Patent ID: 8302209

Claim:
A data processing device comprising: a data storage section that stores data; an authentication information storage section that stores first authentication information registered by a user; an input section that allows the user to input second authentication information; a first judgment section that permits reading of the data stored in the data storage section when the first authentication information matches the second authentication information, and does not permit reading of the data stored in the data storage section when the first authentication information does not match the second authentication information by acquiring the first authentication information from the authentication information storage section when the second authentication information is input by the input section and by comparing the first authentication information with the second authentication information; a slot into which an external storage device can be inserted; a writing admission section that permits writing of the data stored in the external storage device into the data storage section without input of the any authentication information when the external storage device is inserted into the slot; a registration section that registers at least one external storage device as a storage device from which data is permitted to be read when the at least one external storage device is inserted into the slot in the data processing device; a second judgment section that permits reading of data stored in the data storage section when the external storage device is a registered external storage device and does not permit reading of the data stored in the data storage section when the external storage device is an unregistered external storage device by judging whether or not the external storage device is an external storage device registered by the registration section when the external storage device is inserted into the slot; and wherein the registration section generates authentication information and writes the generated authentication information into the external storage device inserted into the slot, and wherein the second judgment section reads the authentication information from the external storage device inserted into the slot and judges that the external storage device is a registered external storage device when the read authentication information matches the generated authentication information.