Method for approving use of card by using blockchain-based token id and server using method

An intermediary server for approving use of a card using a token ID, comprising:

• a communication part for, on condition that a registration process of registering, in a blockchain database, a card token ID corresponding to card information on a user, user identification information to be used for identifying the user, a push token ID corresponding to an app installed on a user device of the user, and a public key of the user has been performed and on condition that a blockchain transaction ID corresponding to the registration process is being managed, acquiring payment request information, which includes the user identification information and order data corresponding to the use of the card of the user, from a service-providing device;
• and
• a processor configured to execute instructions to perform or support another device to perform:
• (I) a process of obtaining the push token ID registered in the blockchain database by using the blockchain transaction ID corresponding to the user identification information included in the payment request information and a process of transmitting or supporting another device to transmit an authentication request for the order data to the user device corresponding to the obtained push token ID;
• (II) if a user signature value created by signing the order data with a private key of the user is obtained from the user device in response to the authentication request for the order data, a process of confirming whether the user signature value is valid by using the public key of the user registered in the blockchain database, and if the user signature value is determined as valid, a process of registering or supporting another device to register the order data in the blockchain database;
• and (III) (i) a process of transmitting or supporting another device to transmit approval request information, including the order data and the card token ID corresponding to the user identification information, to at least one financial server, a process of instructing the financial server to verify the order data included in the approval request information by referring to the order data registered in the blockchain database, wherein the order data corresponds to the card token ID included in the approval request information, and a process of instructing the financial server to transmit approval result information corresponding to a verification result to the intermediary server and (ii) if the approval result information is obtained from the financial server, a process of registering or supporting another device to register the approval result information in the blockchain database and a process of transmitting or supporting another device to transmit the approval result information to at least one of the service-providing device and the user device.