{"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":"e912fb177bb51ef30df031c8b3bb48f5968040bd963218ef9b7d389ffa43fcba"}