Method of accessing data on a copy protected data carrying disc
View Patent ↗The method and apparatus described utilise the fact that CDs manufactured from the same master will have distinctive physical characteristics attributable to the physical manufacturing process of the master to distinguish counterfeit CDs from genuine discs. For a genuine disc, the relative angular orientation of specified sections of the recorded data are determined and recorded. The relative angular orientation of the same sections of data on a test disc are also determined. Where the relative angular orientations are the same it is concluded that the test disc derives from the same source as the genuine disc and is therefore bona fide. Where there is no correlation, the test disc may be identified as counterfeit. The relative angular orientations, or other physical characteristics of the discs, may be physically measured, or may be calculated from information gained by reading the data on the disc. The disclosed technique can also be used to copy protect discs.
1. A method of accessing data on a data carrying disc, where a genuine data carrying disc has been protected by recording selected data thereon such that the recorded selected data has predetermined physical characteristics, the accessing method comprising:
extracting the selected data from a disc and determining the physical characteristics thereof; and
enabling access to the data on said disc if the physical characteristics determined from the disc are substantially the same as said predetermined physical characteristics of said genuine disc; wherein a copy of said genuine disc can be played successfully, and access is otherwise not enabled if the determined physical characteristics are not substantially the same as said predetermined physical characteristics.
2. A method of accessing data on a data carrying disc according to claim 1 , wherein said predetermined physical characteristics are recorded as a fingerprint.
3. A method of accessing data on a data carrying disc according to claim 2 , further comprising:
rotating the disc in a disc reader to extract the selected data therefrom;
determining a location in time of the selected data which has been extracted from said disc;
measuring the angular orientation on said disc of said selected data; and
comparing the time location determined and the angular orientation measured with the recorded fingerprint.
4. A method of accessing data on a data carrying disc according to claim 3 , wherein the disc reader has a motor for rotating the disc, and an encoder associated with the motor, and wherein the angular orientation is measured using said encoder.
5. A method of accessing data on a data carrying disc according to claim 3 , wherein data is recorded onto said genuine disc according to CD standards with timing information recorded in the Q-subchannel, and wherein timing information from Q-subchannel blocks is utilised both in determining the time location, and in measuring the angular orientation of the selected data.
6. A method of accessing data on a data carrying disc according to claim 1 , wherein the physical characteristics of the selected data on the copy protected disc are determined by making physical measurements on said disc.
7. A method of accessing data on a data carrying disc according to claim 6 , the method further comprising:
rotating said disc in a disc reader to extract the selected data therefrom;
determining a location in time of said selected data which has been extracted from said disc; and
measuring the angular orientation on said disc of said selected data.
8. A method of accessing data on a data carrying disc according to claim 7 , wherein data is recorded onto said genuine disc according to CD standards with timing information recorded in the Q-subchannel, and wherein timing information from Q-subchannel blocks is utilised both in determining the time location, and in measuring the angular orientation of said selected data.
9. A method of accessing data on a data carrying disc according to claim 7 or claim 8 , wherein the disc reader has a motor for rotating the disc, and an encoder associated with the motor, and wherein the angular orientation is measured using said encoder.
10. A method of accessing data on a data carrying disc according to claim 1 , wherein physical characteristics of said disc are determined by extracting the selected data from said disc and processing the selected data to determine the physical characteristics, the method further comprising:
rotating said disc in a disc reader to extract the selected data therefrom;
the disc reader having a pickup, and determining the time taken for the disc reader pickup to move between a reference location to said selected data; and
computing a location for said selected data from the time determined.
11. A method of accessing data on a data carrying disc according to claim 10 , further comprising the step of utilising positioning data read from said disc to enable determination of said physical characteristics.
12. A data storage medium storing data comprising a theoretical model of a genuine data carrying disc for use in protecting data carrying discs, the model describing the information to be carried on the genuine disc and the intended locations of the information on the genuine disc in a manner enabling the relative locations of any two pieces of the information to be calculated, wherein a copy of said genuine disc can be played successfully, and by measuring the relative locations the copy is distinguished from the genuine disc.
13. A data storage medium according to claim 12 , wherein the information and its intended locations are described in a manner enabling the relative angular orientations of any two pieces of the information to be calculated.
14. A disc carrying data, the data comprising a fingerprint for use in a method of determining the genuineness of the disc, the fingerprint identifying selected data recorded on the disc and identifying physical characteristics of the selected data, wherein a copy of the disc can be played successfully, and by measuring the physical characteristics the copy is distinguished from the genuine disc.
15. A disc according to claim 14 , wherein the identified physical characteristics of the selected data are the locations of the selected data on the disc.
16. A disc according to claim 15 , wherein the identified physical characteristics of the selected data are the angular orientations of the selected data on the disc.
17. A disc according to claim 15 , wherein the selected data identified comprise selected frames of the data recorded on the disc.
18. A disc according to claim 14 , wherein the selected data identified comprise selected frames of the data recorded on the disc.
19. A method of accessing data on a copy protected data carrying disc, where a data carrying disc has been copy protected by recording selected data thereon such that the recorded selected data has predetermined physical characteristics, the accessing method comprising:
extracting the selected data from said copy protected disc and determining the physical characteristics thereof; and
enabling access to the data on said disc if the physical characteristics determined from the disc are substantially the same as said predetermined physical characteristics, wherein the physical characteristics of the selected data on the copy protected disc are determined by making physical measurements on said disc.
20. A method of accessing data on a copy protected data carrying disc according to claim 19 , wherein said predetermined physical characteristics are recorded as a fingerprint.
21. A method of accessing data on a copy protected data carrying disc according to claim 20 , further comprising:
rotating the copy protected disc in a disc reader to extract the selected data therefrom;
determining a location in time of the selected data which has been extracted from said disc;
measuring the angular orientation on said disc of said selected data; and
comparing the time location determined and the angular orientation measured with the recorded fingerprint.
22. A method of accessing data on a copy protected data carrying disc according to claim 21 , wherein the disc reader has a motor for rotating the disc, and an encoder associated with the motor, and wherein the angular orientation is measured using said encoder.
23. A method of accessing data on a copy protected data carrying disc according to claim 21 , wherein data is recorded onto said copy protected disc according to CD standards with timing information recorded in the Q-subchannel, and wherein timing information from Q-subchannel blocks is utilised both in determining the time location, and in measuring the angular orientation of the selected data.
24. A method of accessing data on a copy protected data carrying disc according to claim 19 , the method further comprising:
rotating said disc in a disc reader to extract the selected data therefrom;
determining a location in time of said selected data which has been extracted from said disc; and
measuring the angular orientation on said disc of said selected data.
25. A method of accessing data on a copy protected data carrying disc according to claim 24 , wherein data is recorded onto said copy protected disc according to CD standards with timing information recorded in the Q-subchannel, and wherein timing information from Q-subchannel blocks is utilised both in determining the time location, and in measuring the angular orientation of said selected data.
26. A method of accessing data on a copy protected data carrying disc according to claim 24 , wherein the disc reader has a motor for rotating the disc, and an encoder associated with the motor, and wherein the angular orientation is measured using said encoder.
27. A method of accessing data on a copy protected data carrying disc according to claim 19 , wherein physical characteristics of said copy protected disc are determined by extracting the selected data from said disc and processing the selected data to determine the physical characteristics, the method further comprising:
rotating said copy protected disc in a disc reader to extract the selected data therefrom;
the disc reader having a pickup, and determining the time taken for the disc reader pickup to move between a reference location to said selected data; and
computing a location for said selected data from the time determined.
28. A method of accessing data on a copy protected data carrying disc according to claim 27 , further comprising the step of utilising positioning data read from said disc to enable determination of said physical characteristics.