Cryptography – Video cryptography – Copy protection or prevention
Reexamination Certificate
1999-02-16
2003-02-25
Barrón, Gilberto (Department: 2131)
Cryptography
Video cryptography
Copy protection or prevention
C380S202000, C380S203000, C713S179000, C713S181000, C713S152000, C713S152000, C705S051000, C705S052000, C705S057000, C369S084000
Reexamination Certificate
active
06526146
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an information recording system and, more particularly, to a system adapted for preventing illegal copying with enhanced certainty.
Recently, there are known home apparatus which are equipped with functions of digitally recording and/or reproducing information in or from a recording medium. If video or music data for example are recorded digitally, resultant deterioration is minimized in recording or reproduction, and when the information recorded on such a recording medium is replicated so many times, it is possible to produce satisfactory recording media as replicas which are substantially equal in quality to the original recording medium. Consequently, unauthorized articles not licensed by a copyright holder may be copied and distributed illegally. With regard to this problem, it is socially demanded now that such illegal copying be prevented.
Normally, data of motion pictures and so forth are transmitted with copy control information termed CGMS (Copy Generation Management System). The CGMS is composed of two bits signifying “copy free”, “copy once approved” or “copy prohibited”. Attachment of such CGMS is prescribed in accordance with each data format specified in the MPEG (Moving Picture Experts Group) or DV (Digital Video) standards.
In recording data, a recorder checks the CGMS attached to the data and, if the CGMS signifies prohibition of copy, the data are not recorded. Meanwhile, if the CGMS signifies approval of copy once, it is changed to prohibition of copy and then the data are recorded in the recording medium. It is a matter of course that, if the CGMS signifies no restriction of copy, the data are copied freely in the recording medium. Thus, illegal copy is prevented by limiting the copy generation.
However, a device termed a bit stream recorder is incapable of cognizing the CGMS attached to the data. For the purpose of enabling such a device also to execute proper copy generation management, there is proposed an improvement where, in a digital IEEE1394 serial bus, CGMS is stored at specific positions in a header of an isochronous packet, so that even a bit stream recorder is rendered capable of executing copy generation management.
Supposing now that a recording medium containing a copy once approval CGMS has been copied to produce a replica recording medium by a bit stream recorder incapable of cognizing the CGMS, then such copy once approval CGMS is recorded as it is in the new recording medium also. Although it is difficult to prevent that the newly replicated recording medium is copied again to a further recording medium by a bit stream recorder incapable of cognizing the CGMS, further possible copying of the data needs to be avoided in case the recording medium replicated by copying is loaded in a CGMS cognizant device. In this case, the device copies the data to another new recording medium after changing the copy once approval CGMS to a copy prohibition CGMS. If such copying is permitted, it follows that the original recording medium is copied twice eventually. That is, even in the case of a CGMS cognizant device, proper copy generation management fails to be executed.
SUMMARY OF THE INVENTION
The present invention has been accomplished in view of the circumstances mentioned above And it is an object of the invention to realize exact copy generation management with enhanced certainty.
According to a first aspect of the present invention, there is provided an information recording apparatus which comprises a receiving means for receiving record information transmitted from a transmitter inclusively of copy control information; a decision means for making a decision as to whether the transmitter is a first device capable of cognizing the copy control information, or a second device incapable of cognizing the copy control information; a storage means for storing first update information to update the copy control information when the transmitter is the first device, or storing second update information to update the copy control information when the transmitter is the second device; and a recording means for updating, in response to the result of the decision obtained from the decision means, the copy control information included in the record information received by the receiving means, on the basis of the first or second update information stored in the storage means, and then recording, in the recording medium, the information inclusive of the updated copy control information.
According to a second aspect of the present invention, there is provided an information recording method which comprises the steps of receiving record information transmitted from a transmitter inclusively of copy control information; making a decision as to whether the transmitter is a first device capable of cognizing the copy control information, or a second device incapable of cognizing the copy control information; updating, in response to the result of the decision obtained at the decision step, the copy control information included in the record information received at the reception step, on the basis of the first update information for the first device or the second update information for the second device; and recording, in the recording medium, the record information inclusive of the updated copy control information.
According to a third aspect of the present invention, there is provided a medium for providing a program readable by a computer for enabling an information recording apparatus to execute processes which comprise the steps of receiving record information inclusive of copy control information transmitted from a transmitter; making a decision as to whether the transmitter is a first device capable of cognizing the copy control information, or a second device incapable of cognizing the copy control information; updating, in response to the result of the decision obtained at the decision step, the copy control information included in the record information received at the reception step, on the basis of the first update information for the first device or the second update information for the second device; and recording, in the recording medium, the record information inclusive of the updated copy control information.
According to a fourth aspect of the present invention, there is provided an information reproducing apparatus which comprises a reproducing means for reproducing information from a recording medium; a decision means for making a decision as to whether the information reproduced inclusively of copy control information by the reproducing means is the one recorded in a first recording mode by a first device capable of cognizing the copy control information, or the one recorded in a second recording mode by a second device incapable of cognizing the copy control information; a storage means for storing at least either first update information to update the copy control information in case the reproduced information is the one recorded in the first recording mode, or second update information to update the copy control information in case the reproduced information is the one recorded in the second recording mode; and an output means for updating, in response to the result of the decision obtained from the decision means, the copy control information included in the information reproduced by the reproducing means, on the basis of the first or second update information stored in the storage means, and then outputting the reproduced information inclusive of the updated copy control information.
According to a fifth aspect of the present invention, there is provided an information reproducing method which comprises the steps of reproducing information inclusive of copy control information from a recording medium; making a decision as to whether the information reproduced at the reproducing step is the one recorded in a first recording mode by a first device capable of cognizing the copy control information, or the one recorded in a second recording mode by a second device incapable of cognizing
Asano Tomoyuki
Hashimoto Megumu
Osawa Yoshitomo
Barrón Gilberto
Darrow Justin T.
Frommer William S.
Frommer & Lawrence & Haug LLP
Simon Darren M.
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