{"p":"can-20","op":"mint","tick":"can","amt":"1000","rows":[{"df":"qa","content":[{"q":"How do you ensure the validity of transactions and expiration time in a blockchain?","a":"Encryption algorithm: Blockchain uses  encryption technology to encrypt transaction information, allowing only users who possess the decryption key to access and process the information."}]}],"pr":"a114a3a5061b90a87a28d5e8df81280673fb1e49e241eaaf7d5d85c492138fb4"}