Copyright control of encrypted data using uncorrected errors in an error correcting code
First Claim
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1. A data storing medium, comprising:
- a digital data area in which one of encrypted digital data and non encrypted digital data is written;
a control data area in which control data necessary for reproducing recorded digital data is written; and
a plurality of copyright control information areas in which is written the same copyright control information necessary for decrypting the encrypted digital data,wherein said plurality of copyright control information areas are spaced apart by a predetermined interval,wherein said plurality of copyright control information areas are embossed so as to be write prohibited,wherein said control data area is write permitted,wherein, data written to the area for the copyright control information is converted so that the data is not corrected by an error correcting process performed when the encrypted digital data is reproduced, andwherein a data converting process converting the copyright control information is a process that satisfies a relation of 2a+b>
d where “
a”
is a number of lines that are not erased as an error of the copyright control information, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of the error correction code.
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Abstract
A data storing medium has a digital data area in which encrypted digital data or non-encrypted digital data is written, a control data area in which control data necessary for reproducing recorded digital data is written, and a copyright control information area in which copyright control information necessary for decrypting encrypted digital data is written, wherein the copyright control information area is write-prohibited, and wherein the control data area is write-permitted.
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Citations
22 Claims
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1. A data storing medium, comprising:
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a digital data area in which one of encrypted digital data and non encrypted digital data is written; a control data area in which control data necessary for reproducing recorded digital data is written; and a plurality of copyright control information areas in which is written the same copyright control information necessary for decrypting the encrypted digital data, wherein said plurality of copyright control information areas are spaced apart by a predetermined interval, wherein said plurality of copyright control information areas are embossed so as to be write prohibited, wherein said control data area is write permitted, wherein, data written to the area for the copyright control information is converted so that the data is not corrected by an error correcting process performed when the encrypted digital data is reproduced, and wherein a data converting process converting the copyright control information is a process that satisfies a relation of 2a+b>
d where “
a”
is a number of lines that are not erased as an error of the copyright control information, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of the error correction code. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A data recording apparatus for writing encrypted digital data to a data storing medium, comprising:
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means for writing the encrypted digital data and copyright control information for decrypting the encrypted digital data to the data storing medium so that when the encrypted digital data is reproduced the copyright control information is not obtained by recording dummy information in a sector of the data storing medium, so as to form a write-prohibited area containing the copyright control information; and means for encoding the copyright control information with an error correcting code, wherein, data written to the area for the copyright control information is converted so that the data is not corrected by an error correcting process performed when the encrypted digital data is reproduced, and wherein a data converting process converting the copyright control information is a process that satisfies a relation of 2a+b>
d where “
a”
is a number of lines that are not erased as an error of the copyright control information, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of the error correction code. - View Dependent Claims (8, 9, 10, 11)
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12. A data writing method for a data storing medium having a first area in which digital data is written and a second area in which control data necessary for reproducing the data from the first area is written, the data writing method comprising the step of:
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writing the control data to the second area in such a manner that part of the control data is not reproduced, wherein the control data written in the second area contains copyright control data about the digital data written in the first area, and causing the copyright control data to be written in the second area in such a manner that the copyright control data is reproduction-prohibited wherein the copyright control data includes an error correction code and is converted in such a manner that a relation of 2a+b>
d is satisfied where “
a”
is a number of lines that are not erased as an error of the copyright control data, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of the error correction code. - View Dependent Claims (13)
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14. A data writing method for a data storing medium having a first area in which digital data is written and a second area in which different data is written that is to be read before the digital data is read when the digital data is reproduced, the data writing method comprising the steps of:
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converting the different data in such a manner that the different data is not corrected by an error correcting process; and writing the different data to the second area in such a manner that part of the different data is not reproduced wherein the different data is converted in such a manner that a relation of 2a+b>
d is satisfied where “
a”
is a number of lines that are not erased as an error of the different data, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of a error correction code used in the error correcting process. - View Dependent Claims (15, 16, 17, 18)
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19. A data writing apparatus having a data storing medium having a first area in which digital data is written and a second area in which control data necessary for reproducing the data from the first area is written, the data writing apparatus comprising:
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a writing portion for writing data to the data storing medium; and a data processing portion for supplying data to said writing portion in such a manner that a part of the control data comprising copyright control data is reproduction-prohibited, wherein said data processing portion converts the copyright control data of the control data in such a manner that the copyright control data is not corrected by an error correcting process, wherein said data processing portion converts the copyright control data in such a manner that a relation of 2a+b>
d is satisfied, where “
a”
is a number of lines that are not erased as an error of the copyright control data, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of an error correction code used in the error correcting process. - View Dependent Claims (20)
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21. A data writing apparatus for a data storing medium having a first area in which digital data is written and a second area in which different data that is read before the digital data is read from the first area when the digital data is reproduced from the first area, the data writing apparatus comprising:
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a writing portion for writing data to the data storing medium; and a data processing portion for supplying data to said writing portion in such a manner that at least part of the different data comprising copyright control data is reproduction-prohibited, wherein said data processing portion converts the different data in such a manner that the different data is not corrected by an error correcting process, and wherein said data processing portion converts the copyright control data in such a manner that a relation of 2a+b>
d is satisfied where “
a”
is a number of lines that are not erased as an error of the copyright control data, “
b”
is a number of lines that are erased thereof, and “
d”
is a minimum distance of a error correction code that is used in the error correcting process. - View Dependent Claims (22)
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Specification