Dynamic copy protection of optical media
View Patent ↗A method for copy protection includes receiving data in a recording module representing content to be recorded on a recording medium, the data including an indication that the content is to be protected from unauthorized copying. Responsive to the indication, the recording module signals a protection module to initiate a protection protocol in synchronization with the recording module. The protection module generates control information, so as to prevent the unauthorized copying of the content that is to be protected, and conveys the control information to the recording module, in accordance with the protocol. The recording module combines the control information with the data representing the content in the recording module, for recording on the recording medium.
1. A method for preventing copying of a compact disk (CD) by an unauthorized readout device which performs a synchronization by reading a subcode symbol S0 followed by a subcode symbol S1 in consecutive frames at the start of a sector before reading out content, the method comprising:
preparing data to be written to a sector of the CD, the sector comprising a plurality of frames, each of the frames comprising multiple symbols including a subcode symbol S0 and a subcode symbol S1;
arranging the symbols in at least one of the frames so that the subcode symbol S1 occurs before the subcode symbol S0, causing an error condition to occur when the unauthorized readout device performs the synchronization, thereby preventing the unauthorized readout device from reading out content; and
recording the symbols in the sector on the CD.
2. A method according to claim 1 , wherein arranging the symbols comprises arranging the subcode symbol S0 and the subcode symbol S1 in the at least one of the frames so that they are not consecutive.
3. A method according to claim 1 , wherein the subcode symbol S0 and the subcode symbol S1 in the at least one of the frames are arranged so that the at least one of the frames does not begin with either the subcode symbol S0 or the subcode symbol S1, and so that the beginning subcode symbol of the at least one of the frames is overwritten with arbitrary data.
4. A method according to claim 1 , wherein the arranging the symbols and the recording the symbols is repeated for at least one more consecutively following sector.
5. Apparatus for preventing copying of a compact disk (CD) by an unauthorized readout device which performs a synchronization by reading a subcode symbol S0 followed by a subcode symbol S1 in consecutive frames at the start of a sector before reading out content, the apparatus comprising:
a protection processor, adapted to receive data to be written to a sector of the CD, the sector comprising a plurality of frames, each of the frames comprising multiple symbols including a subcode symbol S0 and a subcode symbol S1, the protection processor being adapted to arrange the symbols in at least one of the frames so that the subcode symbol S1 occurs before the subcode symbol S0, causing an error condition to occur when the unauthorized readout device performs the synchronization, thereby preventing the unauthorized readout device from reading out content; and
a recording device, coupled to receive the symbols from the protection processor, and to record the symbols in the sector on the CD.
6. Apparatus according to claim 5 , wherein the protection processor is adapted to arrange the subcode symbol S0 and the sub code symbol S1 in the at least one of the frames so that they are not consecutive.
7. Apparatus according to claim 5 , wherein the protection processor is adapted to arrange the subcode symbol S0 and the subcode symbol S1 in the at least one of the frames so that the at least one of the frames does not begin with either the subcode symbol S0 or the subcode symbol S1, and so that the beginning subcode symbol of the at least one of the frames is overwritten with arbitrary data.
8. Apparatus according to claim 5 , wherein the protection processor is further adapted to repeat the arranging the symbols for at least one more consecutively following sector.
9. A computer software product for preventing copying of a compact disk (CD) by an unauthorized readout device which performs a synchronization by reading a subcode symbol S0 followed by a subcode symbol S1 in consecutive frames at the start of a sector before reading out content, the product comprising a computer-readable medium in which program instructions are stored, which instructions, when read by a computer that receives data to be written to a sector of the CD, the sector comprising a plurality of frames, each of the frames comprising multiple symbols, cause the computer to arrange the symbols in at least one of the frames to be recorded to the sector of the CD so that the subcode symbol S1 occurs before the subcode symbol S0, causing an error condition to occur when the unauthorized readout device performs the synchronization, thereby preventing the unauthorized readout device from reading out content.
10. A product according to claim 9 , wherein the instructions cause the computer to arrange the subcode symbol S0 and the subcode symbol S1 in the at least one of the frames so that they are not consecutive.
11. A product according to claim 9 , wherein the instructions cause the computer to arrange the subcode symbol S0 and the subcode symbol S1 in the at least one of the frames so that the at least one of the frames does not begin with either the subcode symbol S0 or the subcode symbol S1, and so that the beginning subcode symbol of the at least one of the frames is overwritten with arbitrary data.
12. A product according to claim 9 , the instructions further causing the computer to repeatedly arrange the symbols so that the subcode symbol S1 occurs before the subcode symbol S0 for at least one more consecutively following sector.
13. A data storage medium that is resistant to copying by an unauthorized readout device which performs a synchronization by reading a subcode symbol S0 followed by a subcode symbol S1 in consecutive frames at the start of a sector before reading out content, the medium comprising a compact disk (CD) containing data in at least one sector thereon, the at least one sector comprising a plurality of frames, each of the frames comprising multiple symbols including a subcode symbol S0 and a subcode symbol S1, while in at least one of the frames in the at least one sector, the subcode symbol S1 occurs before the subcode symbol S0, causing an error condition to occur when the unauthorized readout device performs the synchronization, thereby preventing the unauthorized readout device from reading out content.
14. A medium according to claim 13 , wherein the at least one of the frames does not begin with either the subcode symbol S0 or the subcode symbol S1, and wherein the beginning subcode symbol of the at least one of the frames contains arbitrary data.
15. A medium according to claim 13 , wherein the at least one sector includes at least one more consecutively following sector.