This technology relates to an information processing device and an information processing method capable of detecting that at least one of data and a parameter of a command is falsified. A command reception unit of an IC card receives a read command from a reader/writer through an antenna. A MAC calculation unit calculates a MAC based on a read address included in a parameter of the read command and read data to be transmitted to the reader/writer. A response transmission unit transmits the read data and the MAC to the reader/writer through the antenna. This technology is applicable to the IC card, for example.