Recording apparatus, reproducing apparatus and optical recording medium
AssigneeSony Corporation
InventorsYoshizumi Inazawa, Tadao Suzuki
Life of this patent
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Abstract
A recording apparatus for modulating a master key used for encrypting main data in a pit-width direction by changing a light amount of a laser beam to then record it on an optical recording medium and records the main data encrypted by using the master key with correcting the main data so as to have a certain pit width and a pit length so that a jitter resulting in intersymbol interference of adjacent pits should be reduced. A reproducing apparatus for reproducing the recorded optical recording medium, and to thereby prevent an optical recording medium from being duplicated by an illegal copy.
Claims20
A recording apparatus for recording a modulated scrambled data signal encrypted with key data on an optical recording medium, comprising:
- edge change detecting means for detecting a change pattern of an edge of said modulated scrambled data;
- timing correcting means for correcting a timing of an edge rising/falling position of pulses forming said modulated scrambled data signal so that jitter resulting from intersymbol interference upon reproduction is reduced depending upon the change pattern of the edge detected by said edge change detecting means;
- and
- light amount controlling means for controlling a light amount of a light beam irradiated on said optical recording medium based on a timing output from said timing correcting means, wherein when said key data used for encrypting main data is recorded on said optical recording medium, said light amount controlling means is controlled in accordance with said key data.
A reproducing apparatus for reproducing encrypted data on an optical recording medium, wherein main data is recorded after being encrypted at a first signal level and key data for decrypting said main data is recorded at a second signal level different from said first signal level, comprising:
- binarizing means for binarizing a reproduction signal reproduced from said optical recording medium with a slice level;
- key detector means for detecting key data from said reproduction signal;
- demodulator means for demodulating said reproduction signal binarized by said binarizing means;
- and
- decoder means for decrypting said reproduction signal demodulated by said demodulator means using the key data detected by said key detector means.
An optical recording medium recorded with modulated scrambled data encrypted with key data at a reference period in a form of one of a mark and a space, comprising:
- encryption data represented by a width of one of said mark and said space;
- and
- main data encrypted using said encryption data represented by a length and an interval of one of said mark and said space.
Dependencies are inferred from the claim text.