A data processing method including reading first image processing apparatus structural information by the control unit from a portable storage medium, obtaining second image processing apparatus structural information by the control unit, determining whether to allow data in the storage device to be used or not in the first image processing apparatus by the control unit based on the read first image processing apparatus structural information and the obtained second image processing apparatus structural information and reading the identification information specific to the first image processing apparatus by the control unit from the portable storage medium and storing the read identification information specific to the first image processing apparatus in the storage device by the control unit when the control unit determines to allow the data in the storage device to be used in the first image processing apparatus.