RFID tag device and method for authenticating the same

The RFID tag device and the authentication method is disclosed. RFID tag device of the present invention includes a device, the device recognition unit, RF processing section and a control unit. Device outputs a second signal in response to the first signal input. The device recognizing unit outputting a first signal by a control signal to the device, and to receive a second signal and outputs the N-bit (N is an integer greater than 1) of data. RF processor receiving an RF signal, and extracts a command from the RF signal. The control unit outputs a control signal to the device recognition unit according to the extracted command, corresponding to the extracted command to process receiving the N bit data.