{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"How to prevent the double-spending problem in blockchain?","a":"Transactions need to go through a certain number of confirmations before they  are considered valid. In the Bitcoin system, a transaction requires 6 confirmations to be considered final."}]}],"pr":"a03c9867aa3bfb4c4e7051fccb8b25d48c0e78214b35aef547f88642d43dddcf"}