Method and system for inquiring personal data necessary for target marketing and rewarding for the inquiring

A personal data reading and rewarding method comprising:

• providing, by a user, personal data of the user to a server;
• encrypting, by the server, the personal data and storing the encrypted personal data in at least one node on a blockchain;
• storing a private key and a decentralized identity (DID)-type unique number issued from the server for DID-type identity authentication in a user's terminal and storing a DID document in which a public key corresponding to the private key, issuing information, and identification information about a node storing the personal data are recorded on the blockchain;
• delivering, by a company member, a request document containing a request for the personal data to the user;
• confirming, by the user, the request document;
• allowing accessing the personal data by the user signing the request document with the private key and transmitting a signed document to the server;
• obtaining, by the server, the personal data by accessing the node based on the identification information about the node recorded in the DID document when integrity of the signature is verified through the blockchain;
• and
• providing, by the server, the personal data to the company member.