blockchain technology can be used to prevent forgery and falsification of contracts, allow sellers and buyers to conduct real estate transactions directly online, and reduce transaction fees due to the absence of brokers.

In addition, according to the present invention, there is an effect that can confirm that the shortcomings of the current real estate electronic contract, such as the complicated procedure requiring a certified real estate agent and the centralized storage of related data, are improved in stages.

In addition, the blockchain technology according to the present invention has the advantage of allowing investment in small amounts due to its characteristics, and also making it easy to access or view information.

In addition, according to the present invention, since it can be traded like stocks, investment in overseas products can also be traded through a simplified process rather than the existing complicated procedures. In this way, the real estate investment sector can also be improved through the introduction of blockchain.

In addition, according to the present invention, a network with high credibility can be operated, and since the identity of network participants is verified, responsibility can be clearly determined when a problem occurs.

In addition, according to the present invention, since only some nodes execute the chain code, there is an advantage in that parallel operation is possible and a large number of transactions can be processed at a high speed.

Figure 1 is a conceptual block diagram of artificial intelligence real estate valuation.
Figure 2 is a diagram showing the first change in the real estate electronic contract flow.
Figure 3 is a diagram showing the second change in the real estate electronic contract flow.
Figure 4 is a diagram of a real estate transaction model system construction according to one embodiment of the present invention.
Figure 5 is an example of system chain code execution installed on a guarantee (Peer).
Figure 6 is a structural diagram of a Hyperledger Fabric block.
Figure 7 is a diagram showing the installation of software and tools.
Figure 8 is an example showing files to be executed.
Figure 9 is an example of Docker program installation.
Figure 10 is an execution diagram of the chain code development process.
Figure 11 is an electronic contract for real estate lease.
Figure 12 is the login screen for the real estate transaction electronic contract system.
Figure 13 is a diagram for verifying the identity of the parties to a transaction and the identity of a certified broker.
Figure 14 is a drawing showing the verification of identification and fingerprint biometric registration information.

Hereinafter, the present invention will be described in detail based on the attached drawings.

Figure 1 is a conceptual block diagram of artificial intelligence real estate valuation, Figure 2 is a diagram showing the first change in the flow of real estate electronic contracts, and Figure 3 is a diagram showing the second change in the flow of real estate electronic contracts. Figure 4 is a diagram showing the construction of a real estate transaction model system according to an embodiment of the present invention, and Figure 5 is an example of the execution of a system chain code installed in a guarantor (Peer).

Figure 6 is a structural diagram of a Hyperledger Fabric block, and Figure 7 is a diagram showing software and tool installation. Figure 8 is an example of files to be executed, Figure 9 is an example diagram of Docker program installation, and Figure 10 is an execution diagram of the chain code development process.

Blockchain technology refers to a technology in which, when a certain data called a transaction is generated, one of multiple node devices participating in a blockchain network generates a new block containing the transaction based on a previous block included in blockchain data in which multiple blocks are linked into a chain, links the block to the blockchain data into a chain, and then distributes the block to other node devices via the blockchain network, thereby allowing the specified data to be distributed and stored in multiple node devices.

Figure 1 is a conceptual diagram of artificial intelligence real estate valuation.

The blocks illustrated in FIG. 1 or the steps of the flowchart may be interpreted as computer program instructions that are loaded onto a processor or memory of a data processing capable device such as a general-purpose computer, a special-purpose computer, a portable notebook computer, a network computer, and perform designated functions. Since these computer program instructions can be stored in a memory equipped on a computer device or a computer-readable memory, the functions described in the blocks of the block diagram or the steps of the flowchart may also be produced as a manufactured product that includes a command means for performing the same.

With the development of information technology, an automated valuation model (hereinafter referred to as "AVM") has emerged that automatically evaluates the value of real estate using computer programs. Real estate industry organizations and the media refer to the AVM used in the United States and European countries as an "automatic valuation model," "automatic valuation model," or "automatic market price calculation technique."

AVM can use regression, adaptive estimation, neural networks, expert reasoning, and artificial intelligence programs.

AVM is a mathematical computer software program that market analysts use to estimate market value based on location, market conditions, and real estate characteristics from information collected separately in advance. AI real estate valuation automatically calculates the price or index of a real estate using AI based on data such as the physical characteristics of the real estate, surrounding environment, and location along with the actual transaction price information of the real estate.

Figure 2 is a diagram showing the first change in the real estate electronic contract flow, and Figure 3 is a diagram showing the second change in the real estate electronic contract flow.

The changes in the flow of real estate electronic contracts are shown in Figures 2 and 3, with Figure 2 showing the first change and Figure 3 showing the second change in stages.

The first change that can be seen in Figure 2 is the abolition of the public electronic document repository and the simplification of the identity verification process. The concept of a public electronic document repository will disappear due to decentralization, which is the biggest feature of blockchain technology.

Accordingly, instead of the centralized management of information through a third party, which was a shortcoming of the current real estate electronic contract system, decentralization of information is achieved, which can reduce the loss of documents and records and increase security. The identity verification process can be simplified.

Currently, in Step 2, personal identification is carried out using methods such as a personal cell phone or public certificate, but there is a risk of personal information leakage, so there is a need to strengthen security for this.

Therefore, if blockchain technology, which has the characteristics of a distributed ledger, is utilized based on the information of individuals and individuals stored in a ‘block’, the authentication procedures of transaction parties can be reduced. Finally, since the property is registered through the owner’s signature and can be confirmed by all participants during the transaction, false properties and ‘information asymmetry’ can be minimized.

Figure 3 shows the second change in the real estate electronic contract flow.

The second change in the real estate electronic contract flow consists of login (step 1-1), contract writing between the seller (lessor) and buyer (lessee) (step 1-2), electronic pad signature (step 1-3), timestamp reflection (step 1-4), actual transaction report and confirmation date assignment (step 1-5).

The actual transaction report and confirmation date assignment corresponding to the above steps 1-5 are carried out by the government. The government does not intervene in the contract at all, and contracts made between individuals are reported to the government so that the government can understand the relevant contents and make more appropriate choices in terms of institutional and policy.

Since the process of reporting and granting a confirmation date by the government entity is based on blockchain, it has a decentralized nature as it is stored in the form of a distributed ledger that is stored by all parties including the seller (lessor), buyer (lessee), and the government, rather than the centralized data management that stores data in the existing Certified Electronic Document Center (hereinafter referred to as the Public Electronic Document Center).

A comparison of the current real estate electronic contract process and the first and second changes in the real estate electronic contract process flow brought about by the introduction of blockchain is shown in [Table 1]. As mentioned above, it can be confirmed that improvements are being made in stages, such as the complex procedures requiring a licensed real estate agent, and the centralized storage of related data.

Table 1 below shows a comparison of changes in the real estate electronic contract procedure flow.

The introduction of blockchain technology can bring about changes not only in the real estate electronic contract system but also in the investment field.

The characteristics of investment methods before and after the introduction of blockchain technology are as shown in [Table 2].

In the existing real estate investment, the transaction amount is relatively high. Real estate-related information is also limited and has strong information asymmetry, and real estate investment is a service for only a few. Likewise, the existing real estate investment process is complicated and has many elements that can delay it. In particular, in the case of overseas products, there are disadvantages such as the confirmation procedure and transaction period for investment products are very long, and the cash liquidation procedure is complicated.

However, the introduction of blockchain technology has the advantage of allowing investment in small amounts due to its characteristics, and it is also easy to access and view information.

Since it can be traded like stocks, investments in overseas products can also be traded through a simplified process rather than the existing complex procedures. In this way, the real estate investment sector can also be improved through the introduction of blockchain.

The following [Table 2] shows a comparison of real estate investment systems before and after the introduction of blockchain.

The model of the present invention is based on a private method, so it is composed of organizations of designated stakeholders such as the Association of Certified Real Estate Brokers, the Korean Association of Legal Scriveners (registration office), banks, and city, county, and district offices (comprehensive real estate study system). The present invention is constructed to operate by separating each channel in order to distinguish between sales and rentals in real estate transactions.

The model presented in this invention has the advantage of not requiring the concept of cryptocurrency because it is a private blockchain platform. Users and nodes within each stakeholder are managed independently, and additional identity verification and authorization procedures are required to participate in the network.

Therefore, according to the present invention, a network with high credibility can be operated, and since the identity of network participants is verified, responsibility can be clearly determined when a problem occurs.

Additionally, since only some nodes execute the chaincode, it has the advantage of being able to operate in parallel and process a large number of transactions at high speed.

In addition, general programming languages can be used in chain code. Since information is disclosed only to network participants, it is advantageous for personal data processing and can provide confidentiality. Even if you do not participate in the network, information that each organization wants to disclose, such as public notice prices, information related to the process of recruiting sellers and buyers, can be disclosed to an unspecified number of people using other platforms.

Figure 4 is a diagram of a real estate transaction model system construction according to one embodiment of the present invention.

The blockchain-based real estate transaction model system consists of Channel 1 and Channel 2. Since real estate rental and sale have different transaction procedures, they are separated into Channel 1 and Channel 2, and Channel 1 is used for sale, and Channel 2 is used for rental.

As shown in Figure 4, it is composed of four organizations: the Association of Certified Real Estate Brokers, the Korean Association of Legal Scriveners (registration office), banks, and city/county/district offices (comprehensive real estate study system).

A seller (lessor) or buyer (lessee) requests the Association of Certified Real Estate Brokers to conduct a transaction for the sale or lease of a real estate product.

After the seller (lessor) and buyer (lessee) negotiate through the Real Estate Brokers Association and agree on the contract terms, the contract is processed through the blockchain model system.

On the contract date, the seller (lessor) and buyer (lessee) connect to the Real Estate Brokers Association's guarantee (Peer) through a personal computer or mobile application.

As the contract is processed, the contract is made in one stop through the Korea Association of Certified Real Estate Brokers (registration office), bank, city/county/district office (comprehensive real estate study system) connected as nodes on the blockchain, and even post-contract processes such as real estate transaction reporting and acquisition tax payment are carried out simultaneously.

This model system uses a digital certificate authority (CA) for both the seller and the buyer to verify their identity. Therefore, it is safe from problems such as fraud and identity theft.

The component uses MSP (Membership Service Provider), which refers to a protocol for issuing and verifying certificates for each organization and a cryptographic mechanism for user authentication.

Restricts access to data provided by a specific organization so that calls can only be made by that organization.

Therefore, each organization consists of a Peer for connecting with other organizations, a CA for identity verification, an MSP for calling related data, and a DApp for storing data.

A. Channel 1 (real estate transaction) is comprised of four organizations: the Association of Certified Real Estate Brokers, the Korean Association of Legal Scriveners (registration office), banks, and city/county/district offices (comprehensive real estate study system).

The real estate transaction process consists of the transaction creation stage for the product to be sold, the stage for guaranteeing the real estate transaction, the simulation stage for writing and signing a contract and the confirmation stage through digital certificates, the block creation stage for the real estate transaction and the verification stage for the latest block of the created blocks, the stage for recording and updating the distributed ledger and reflecting the timestamp, and the stage for paying the acquisition tax and reporting the actual transaction through payment of the purchase price and completion of the registration transfer.

B. Channel 2 (real estate lease transactions) is different from Channel 1 for real estate sales transactions in that two organizations participate: the Association of Certified Real Estate Brokers and the city/county/district office (Real Estate Comprehensive Study System).

Banks can be connected as needed and the contracting phase proceeds similarly to Channel 1.

Real estate lease transactions consist of the following stages: transaction creation for channel lease products, guarantee of real estate lease transactions, simulation of writing and signing lease agreements and verification using digital certificates, block creation for real estate lease transactions and verification of the latest block of the created blocks, distributed ledger recording and update and timestamp reflection, and lease payment and address transfer as needed.

As mentioned above, Channel 1 is in charge of real estate sales transactions, and Channel 2 is in charge of real estate lease transactions. Therefore, four organizations (Certified Real Estate Brokers Association, Korean Association of Legal Scriveners, banks, city/county/district offices) necessary for real estate sales transactions participate in Channel 1.

On the other hand, only two organizations necessary for real estate rental transactions (Certified Real Estate Brokers Association and city/county/district office) participate in Channel 2.

The transaction process is entirely computerized due to the introduction of blockchain.

The transaction creation stage, transaction guarantee stage, contract simulation and certificate verification stage, block creation and latest block verification stage, and distributed ledger recording and timestamp reflection stage are performed identically on both Channel 1 and Channel 2.

Afterwards, Channel 1 includes the stages of payment of purchase price and transfer of registration, payment of acquisition tax, and reporting of actual transaction.

Conversely, Channel 2 includes the stages of rent payment and address change, and all real estate sales and rental transactions are carried out through cooperation between institutions participating in Channel 1 and Channel 2 throughout the entire process.

A. Users can execute chaincode installed on the peer network through distributed applications. Chaincode can be broadly divided into two types of functions: read (query) and write (write/update).

Chaincode is a program for implementing smart contracts. In Hyperledger Fabric, the term smart contract is used as chaincode and is executed in a dedicated container.

Chaincodes that are executed upon request of a transaction can read and write the state DB or query past recorded history, and unlike general chaincodes that access the ledger at the application level, the following chaincodes (system chaincodes) are used at the system level.

- QSCC (Query System ChainCode) used when reading data stored in a block.

- ESCC (Endorsement System ChainCode) responsible for the guarantee policy.

- VSCC (Validation System ChainCode) used when verifying blocks.

- CSCC (Configuration System ChainCode) used when setting up a channel.

- LSCC (Lifecycle System ChainCode) that performs everything from chaincode installation to application.

Figure 5 shows an example of executing a system chaincode installed on a peer.

Among them, CSCC, LSCC, and QSCC can be executed by users as CLI commands, and ESCC and VSCC are executed by the Endorsing peer, which is responsible for guaranteeing transactions, and the Committing peer, which is responsible for verifying blocks.

A. Peer: A unit representing a node within the organization of a Hyperledger Fabric blockchain, acting as an Endorser and Committer, and having a chain code, world state database (DB), and blockchain.

There are different types of peers, such as Endorser Peer, which acts as a guarantor, Committer Peer, which acts as a validator, Leader Peer, which shares blocks received from the orderer within the organization, and Anchor Peer, which acts as an information exchange between peers between organizations. The roles can overlap, and depending on performance and speed, there can be a peer that plays only one role.

B. Distributed ledger technology and ledger: The technology and ledger that allows participants to share the same information (ledger) is called distributed ledger technology, and the ledger is stored using the world state DB and Blockchain.

D. World State DB: This is a data storage that manages the current value of the result of executing a transaction. Basically, it uses Level DB, which uses a key-value storage method, but it also uses Apache's Couch DB, which uses a JSON format storage method.

A. Peer compares the transaction and version value before updating the world state DB. The content of the transaction is updated only when the transaction's version value and the world state DB's version value are the same.

Ma. A block in Hyperledger Fabric is a block in which transactions that have occurred over a certain period of time or a certain amount of space are connected in the order generated through a cryptographic hash method after going through a consensus process and stored as data called blockchain. Figure 6 is a structural diagram of a Hyperledger Fabric block.

Hyperledger Fabric's blockchain has a similar structure to other general blockchains, but the difference is that when executing chaincode, the Read/Write set history stored in the world state DB is stored in the blockchain. Therefore, the history of past records stored in the DB can be searched in the blockchain using chaincode. Blockchain is made up of several blocks connected, and if you look at the structure of Block 1, it consists of Header, Date, and Metadate fields as shown in Figure 6 and [Table 3].

B. PKI (Public Key Infrastructure) and Identity: In Hyperledger Fabric, various types of network nodes such as peers, orderers, and clients use digital certificates based on PKI (Public Key Infrastructure) to verify each other's identity.

PKI, managed by a network node called CA (Certificate Authority), is a technology that securely provides, creates, and manages digital certificates.

The components of PKI include digital certificates, public/private keys, CA, and CRL (Certificate Revocation Authority). For digital certificates, PKI uses X.50982 digital certificates, an international standard for digital certificate creation defined by the International Telecommunication Union (ITU-T81). Network nodes around the world can create digital IDs using the globally agreed X.509 international standard to prove each other's identities. It is a digital identity verification method widely used for identity verification in many fields of the Internet, not just in Hyperledger Fabric.

4. Public Key and Private Key: Integrity, which is important in communication, guarantees that data is not falsified or modified, and identity authentication and data encryption prove integrity. Integrity can be proven using public keys and private keys. Encryption with a private key can be used for identity authentication, and encryption with a public key can be used to disclose data only to relevant parties.

Ah. CA(Certificate Authority): To prevent man-in-the-middle attacks (MITM) by hackers, a CA(Certificate Authority) is used as an authentication node, and Fabric-CA plays the role of CA in Hyperledger Fabric. When user A registers his/her public key in CA and another user B needs user A's public key, he/she requests user A's public key from CA, and CA securely transfers user A's public key to user B using encryption techniques. Korea Internet & Security Agency operates CA, and performs tasks such as creating and issuing digital certificates and authenticating users when registering public keys.

CRL (Certificate Revocation Lists): CRL is a list of revoked certificates, and CA manages revoked certificates using CRL.

Tea. MSP(Membership Service Provider): MSP manages Hyperledger Fabric membership, including roles, affiliations, and permissions, such as peer, orderer, Fabric-CA, and Admin.

MSP is divided into local MSP, which is used when assigning node roles, and channel MSP, which is used when defining membership and granting authority to channel members.

Every network node in Hyperledger Fabric must have at least one local MSP defined, which defines whether a node is a client, peer, or order, and also defines the permissions for each node, such as whether the client is an Admin or a general user.

Members who participate in a channel using their own local MSP create a channel MSP, and when an organization wants to participate in a channel, channel members refer to the channel MSP to guarantee or reject it. In addition, the roles and authority of channel members are granted according to the channel MSP.

MSP consists of 9 types of certificates. Users of each organization can generate certificates through the organization's CA, and install or run chaincode on the channel to which the organization belongs through peers. In addition, MSPs can be created for each organization, and MSPs and CAs can be configured redundantly within the organization.

Tea. Orderer: The orderer uses a distributed messaging system (Kafka, Raft, etc.) to sort all transactions in the Hyperledger Fabric network and then generates the latest block. The process is that the endorsing peer executes the chaincode, determines whether the transaction is endorsed, and sends it to the orderer. The orderer then creates a block that simply sorts the blocks in the order they are received. The latest block created in this way is then sent to the committer peer. The committer peer of each organization that receives it verifies the block, and if there are no problems, it adds and updates the latest block to the blockchain and world state DB of its local storage.

TA. Organization: An organization is a unit in which multiple institutions or companies with similar interests participate through consultation in the Hyperledger Fabric network. Each peer that performs transaction guarantee and block verification and the orderer that creates the latest block belong to the organization.

A. Channel: There can be multiple independent channels within a single network, and each channel has an identical distributed ledger (Blockchain and World state DB) that only the members who have participated in the channel can access. Part of the organization can also participate in and configure the channel, and since communication between peers is only possible through the channel, data confidentiality is also provided.

The model system uses Hyperledger Fabric, a blockchain that supports smart contracts and can simultaneously execute many tasks across the country without using cryptocurrencies such as Bitcoin or Ethereum.

Ethereum requires payment of gas as a processing fee for each transaction, and if the fee is not paid, the work progress is stopped, but Hyperledger Fabric does not require fees because there is no mining, and only authorized participants can participate and each task can be performed differently, so it is economical and the responsibility issue can be clearly resolved. For this reason, the Hyperledger Fabric method is used in the present invention.

Hyperledger Fabric automatically saves the transaction process and results in the blockchain and database (World state DB) by operating Chaincode (a function of smart contracts), so there is no problem of default, and when there is a problem of canceling (terminating) or withdrawing the transaction due to invalidity or cancellation after the transaction, Hyperledger Fabric can flexibly solve the problem after the transaction because the blockchain that records the transaction process cannot be changed due to the irreversible nature, but the database that stores the results can be changed. However, Ethereum cannot be changed due to the irreversible nature of the blockchain, and it is difficult although there are irregular methods such as hard forks.

When a seller or buyer requests a sale or lease to a brokerage corporation or a local brokerage of a brokerage association and agrees to the contract terms after mutual consultation, the seller and buyer or the lessor and lessee are connected to the brokerage peer through the PC or mobile app application DApp on the contract date, and the contract is processed by the blockchain model system. In the case of a sale, when the execution conditions are met, the registration is concluded in one-stop, and the payment of acquisition and registration tax and the actual real estate transaction report are processed at the same time, as shown in Figure 4.

<Example 1>

The blockchain-based real estate transaction model system consists of two channels.

Channel 1 is for buying and selling, and Channel 2 is for leasing.

Channel 1 model is a consortium of four organizations (Organizations) for real estate transactions: a brokerage firm (association), a bank, a law association (registry office), and a city/county/district office (comprehensive real estate study system), and is made up of Channel 1 for real estate transactions. The real estate transaction processing process is as follows.

(1) Transaction creation stage for real estate transactions

Among the organizations of the real estate transaction model system, the real estate brokerage corporation or brokerage association organization becomes a guarantee (peer) node for each real estate brokerage office that receives a request from a customer within the brokerage corporation or brokerage association in each region of the country.

Sellers and buyers, with the help of their chosen brokers, request sales and purchases to the brokerage application (DApp) installed by the real estate brokerage corporation or association. The requested application (DApp) uses the international ITU-T standard X.509 through the CA (Certificate Authority) to create digital certificates of the seller and buyer, create a transaction of the transaction details, and send it to the guarantor (peer) of the brokerage corporation (association).

(2) Guarantee stage of real estate transaction

Each regional real estate brokerage peer belonging to the brokerage corporation (association) becomes an endorsing peer and checks whether the seller and buyer MSP are valid, whether they have the authority to update the distributed ledger, and whether there was an identical transaction version to prevent double spending.

The contract (Read/Write set) generated as the simulation result value of the contract content is checked to determine whether the transaction is guaranteed. If there is no problem through this process, the guarantee peer broker sends the Read/Write set of the contract and the digital certificate signed by the broker's own identity to the seller and buyer DApps.

For overall sharpening and background clarity of images such as contracts (Read/Write set), ID cards, photos, fingerprints, etc., it is recommended to use the following filters as an example.

<filter>

ASHARP(0.44,8,0,false)

FilterRangeEX(0,3884,3903,37380,"SORA_SA(L=4.2,F=12,W=1,HQBF=false,SS=1.01)")

→ L. If it is too large, steps and halos will appear on the line, and the line will be misaligned (stable value 0~3, 5 is possible depending on the source).

→ Blocking is applied to the F. L value. When it is 0, the L effect is maximum, and as it goes up from 1 to 16, the reduction in the L effect becomes weaker. In other words, the closer it is to 16, the more the L effect is maximized. The overall texture sharpening increases.

Be careful because if you set it to 0 or 14 or higher to maximize sharpening, it can cause side effects such as significant residue. If you set it to 8 or lower, blur occurs. It is recommended to preview with the ASHARP (AVS) filter linked to the buzzer (recommended value 8~12 / 14 is possible depending on the source). → SS is the ss value of the resolution x. The larger the SS value, the lower the strength of the corresponding filter. It increases when SS is small (recommended value 1.01).

(3) Sales contract simulation and digital certificate verification steps

The seller and buyer receive a contract and a contract (Read/Write set) created as a result of the simulation from an endorsing peer (an intermediary) through a decentralized application (DApp), review the contents, check whether the intermediary has a digital certificate, and with the help of each intermediary, the seller and buyer electronically sign the contract and then send it to the orderer to create a block.

(4) Block creation stage for real estate transaction

The orderer, who receives a transaction containing a Read/Write set of the real estate transaction contract, digital certificates of the transaction parties, and digital certificates of the broker who is the guarantor peer, creates the latest block.

The orderer does not look at the contents of the transaction, but simply sorts the transactions to be included in the block in order by checking the timestamp field, etc., to create a block of real estate transactions. The orderer then sends the latest block created in this way to peers such as brokerage firms (associations), law associations (registry offices), banks, and city/county/district offices for verification.

(5) Latest block verification stage for real estate transaction

The committer peer of each organization that receives the latest block from the orderer executes VSCC (Validation System ChainCode) to check whether the digital certificate of the endorsing peer for each transaction included in the latest block of the real estate transaction complies with the guarantee regulations, and also checks the contents of the contract (Read/Write set result value) for each transaction included in the latest block.

Checks whether the block version of the World State DB and the current blockchain version match when the key value included in the Read set is used.

After verifying this, if it is judged as invalid, the contents of the invalid transaction will not be reflected in the latest block.

After completing this check, the committing peer marks each transaction with a valid or invalid tag, depending on whether the transaction has been verified.

(6) Distributed Ledger Recording and Update Step

When the latest block of a real estate transaction passes the verification stage, the local real estate brokerage firm (association), bank, law association (registry office), and city/county/district office peers in the area add the latest block of the real estate transaction to the blockchain stored in their local storage and save the contract process. Because of the irreversible nature, the blockchain cannot be changed, but the result of the contract is recorded and saved in the DB, so it can be modified and changed. During the verification process, only the contents of transactions with valid tags are updated as a result in the database (World State DB).

Since the blockchain records all processes, transaction contents of invalid tags are also stored in the blockchain, but only the results of valid transactions are stored in the DB.

(7) Payment of purchase price and completion of registration transfer stage

Finally, when the real estate transaction is finally updated in the World State DB of each organization of the brokerage firm (association), the law association (registry office), the bank, and the city/county/district office, the seller's ownership is transferred to the buyer and it can be confirmed that the purchase price has been deposited from the buyer's bank account to the seller's bank account and that the actual transaction has been reported to the city/county/district office.

(8) When a real estate transaction is modified or cancelled

When it is necessary to modify some of the contents of a completed contract or a reason for termination occurs, this model system based on the Hyperledger Fabric method cannot change the blockchain that records only the contract process due to its irreversible nature, but the World state DB that records and stores the results can be changed, so unlike other blockchains, the results such as modification of the contract contents or termination of the contract can be changed.

The relevant broker (Endorsing Peer) belonging to the brokerage corporation (association) writes a termination or modification contract, and then has the seller and buyer sign it through DApp and sends it to the orderer to create a block for the termination or modification of the real estate transaction. The orderer then sends the latest block created in this way to the peers of the brokerage corporation (association), the law association (registry office), the bank, and the city/county/district office for verification.

The committer peer of each organization that receives the latest block of contract termination or modification executes VSCC (Validation System ChainCode) to check whether the digital certificate of the endorsing peer for each transaction included in the latest block of real estate transactions complies with the guarantee regulations, and also checks the contents of the termination or modification contract (Read/Write set result value) for each transaction included in the latest block.

When the latest block of real estate transaction release or modification passes the verification stage, the local real estate brokerage (association), bank, law association (registry office), and city/county/district office's committer peers add the release or modification contract process to the blockchain stored in their local storage and save the latest block of the real estate transaction release or modification contract, and only the contents of the release or modification contract transaction with a valid tag in the verification process update the release or modification contract result in the database (World State DB).

<Example 2>

The blockchain-based real estate transaction model system consists of two channels.

Channel 1 is for buying and selling, and Channel 2 is for leasing.

The blockchain-based real estate transaction model system for rental is composed of a consortium of two organizations: a brokerage firm (association) and a city/county/district office, and when necessary, the bank connects to the outside world through the Couch DB.

It is executed as Channel 2 for rental purposes. The rental transaction processing process is as follows.

(1) Real estate lease transaction creation step

Among the organizations of the real estate transaction system, the real estate brokerage corporation or brokerage association organization has real estate brokerage offices within each region of the country as peer nodes.

The landlord and tenant request a lease or rental to the brokerage application (DApp) installed by the real estate brokerage corporation or association with the help of the exclusive real estate brokerage of their choice, and the requested application (DApp) creates a digital certificate of the landlord and tenant using the international ITU-T standard X.509 through the CA (Certificate Authority), creates a transaction of the lease transaction details, and sends it to the guarantor peer of the brokerage corporation (association).

(2) Real estate transaction guarantee stage

The real estate peers of each region belonging to the brokerage corporation (association) become endorsing peers and check whether the seller and buyer MSPs are valid, whether they have the authority to update the distributed ledger, and whether there was an identical transaction to prevent double spending. In addition, the contract draft (Read/Write set) generated as the simulation result value of the contract content is checked to determine whether the transaction is guaranteed. If there is no problem through this process, the endorsing peer broker transmits the contract Read/Write set and the digital certificate signed with the broker's own Identity to the landlord and tenant application DApp. For the overall sharpening and background of the image such as the contract draft (Read/Write set), ID card, photo, fingerprint, etc., it is desirable to use the following filter as an example.

<filter>

ASHARP(0.44,8,0,false)

FilterRangeEX(0,3884,3903,37380,"SORA_SA(L=4.2,F=12,W=1,HQBF=false,SS=1.01)")

→ L. If it is too large, steps and halos will appear on the line, and the line will be misaligned (stable value 0~3, 5 is possible depending on the source).

→ Blocking is applied to the F. L value. When it is 0, the L effect is maximum, and as it goes up from 1 to 16, the reduction in the L effect becomes weaker. In other words, the closer it is to 16, the more the L effect is maximized. The overall texture sharpening increases.

If you set it to 0 or 14 or higher to maximize sharpening, be careful as it can cause significant side effects such as residue. If you set it to 8 or lower, blurring occurs. It is recommended to preview with the ASHARP (AVS) filter linked to the buzzer (recommended value: 8~12 / 14 is possible depending on the source).

→ SS is the ss value of resolution x. The larger the SS value, the lower the strength of the filter. The smaller the SS, the greater it becomes (recommended value: 1.01).

(3) Lease contract simulation and digital certificate verification steps

The decentralized applications (DApps) of the landlord and tenant receive the contract (Read/Write set) created as a result of the simulation from the endorsing peer, the broker, and review the contents. They also check for the presence of the broker's digital certificate to ensure that there are no abnormalities. After receiving the electronic signatures of the landlord and tenant with the help of each broker, they send it to the orderer to create a block.

(4) Block creation step for real estate lease transactions

The orderer, which receives a transaction containing the Read/Write set of the real estate lease transaction contract, the digital certificates of the transaction parties, and the digital certificates of the brokerage firm as the guarantor peer, creates the latest block. At this time, the orderer does not look at the contents of the transaction, but simply sorts the transactions to be included in the block in order by checking the timestamp field, etc., to create a block of real estate transactions. The orderer sends the latest block created in this way to the brokerage firm (association) and the committer peer of the old city/county for verification.

(5) Latest block verification stage for real estate transactions

The committing peer of each organization that receives the latest block from the Orderer executes VSCC (Validation System ChainCode) to check whether the digital certificate of the Endorsing Peer for each transaction included in the latest block of the real estate transaction complies with the guarantee regulations, and also checks the contents of the lease agreement (Read/Write set result value) for each transaction included in the latest block.

Check if the block version of the World State DB and the current blockchain version match when the key value included in the Read set is used. After checking this, if it is judged as invalid, the contents of the invalid transaction will not be reflected in the latest block.

After completing this check, the committing peer marks each transaction with a valid or invalid tag, depending on whether the transaction has been verified.

(6) Recording and updating steps in the distributed ledger

When the latest block of a real estate transaction passes the verification stage, the local real estate brokerage (association) and city/county/district office peers in the area add and store the latest block of the real estate transaction to the blockchain stored in their local storage, and only the contents of transactions with valid tags are updated in the database (World State DB) during the verification process. The transaction contents of invalid tags are stored in the blockchain, but not in the DB.

(7) Lease payment and key transfer stage

Finally, when the real estate transaction is finally updated in the World State DB of the brokerage corporation (association) and each organization of the city/county/district office, the city/county/district office's confirmation date is recorded in the lease agreement, and when the lease payment is confirmed to have been deposited in an externally linked bank, the electronic key of the leased property is automatically transferred from the lessor to the lessee.

The lessor cannot use the key during the contract period, and the lessee can freely use the leased property during the contract period as long as there is no violation of the terms of the contract.

(8) When a real estate lease transaction is modified or terminated

When it is necessary to modify some of the contents of a completed contract or a reason for termination arises, this model system based on the Hyperledger Fabric method cannot change the blockchain that records only the contract process due to its irreversible nature, but the World state DB that records and stores the results can be changed, so unlike other blockchains, the results such as modification of the contract contents or termination of the contract can be changed.

The relevant broker (Endorsing Peer) belonging to the brokerage corporation (association) writes a termination or modification contract, and then has the seller and buyer sign it through DApp and sends it to the orderer to create a real estate transaction termination or modification block. The orderer then sends the latest block created in this way to the brokerage corporation (association) and city/county/district office peers for verification.

The committer peer of each organization that receives the latest block of contract termination or modification executes VSCC (Validation System ChainCode) to check whether the digital certificate of the endorsing peer for each transaction included in the latest block of real estate transactions complies with the guarantee regulations, and also checks the contents of the termination or modification contract (Read/Write set result value) for each transaction included in the latest block.

When the latest block of real estate lease termination or modification passes the verification stage, the local real estate brokerage (association) or city/county/district office committer peer adds the termination or modification contract process to the blockchain stored in their local storage and stores the latest block of the real estate transaction termination or modification contract, and updates the termination or modification contract result in the database (World State DB) only for the contents of the termination or modification contract transaction with a valid tag during the verification process.

When a lease agreement is terminated, once the real estate transaction in the DB is finally updated with the termination agreement, the date of confirmation by the city/county/district office on the lease agreement is canceled, the lease payment is refunded to the lessee from an external bank, and the electronic key of the leased property is automatically transferred from the lessee to the lessor, so the lessee cannot use it.

<Example 3>

Figure 7 shows a method for installing software and tools. Hereinafter, a method for implementing the system of the present invention will be described.

The software required for the operation of the model system consists of ① VirtualBox and Vagrant installation software: VirtualBox and Vagrant 2.0, ② Ubuntu Linux guest OS installation: Ubuntu 16.04.3 LTS, ③ Tools and software to be installed on Ubuntu: Docker, Python 2.7, GO, Node.js.

(1) Install VirtualBox and Vagrant: Go to VirtualBox (Oracle VM VirtualBox) and download and install. VirtualBox is an x86 virtualization software developed by Oracle that can use various guest OSs as virtual machines.

Vagrant can be downloaded and installed from the official website, and is a tool that makes it easier to handle virtualization software and configuration management tools such as VirtualBox.

Install Ubuntu: Download and install Ubuntu 16.04.3, a Linux guest OS, from the official Ubuntu website.

(2) Docker Community Edition (CE) and Docker Compose Installation: Docker is an open source virtualization platform based on containers, and is executed with Docker software and the Docker Compose tool. Various components of this model system are provided in the form of containers assuming the use of Docker. When using Docker, the ‘image’ includes files and settings necessary for container execution. A ‘container’ refers to a single process as a running program, a ‘volume’ is a directory that can be mounted and used in a container, and ‘Docker-compose’ is an automation tool that manages the execution order and dependencies between containers.

(3) Node.js installation: Node.js is used in the Hyperledger Fabric SDK.

Installing the GO language: When developing a smart contract (Chaincode), use the GO language. After checking the URL on the official GO homepage, install it using wget.

Install Python 2.7.

(4) Files to run for Hyperledger Fabric installation:

Figure 8 shows the files to be executed.

#generate.sh

- Create a directory of password information for components included in the network

- Generate genesis file and channel, anchor peer transaction required to start the network

#start.sh

Running Fabric Containers: CA, Orderer, Peer, couchdb

Create channel, join channel

#stop.sh

teardown.sh

Terminate running containers, terminate network between containers, delete newly created chaincode image

(5) Model system implementation

(54.1) Installing Docker using the Linux package manager (apt-get)

- sudo apt install docker.io

- sudo apt install docker-compose

- sudo apt install software-properties-common

- sudo usermod-aG docker $USER #Give permission to the currently logged in user

- rebooting

- After rebooting, run docker version

Figure 9 shows an example of Docker program installation.

Installing Curl, Node.js, and Go languages

(1) Install Curl

- sudo apt-get install curl

(2) Node.js installation

- sudo apt-get update

- sudo apt-get install build-es ential libssl-dev

- curl-sL ht ps:/raw.githubusercontent.com/reationix/nvm/v0.31.0/

install.sh -o install_nvm.sh

- bash install _nvm.sh

- source ~/.profile

- nvm install v8.11.1

(3) Go language installation

- curl -O

https://storage.googleapis.com/golang/go1.11.2.linux-amd64.tar.gz

- tar -xvf go1.11.2.linux-amd64.tar.gz

- sudo mv go /usr/local

- sudo ln -s /usr/local/go/bin/go /usr/local/bin/go

- gedit ~/.profile

export GOPATH=$HOME/go

export PATH=$PATH:/usr/local/go/bin:$GOPATH/bin

- source ~/.profile

(4) Hyperledger fabric installation

Hyperledger Fabric consists of a fabric network, chaincode (smart contract), and application.

Fabric images can be checked with the executable fabric program docker images, and containers can be checked with the running fabric components docker ps.

(5) Installing Docker image

<virtual box image including run script>

- Ubuntu 16.04 LTS

- cURL, node.js, python, go-language, docker, docker-compose

- Hyperledger v1.4

- Image Name: ubuntu1604_fabric.ova

- ID: bstudent Passwd:1234

(6) Install client and start network: /startFabric.sh

#chaincode development

- Chaincode interface implementation

- Init, Invoke

- Other configuration functions

#Configure chaincode, name, policy, etc. in the script when running the network.

or connect to the CLI of a running network and deploy.

#Call chaincode within the network using CLI commands or Web Interface.

The development and execution of the chain code, the electronic contract for real estate purchase and sale, the login screen for the electronic contract system for real estate transactions, the identity verification of the parties to the transaction and the identity verification of the certified real estate agent, and the verification of identification and fingerprint biometric registration information are shown in Figures 10 to 14.

Figure 10 shows the chaincode development and execution diagram.

According to Figure 10, the chaincode development stage includes developing a chaincode interface, etc., and the stage for running the network includes configuring the chaincode, name, policy, etc. or accessing the CLI of the running network to deploy it. The final stage is calling the chaincode within the network with a CLI command or web interface.

Figure 11 shows an electronic real estate lease contract.

Figure 11 is an example of an electronic contract for a real estate lease.

It features the application of timestamp (TSA) technology and certified electronic signature technology.

Figure 12 shows the login screen for the real estate transaction electronic contract system.

Figure 12. Login to the real estate transaction electronic contract system includes a public certificate login and a mobile phone authentication login.

Figure 13 is a diagram showing the identity verification of the parties to a transaction and the identity verification of a certified broker. Figure 13 is a captured photo of a computer screen, and can be used to verify the information of the parties to a transaction and the identity verification of a certified broker.

Figure 14 shows the verification of identification and fingerprint biometric registration information.

Figure 14 is a photo captured from a computer screen showing the attachment of an ID photo (front) and registration of fingerprint biometric information (optional).

Although the present invention has been described with reference to the accompanying drawings and with reference to preferred embodiments thereof, it will be apparent to those skilled in the art that many obvious modifications may be made therein without departing from the scope of the technical idea of the present invention. Accordingly, the present invention should be construed in accordance with the claims which are written to include such many modifications.

The present invention relates to a real estate transaction system using blockchain technology and a method thereof, which reduces the loss of documents and records and enhances security by decentralizing information rather than the centralized management of information through a third party, which was a shortcoming of the current real estate electronic contract system, and can prevent forgery and alteration of contracts by using blockchain technology, and can reduce transaction fees by allowing sellers and buyers to conduct transactions directly online during real estate transactions and eliminating the need for brokers. Therefore, it has industrial applicability.

Claims (8)

delete delete delete delete delete It consists of four systems: the Certified Real Estate Brokerage Association System, the Korean Association of Legal Scriveners (Registration Office) System, the Bank System, and the City, County, and District Office Real Estate Integrated System.
In order to limit access to data provided by a specific system among the above four systems so that it can only be called by the relevant organization, each system configures a Peer for connection with other systems, a CA for identity verification, an MSP for calling related data, and a DApp for data storage; in a real estate transaction method that uses Hyperledger Fabric, which does not use cryptocurrencies such as Bitcoin or Ethereum among blockchains that enable smart contracts,
A step in which the seller (lessor) and buyer (lessee) connect to the peer of the above-mentioned real estate agent association system through a personal PC or mobile application;
A step in which both the seller (lessor) and buyer (lessee) use a digital certificate (Certificate Authority, CA) to verify their identity;
Transaction creation step for real estate transaction products;
Steps to guarantee real estate transaction sales;
Verification step through digital certificate for writing and signing the sales contract (Read/Write set);
Block creation step for the above real estate transaction;
The latest block verification step of the generated blocks;
Distributed ledger recording and update stage, purchase price payment and registration transfer completion stage, acquisition tax payment and actual transaction reporting stage;
Including, but not limited to,
In the verification step using the above digital certificate, a filter is used to improve the image clarity of the contract (Read/Write set), and the filter is:
FilterRangeEX(0,3884,3903,37380,"SORA_SA(L=4.2,F=12,W= 1,HQBF=false,SS=1.01)")
A real estate transaction method using blockchain, characterized by:
delete In claim 6, a method for constructing four systems, namely, the Certified Real Estate Brokerage Association System, the Korean Association of Legal Scriveners (Registration Office) System, the Bank System, and the City, County, and District Office Real Estate Integrated System
Steps to install Docker using the Linux package manager (apt-get);
Steps to install Curl, Node.js, and Go languages;
A real estate transaction method using blockchain, characterized by including a step of installing Hyperledger fabric; a step of installing a Docker image; and a step of installing a client.

Images