{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"How is the double-spending attack implemented in blockchain?","a":"Preparation phase: The attacker needs to have a certain level of knowledge about blockchain technology, understanding the working principle and consensus mechanism of the blockchain network."}]}],"pr":"f653a9d683a25a37693c3773d2efbb932c4969bf2f8a00c2b5fdc4e906c8f43c"}