JP2001292432A - Conditional reception control method - Google Patents

Abstract

(57) [Problem] To provide a conditional access control system capable of preventing an increase in processing load on a transmitting side and a receiving side even when the number of receiving stations increases. SOLUTION: A scramble key list 2, 9 comprising at least one scramble key and index information corresponding to the scramble key is provided in a transmitter and a receiver, and the transmitter selects the scramble key list and the index information, The scramble key indicated by the index information is scrambled to transmit the data, and at the same time, the index information is transmitted to the receiving device. The receiving device extracts the scramble key from the scramble key list 9 based on the transmitted index information. , Descramble the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data distribution system for broadcasting, distributing and communicating data such as video data and audio data via a medium such as a radio or a cable. Related to conditional access control for permitting reception only to a group of receiving devices, and more particularly to a conditional access control method capable of preventing an increase in the processing load on the transmitting side and the receiving side when the number of receiving stations increases. It is.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing a configuration of a conventional conditional access control system according to a scrambling system in a digital broadcasting system shown in, for example, the Telecommunications Technology Council Report No. 74. In FIG. 9, reference numeral 1 denotes a scrambling unit for scrambling data based on the scrambling key, and 13a denotes a scrambling key (K).
s) and 16 are common information (ECM: Entitlement Common M) obtained by encrypting the scramble key.
common information (ECM) encrypting unit for generating an Esage), a work key (Kw) 14a for encrypting a scramble key, and an individual information (EMM: Entitlement Management) 17 for encrypting the work key.
ent Message) (EM)
M) an encryption unit, 15a a master key (Km) for encrypting a work key, 4 information for identifying a program (PSI: Program Specific Inf)
information (PS) for generating the
I) a transmission unit 5 is a multiplexing unit that multiplexes scrambled data (hereinafter, referred to as scrambled data), common information, individual information, and program information.

[0003] Reference numeral 6 denotes a separating unit for separating scrambled data, common information, individual information, and program information from the received multiplexed data, 15b a master key (Km) for decoding individual information, and 19 an individual using a master key. Individual information (EMM) decryption unit for generating a work key from information, 14
b is a work key (Kw), 18 is a common information (E) that generates a scramble key from common information using a work key.
CM) decoding section, 13b is a scramble key (Ks), 7
Is a descrambling unit for descrambling data based on the scramble key, and 10 is a program information (PSI) receiving unit for receiving program information.

On the transmitting side, the data is scrambled using the scramble key, and at the same time, the work key is encrypted using the master key of the terminal that is permitted to receive, the individual information is generated, and multiplexed. Also, the scramble key is encrypted using the work key to generate common information, and multiplexed. On the receiving side, on the other hand, the individual information is decrypted using the master key to extract the work key, and the common information is decrypted using the work key to extract the scramble key. Data is descrambled using the extracted scramble key to obtain data.

[0005]

Since the conventional conditional access control system is configured by the triple key system as described above, common information and individual information for each receiving terminal are generated and transmitted. Since the work information (Kw) is encrypted with the master key (Km) unique to the receiving terminal, the processing load on the transmitting side and the receiving side increases as the number of receiving stations increases as the amount of individual information increases. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a scramble key list including at least one scramble key and index information corresponding to the scramble key is transmitted to a transmitter and a receiver. The transmitting device selects a scramble key list and index information, transmits data by performing scrambling with the scramble key indicated by the index, and simultaneously transmits the index information to the receiving device, and the receiving device transmits the transmitted index. A conditional access control method that extracts the scramble key from the scramble key list based on the information and descrambles the data to prevent the processing load on the transmitting and receiving sides from increasing even if the number of receiving stations increases. The purpose is to obtain.

[0007]

According to the present invention, there is provided a conditional access control system comprising at least one scramble key list including a scramble key used for scrambling and descrambling data and index information corresponding to the scramble key. A receiving device, and a transmitting device having the same scrambling key list as the scrambling key list each receiving device has,
The transmitting apparatus selects a scramble key from the scramble key list of the receiving apparatus to be received, scrambles the data using the selected scramble key, transmits the scramble key, and transmits index information corresponding to the selected scramble key. Then, the receiving device reads a scramble key corresponding to the received index information from the scramble key list and descrambles the received data.

[0008] In the scramble key list, a scramble key common to all receiving apparatuses is assigned to a certain index. Further, the scramble key list is a list in which a common scramble key is assigned to a certain index for a part of the receiving apparatus. The receiving device has a common scramble key list for each group. Further, data transmission is performed by dividing the packet into fixed-length packets, and index information is added to a packet independent of the packet of the data to be scrambled. Furthermore, a packet of data to be scrambled and a packet with index information added are transmitted on the same medium. Also, the packet of the data to be scrambled and the packet with the index information added are transmitted by different media.

Further, data transmission is performed by dividing the packet into fixed-length packets, and index information is added to a part of the packet of the data to be scrambled. The packet is a transport stream packet conforming to the MPEG2 standard. Further, as a bit indicating index information, a scramble control bit of a transport stream packet of media data such as video, audio, and data is used. Furthermore, a scramble control bit is used as a bit indicating index information, and index information is assigned to each medium such as video, audio, and data. Further, as a bit indicating the index information, a PID (Packet Identification) bit of a transport stream packet of media data is used.
Further, as a bit indicating index information, PID
Some of the use bits are used.

[0010] In addition, as bits indicating index information, a part of bits for PID is used.
The same index information is assigned to each medium such as voice and data. Further, in the case where index information is added to a packet independent of the packet of the data to be scrambled, the packet is a transport stream packet conforming to the MPEG2 standard. Furthermore, as a bit indicating index information, a PID bit of a PMT (program map table) which is control data is used. In addition, a part of the PID bits of the PMT is used as the bit indicating the index information, and the same index information is assigned to a plurality of PMTs.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram showing a configuration of the first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a scrambling unit for scrambling data based on a scramble key, 2 denotes a scramble key list composed of a scramble key and index information, and 3 denotes a scramble key selected from a scramble key list 2. And output it to
The index information transmitting unit reads out the index information corresponding to the scramble key and sends it to the multiplexing unit 5 described later. Note that the selection of the scramble key is performed such that only the receiving device that wants to receive can descramble. Reference numeral 4 denotes a program information (PSI) transmitting unit for generating information for identifying a program, and reference numeral 5 denotes a multiplexing unit for multiplexing scramble data, index information, and program information. Reference numeral 6 denotes a separating unit for separating scrambled data, index information, and program information from the received multiplexed data, 7 a descrambling unit for descrambling data based on a scramble key, and 8 receiving and receiving index information. An index information receiving unit that reads a scramble key corresponding to the index information from the scramble key list 9 and outputs the scramble key to the descramble unit 7 is a program information (PSI) receiving unit that receives program information.

FIG. 5, FIG. 6, and FIG. 7 are explanatory diagrams for explaining the structure of the scramble key list. The scramble key list 1 is the receiving device 1, the scramble key list 2 is the receiving device 2, and the scramble key list 3 is the receiving device. This corresponds to No. 3. Note that the transmission device has all of the scramble key lists 1, 2, and 3. FIG. 5 is an example of a scramble key list in which all the scramble keys of the respective receiving apparatuses are different from each other. FIG. 6 is an example in which a scramble key common to all receiving stations is held at index 0, and FIG. 5 shows an example in which a common scrambling key is held and a common scrambling key is held in some of the receiving stations in indexes 1 to 3.

On the transmitting side, a scramble key held by a receiving device that permits reception is selected, data is scrambled using the scramble key, and at the same time, index information corresponding to the selected scramble key is read and multiplexed. . On the other hand, the receiving side extracts the scramble key from the scramble key list based on the received index information, descrambles the data, and acquires the data. Only when the scramble key matches, data can be normally acquired, so that conditional access is performed.

In the first embodiment, data transmission is performed in fixed-length packets. The index information is added to a packet independent of the packet of the data to be scrambled and transmitted. Further, a plurality of receiving apparatuses may be divided into groups, and each group may have a common scramble key list. Each of the receiving apparatuses in a certain group has, for example, the scramble key list 1 shown in FIG. If each of the receiving apparatuses in another group has, for example, the scramble key list 2 in FIG. 5, limited reception control can be performed for each group.

Embodiment 2 FIG. 2 is a block diagram showing a configuration of the second embodiment of the present invention. In FIG. 2, portions denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and description thereof will be omitted. The second embodiment is different from the first embodiment in that index information is transmitted using a medium different from the medium for transmitting the data to be scrambled as shown in FIG. 2, but the operation of conditional access control is different from that of the first embodiment. This is the same as the first embodiment. The multiplexing unit 5 multiplexes the scramble data and the program information. The separating unit 6 separates scrambled data and program information from the received multiplexed data. Further, as in the first embodiment, the scramble key list shown in FIGS. 5, 6, and 7 is used.

As another medium, for example, if the scramble data is a wireless system, a wired system is used for the index information. Alternatively, the index information may be sent on a floppy (registered trademark) disk or the like. As in the first embodiment, data transmission is performed in fixed-length packets. The index information is added to a packet independent of the packet of the data to be scrambled and transmitted. However, this is another case where the index information is transmitted on a floppy disk or the like. According to the second embodiment, confidentiality can be improved.

Embodiment 3 FIG. 3 is a block diagram showing a configuration of the third embodiment of the present invention. In FIG. 3, portions denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and description thereof will be omitted. In the third embodiment, data transmission is performed by dividing into fixed-length packets as in the first embodiment, but index information is added to a part of the packet of the data to be scrambled. Therefore, the output signal of the scramble unit 1 is input to the index information transmitting unit 3, added to the index information, and transmitted to the multiplexing unit 5. That is, the index information transmitting unit 3 outputs the scramble key selected from the scramble key list 2 to the scramble unit 1, reads the index information corresponding to the scramble key, and adds it to a part of the packet of the data to be scrambled. To the multiplexing unit 5. Also, the index information receiving unit 8 receives the scrambled data to which the index information is added, sends the scrambled data to the descrambling unit 7, and extracts the index information from the received data.
The scramble key corresponding to the index information is read from the scramble key list 9 and output to the descramble unit 7.

Note that the scramble key list shown in FIGS. 5, 6, and 7 is used as in the first embodiment. In the third embodiment, fixed-length packets for transmitting data are constituted by transport stream packets conforming to the MPEG2 standard. FIG.
FIG. 3 is an explanatory diagram illustrating a configuration of a transport stream packet conforming to the EG2 standard. MPEG2
(Moving PictureExperts Gr
up2) is a high-efficiency encoding technology for multimedia data that is being internationally standardized by the International Standardization Technical Committee on Information Processing.

Next, the operation will be described. On the transmitting side, a scramble key held by the receiving device that permits reception is selected, data is scrambled using the scramble key, and at the same time, index information corresponding to the selected scramble key is transmitted to the transport stream (TS: PID of Transport Stream)
12 or added to the scramble control bit 11 and transmitted. On the other hand, the receiving side extracts the index information from the PID 12 or the scramble control bit 11 of the received transport stream, extracts the scramble key from the scramble key list, descrambles the data, and acquires the data. Only when the scramble key matches, data can be normally acquired, so that conditional access is performed.

Next, how to add index information will be described. First, the case of adding to the scramble control bit 11 will be described. As shown in FIG. 8, there are two scramble control bits. Therefore, up to four indices can be expressed. You can also change the index depending on the media,
An index is assigned to each medium such as video, audio, and data. For example, if a scramble key list as shown in FIGS. 5 to 7 is used, conditional access control can be performed for each medium.

Next, the case of adding to the PID 12 will be described. As shown in FIG. 8, PID (Packet Ide)
identification) identifies the packet 13
This is the bit ID. One is to use the PID itself as index information. For example, the PID of the video
Assuming that PID = 10 and voice PID = 11, the index information is 10,11. The second is to use the upper 2 bits of the PID as index information. In this case, the same conditional access control as when the above-mentioned scramble control bit is used can be performed. Third, the PID is different for each medium. Therefore,
If all the 13 bits of the PID are used as the index information, all the index information will also be different. Therefore, if the upper 2 bits of the PID are assigned to the index, the PMT (Progr.
The same index information can be assigned to the video, audio, and the like of the same program (program) defined by the “Am Map Table”. Therefore, the conditional access control of the program can be performed collectively. According to the third embodiment, since there is no need to transmit individual index information, a transmission band can be saved as compared with the first and second embodiments.

Here, a method for identifying a program will be described. In MPEG2, media multiplexing is performed using fixed-length packets called transport stream (TS) packets. As shown in FIG. 8, the header of the TS packet has a PID (packet ID), and a unique value is assigned to each of the control data and the media data. In the TS packet, there is a program association table (PAT) that defines what kind of program (program) is present. The PAT defines a PID of a program map table (PMT) corresponding to programs 1, 2,... Each PM
In T, the PID of a medium constituting a program such as video and audio is defined (see below). Therefore, the user can obtain the PID of the desired program by following the PAT and PMT. The receiving side filters desired data from the data stream based on the PID.

[0023]

Embodiment 4 FIG. 4 is a block diagram showing a configuration of the fourth embodiment of the present invention. In FIG. 4, portions denoted by the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and description thereof will be omitted. In the fourth embodiment, data transmission is performed in fixed-length packets as in the first embodiment, but index information is added to the PID of the PMT. Therefore, the index information is P
The MT information is output to the multiplexing unit 5 via the program information (PSI) transmitting unit 4 for generating and transmitting the MT information. That is, the index information transmitting unit 3 outputs the scramble key selected from the scramble key list 2 to the scramble unit 1, reads the index information corresponding to the scramble key, and outputs the program information (PSI) transmit unit 4.
Send to The program information (PSI) transmission unit 4
The index information is added to the MT PID and transmitted to the multiplexing unit 5. Further, the program information (PSI) receiving unit 10 extracts the index information from the received PMT information and outputs it to the index information receiving unit 8. The index information receiving unit 8 stores a scramble key corresponding to the received index information in a scramble key list 9.
And outputs it to the descrambling unit 7

The scramble key list shown in FIGS. 5, 6, and 7 is used as in the first embodiment. Further, similarly to the third embodiment, the fixed-length packets for transmitting data are constituted by transport stream packets conforming to the MPEG2 standard.

Next, the operation will be described. The transmitting side selects the scrambling key held by the receiving device that permits reception, scrambles the data using the scrambling key, and adds index information corresponding to the selected scrambling key to the PMT PID for transmission. I do. On the other hand, the receiving side extracts the index information from the PID of the received PMT, extracts the scramble key from the scramble key list, descrambles the data, and acquires the data. Only when the scramble key matches, data can be normally acquired, so that conditional access is performed.

Next, how to add index information will be described. One is to use the PMT PID itself as index information. Program 1 P
Assuming that the MT PID is 10 and the PMT PID of the program 2 is 20, the upper digits 1 and 2 are used as index information. In this way, index information such as video, audio, and data defined by the PMT can be defined collectively. Accordingly, conditional access to all media included in the program can be controlled collectively.
The second is to define index information using some bits of the PMT PID. In this case, if the index information of the PMT is the same for each program, a plurality of programs can be designated by the same index (same key). Accordingly, conditional access control of a plurality of programs can be performed simultaneously.

In the third and fourth embodiments, the description has been given of the case where the packet for transmitting data is constituted by a transport stream packet conforming to the MPEG2 standard. In the transport stream packet.

[0029]

As described above, the present invention provides at least one receiving apparatus having a scramble key list including a scramble key used for data scrambling and descrambling and index information corresponding to the scramble key, and a receiving apparatus. A transmitting device having all the same scrambling key list as the scrambling key list that each device has, the transmitting device selects a scrambling key from the scrambling key list of the receiving device to be received, and selects the selected scrambling key. While scrambling the data using and transmitting it,
Since the index information corresponding to the selected scramble key is transmitted, and the receiving device reads the scramble key corresponding to the received index information from the scramble key list and descrambles the received data, the number of receiving stations is determined. This has the effect of preventing the processing load on the transmission side and the reception side from increasing even if the number increases.

Further, since the data is transmitted in fixed-length packets and index information is added to a part of the packet of the data to be scrambled, individual index information is transmitted. There is no need to save the transmission bandwidth.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating an example of a scramble key list according to the first, second, third, and fourth embodiments.

FIG. 6 is an explanatory diagram showing another example of the scramble key list in the first, second, third, and fourth embodiments.

FIG. 7 is an explanatory diagram showing still another example of the scramble key list in the first, second, third, and fourth embodiments.

FIG. 8 is an explanatory diagram illustrating the configuration of a transport stream packet conforming to the MPEG2 standard.

FIG. 9 is a block diagram showing a configuration of a conventional conditional access control system.

[Explanation of symbols]

1 Scramble part, 2 Scramble key list, 3
Index information transmitter, 4 Program information (PSI)
Transmitter, 5 multiplexer, 6 demultiplexer, 7 descrambler, 8 index information receiver, 9 scramble key list, 10 program information (PSI) receiver, 11
Scramble control bit, 12 PID.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 7/173 640 H04L 9/00 641

Claims (17)

[Claims] 1. At least one receiving apparatus having a scrambling key list including a scrambling key used for data scrambling and descrambling and index information corresponding to the scrambling key, and each of the receiving apparatuses has A transmission device having the same scramble key list as the scramble key list, the transmission device selects a scramble key from a scramble key list of a reception device to be received, and scrambles data using the selected scramble key. Multiply and transmit, and transmit index information corresponding to the selected scramble key,
A conditional access control method characterized by reading a scramble key corresponding to received index information from a scramble key list and descrambling received data. 2. The conditional access control system according to claim 1, wherein a common scramble key is assigned to a certain index in the scramble key list for all receiving apparatuses. 3. The conditional access control method according to claim 1, wherein a common scramble key is assigned to a part of the receiving device to a certain index in the scramble key list. 4. The conditional access control method according to claim 1, wherein the receiving device has a common scramble key list for each group. 5. The data transmission according to claim 1, wherein the data transmission is performed in fixed-length packets, and index information is added to a packet independent of the scrambled data packet. 5. The conditional access control method according to any one of 4. 6. The conditional access control method according to claim 5, wherein a packet of the data to be scrambled and a packet with index information are transmitted on the same medium. 7. The conditional access control method according to claim 5, wherein the packet of the data to be scrambled and the packet to which the index information is added are transmitted by different media. 8. The data transmission according to claim 1, wherein the data transmission is performed by dividing the data into fixed-length packets, and index information is added to a part of the packet of the data to be scrambled. The conditional access control method according to any one of claims 1 to 4. 9. The conditional access control system according to claim 8, wherein the packet is constituted by a transport stream packet conforming to the MPEG2 standard. 10. A scramble control bit of a transport stream packet of media data such as video, audio, and data is used as a bit indicating the index information.
The conditional access control method described. 11. A scramble control bit is used as a bit indicating index information, and index information is assigned to each medium such as video, audio, and data.
0 conditional access control system. 12. The conditional access control method according to claim 9, wherein a bit for PID (Packet Identification) of a transport stream packet of media data is used as a bit indicating the index information. . 13. The conditional access control method according to claim 12, wherein a part of PID bits is used as a bit indicating index information. 14. A part of a bit for PID is used as a bit indicating index information.
14. The conditional access control method according to claim 13, wherein the same index information is assigned to each medium such as voice and data. 15. The conditional access control method according to claim 5, wherein the packet is constituted by a transport stream packet conforming to the MPEG2 standard. 16. The conditional access control method according to claim 15, wherein a PID bit of a PMT (program map table) as control data is used as a bit indicating the index information. 17. The conditional access control according to claim 16, wherein a part of the PID bits of the PMT is used as the bit indicating the index information, and the same index information is assigned to a plurality of PMTs. method.