JP2000100067A - Transmitting device of digital signal, transmitting method of digital signal and recording medium of digital signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily control the copy generation of a digital signal by defining a 1st generation information with respect to a 2nd generation information which shows the copy generation of the unciphered digital signal, so as to expand it and also converting these generation information at need. SOLUTION: The enciphering information (EMI) for showing the enciphering mode is set in accordance with the CGMS information (M-CGMS) added to a transport stream TP, and the transport stream TP is enciphered in accordance therewith. The packet is formed by the enciphered transport stream, and the subcode of this packet is outputted by adding the enciphering information. In the case the enciphering information is a logic (1, 0) to show the generation allowing the copy limited for one generation only in the CGMS information, this enciphering information is converted into the logic (0, 1) and outputted by updating the generation of a digital video signal by an updating circuit 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal transmission apparatus, a digital signal transmission method, and a digital signal recording medium, for example, when video data transmitted by digital satellite broadcasting is recorded on an optical disk. Can be. The present invention defines first generation information so as to extend the second generation information indicating the copy generation of an unencrypted digital signal, and also converts the generation information as necessary. By performing the conversion, when the encryption mode is switched according to the copy generation of the digital signal, the copy generation of the digital signal can be easily managed.

[0002]

2. Description of the Related Art Conventionally, CGMS has been used for video signals.
(Copy Generation Management System) restricts illegal duplication.

That is, CGMS is a system that transmits information indicating the copy generation of a video signal (hereinafter referred to as CGMS information) together with the video signal, and restricts copying based on the CGMS information. CGMS is a CGMS-A that transmits CGMS information in a vertical blanking period of a video signal for a video signal based on an analog signal;
CGMS for digital video signals
-D.

[0004] In these CGMS-A and CGMS-D, three copy generations are defined by 2-bit CGMS information, as shown in FIG. 7, so that the copy of the video signal generation is not restricted at all. Generation (Fr
ee), a generation that allows only one copy (Copy Once)
), And indicates that it is one of the generations (No Copy) in which copying is not permitted.

[0005] Of these, the generation in which copying is not restricted at all (Free) is set to a private video signal obtained from, for example, a digital video camera or the like, and the generation (Copy Once) in which only one generation is permitted to copy is, for example, reproduced. This is a video signal obtained from a dedicated optical disk or the like, which is set so that the copyright holder permits copying only for private copying. In addition, generations where copying is not allowed (No Copy
) Is the generation that allows only one copy (Copy Once)
), Or a video signal obtained from a reproduction-only optical disk or the like, which is set to a video signal or the like for which the copyright holder also prohibits private copying.

[0006] Such CGMS information is transmitted, for example, by being assigned to an MPEG (Moving Picture Experts Group) header which is an industry standard.

Accordingly, in the recording apparatus for recording the video signal transmitted in this way, the recording of the generation (No Copy) video signal whose copying is not permitted is stopped according to the CGMS information. For a generation (Copy Once) for which only one generation is permitted to copy, a video signal is recorded on a desired recording medium, and at this time, the CGMS information is updated to describe that the generation is a generation for which copying is not permitted (No Copy). . On the other hand, for a generation (Free) in which copying is not restricted at all, video signals sequentially input are recorded without updating CGMS information.

[0008]

In the transmission of such a digital video signal, it has been studied to transmit the digital video signal after encrypting it. Further, at this time, in order to reflect the intention of the copyright holder in the security by the encryption. To
Switching the encryption mode in accordance with the copy generation of the digital video signal has been studied.

In this case, it is considered that strong encryption is applied to a digital video signal for which the copyright holder prohibits private copying. For digital video signals for which the copyright holder permits only private copying, looser encryption will be applied. Furthermore, it is considered that such a copy of a digital video signal that allows only private copying requires only mild encryption, and that a copy whose digital copy is not restricted at all does not require encryption.

Therefore, in this case, by setting the encryption mode according to the conventional CGMS information, it is considered that this type of encryption mode can be easily set, reflecting the intention of the copyright holder.

However, in the CGMS information, a generation in which copying is not permitted (No Copy) is a generation in which copying is not permitted from the beginning (No Copy), or a copy of a generation in which copying is permitted only for one generation (Copy Once). It is difficult to determine whether an object is an object, and after all, the encryption mode can be switched in only three stages, including the case where no encryption is performed.

In this case, since there is one undefined code “0,1” in the CGMS information, the CGMS information is redefined using this undefined code, and the encryption mode is set according to the CGMS information. Can be easily set. However, if you do this,
There is a problem that compatibility with conventional devices using CGMS information cannot be maintained.

On the other hand, a method of separately setting information indicating the copy generation to cope with such four-stage encryption is conceivable. In this case, it is necessary to manage two types of generation information. As a result, there is a problem that the processing becomes complicated.

The present invention has been made in view of the above points, and in the case where the encryption mode is switched in accordance with the copy generation of a digital signal, it is possible to easily manage the copy generation of the digital signal. It is an object of the present invention to propose a digital signal transmission device, a digital signal transmission method, and a digital signal recording medium that can be used.

[0015]

According to the present invention, there is provided a digital signal transmission apparatus or a method for transmitting a digital signal according to the first generation information added to a digital signal. In accordance with the encryption mode, the digital signal and the first generation information are encrypted to generate an encrypted digital signal, and the encrypted information indicating the encryption mode and the encrypted digital signal are transmitted. The generation information is information indicating the copy generation of the digital signal, and is information that is set in place of the second generation information. A larger number of types of generations are set than the second generation information. The second generation information is information indicating a copy generation of an unencrypted digital signal.

Also, the present invention is applied to a digital signal transmission apparatus or a digital signal transmission method, reproduces an encrypted digital signal from a recording medium, decrypts the encrypted digital signal, and performs encryption. The first generation information added to the released digital signal is converted into second generation information. At this time, the second generation information is information indicating the copy generation of the unencrypted digital signal, and the first generation information is information indicating the copy generation of the digital signal. The number of generations to be expressed is set to be larger than that of the second generation information.

Further, when applied to a digital signal recording medium, the digital signal is encrypted in an encryption mode corresponding to the added first generation information, and is recorded together with the encryption information indicating the encryption mode. The first generation information is information indicating the copy generation of the digital signal, and is information set in place of the second generation information. The type of generation to be expressed is smaller than the second generation information. Are set so that the second generation information is information indicating a copy generation of an unencrypted digital signal.

According to an encryption mode corresponding to the first generation information added to the digital signal, the digital signal and the first generation information are encrypted to generate an encrypted digital signal, which is transmitted together with the encrypted information. At this time, the first generation information is information indicating the copy generation of the digital signal,
This information is set in place of the second generation information. The number of types of generations to be expressed is set to be larger than that of the second generation information, and the second generation information is encrypted. If the information indicates the copy generation of the digital signal that does not exist, the copy generation can be managed by centrally managing the second generation information and the first generation information. Compatibility can be achieved.

When reproducing an encrypted digital signal from a recording medium, the digital signal is decrypted in accordance with encryption information indicating an encryption mode, and the added first generation information is replaced with second generation information. At this time, the second generation information is information indicating the copy generation of the unencrypted digital signal, the first generation information is information indicating the copy generation of the digital signal, and the second generation information is This information is set in place of the generation information. If the number of types of generations to be expressed is set to be larger than that of the second generation information, similarly, the conventional second generation information , The first generation information can be centrally managed to manage the copy generation, and compatibility with conventional devices can be achieved. Also, the copy generation can be managed by updating the first and second generation information as needed.

Further, the present invention is applied to a digital signal recording medium, and is encrypted by an encryption mode corresponding to the added first generation information, and the digital signal is recorded together with the encryption information indicating the encryption mode. , The first generation information is
This information indicates the copy generation of the digital signal, and is information that is set in place of the second generation information. The number of types of generations to be expressed is set more than the second generation information. If the generation information is the information indicating the copy generation of the unencrypted digital signal, similarly, the conventional second generation information and the first generation information can be integrally managed. Copy generation can be managed, and compatibility with conventional devices can be achieved. Also, the copy generation can be managed by updating the first and second generation information as needed.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1) Configuration of Embodiment FIG. 2 is a block diagram showing a satellite broadcasting system according to an embodiment of the present invention. In this satellite broadcasting system 1, various digital broadcasts are uplinked from a broadcast station 2 to a satellite 3, and digital broadcasts downlinked from the satellite 3 are received at homes 4.

Here, in the broadcasting station 2, transport streams TP1 to TPN based on digital video signals and digital audio signals are multiplexed by a multiplexer (MUX).
After time-division multiplexing by 5, the signal is modulated by a modulator (MOD) 6. Further, the modulated signal obtained from the modulator 6 is frequency-multiplexed with another modulated signal generated in the same manner, and uplink is performed from the antenna 8.

At this time, the broadcasting station 2 converts the digital video signal and digital audio signal supplied from the server or the like into transport streams TP1 to TPN according to the MPEG format, and multiplexes the transport streams TP1 to TPN. Performs time division multiplexing. In this embodiment, conventional CGMS information (CGMS-D) is added to the digital video signal thus converted into the transport streams TP1 to TPN.

On the other hand, the transport stream T
The CGMS information in P1 to TPN is defined by extending the conventional CGMS information (CGMS-D) as a copy protection descriptor among various descriptors, as shown in FIG. That is, when the 2-bit copy control type is "0, 1", the CGMS information is the same as the conventional CGMS information (CGM) as described above with reference to FIG.
Copy control information (DRCD: Di) defined in the same way as SD)
gital Recoding Control Data). The copy control type is a field indicating the presence / absence of encryption by 2 bits. When the logic is "0, 1", the transport stream encryption processing is instructed. When the logic is "1, 1", the encryption is performed. Indicates not to process.

Further, in this embodiment, when the copy control type is "0, 1", the extended CG
Define MS information (M-CGMS). Here, this extended CGMS information (M-CGMS) is
According to the MS information (CGMS-D), generation (Free) (logical "0, 0") in which copying is not restricted at all, generation (Copy Once) (logical "1,
0 "), and a generation (Never Copy) (logical" 1, 1 ") in which copying is not permitted.

In addition to this, extended CGMS information (M-
CGMS) is conventional CGMS information (CGMS-
In D), a copy prohibited generation (No More Copy) thereafter is defined for the logic "0, 1" which is not defined at all. Thus, in this embodiment, a copy-prohibited one (1, 1) is distinguished from a copy-prohibited one (1, 0) that can be copied only once (1, 0). It has been made possible. Note that, in order to enable trial listening of a program by a so-called time shift, CGMS information (M-CGMS) in digital satellite broadcasting is set to a generation other than a generation (Negative Copy) (logical "1, 1"), which is generally not allowed to be copied. Is done.

In the copy protection descriptor,
Following the copy control type field, an analog copy protection field is formed.
Here, the analog copy protection regulates the output of a video signal by an analog signal, and includes four steps to limit copying, including a case where copying is not limited at all.

That is, the analog copy protection is stipulated to output a video signal without performing any copy guard processing when the code "0, 0" is set to permit copying. When the code “0, 1” indicating the copy guard of 1 is set, it is defined that the pseudo sync signal and the AGC pulse are inserted into the video signal and output. Also, when the code "1, 0" indicating the type 2 copy guard is set, in addition to the type 1 processing, two continuous lines are inverted, and a divided burst is inserted to output a video signal. When the code "1,1" indicating the type 3 copy guard is set, in addition to the type 1 processing, four continuous lines are inverted, a divided burst is inserted, and a video signal is output. Stipulated.

In this embodiment, the copy control type is the conventional CGMS information (CGMS-
The copy control type is set when converting a digital video signal and a digital audio signal into a transport stream so as to correspond to D), and the copy control type indicates a copy generation of the video signal by an analog signal.
It corresponds to MS information (CGMS-A).

When generating the transport streams TP1 to TPN, the broadcast station 2 uses the conventional CGMS information (CGMS-CG) added to the digital video signal.
D) is an extended CGMS in the format shown in FIG.
Convert to information (M-CGMS). In addition, broadcast station 2
Conditional reception (CA: Conditional Acces) of transport streams transmitted by time-division multiplexing in this way
The program of s) is transmitted through the scrambler 9 after being encrypted by the encryption method adopted by the broadcasting station 2.

In this way, the conventional C
When converting the GMS information (CGMS-D) into the extended CGMS information (M-CGMS), the conventional CGMS information (CGMS-D) for managing the copy generation in three stages has been expanded to manage the copy generation in four stages. CGMS information (M-
Broadcast station 2 by converting to CGMS) and because the codes indicating the three copy generations in the CGMS information (CGMS-D) correspond to the codes indicating the copy generations in the CGMS information (M-CGMS). , Simply update the copy control type field and
Convert MS information. In this embodiment,
It indicates that the frame between the CGMS information and the content is encrypted by hatching.

Thus, in the encryption of such digital satellite broadcasting, regardless of the copyright of the content, it is set from the viewpoint of whether or not to permit the trial listening by charging. As a result, the broadcast station 2 transmits the CGMS information and the content by encrypting the broadcast station 2 using its own encryption, and separately transmits the key data for decrypting the encryption in a packet or the like.

The home 4 receives a broadcast wave that is downlinked from the satellite 3 via the antenna 10, and
A desired broadcast wave is received by processing by an RD (Integrated Receiver Decoder) 11. Further home 4
In, about the program by this received broadcast wave,
A digital video signal DV and a video signal AV based on an analog signal are output to various devices. In the home 4, the received program is recorded and reproduced on the optical disk device 12 as a bit stream recorder via the IEEE1394 bus BUS.

FIG. 1 is a block diagram showing the IRD 11 and the optical disk device 12. In the IRD 11, the tuning circuit 21 receives a broadcast wave from the antenna 10 via a down-converter (not shown), and receives a desired broadcast channel from the broadcast wave. Further, the channel selection circuit 21 outputs a transport stream TP of a program selected by the user by selectively taking in a desired bucket from the received broadcast channel and extending the time axis.

The descrambler 22 includes the tuning circuit 2
If the transport stream TP output from 1 has been encrypted, it is decrypted and output.

The decoder (DEC) 23 processes the transport stream TP output from the descrambler 22 to generate a digital video signal and a digital audio signal. When the user selects the trial listening of the optical disk device 12 instead of the digital satellite broadcast, the decoder 23 replaces the transport stream TP output from the descrambler 22 with the transport stream T output from the descrambler 24.
P, thereby outputting a digital video signal and a digital audio signal reproduced by the optical disk device 12.

At this time, the decoder 23 converts the extended CGMS information (M-CGMS) added to the transport stream according to the conversion rule shown in FIG.
It is converted into S information (CGMS-D), added to a digital video signal, and output.

As described above, the transport stream TP output from the descrambler 22 is simply transmitted via the transmission path of digital satellite broadcasting, and the transport stream T
The CGMS information (M-CGMS) added to the P is the extended CGMS information (M-CGMS) corresponding to the conventional CGMS information (CGMS-D) added to the digital video signal.
-CGMS). Thus, in this embodiment, when processing the transport stream TP output from the descrambler 22, the decoder 23 simply holds the code of the extended CGMS information (M-CGMS) at the same value. CGMS information (M-CGMS) extended by format conversion is converted to conventional CGMS information (CGMS-
D).

On the other hand, in this embodiment,
The transport stream reproduced by the optical disc apparatus 12 is input from the descrambler 24 to the decoder 23. In this case, the decoder 23
In the transport stream that is input to, a copy generation of only one generation proceeds, and a copy prohibited generation (No More Copy) occurs after this. In this case, the CGMS added to the transport stream TP
In information (M-CGMS), logic “0, 1” not defined in conventional CGMS information (CGMS-D)
Will exist.

In the decoder 23, the extended CGMS information (M-CGMS) is converted to logic "0, 1".
, The code based on the logic “0, 1” is
The GMS information (CGMS-D) is converted into a code based on logic "1, 1" indicating a generation (No Copy) in which copying is not permitted, and then the format is converted to conventional CGMS information (CGMS-D). In this way, when the transport stream TP is input from the descrambler 24, the decoder 23 transmits the encrypted information (EMI) detected by the descrambler 24 and the CGMS information (M-CGM) added to the transport stream TP.
S). Further, the decoder 23 determines that the copy generation based on the encrypted information (EMI) is C
If the copy information is advanced from the GMS information (M-CGMS), the CGMS information (M-CGMS) is added to the copy generation based on the encryption information (EMI).
-CGMS).

Here, the encrypted information (EMI) is based on the IEEE
CGMS information (MC) that is used to specify the encryption mode in 1394 and is extended as shown in FIG.
GMS) to define an encryption mode. That is, the encryption information (EMI) specifies not to be encrypted when the logic is “0, 0”, and specifies the encryption by mode C having the lowest level when the logic is “0, 1”. Further, the encryption information (EMI) designates encryption by mode B having the next highest level after mode C in the case of logic "1,0", and has the highest level in the case of logic "1,1". Specifies encryption in mode A.

As a result, the decoder 23 updates the copy information constituting means for updating the copy generation based on the CGMS information (M-CGMS).

Digital-to-analog conversion circuit (D / A) 2
5 performs digital-to-analog conversion processing of the digital video signal and digital audio signal output from the decoder 23, and outputs a video signal and an audio signal based on the analog signal to an external device. In these processes,
The digital-to-analog conversion circuit (D / A) 25 outputs CGMS information (CGMS-CG) added to the digital video signal.
D) is a CGM corresponding to a video signal based on an analog signal.
After being converted into S information (CGMS-A), it is added to a video signal and output.

The copy guard circuit 26 performs copy protection processing on the video signal in accordance with the CGMS information (CGMS-A) of the video signal and the analog copy protection described above with reference to FIG. 3, and outputs the video signal to an external device.

The interface (I / F) 28 outputs the digital video signal and digital audio signal output from the decoder 23 to an external device in a predetermined format.

The scrambler 30 encrypts the transport stream TP output from the descrambler 22 and outputs it. At this time, the scrambler 30
Is the CGM added to the transport stream TP
Encryption information (EMI) indicating an encryption mode is set according to the S information (M-CGMS), and the encryption information (EM) is set.
The transport stream TP is encrypted according to I).

The scrambler 30 forms a packet from the transport stream encrypted in this way, and adds encryption information (EM
I) is added and output.

The interface (I / F) 31 is connected to the IE
An input / output circuit of the EE1394 bus BUS is configured to output output data of the scrambler 30 to an external device, and output data input by designating the IRD 11 from the external device to the descrambler 24. Thereby, IRD11
Is connected to an external device via the IEEE 1394 bus BUS so that a reception result and the like can be input and output.

The descrambler 24, contrary to the scrambler 30, decrypts the input data input from the interface 31 according to the encryption information (EMI) added to the input data and outputs the decrypted data. Further, the descrambler 24 uses the encrypted information (EM
I) to the decoder 23.

In the optical disk device 12, an interface (I / F) 40 is an IEEE 1394 bus BUS.
The IRD 11 is connected to other external devices via the IRD 11 and inputs and outputs various data to and from these devices. In these processings, the interface (I / F) 40
Inputs a transport stream packet output from the IRD 11 via the E1394 bus BUS,
Output to the descrambler 41. The output data of the scrambler 42 is output to the IRD 11.

The descrambler 41 receives the output data of the interface 40, and uses the subcode added to the packet, which is the output data, to encrypt information (EMI).
Is obtained, and the encryption is released in accordance with the encryption information (EMI). The descrambler 41 expands the packet decrypted in this way on the time axis, and outputs the packet along with the encrypted information (EMI) by the transport stream TP.

When the encryption information (EMI) is a logic "1, 0" indicating that only one generation is permitted to copy in the CGMS information (M-CGMS), the updating circuit 43 updates the encryption information (EMI). By converting the digital video signal to logical "0, 1", the copy generation of the digital video signal based on the transport stream TP is updated and output only for the encrypted information (EMI).

The scrambler 44 encrypts the transport stream TP output from the descrambler 41 by the encryption method set for the optical disk device 12 and outputs the encrypted data. At this time, Scrambler 4
No. 4 stops the processing of the transport stream TP when the transport stream TP is transmitted in the mode C corresponding to the copy prohibition according to the encryption information (EMI). As a result, in the optical disk device 12, copying is stopped for the generation of copy prohibition.

The recording system 45 processes the output data of the scrambler 44 in a format suitable for recording on the optical disk 46 and then records the data on the optical disk 46 together with the encrypted information (EMI). Thus, in this embodiment, the reception result of the transport stream encrypted and transmitted as necessary can be recorded on the optical disc 46.

As shown in FIG. 5, the reproduction system 48 receives the return light obtained by irradiating the optical disk 46 with a light beam, processes the return light, and thereby encrypts the transport stream TP recorded on the optical disk 46. Encrypted information (E
MI). The descrambler 49 decrypts the transport stream TP reproduced by the reproducing system 48 and outputs it.

The scrambler 42 encrypts the transport stream TP output from the descrambler 49 and outputs it. At this time, the scrambler 42
Encrypts the transport stream according to the reproduced encryption information (EMI), like the scrambler 30.

(2) Operation of the Embodiment In the above configuration, a program by digital satellite broadcasting (FIG. 2) is supplied to the broadcasting station 2 by transport streams TP1 to TPN in an MPEG format via a server or the like. Here, the signals are time-division multiplexed and frequency multiplexed, and uplinked to the satellite 3, then downlinked from the satellite 3 and provided to each home 4.

At this time, in the digital video signal, the conventional CGMS information (CGM
SD) (FIG. 7) extended CGMS information (M-CGM)
S) (FIG. 3) and is added to each of the transport streams TP1 to TPN. At this time, the extended CGMS information (M-CGMS) is formed so as to indicate an extra copy generation by three copy generations in the conventional CGMS information (CGMS-D), and is further formed by the conventional CGMS information (CGMS-CGMS). −D), generation (Free) in which no copy is restricted by logic “0,0”, logic “1,
0 (copy onc)
e), generations (No Copy) for which copying by the logic "1,1" is not permitted are generated by allocating to the descriptors of the respective transport streams TP1 to TPN without any change in the logic level.

When a program related to conditional access is transmitted in this way, the corresponding transport stream TP1 is encrypted by the scrambler 9 and transmitted.

Thus, the conventional CGMS information (CGMS information)
-D), a digital video signal of a generation (Copy Once) in which copying by only one generation according to the logic "1,0" is permitted, and in a digital video signal of a program related to conditional access, the logic " CGMS information (M-CGM
After the descriptor according to S) is added, the whole is encrypted and transmitted according to the digital satellite broadcast format.

Each program transmitted in this manner is stored in the IR
In the channel selection circuit 21 of D11 (FIGS. 1 and 5), the transport stream TP of the program desired by the user is demodulated, and the transport stream TP is converted by the decoder 23 into a digital video signal and a digital audio signal. Further, the digital video signal and the digital audio signal are converted into analog signals by a digital-to-analog conversion circuit and transmitted to an external device, whereby a desired program can be previewed through, for example, a monitor device.

At this time, each transport stream TP
CGMS information (M-CGMS) added to the file
Is the transport stream T at the decoder 23.
When P is converted into a digital video signal and a digital audio signal, the signal is converted into conventional CGMS information (CGMS-D), contrary to the processing in the broadcasting station 2. Further, the conventional CGMS information (CGMS-D) is converted into CGMS information (CGMS-A) indicating a copy generation of a video signal by an analog signal, and the CGMS information (CGMS-D) is converted.
MS-A) is added to the analog video signal output from the IRD 11. In the IRD 11, a copy guard process is further executed by the copy guard circuit 26 in accordance with the CGMS information (CGMS-A), thereby preventing illegal copying.

That is, the conventional CGMS according to the above-described example
In the digital video signal of the generation (Copy Once) in which only one generation by the logic "1,0" is permitted in the information (CGMS-D), and the digital video signal of the program related to the conditional access, the descrambler 22 After decryption, extended C with logic "1,0"
The GMS information (M-CGMS) is transmitted to the decoder 23 by the decoder 23.
Conventional CGMS information (CGMS-
D), and this CGMS information (CGMS-D) is further converted to conventional CGMS information (CG
MS-A). Thus, the digital video signal is converted into an analog video signal according to the CGMS information (CGMS-A) and output.

In the IRD 11, the digital video signal and digital audio signal demodulated by the decoder 23 are
8 and output to an external device in a predetermined format. At this time, in the digital video signal, conventional CGMS information (CGMS-D) converted from the extended CGMS information (M-CGMS) is added and output. Thereby, the CGMS information (C
By grasping the copy generation according to GMS-D) and restricting the copy, it is possible to effectively protect the copyright.

On the other hand, the transport stream TP demodulated by the descrambler 22 is output to the IEEE 1394 bus BUS via the interface 31 and supplied to the optical disk device 12 and other external devices via the IEEE 1394 bus BUS. Is done.

At this time, the transport stream T
In P, encryption information (EMI) indicating an encryption mode is set according to the extended CGMS information (M-CGMS) (FIG. 4), and encryption processing is performed according to the encryption information (EMI). That is, the conventional CGMS according to the above-described example
Regarding the digital video signal of the generation (Copy Once) in which only one generation by the logic "1, 0" is permitted in the information (CGMS-D), regardless of the presence or absence of the program related to the conditional access, the logic "1, 0" 0 (EM)
I) is set, and is encrypted and transmitted by the mode B encryption processing in accordance with the encryption information (EMI) based on the logic “1, 0”.

The transport stream TP encrypted and transmitted as described above is transmitted to the descrambler 41.
Is decrypted by a process in accordance with the encrypted information (EMI), and in a subsequent scrambler 44, an encryption process for recording on the optical disk 46 is performed, and thereafter, is recorded on the optical disk 46 by the recording system 45. .

At this time, logic "1, 1" for inhibiting copying
In the transport stream TP to which the extended CGMS information (M-CGMS) is added, the recording on the optical disk 46 is stopped, and the copy is prohibited for the copy-prohibited generation to protect the copyright. Can be

Further, at this time, in the transport stream TP, the encrypted information (EMI) is updated for one generation, and the optical disk 4 is updated together with the updated encrypted information (EMI).
6 is recorded.

That is, in the transport stream TP to which the extended CGMS information (M-CGMS) based on the logic “1,0” according to the above example is added,
By indicating that the GMS information (M-CGMS) is a generation that permits copying only for one generation, the updating circuit 43
In, the encryption information (EMI) corresponding to the CGMS information (M-CGMS) is updated to the logic “0, 1” for prohibiting the copy following the logic “1, 0” and the optical disc 4
6 is recorded.

On the other hand, in the transport stream TP recorded on the optical disk 46 (FIG. 5), the encrypted transport stream TP is reproduced via the reproducing system 48, and this transport stream TP
Is decrypted by the descrambler 49. This allows the conventional CGMS information (CGMS information) according to the above example to be obtained.
-D), in a digital video signal of a generation (CopyOnce) in which only one generation by logic "1,0" is permitted to be copied, the extended CGMS by logic "1,0"
The information is output from the descrambler 49 together with the encryption information (EMI) by the logic “0, 1” by the transport stream TP which is decrypted with the information (M-CGMS) added.

The read-only optical disk is an optical disk 4.
When the transport stream TP is loaded in the transport stream TP, the transport stream TP encrypted in the same manner is played back via the playback system 48, and the encryption of the transport stream TP is decrypted by the descrambler 49. Thus, in this case, the extended CG by the logic "1,0" that permits copying only once or the logic "1,1" that does not permit copying
The transport stream TP, which has been decrypted with the MS information (M-CGMS) added thereto, is encrypted together with the corresponding logical "1,0" or logical "1,1" encrypted information (EMI) together with the desk. Output from the rambler 49.

The transport stream TP reproduced from the optical disk 46 in this manner is encoded by the scrambler 42 with encryption information (EM) indicating the encryption mode.
Encryption processing is performed according to I). Further, the data is output to the IEEE 1394 bus BUS via the interface 31, and is thereby supplied to the IRD 11, other external devices and the like via the IEEE 1394 bus BUS.

In this case, the extended CGMS information (MC) by the logic “1, 0” according to the example described with reference to FIG.
GMS), the transport stream TP is added to the transport stream TP by the logic “1, 0”, and the transport stream TP is encrypted by the mode C corresponding to the encryption information (EMI) of the logic “0, 1”. And sent out.

The transport stream TP sent to the bus BUS in this manner is transmitted to the interface 31
Is input to the descrambler 24, where the encryption is decrypted and the encrypted information (EMI) is detected. After being further converted into a digital video signal and a digital audio signal in the subsequent decoder 23,
The digital video signal and the digital audio signal are output to an external device via the interface 28, and the video signal and the audio signal based on the analog signal are output via the copy guard circuit 26.

At this time, the extended CGMS information (M-CGMS) added to the transport stream TP
When the decoder 23 converts the digital signal into a digital video signal and a digital audio signal, the copy generation is updated in accordance with the encryption information (EMI), and then the CGMS information (CGMS-
D). In this conversion, CGMS information (CGMS-D) is included in the transport stream TP transmitted from the optical disk device 12 in this manner.
Includes a generation that is reproduced from the optical disk 46 that is not defined and whose subsequent copy is prohibited, and for the logic “0, 1” related to this generation, the logic “1” that similarly prohibits the subsequent copy , 1 ”to CGMS information (CGMS-D).

Thus, the optical disk device 12
The transport stream output from
It is processed in the same manner as the transport stream received by the IRD 11, and is output to an external device by a digital video signal and a digital audio signal, or a video signal and an audio signal by an analog signal.

(3) Effects of the Embodiment According to the above configuration, the conventional CGMS information (CGM
In addition to extending the copy generation that can be represented by the CGMS information (M-CGMS) extended by defining a code that is not defined in SD) and converting the generation information as necessary, When the encryption mode is switched according to the copy generation of the signal, the copy generation of the digital signal can be easily managed.

(4) Other Embodiments In the above-described embodiment, the case where a digital video signal is transmitted by digital satellite broadcasting and encryption is performed in a format by a broadcasting station has been described. The encryption mode is not limited to this, and in this case, the encryption mode may be switched by the extended CGMS information (M-CGMS). In this way, the processing of the encrypted transport stream by various digital satellite broadcasting systems can be temporarily managed on the IRD side.

In the above-described embodiment, the extended CGM is defined so that an undefined code is defined in the conventional CGMS information (CGMS-D) using two bits.
Although the case where the S information (M-CGMS) is defined has been described, the present invention is not limited to this. For example, CGMS extended by 3-bit code with respect to conventional 2-bit CGMS information (CGMS-D), for example. Information (M-CGM
S) may be defined. In this way, the copy generation can be managed more finely.

Further, in the above-described embodiment, a case has been described in which a transport stream is recorded on an optical disk device by applying the present invention to a digital satellite broadcasting system. However, the present invention is not limited to this. This can be widely applied to the case of recording, for example.

In the above-described embodiment, the IEEE
Although the case where the transport stream is transmitted by E1394 has been described, the present invention is not limited to this. When the transport stream is transmitted by various interfaces, the transport stream is transmitted by a recording medium such as an optical disk, a magnetic tape, and a magnetic disk. It can be widely applied to transmission.

Further, in the above-described embodiment, the case has been described where the digital video signal is transmitted by managing the encryption processing using the CGMS information which is the generation information. However, the present invention is limited to the case where the encryption processing is managed. Instead, it can be widely applied to various management of digital video signals based on these generation information.

Further, in the above embodiment, the case where the digital video signal is transmitted by the transport stream has been described. However, the present invention is not limited to this.
The present invention can be widely applied to transmitting digital video signals in various formats, and further to transmitting various digital signals such as digital audio signals.

[0086]

As described above, according to the present invention, the first generation information is defined so as to extend the second generation information indicating the copy generation of the unencrypted digital signal. In addition, by converting these generation information as needed, in the case where the encryption mode is switched according to the copy generation of the digital signal, the copy generation of the digital signal can be easily managed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a receiving side applied to a satellite broadcasting system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an overall configuration of a satellite broadcasting system.

FIG. 3 is a table showing descriptors added to a transport stream.

FIG. 4 is a table showing encryption information.

FIG. 5 is a block diagram for explaining a transport stream reproduced by comparison with FIG. 1;

FIG. 6 is a chart for explaining a process of changing extended CGMS information into conventional CGMS information.

FIG. 7 is a table showing conventional CGMS information.

[Explanation of symbols]

1 ... satellite broadcasting system, 2 ... broadcasting station, 3 ... satellite,
4. Home, 9, 22, 30, 42, 44 Scrambler, 24, 41, 49 Descrambler, 46
……optical disk

Claims (6)

[Claims] An encryption means for encrypting the digital signal and the first generation information to generate an encrypted digital signal in an encryption mode according to the first generation information added to the digital signal. Transmitting means for transmitting the encrypted digital signal and encryption information indicating the encryption mode, wherein the first generation information is information indicating a copy generation of the digital signal; This is information that is set in place of the generation information of the second generation information. The type of generation to be expressed is set more than the second generation information, and the second generation information is an unencrypted digital data. A digital signal transmission device, which is information indicating a copy generation of a signal. 2. An encrypted digital signal is generated by encrypting the digital signal and the first generation information in an encryption mode according to the first generation information added to the digital signal. The first generation information is information indicating a copy generation of the digital signal, and is information set in place of the second generation information. More types of generations to be expressed are set as compared to the second generation information, and the second generation information is information indicating a copy generation of an unencrypted digital signal. A method for transmitting a digital signal, comprising: 3. A reproducing means for reproducing a digital signal encrypted from a recording medium, a decryption means for decrypting the encrypted digital signal, and a decryption by the decryption means. Information conversion means for converting the first generation information added to the obtained digital signal into second generation information, wherein the second generation information is information indicating a copy generation of the unencrypted digital signal. Wherein the first generation information is information indicating a copy generation of the digital signal, and is information set in place of the second generation information. A digital signal transmission device characterized in that many types of generations to be expressed are set. 4. An encrypted digital signal is reproduced from a recording medium, the encrypted digital signal is decrypted, and the first digital signal added to the decrypted digital signal is reproduced.
Is converted into second generation information, wherein the second generation information is information indicating a copy generation of an unencrypted digital signal, and the first generation information is a copy of the digital signal. This is information indicating a generation, which is set in place of the second generation information, and is characterized in that a larger number of types of generations are set than in the second generation information. A method for transmitting digital signals. 5. A digital signal recording medium for recording an encrypted digital signal, wherein the digital signal is encrypted in an encryption mode according to the added first generation information, The first generation information is recorded together with encryption information indicating an encryption mode, the first generation information is information indicating a copy generation of the digital signal, and the information is set in place of the second generation information. The number of types of generations to be expressed is set more than the second generation information, and the second generation information is information indicating a copy generation of an unencrypted digital signal. Signal recording medium. 6. The digital signal recording medium according to claim 5, wherein said digital signal is a digital video signal.