JP2000295202A - Limited reception system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly execute descrambling when a channel is changed-over by permitting a transmitting device to scramble a plurality of channels through the use of common key data, permitting a receiving device to hold common key data and executing descrambling by means of common key data which is held in a key holding means even when any channel is selected. SOLUTION: A key managing device 1.1 generates a work key Kw and stores it in individual information EMM. Then a work key Kw enciphering device 1.2 enciphers individual information EMM through the use of an individual key Kmi which is previously received from the key managing device 1.1 and transmits it to a transport stream TS multiplexing part 1.3 as enciphered individual information EMM. Besides, a scramble key Ks is generated by the device 1.1 and stored in common information ECM. Then a scramble key Ks enciphering part 1.4 enciphers common information ECM through the use of the work key K2 which is previously received from the device 1.1 and transmits it to the Ts multiplexing part 1.3 as common information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cable television,
In a satellite broadcast, terrestrial broadcast, or the like, a conditional access system that scrambles and broadcasts a program and enables descrambling only when the user has a right to view, especially when the channel is switched, descrambling can be started quickly. It is like that.

[0002]

2. Description of the Related Art MP is a conventional standard conditional access method.
In EG2SYSTEMS (ISO / IEC13818-1), the transmitting side converts the contents such as video and data into a scramble key Ks.
After the scramble key Ks is stored in an ECM (Entitlement Control Messages: common information), the common information ECM is transmitted to the work key Kw.
And send it. The work key Kw is stored in advance in an EMM (Entitlement Management Messages: individual information), and then encrypted with Kmi and transmitted.

On the other hand, when receiving the encrypted individual information EMM, the receiving side receives the individual key Km
i, and the work key Kw is extracted from the EMM and held. When receiving the encrypted common information ECM and the scrambled content stream,
The CM is decrypted with the work key Kw, the scramble key Ks is extracted from the ECM, and the scrambled content stream is descrambled using the extracted Ks. The descrambled video is converted into an analog signal that can be viewed by an AV decoder.

[0004]

In the conventional standard conditional access system, the scrambler key Ks is newly obtained from the ECM every time the channel is switched, so that the descrambling is restarted. There was a problem that it took time before.

In order to avoid this problem, a unique method of directly controlling whether a channel can be viewed or not is adopted instead of the standard method using the ECM on the transmitting side.
There is a problem that only a receiving device of a unique system adapted to a system on the transmission side can cope with the problem, and a receiving device of a standard conditional access system using an ECM cannot perform conditional reception.

The present invention solves such a problem, and it is possible to quickly descramble when a channel is switched, and to perform conditional reception even in a standard conditional access receiving apparatus using an ECM. It is an object of the present invention to provide a conditional access system that can perform the processing itself without any trouble.

[0007]

Therefore, in the conditional access system according to the present invention, the transmitting apparatus scrambles a plurality of channels using common key data, and the receiving apparatus sets a key for holding the common key data. A storage unit is provided, and descramble is performed using the common key data stored in the key storage unit, regardless of which channel is selected.

Therefore, even if the receiving channel is switched to another channel having the right to view, the receiving device uses the held scramble key without switching to the reception of the common information ECM. Can descramble the data of the channel.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides a key generating means for generating key data for scrambling a plurality of channel data, and a scrambling means for scrambling the channel data using the key data. And a receiving device including a descrambling means for descrambling an arbitrary channel selected from a plurality of channels using the key data, wherein the transmitting device comprises a plurality of transmitting devices. Channel is scrambled using common key data,
The receiving device includes key holding means for holding the common key data, and descrambles using the common key data held in the key holding means regardless of which channel is selected. In a case where the receiving device switches a channel being received to another channel having a right to view, the receiving device descrambles the data of the channel without waiting for reception of the common information ECM, thereby enabling viewing.

[0010] According to a second aspect of the present invention, the transmitting device transmits the common key data included in the related information for storing the key data, and the receiving device transmits the common key data acquired from the related information. It is designed to be held by key holding means,
When the transmission device scrambles each channel data using the common key data, the transmission device transmits the key data with related information (that is, the individual information EMM and the common information ECM), and the reception device obtains the key data from the related information. The common key data obtained is used for descrambling of each channel.

According to a third aspect of the present invention, the transmitting apparatus transmits the related information storing the key data together with the identification information indicating whether the key data is the common key data. A special key decryption module that obtains common key data held by the key holding unit from related information including identification information indicating common key data, and a general-purpose key module that obtains key data from related information each time the receiving channel changes A key decryption module, and when the related information includes identification information indicating common key data, the data is obtained by using the common key data acquired by the special key decryption module and held by the key holding means. If the related information does not include identification information indicating the common key data, descrambling is performed using the key data obtained by the general-purpose key decryption module. Are those, it can be by a single receiving device, corresponding to the method of the two kinds of conditional access system and conventional general limited reception method according to claim 1.

According to a fourth aspect of the present invention, the transmitting device transmits the related information storing the key data, and the receiving device obtains the common key data held by the key holding unit from the related information. A decryption module, and obtains key data from the related information every time the reception channel changes, a mountable general-purpose key decryption module, and a detection unit that detects whether or not the general-purpose key decryption module is mounted, and the detection unit includes: When the implementation of the general-purpose key decryption module has not been detected, descrambling is performed using the common key data acquired by the special key decryption module and held by the key holding unit. Is detected, the data is descrambled using the key data obtained by the general-purpose key decryption module,
One receiver can support two systems, the conditional access system of claim 1 and the conventional general conditional access system.

[0013] According to a fifth aspect of the present invention, when the receiving channel of the receiving device is changed, the special key decryption module receives information on the channel currently being received and determines whether or not viewing is possible. It is determined whether or not the switched channel is a channel having a viewing right, and if it is a channel having a viewing right, descrambling by common key data is started.

[0014] According to a sixth aspect of the present invention, the receiving apparatus, based on the related information received after the change of the receiving channel,
It checks the availability of viewing and stops the descrambling if there is no viewing right. The program information of the related information is checked, and if there is no viewing right, the descrambling is stopped. Reception security can be improved.

According to a seventh aspect of the present invention, the transmitting apparatus transmits the program including the program identification information in the related information, and does not have the special key decrypting module, but includes only the general-purpose key decrypting module. The determination of whether or not viewing is possible is made based on the identification information, and the conditional access system according to claim 1 can perform the conditional access process even with a conventional receiving apparatus using the conditional access system.

According to the invention described in claim 8, the general-purpose key decryption module is constituted by an IC card,
It is provided with a slot for inserting a C card, and a general conditional access module can be used as a general-purpose key decryption module.

According to a ninth aspect of the present invention, the receiving device includes program download means, and the special key decryption module is replaced by downloading from the transmitting device. It can be changed according to.

According to a tenth aspect of the present invention, the special key decryption module and the descrambler of the receiving device are PCMCIA.
The receiving device mounted on the card has a slot of the PCMCIA card, and the algorithm of the special key limited receiving system can be changed as needed.

[0019] According to an eleventh aspect of the present invention, the transmitting device comprises:
The related information storing the common key data is transmitted together with the version information, and the receiving apparatus continues to descramble using the same common key data held by the key holding unit until the version number is updated. Thus, there is no need to decode the related information until the content of the common information ECM is changed, and the processing load on the receiving device can be reduced.

[0020] According to a twelfth aspect of the present invention, the transmitting device comprises:
The related information containing the common key data is transmitted including a plurality of types of scramble keys, and the receiving apparatus holds the plurality of types of scramble keys in the key holding unit, and determines which scramble from the information of the non-scramble part of the content data packet. Identifies whether a key is used and selects a scramble key to be used for descrambling,
It is not necessary to strictly synchronize the update of the scramble key with the update timing of the common information.

According to a thirteenth aspect of the present invention, the receiving apparatus comprises:
Comprising program multiplex information holding means for holding program multiplex information,
Except when the program multiplex information is updated, the station is selected based on the program multiplex information held in the program multiplex information holding means, and the station is selected and the related information is received without waiting for the reception of the PSI. Is possible, and the response when changing channels is further improved.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

In the system of the embodiment, the transmitting device 12
8 is a scramble key Ks, a work key Kw, and an individual key K
a key management device 11 for generating and managing mi, a Kw encryption unit 12 for encrypting the individual information EMM storing the work key Kw with Kmi, and a common information ECM storing the scramble key Ks.
A Ks encryption unit 14 for encrypting the content with Kw, a content generation unit 16 for generating content such as video and data, and converting the content to the data format of a TS packet (Transport Stream Packet) of MPEG2 SYSTEMS (ISO / IEC13818-1). TS encoder 17 for conversion and MPEG2
SYSTEMS PSI (Program Specific Informati
on) according to channel and program information, individual information EMM, common information ECM,
MPEG-2SY transport stream and PSI
A TS multiplexing unit 13 for multiplexing as stipulated by STEMS (180 / IEC13818-1), and a scrambler 15 for scrambling only the content stream from the data multiplexed by the TS multiplexing unit 13 with the scramble key Ks. , A 64Q modulator 18 for 64Q modulating transmission data, and a frequency multiplexing unit 126 for frequency multiplexing the modulated signal.

On the other hand, the receiving apparatus 110 includes a frequency separating section 127 for separating the frequency of the signal received from the transmission line 19, a 64QAM demodulating section 111 for performing 64QAM demodulation of the received signal, a PSI, a video stream, and a common information ECM from the received signal. , A TS separator 112 for separating the individual information EMM, etc., a descrambler 114 for descrambling the video stream of the selected channel using Ks, and a TS decoder for converting the descrambled stream into a content stream format. 123, an AV decoder 124 for converting the content stream into a viewable analog signal, and a PSI
Program- to be filtered based on information
A control CPU 113 for transmitting the ID to the TS separation unit 112, descrambler 114, etc., a special key decryption module 115 for decrypting Ks, and a general-purpose key decryption module 116 composed of an IC card for decrypting Ks are provided. I have.

When the transmitting side uses a common Ks for a plurality of channels, the special key decryption module 115
, And decrypts the EMM with the individual key Kmi117 that is held in advance to extract Kw.
A ws decoding unit 118 and a Ks decoding unit 119 for decoding the ECM with Kw and extracting Ks are provided. The Ks decoding unit 119 is informed of the selected channel from the control CPU 113.

When the transmitting side does not use a common Ks for a plurality of channels, the general-purpose key decryption module 116 composed of an IC card decrypts the Ks. Similarly, a Kw decryption unit 121 that decrypts the EMM with the individual key Kmi120 to extract Kw and a Kw that decrypts the ECM with Kw and extracts Ks
s decoding section 122. This general-purpose key decryption module 116 is exchangeable by replacing an IC card.

First, an outline of transmission and reception in this system will be described.

On the sending side, the key management device 11 sends the work key Kw
Is generated and stored in the individual information EMM.
The encryption unit 12 stores the individual information EMM in advance in a key management device.
It encrypts using the Kmi received from 11 and sends it to the TS multiplexing unit 13 as encrypted individual information. TS
"Transport Stream Packet" in MPEG2 SYSTEMS (ISO / IEC13818-1).

The scramble key Ks is stored in a key management device.
After generating and storing the common information ECM in the common information ECM, the Ks encryption unit 14 encrypts the common information ECM using Kw received in advance from the key management device 11, and generates a TS multiplexing unit as encrypted common information. Send to 13.

Also, contents such as video and data are sent from the contents generation unit 16 to the TS encoder
TS in EG2SYSTEMS (ISO / IEC13818-1)
It is converted into the data format of the packet (Transport Stream Packet). The content data such as video information in the form of TS is sent to the TS multiplexing unit 13.

In the case of a multi-program configuration, content data is sent from a plurality of content generation units to respective TS encoders, and the TS encoder 17 converts the content data into TS packets and sends them to the TS multiplexing unit 13.

Further, the multiplex information generation unit 125
A 2SYSTEM PSI is generated according to the channel and program information, and sent to the TS multiplexing unit 13.

The individual information EM sent to the TS multiplexing unit 13
M, common information ECM, content stream and PSI
Are multiplexed as specified in MPEG2 SYSTEMS (18O / IEC13818-1) and sent to the scrambler 15. The scrambler 15 scrambles only the content stream using the scramble key Ks passed from the Ks encryption unit 14, sends the scrambled transport stream to the 64Q modulation unit 18, and performs 64QAM modulation. In addition, the frequency multiplexing unit 12 together with the 64QAM-modulated signal is used.
At 6, frequency multiplexing is performed, and transmitted to the transmission path 19.

On the other hand, in the receiving apparatus 110, the signal received from the transmission line 19 is frequency-separated by the frequency separation
The signal demodulated by the AM demodulation unit 111 is demodulated by the TS separation unit 1
Separated by 12.

The control CPU 113 acquires a Program-ID to be filtered based on the PSI information of the channel selected by the receiving device operation unit, and transmits the Program-ID to the TS separation unit 112, whereby the TS separation unit 112 The transport stream obtained by demodulating the channel can be separated into related information (hereinafter, collectively referred to as common information ECM and individual information EMM), a video stream, and the like. Further, the control CPU 113 sets the Pr to be descrambled.
The program-ID is set in the descrambler 114, and the selected channel is set in the Ks decoding unit 119.

The receiving apparatus 110 has a special key decrypting module 115 mounted on a circuit board in the receiving apparatus and a general-purpose key decrypting module 116 composed of an IC card.
The related information separated by the S separation unit 112 is sent to either the special key decryption module 115 or the general key decryption module 116, where the scramble key Ks for descrambling the content is extracted.

For example, when the special key decryption module 115 is used, the individual information EMM separated by the TS separation unit 112 is decrypted by the Kw decryption unit 118 using the individual key Kmi 117 which is stored in advance, and The work key Kw stored in the EMM is extracted, and the Ks decryption unit 119
Is set to Further, the common information ECM separated by the TS separation unit 112 is decrypted by the Ks decryption unit 119 using the work key Kw retrieved earlier, and the Ks stored in the common context ECM is retrieved and the Ks decrypted. The rambler 114 is set.

A content stream such as a video separated by the TS separation unit 112 is transmitted to a descrambler 114 by a descrambler 114.
The content is descrambled using the set scramble key Ks, sent to the TS decoder 123 and converted into a content stream format.
Is converted into an analog signal that can be viewed.

The above is an outline of the transmission / reception method. Next, a more detailed transmission / reception method will be described while showing specific contents of the common information ECM and the individual information EMM.

As processing on the transmitting side, first, the key capping device 11
Generates the individual information EMM in the data format shown in FIG. 3 for each receiving device. Also, the Kw encryption unit 12 uses only the encryption unit having the data format shown in FIG.
The packet is encrypted by i, converted into a TS packet, and transmitted through the TS multiplexing unit 13 before the program is transmitted.

The meaning of each field of the individual information EMM is as follows. The module identification flag of the non-encrypted part includes the special key decryption module 115 or the general key decryption module 1
Information identifying which of 16 is used is entered. Here, identification information indicating the special key decryption module 115 is entered. The ID for identifying the receiving device is entered in the receiving device ID. The version information contains the version information of the individual information for each receiving device ID. That is, when sending the individual information to the receiving device, the sending side increments the value of the version information and sends it each time updating the individual information for each receiving device ID.
In the field to be encrypted, a work key and individual authorization information to be given to the corresponding receiver ID are entered.

The key management device 11 generates the common information ECM of the data format shown in FIG. 2 for each channel. The Ks encryption section 14 encrypts only the encryption section having the data format shown in FIG.
It is packetized and transmitted through the TS multiplexing unit 13.

The meaning of each field of the common information ECM is as follows. As with the individual information EMM described above, the module identification flag and the version information are added to the non-encrypted part. However, the version information will only be updated if a non-scramble key such as the program identification information of the encryption unit is updated.
The version information of the common information of all channels is updated all at once. Normally, a number is set in the version information, and the version information is incremented and set for each update.

The scrambling key and the program identification information are put in the encryption section. As the scramble key, a key common to each channel is set as two types of scramble keys 1 and 2. The information as to which scramble key is used at a certain point in time is determined by transport in the TS packet header of the content stream.
Set in _scramble1ing-control. For example, the scramble key Ks is updated by changing the scramble key 1 and the scramble key 2 alternately every minute.

The Ks encryption unit 14 sets Ks for the scrambler 15 in common to all scrambled content streams. Further, the Ks encryption unit 14 generates and transmits common information ECM in which a common scramble key is set for each channel.

On the other hand, in the receiving apparatus 110, when the related information is received, the TS separation unit 112 refers to the information of the module identification flag of the related information, and according to the flag,
Special key decryption module 115 or general-purpose key decryption module 1
The relevant information is distributed to any one of 16 and sent.

The individual information EMM sent to the special key decryption module 115 is transmitted to the Kw decryption unit 118 by the receiving device I.
Only when D matches the corresponding receiving device and it is determined from the version information that it has been updated from the previously received individual information, decryption is performed with the individual key Kmi117, Kw and individual authorization information are extracted, and Ks decryption is performed. Is set in the conversion unit 119. Note that the filtering by the receiving device ID may be performed in advance by the TS separation unit 112.

When the TS separating section 112 receives the common information ECM and distributes the common information ECM to the special key decryption module 115 based on the module identification flag, first, the common information ECM currently being received is converted to the special key decryption module 115.
The control CPU 113 is notified that decryption processing has been performed. Next, the Ks decoding unit 119 to which the common information ECM is input
Then, only when it is determined that the version information has been updated from the previously received common information, the ECM is decrypted using the work key Kw set earlier. Then, it compares the individual authorization information and the program identification information from the decrypted data, extracts the scramble key 1 and the scramble key 2 only when the user has the channel viewing right, and sets both keys in the descrambler 114.

The descrambler 114 transmits the transport in the TS packet header of the content stream.
-Scrambling-control,
Whether to use the scramble key 1 or the scramble key 2 for descrambling is selected for each TS packet. Further, these keys are held in the Ks decryption unit 119 for processing at the time of channel change described later.

Next, processing when the channel is changed by the receiving device operation unit will be described.

When the channel is changed, the control CPU 11
3 determines whether the currently used decryption module is the special key decryption module 115 or the general-purpose key decryption module 116 from the above-described notification information, and when the special key decryption module 115 is used, Control CPU 113 to K
The changed channel information is notified directly to the s decoding unit 119.

The Ks decoding section 119 determines from the individual authorization information whether or not the notified channel is a channel having the viewing right, and if the channel has the viewing right, the scramble key Ks which is already held is determined by the desk. Rambler 114
Set to. If the scramble key is not set in the Ks decryption unit 119, the new common information ECM is received and decrypted to extract the scramble key Ks. Even after the channel is changed, the common information ECM is received, the program identification information is extracted and compared with the individual authorization information. As a result, if there is no viewing right, supply to the descrambler 114 to Ks is stopped.

In the case where the receiving device 110 does not newly verify the reception channel from the common information after changing the channel, the program identification information is not required in the common information. In this case, the common information itself can be made common to each channel.

In the receiving apparatus 110, the special key decryption module 115 and the descrambler 114
M, the decryption method and algorithm of the special key decryption module 115 by downloading data from the transmitting device,
The descrambling method may be replaced.

Further, the special key decryption module 115 and the descrambler 114 are mounted on a PCMCIA card, and the receiving device 110 is provided with a PCMCIA slot.
Special key decryption module 11 by replacing card
The decoding method, algorithm, and descrambling method of 5 may be replaced.

Next, in a receiving apparatus having no special key decryption module and having only the general key decryption module 116,
The case of receiving using the related information for the special key decryption module will be described. This assumes that the transmitting side uses this system and the receiving side is a conventional general-purpose receiving device that has only a function that can change the CA method using an IC card or the like. The method will explain that even in such a receiving apparatus, the effect of speeding up when changing channels is not obtained, but the conditional access processing itself is performed without any problem.

FIG. 6 shows the configuration of this receiving apparatus. FIG.
The only difference is that there is no special key decryption module 115 as compared with the receiving device of FIG.

In the conventional general-purpose receiving apparatus, there is no mechanism for referring to the information of the module identification flag of the related information, so that the TS separating section 112 determines that the receiving apparatus ID included in the individual information EMM is If they match and it is determined from the version information that the individual information has been updated from the previously received individual information, all the individual information EMM is sent to the general-purpose key decryption module 116.

In the general-purpose key decryption module 116, the Kw decryption unit 121 decrypts the EMM by using the individual key Kmi 120 which is possessed in advance, extracts Kw and the individual authorization information, and sets them in the Ks decryption unit 122. The Ks decryption unit 122 decrypts the common information ECM using the previously set work key Kw, compares the individual authorization information with the program identification information from the decrypted data, and has the channel viewing right. Only in this case, the scramble key 1 and the scramble key 2 are taken out, held in the Ks decryption unit 121, and both keys are set in the descrambler 114.

The descrambler 114 transmits the transport in the TS packet header of the content stream.
_Scramble1_control with reference to
Whether to use the scramble key 1 or the scramble key 2 for descrambling is selected for each TS packet.

When a channel is changed by the receiving device operation unit, the reception of new common information in the corresponding channel is waited, and when it is received, it is decrypted to extract the scramble key Ks and descramble the content stream. That is, the stored scramble key is not used as in the receiving apparatus for the present system having the special key decryption module 115.

Next, a case will be described in which the receiving apparatus 110 of FIG. 1 performs processing using the general-purpose key decryption module 116. This is because the receiving apparatus according to the present invention uses a conventional general C
It is assumed that reception by the A method is performed.

In this case, the transmitting side transmits the individual information EMM in the data format shown in FIG. 5, and transmits the common information ECM in the data format shown in FIG. The module identification flags of these non-encrypted parts contain information designating the use of the general-purpose key decryption module. Also, EM
The work key and the individual tier information corresponding to the corresponding receiver ID are entered in the encrypted field of M.
The data field of the CM to be encrypted contains a scrambler key and program tier information.

The receiving device has an IC card slot,
A configuration is provided in which an IC card incorporating the general-purpose key decryption module 116 can be inserted.

When the receiving apparatus receives the individual information EMM shown in FIG. 5, the TS separation section 112 refers to the information of the module identification flag of the related information, and requests the use of the general-purpose key decryption module 116 therefrom. , The individual information is distributed and sent to the general-purpose key decryption module 116 of the IC card. The subsequent processing is the same as the processing in the special key decryption module 115, and the Kw decryption unit 121
Ks and individual tier information are taken out and Ks decoding section 122
Set to.

When the TS separation unit 112 receives the common information ECM shown in FIG. 4, before distributing to the general-purpose key decryption module 116 based on the module identification flag,
The common information ECM currently being received is stored in the general-purpose key decryption module 11.
In step 6, the control CPU 113 is notified that the decryption process has been performed. Also, the Ks decoding unit 122 that has received the common information ECM
When the version information is updated from the previously received common information, the ECM is decrypted with the work key Kw and the individual tier information and the program tier are decrypted from the decrypted data, similarly to the processing in the special key decryption module 115. By comparing the information with the information and extracting the scramble key when there is a channel viewing right. However, the extracted scramble key is not stored in the Ks decryption unit 121, but is set in the descrambler 114.

Next, when the channel is changed, the control C
The PU 113 determines whether the currently used decryption module is the special key decryption module 115 or the general-purpose key decryption module 116 from the above-described notification information, and does nothing in the case of the general-purpose key decryption module 116. .

Receiving apparatus 110 waits for the reception of new common information ECM, and upon receiving the same, after Ks decryption section 122 of general-purpose key decryption module 116 decrypts the work information with the work key, receiving apparatus 110 compares the program tier information with the individual tier information. It is determined whether or not the viewing right is granted based on the combination.

In order to extract the content stream of the corresponding channel from the multiplex information at the time of channel selection, PSI information is obtained and extracted each time a channel is selected. However, the time required until the content stream is actually obtained from the channel selection is obtained. In order to further shorten the time, PSI information may be stored in the receiving device in advance, and the content stream and the related information of the corresponding channel may be separated based on the PSI information.

In the present embodiment, the receiving apparatus determines whether to send the related information to the special key decryption module 115 or the general key decryption module 116 by referring to the module identification flag of the related information. However, for example, when the general-purpose key decryption module 115 is mounted on an IC card, a physical IC
A card insertion detecting means is provided, and when the IC card is inserted, the relevant information is sent to the general-purpose key decryption module in the IC card, and when the IC card is not inserted,
The same effect can be obtained even if the related information is distributed by sending the related information to the special key decryption module 115 in the receiving device. In that case, the module identification flag is not required in the related information.

[0071]

As is apparent from the above description, in the conditional access system of the present invention, when the channel being received by the receiving device is switched to another channel having a right to view, the data of that channel is transmitted. Can be descrambled quickly.

Further, one receiver can support both the conditional access system of the present invention and the conventional general conditional access system.

Further, even with a conventional conditional access receiving apparatus, the effect of high-speed descrambling at the time of channel switching cannot be obtained, but conditional access processing itself can be performed without any problem.

In a receiving device provided with a program download means or a receiving device in which a special key decryption module and a descrambler are mounted on a PCMCIA card, an algorithm of a special key limited reception system using common key data is used as required. Can be changed.

Also, by including the version number in the related information for transmitting the common key data,
Until the version number is updated, decoding of the related information becomes unnecessary, and the processing load on the receiving device can be reduced.

When the receiving apparatus holds a plurality of common key data and selects a scramble key to be used for descrambling based on information of a non-scramble part of the content data packet, updating of the scramble key is performed. It is not necessary to strictly synchronize the update timing of the common information.

Also, the receiving device holds the program multiplex information,
In the case of selecting a channel based on this program multiplex information,
Channel selection and related information can be received without waiting for reception of the PSI, and the response at the time of channel change can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmitting device and a receiving device of a conditional access system according to an embodiment of the present invention;

FIG. 2 is a diagram showing a data format of common information for a special key module according to the embodiment of the present invention;

FIG. 3 is a diagram showing a data format of individual information for a special key module according to the embodiment of the present invention;

FIG. 4 is a view showing a data format of common information for a general-purpose key module according to the embodiment of the present invention;

FIG. 5 is a diagram showing a data format of individual information for a general-purpose key module according to the embodiment of the present invention;

FIG. 6 is a block diagram showing a configuration of a conventional general-purpose receiving device applicable to the conditional access system according to the embodiment of the present invention.

[Explanation of symbols]

 11 Key management device 12 Kw encryption unit 13 TS multiplexing unit 14 Ks encryption unit 15 Scrambler 16 Content generation unit 17 TS encoder 18 64Q modulation unit 19 Transmission line 110 Receiver 111 64QAM demodulation unit 112 TS separation unit 113 Control CPU 114 Descrambler 115 Special key decryption module 116 General-purpose key decryption module 117, 120 Individual key Kmi 118, 121 Kw decryption unit 119, 122 Ks decryption unit 123 TS decoder 124 AV decoder 125 Multiplex information generation unit 126 Frequency multiplexing unit 127 Frequency Separator 128 transmitter

Claims (13)

[Claims] 1. A transmitting apparatus comprising: key generating means for generating key data for scrambling a plurality of channel data; scrambling means for scrambling the channel data using the key data; A receiving device comprising a descrambling means for descrambling an arbitrary channel selected from the key data using the key data, the transmitting device scrambles the plurality of channels using common key data, The receiving device includes a key holding unit that holds the common key data, and descrambles using the common key data held in the key holding unit even when any channel is selected. Conditional access system. 2. The transmitting device transmits the relevant key information including the common key data in related information for storing the key data, and the receiving device transmits the common key data acquired from the relevant information to the key information. 2. The conditional access system according to claim 1, wherein the conditional access system holds the information by a holding unit. 3. The transmitting apparatus transmits related information storing key data including identification information indicating whether the key data is common key data, and the receiving apparatus transmits the common key data. A special key decryption module for acquiring common key data held by the key holding means from related information including identification information indicating the following, and a general-purpose key decryption module for acquiring key data from the related information every time a reception channel changes Module, and when the related information includes identification information indicating common key data, using the common key data acquired by the special key decryption module and held by the key holding unit. When descrambling and the related information does not include identification information indicating common key data,
3. The apparatus according to claim 2, wherein the descrambling is performed by using the key data obtained by the general-purpose key decryption module.
3. The conditional access system according to 1. 4. The transmitting device transmits related information storing key data, and the receiving device includes a special key decryption module that obtains common key data held by the key holding unit from the related information. Acquires key data from the related information each time a reception channel changes, comprising a mountable general-purpose key decryption module, and a detection unit for detecting whether or not the general-purpose key decryption module is mounted, wherein the detection unit includes When the implementation of the general-purpose key decryption module has not been detected, the special key decryption module acquires
The key data obtained by the general-purpose key decryption module is descrambled using the common key data held by the key storage means, and the detection means detects the implementation of the general-purpose key decryption module. 3. The conditional access system according to claim 2, wherein the descrambling is performed by using. 5. The method according to claim 3, wherein when the receiving channel of the receiving device is changed, the special key decryption module receives information on a currently receiving channel and determines whether or not viewing is possible. Or the conditional access system according to 4. 6. The receiving apparatus according to claim 5, wherein the receiving apparatus confirms whether or not viewing is possible based on the related information received after the receiving channel is changed, and stops the descrambling if there is no viewing right. The conditional access system described. 7. The transmitting apparatus transmits the related information including program identification information, and the receiving apparatus including only the general-purpose key decryption module without the special key decryption module includes the program identification information. 5. The conditional access system according to claim 3, wherein whether or not viewing is possible is determined based on the condition. 8. The device according to claim 3, wherein the general-purpose key decryption module is configured by an IC card, and the receiving device includes a slot into which the IC card is inserted.
Or the conditional access system according to 7. 9. The conditional access system according to claim 3, wherein the receiving device includes a program download unit, and replaces the special key decryption module by downloading from the transmitting device. . 10. The special key decryption module and a descrambler of a receiving device are mounted on a PCMCIA card,
5. The conditional access system according to claim 3, wherein the receiving device includes a slot of the PCMCIA card. 11. The transmitting device transmits the related information storing the common key data including version information,
The conditional access system according to claim 2, wherein the receiving apparatus continues to descramble using the same common key data held by the key holding unit until the version number is updated. 12. The transmitting apparatus transmits the related information including the common key data including a plurality of types of scramble keys, and the receiving apparatus stores the plurality of types of scramble keys in the key holding unit. 3. A scramble key used for descrambling is selected by identifying which scramble key is used from information on a non-scramble part of the content data packet.
3. The conditional access system according to 1. 13. The receiving apparatus includes program multiplex information holding means for holding program multiplex information, and based on the program multiplex information held in the program multiplex information holding means except when the program multiplex information is updated. 3. The conditional access system according to claim 2, wherein the station is selected.