IC card and method of checking personal identification number of the same

摘要

An IC card according to the present invention includes data processing means for processing data; a memory for storing a personal identification number; a power-supply terminal to which a power-supply voltage is applied by an external unit; an input/output terminal for inputting data from and outputting data to the external unit; a voltage detecting circuit for detecting the power-supply voltage applied to the power-supply terminal from the external unit; and a check-processing circuit for verifying a personal identification number input from the external unit by comparison with a personal identification number stored in the memory in response to a command for verifying applied to the input/output terminal when the power-supply voltage detected in the voltage detecting circuit is at least equal to a threshold voltage and constantly responding that an identification error has occurred when the power-supply voltage detected in the voltage detecting circuit is lower than the threshold voltage.