Provided in the present invention is a method comprising steps of: (a) confirming validity of a currency issuing transaction and a currency issuer when the currency issuing transaction including (i) a specific unique nonce, (ii) a receiver of the currency, (iii) issued amount of the currency, (iv) a public key of the currency issuer, and (v) a signature value of the currency issuer signing the (i), (ii), (iii), and (iv) with a private key of the currency issuer is obtained, and if valid, registering the currency issuing transaction on a private BCDB, wherein registering includes updating a balance database by referencing amount of change in balance due to the issued amount of the currency, included in the currency issuing transaction; and (b) registering, on the public BCDB, a specific representative hash value generated by calculating an associated hash value matching the specific hash value, when a specific condition is satisfied.