{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"Why do blocks in a blockchain need a consensus mechanism?","a":"Preventing double-spending attacks: The consensus mechanism ensures the  consistency of transaction order, avoiding multiple confirmations of the same transaction, thereby preventing double-spending attacks."}]}],"pr":"edafba22b462a4fe449c9e495130657a29fc4fa545607d46e95942759a62a43d"}