{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"How to prevent the double-spending problem in blockchain?","a":"Blockchain adopts a  decentralized distributed accounting method, without a centralized institution managing transactions and accounts, so consensus needs to be reached in the network."}]}],"pr":"a0569620b4a40b1273ae2dd4807e8faba2a99d72468c46e705e13f53cce7b449"}