US Patent 8006099 Security management method, program, and information device

In a state in which a fingerprint authentication mode is set, a fingerprint authentication unit authenticates a fingerprint input in accordance with an input instruction, performs unlocking if the authentication is successful, instructs another fingerprint input if the authentication fails, and determines unauthorized use and switches the mode to a PIN code authentication mode if the fingerprint authentication sequentially fails for a predetermined number of times. In a state of the PIN code authentication mode, a PIN code authentication unit authenticates a PIN code input in accordance with an input instruction, performs unlocking if the authentication is successful, instructs another PIN code input if the authentication fails, and determines unauthorized use and turns off the power source if the authentication sequentially fails for a predetermined number of times. Furthermore, when the power source is turned on again after the PIN code authentication unit has turned off the power source, the fingerprint authentication unit sets a state in which the fingerprint authentication mode is set, and keeps the fingerprint authentication mode even if the fingerprint authentication fails sequentially for a predetermined number of times.