[002] In line with the development of network technologies such as an IT technology and the Internet, electronic commerce (e-commerce) services have been spreading. E-commerce may generally be classified as business to business (B2B), business to customer (B2C), customer to customer (C2C), and business to government (B2G) and include a series of actions such as purchasing, delivery, marketing, and provision of services, and the like, as well as movement of money through a wiredly or wirelessly connected network system.
[003] With regard to such e-commerce, a payment method using virtual electronic money has recently become an object of attention. A typical example of electronic money is bit coin. Bit coin is electronic money created by Satoshi Nakamoto in 2009. Transactions of bit coin occur by a distributed database on the basis of a peer-to-peer (P2P) network and bit coin is traded on the basis of public key cryptography. The bit coin is stored in the form of a wallet file. Each wallet is given a public address and a private key corresponding to a password, and articles may be purchased on the basis of the public address. Transactional information of electronic money is blocked in a P2P network and verified, and all the generated blocks form block chains through connection relationship with other blocks during a process in which the blocks are stored through verification.
[004]
[005] FIG. 1 is a diagram illustrating a structure in which electronic money is traded through a block chain. A process of trading electronic money between users will be described with reference to FIG. 1. Each user generates a public key and a private key. Data encrypted using a public key may be decrypted using only a corresponding private key, and conversely, data encrypted using a private key may be decrypted using only a corresponding public key. In order for user B to deliver the electronic money to user C, the user B hashes transaction details (transaction information) of the electronic money using the public key of the user C. Once hashing is done, the past transaction details cannot be restored. After the user B hashes the transaction details using the public key of the user C, the user B signs using his/her private key. The signed result is delivered to the user C. Since the data received by the user C is transaction details encrypted using the public key of the user C, the user C may decrypt the data using his/her private key. By decrypting the encrypted transaction details, transaction of the electronic money is completed.
[006] In the conventional system for transaction using the electronic money forming the block chain, transactions may beperformed only when a seller who wants to sell electronic money and a purchaser who wants to purchase electronic money open an electronic wallet. To this end, a user who wants to trade electronic money accesses an exchange server to open an electronic wallet and transfers real money to the exchange to purchase electronic money. The exchange checks the transfer of the real money and subsequently transfers electronic money to an electronic wallet of the user who has purchased electronic money. When a user wants to sell electronic money, he or she accesses the exchange server and subsequently transfers electronic money, and thereafter, a buyer purchases the transferred electronic money, whereby the real money is moved between the user and the purchaser. That is, the conventional electronic money exchange does not provide a direct exchange between electronic money and real money to the user, but serve to mediate transaction of electronic money between the seller and the purchaser. Meanwhile, in the case of bit coin, which is a representative example of electronic money, one block is generated every about ten minutes. Therefore, since it takes about 10 minutes for a next transaction to be verified after a previous transaction, the use of bit coin as electronic money in a short-time electronic commerce may cause a problem of hindering promptness of transaction.
[007] Examples of transaction using bit coin may include Korean Patent Laid-Open No. 10-2016-0009301 (Payment agency service of private key-based electronic money and method thereof), Korean Patent Registration No. 10-1628007 (Transaction system of digital virtual money having block chain between parties concerned, Korean Patent Registration No. 10-1628009 (Transaction system of digital virtual money having block chain between parties concerned).
[008] However, the conventional technology does not provide direct exchange of electronic money and real money between exchanges and users, and there is a problem that it is difficult to perform an immediate transaction due to time (about 10 minutes) required for verifying a block. In addition, electronic money such as bit coin supports transparency that all transaction details included in each block may be referred to or checked. Therefore, as illustrated in FIG. 2, a third party may check all transaction details included in each block. In addition, since all the source codes of software including the principle of running a transaction system are open, all transactions may be observed transparently. However, it may be difficult to provide security for transaction details to a company or a store who wants not to open transaction details through electronic money to the outside, among users participating in transactions using electronic money.