A method of issuing an electronic voucher by an issuer is provided. The method includes steps of: (a) creating and registering a transaction including a voucher data, a public key and a signature value of the issuer, with a private blockchain database, providing the issuer with a PrivTxid locating the transaction in the private blockchain database, and updating and registering value information including a balance of the voucher data with a BDB; and (b) acquiring and registering a representative hash value calculated using a specific hash value, which is a hash value of the voucher data, the public key, and the signature value, and its corresponding hash values which include a hash value of a delta_n including all balances of all vouchers, identifiable by all PrivTxids locating their transactions, with a public blockchain database, and acquiring a Txid locating the representative hash value in the public blockchain database.