Method and apparatus for preventing unauthorized use by comparing medium identifications

A computer system comprising:

• a disk drive for reproducing a block of data stored in a recording medium, the block of data being for preventing unauthorized use of the recording medium;
• means for reading out an original medium ID information as a part of the data which is stored in a recording medium to be judged for, and prevented against, unauthorized use, the original medium ID information being defined in advance by deforming properties of a preselected area of a blank original recording medium irreversibly, the location of the preselected area of the blank original recording medium being defined by an address information indicating the preselected area in the blank original recording medium, the original medium ID information and the address information being previously formed as a part of data stored in the blank original recording medium;
• means for reading out the original medium ID information and the address information from the recording medium to be judged for unauthorized use;
• means for reading out an information stored in the recording medium to be judged in accordance with the address information read out from the recording medium to be judged;
• and
• means for judging unauthorized use of data based on the read out information and the read out original ID information.

An apparatus for reproducing data stored in a recording medium comprising:

• means for reading out an original medium ID information as a part of the data which is stored in a recording medium to be judged for, and prevented against, unauthorized use, the original medium ID information being defined in advance by deforming properties of a preselected area of a blank original recording medium irreversibly, the location of the preselected area of a blank original recording medium being defined by an address information indicating the preselected area in the blank original recording medium, the original medium ID information and the address information being previously formed as a part of data stored in the blank original recording medium;
• means for reading out the original medium ID information and the address information from a recording medium to be judged for unauthorized use;
• means for reading out an information stored in the recording medium to be judged in accordance with the address information read out from the recording medium to be judged;
• and
• means for judging unauthorized use of data based on the read out information and the read out original ID information.