Issuance of prepaid card with membership card function; issuance of electronic payment cards in connection with bonus and reward schemes; crowdfunding; exchanging cyber money; providing purchase protection insurance for goods purchased using non-fungible tokens [NFTs]; issuance of cyber money for payment of online content fees on the internet; brokerage services for transactions of digital certificates in the form of non-fungible tokens (NFTs) representing ownership and usage rights of blockchain-based digital content; on-line financial brokerage services relating to purchase points for payment on the internet; on-line real-time currency trading; e-wallet payment services; electronic payment services; issuance of electronic gift certificates which may then be redeemed for goods or services; buyer's credit underwriting; providing information relating to art appraisal