Cryptography – Video cryptography – Copy protection or prevention
Reexamination Certificate
2000-01-07
2001-09-11
Swann, Tod (Department: 2132)
Cryptography
Video cryptography
Copy protection or prevention
Reexamination Certificate
active
06289103
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a signal recording apparatus, a signal record (recording, recordable or recorded) medium and a signal reproducing apparatus for prohibiting copying or unauthorized use.
2. Description of the Related Art
Recently, with increased capacity and coming into widespread use of digital recording media, such as optical discs, prohibition of duplication or unauthorized use thereof has become crucial for protecting the copyright of recorded signals. That is, digital audio data or digital video data can be duplicated by copying or dubbing without deterioration, while computer data can be duplicated to give data which are the same as the original data, thus giving rise to troubles, such as copyright infringement, due to unauthorized copying.
With this in view, a pre-set ID bit for preventing unauthorized copying is occasionally recorded on an original signal record medium for prohibiting unauthorized copying in so-called digital dubbing in which data is reproduced from a digital record medium and re-recorded on another digital record medium.
For example, in a system for prohibiting the unauthorized copying in a digital audio data recording/reproducing apparatus termed a rotary head digital audio tape recorder (R-DAT), an inhibiting code for inhibiting digital copying or generation-serial copying, that is for copying generation limitation (inhibiting code of a standard of the serial copying management system or SCMS) is recorded in a main data area for digital audio signals recorded on a digital audio tape as a signal record medium, so that, when the inhibiting code is detected by the digital audio signal recording apparatus, copying recording of the digital audio signals on a new digital audio tape is inhibited.
Meanwhile, in digital dubbing of video signals, in which digital video signals, for example, recorded on a digital record medium, such as a digital disc or a digital tape, are reproduced and re-recorded on another record medium, a pre-set ID bit, that is the inhibiting code of a standard of the serial copying management system (SCMS), may be recorded in the original digital record medium.
In case of a recording system of recording the pre-set ID bit for prohibiting the unauthorized copying on the original digital record medium, the function of preventing unauthorized copying in the above-described digital dubbing operates satisfactorily. However, in case the digital video signals recorded on an original digital record medium are reproduced and D/A converted for analogically recording the converted analog video signals, or in case the analog video signals are again A/D converted for recording in the digital form, the function of preventing unauthorized copying fails to operates satisfactorily, so that recording can be made directly.
That is, if the digital video signals recorded on the digitar record medium is reproduced and D/A converted and the resulting analog video signals are directly recorded analogically or restored by A/D conversion to digital video signals for digital recording, the video signals resulting from dubbing are deteriorated in signal quality to an extremely small extent. This means that copyright protection ia not assured sufficiently, and hence a system is required which positively prohibits such unauthorized copying. In particular, large-capacity disc-shaped recording media have recently become popular, such that a demand has been raised for suitable measures against unauthorized copying of digital video signals recorded on the disc-shaped record medium.
On the other hand, if the pre-set ID bit provided for prohibiting unauthorized copying is skipped in reading, unauthorized copying can be achieved easily. Therefore, suitable measures for prohibiting unauthorized copying by skipping in reading have also been desired.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a signal reproducing method and apparatus, a signal recording method and apparatus, a signal transmitting method and apparatus and a signal record(recording ,recordable or recorded) medium whereby it is possible to prevent unauthorized copying by skipping in reading and it is also possible to inhibit unauthorized copying of analog signal converted from digital data digitally or analogically as well as to inhibit generation-serial copying.
With the method and apparatus for reproducing a signal according to the present invention, digital data or an analog signal D/A converted from the digital data are converted in a pre-set manner based on the recording control information arrayed in a playback mode control signal area and/or each sector header of a signal record medium.
With the method and apparatus for recording a signal according to the present invention, a signal is ciphered using at least a portion of the recording control information designed for controlling the recording on a signal record medium as the key information, or by the key information specified by at least a portion of the recording control information, with this recording control information being arrayed at a pre-set position of a playback mode control signal area of the signal record medium and/or at a pre-set position of each signal recording unit on the signal record medium and being recorded along with the ciphered signal on the signal record medium.
With the method and apparatus for transmitting a signal according to the present invention, digital data or an analog signal D/A converted from the digital data are converted in a pre-set manner based on the recording control information ancillary to transmitted digital data.
With the method and apparatus for transmitting a signal according to the present invention, the signal is ciphered using at least a portion of the transmission management information designed to supervise signal transmission as the key information, or by the key information specified by at least a portion of the recording control information and the transmission management information is transmitted along with the ciphered signal.
With the signal record medium of the present invention, the recording control information for supervising the signal recording on the signal record medium is recorded at a pre-set position in a playback mode control signal area and/or at a pre-set position in each signal recording unit. At least a portion of the recording control information is used as the key information for ciphering the recording signal.
That is, with the present invention, both digital data and the analog signal are converted in a pre-set manner based on the recording control information or the transmission control information. The pre-set conversion may be ciphering or scrambling, for example, for digital data and for analog signals, respectively, whereby both the unauthorized digital copying and unauthorized analog copying may be prohibited from occurring. According to the present invention, since the signal is ciphered based on the recording control information or the transmission control information, deciphering is not feasible if the reading of the recording control information or the transmission control information is skipped, thus enabling prevention of unauthorized copying.
With the video signal reproducing apparatus and method of the present invention, a digital signal is reproduced from a digital disc medium having recorded thereon the video recording control code arrayed in a playback mode control signal recording area provided at a beginning end of a spirally extending recording track and/or in each header of the digital video signal divided into sectors, along with the digital video signal, for ultimately producing at least the analog video signal output. The state of the video recording control code is detected, and the video recording scrambling signal of the mode of the analog video signal and/or the recording inhibiting signal is generated on the basis of the detection output. The video recording scrambling signal and/or the video recording inhibiting signal is annexed in a pre-
Sako Yoichiro
Yoneyama Shigeyuki
Frommer William S.
Frommer Lawrence & Haug LLP.
Polito Bruno
Smithers Matthew
Sony Corporation
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