{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"How to prevent double-spending attacks in blockchain?","a":"Longest Chain Principle: Nodes in the blockchain network choose the main chain based on the longest chain principle. Attackers  need to compromise most of the nodes to alter transaction records, which makes double-spending attacks less feasible."}]}],"pr":"b86dba47f98d83f9dab6fa4c5fb7e5b7a26bfc7fc4dd26dabc1c281668cfa36e"}