Patent ID: 8031869

Claim:
A usage management method for regulating usage of a digital work, wherein information relating to the digital work is recorded on an information recording medium as main data, the main data being recorded on the information recording medium by forming a recording mark by laser irradiation, and wherein copyright management information for the digital work is recorded in an area on the information recording medium in which the information relating to the digital work is recorded, as sub-data superimposed on the main data, by intentionally altering one of a position, a shape and a pattern of the recording mark, the usage management method comprising: a main data extracting step of extracting, as the main data, the information relating to the digital work from reflected light generated by the laser irradiation to the recording mark; a sub-data extracting step of, simultaneously to the main data being extracted from the reflected light in the main data extracting step, extracting, as the sub-data, the copyright management information of the digital work by extracting, from the reflected light, the intentional alteration of the one of the position, the shape and the pattern of the recording mark; a main data storing step of temporarily storing the information relating to the digital work extracted in the main data extracting step; a sub-data storing step of temporarily storing the copyright management information of the digital work extracted in the sub-data extracting step; an updating step of, after the digital work is used, updating the copyright management information temporarily stored in the sub-data storing step, in accordance with a condition designated in the copyright management information; a main data recording step of recording, by forming a recording mark by laser irradiation, the information relating to the digital work stored in the main data storing step to the area of the information recording medium from which the information relating to the digital work has been extracted in the main data extracting step; and a sub-data recording step of updating only the copyright management information in the information recording medium by recording, simultaneously to the information relating to the digital work being recorded in the main data recording step, to the area of the information recording medium, the copyright management information updated in the updating step as sub-data superimposed on the main data by modulating the laser irradiation or displacing a position of the laser irradiation in the main data recording step so as to intentionally alter one of the position, the shape and the pattern of the recording mark.