JP2003110545A - Broadcasting receiver, and descramble key generator and limited broadcasting reception method to be used for the receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need to transmit individual information for a limited broadcasting receiving, and to prevent the limited broadcasting from being unauthorizedly viewed. SOLUTION: In the broadcasting receiver A, in which contents information is scrambled by a scramble key to change a pattern in a prescribed cycle and limited broadcasting to be distributed to a receiving contractor is received, a descramble key generator B for generating the descramble key of the same pattern at the same timing as the scramble key is connected and while the received contents information is scrambled by the scramble key, the received contents information is descrampled by the descramble key applied from the descramble key generator B, and outputted to a reproducing device C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a broadcasting system including a limited broadcast in which content information is scrambled and broadcast-distributed to subscribers, and scrambled content information broadcast-distributed is received and descrambled. The present invention relates to a broadcast receiving device having a limited broadcasting function.

[0002]

2. Description of the Related Art As digital broadcasting begins with communication satellites (CS), cable TV, and terrestrial broadcasting, digital broadcasting is expected to further enhance its services. It seems to go. The most important feature of digital broadcasting is that the introduction of information compression technology can improve the usage efficiency of frequencies required for program transmission, and can significantly increase the number of broadcasting channels compared to analog broadcasting. . Furthermore, since high-level error correction technology can be applied, it is possible to provide high quality and uniform service. In addition, the digitization enables not only the conventional broadcasting of images and sounds but also the broadcasting of characters and data (data broadcasting). For example, news can be sent as character data and PC (personal computer) software can be used. It has become possible to deliver by broadcasting, and systems for providing such services are also appearing one after another.

In such a broadcasting system, when providing a pay broadcasting service for descrambling or decoding based on the contents of the contract, customer management in accordance with the contract period is required. Customer management according to the contract period is, for example,
By paying a predetermined fee, the program on the contract channel can be viewed only during the contract period contracted. Also, the key information for scrambling or decrypting the code at the receiving device must be provided to only legitimate viewers (according to the contract channel and contract period) and reliably in order to prevent unauthorized viewing. is there.

In this sense, conventionally, the limited broadcast is received by using the following key structure.

First, the master key K is set for each limited broadcast receiving device.
Prepared _M, to send the contract to the channel work key Kw of that contract to the viewer that the contract information encrypted with a master key K _M. Here, the work key K _w is a channel-specific key and is updated every contract minimum period (for example, one month). The contract information is information such as the contract period for each channel or the presence / absence of a contract. The work key K _w and the contract information are received and stored prior to receiving the content. When viewing the content, the contract information is referred to identify whether the channel is viewable, and when the content is viewable, the work key K _w is used to encrypt and send the channel key K _{ch of the channel.} Is decrypted, and the scrambled broadcast content is descrambled using this channel key K _ch .

[0006]

As described above, in the conventional digital broadcasting system, in order to realize pay broadcasting, the contract information for each subscriber and the work key of the channel corresponding to the contract information are periodically provided. Had to send to. However, there is a lot of information transmission for each contractor, such as having to transmit a work key for each contractor for each contract minimum period,
Due to an increase in the number of contractors, it is becoming difficult to transmit such limited broadcast reception information.

In view of the above situation, the present invention does not require transmission of individual information for receiving a limited broadcast, and is also effective for preventing unauthorized viewing, a limited broadcast receiving device, a descramble key generation device, and a limited broadcast. The purpose is to provide a receiving method.

[0008]

(1) In order to achieve the above object, a broadcast receiving apparatus according to the present invention uses a scramble key generating apparatus that changes a pattern at a predetermined cycle to generate a scramble key, The scramble key is used in a broadcasting system including limited broadcasting in which content information is scrambled by a scramble key generated by the device and broadcast-delivered to a subscriber, and the scramble key is used when receiving the broadcast-delivered content information. An interface for connecting a descramble key generation device that generates a descramble key of the same pattern at the same timing as the generation device, and the descramble key through the interface when the received content information is scrambled with the scramble key. Descramble key given by the generator Characterized by comprising a descramble processing means for descrambling the received content information.

Further, the descrambling key generation device is
When the descramble key is encrypted and output by a master key individually assigned to each receiving device, a master key storage means for storing the individually assigned master key and an encryption code fetched from the interface are further provided. And a descramble key decryption unit for decrypting the encrypted descramble key with the master key stored in the master key storage unit.

Further, it is characterized by further comprising a master key authenticating means for authenticating whether or not the master key encrypting the descramble key matches the master key stored in the master key storing means.

The limited broadcasting system is a channel,
The scramble key is changed according to at least one of the periods, and when the descramble key generation device generates a descramble key that matches at least one of a specific channel and period, the descramble process The means is characterized by reproducing and outputting only the content information of the channel and period that match the descramble key generated by the descramble key generating device.

Further, when the descramble key generation device generates a plurality of descramble keys according to a channel and a period, a descramble key storage means for storing the plurality of descramble keys and the descrambling key upon inputting a channel selection. And a descramble key search means for searching for a corresponding descramble key from the scramble key storage means.

Further, the interface has a structure in which the scramble key generating device can be attached and detached.

(2) The descramble key generation device according to the present invention uses a scramble key generation device that changes a pattern at a predetermined cycle to generate a scramble key, and uses the scramble key generated by the device to generate content information. It is a descramble key generation device that is used in a limited broadcast receiving device that receives a limited broadcast that is scrambled and distributed to receiving subscribers, and that provides a descramble key for descrambling the received scrambled content information. Then, the descramble key having the same pattern is generated at the same timing as that of the scramble key generating device.

Further, the present invention is characterized by comprising an encryption means for encrypting and outputting a descramble key by a master key individually assigned to each of the limited broadcast receiving devices.

Further, it is characterized in that it has a structure which can be freely attached to and detached from the limited broadcast receiving apparatus.

Further, when the limited broadcast changes the scramble key according to at least one of a channel and a period, a descramble key suitable for at least one of a specific channel and a period is generated. To do.

Further, it is characterized in that the generated descramble key can be rewritten.

Further, a plurality of the descramble keys are generated according to a designated channel or period.

(3) The limited broadcast receiving method according to the present invention is
A scramble key generation device that changes a pattern at a predetermined cycle to generate a scramble key, scrambles content information with the scramble key generated by the device, and broadcasts including limited broadcasts to be broadcasted to subscribers. In a limited broadcast receiving method of a broadcast receiving device used in a system for receiving the content information to be broadcast-distributed, a descramble key generation device for generating a descramble key of the same pattern at the same timing as the scramble key generation device is attached or detached. It is characterized in that the received content information is freely connected and electrically connected, and when the received content information is scrambled with the scramble key, the received content information is descrambled with a descramble key provided from the descramble key generation device.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the following description, the hardware that realizes the limited reception mechanism inside the broadcast receiving apparatus is called a limited reception chip. Since the conditional access chip contains secret information for conditional access, it is assumed that the internal memory and the hardware configuration have a tamper resistant structure that cannot be easily read, written, and changed from the outside.

The broadcast receiving system of this embodiment employs a key structure as shown in FIG. That is, the broadcast content is decrypted with a descramble key K _ch called a channel key, and the descramble key K _ch is the master key K _M.
And is supplied from the descramble key generation device. Here, the channel key K _ch is changed in a relatively short time of about 10 seconds in order to prevent free viewing. Also,
The master key K _M is a key determined for each broadcast receiving device, and the descramble key K _ch is encrypted by the master key K _M and supplied, so that the descramble key generating device can be used by other than the contracted receiving device. if you try to use the broadcast content using the master key K _M which is set to the receiving device, it can not be decrypted different from that of the receiving device has contracted. As a result, it is possible to prevent viewing by a device other than the contracted receiving device or viewing by copying.

In the broadcast receiving system of this embodiment, the data received (or supplied) by the receiving device are the content packet and the channel key packet. The formats are shown in FIGS. 2 and 3, respectively.

First, as shown in FIG. 2, the content packet comprises an information identifier, a channel identifier, a channel key identifier, and broadcast content. The information identifier indicates the type of the packet, and here, an identifier indicating that the packet is a content packet is described. Further, in the present embodiment, since unencrypted broadcast content is also handled, different information identifiers are attached to content packets containing encrypted broadcast content and content packets containing unencrypted broadcast content. .

The channel identifier shows which channel the broadcast content is. In addition, the channel key identifier indicates the identifier of the channel key for decoding the broadcast content. The broadcast content is raw program data and is encrypted with the channel key K _ch specified by the channel key identifier. In addition, in the present embodiment, it is assumed that all of these pieces of information are data represented by a fixed length.

The channel key packet has a packet format as shown in FIG. 3, and includes an information identifier, a master key identifier, a channel identifier, a channel key identifier, and a channel key K _ch . The information identifier indicates the type of the packet, and here, an identifier indicating that it is a channel key packet is described. The master key identifier indicates the identifier of the master key used to decrypt the part from the channel identifier to the channel key of the packet. The channel identifier indicates which channel the channel key is. The channel key identifier indicates the identifier of the channel key included in this packet, and the channel key is the channel key identified by the channel identifier.

Next, the configuration and flow of processing of the broadcast receiving system of this embodiment will be described with reference to the overall configuration diagram shown in FIG. 4 and the processing algorithm (flow chart) shown in FIGS.

As shown in FIG. 4, the broadcast receiving system of this embodiment includes a broadcast receiving apparatus A and a descramble key generating apparatus B for sending a descramble key to the broadcast receiving apparatus A.
And a content playback device C that plays back the content output from the broadcast receiving device A. Broadcast receiver A
Is equipped with the above-mentioned conditional access chip inside shown by the dotted line in the figure. The descramble key generation device B is realized by, for example, an IC card, and is distributed to the receiving contractor by the contract for receiving the limited broadcast.

The broadcast receiving apparatus A performs the following processing according to the processing algorithm shown in FIG.

First, when the receiving section 11 receives a broadcast wave (S11), it is A / D converted by the A / D converting section 12 to be converted into digital data (S12), and the error detecting / correcting section 13 performs it. Error detection / correction is performed (S13).

Next, the channel selector 14 refers to the channel identifier of the content packet to determine whether or not the channel is the channel currently being viewed (reception channel) (S14), and is not the channel currently being viewed. In that case, the processing of the packet is terminated. If the packet is currently being viewed, the packet is sent to the filter unit 15. Here, the channel currently being viewed is the channel designated by the viewer via the channel selection I / F (interface) unit 16, for example, from a remote controller (not shown).

The filter unit 15 refers to the information identifier of the content packet to determine whether or not the packet is scrambled content (S15). If the content is not scrambled, the portion of the broadcast content is cut out from the packet and output to the external playback device C (S16). If the content is scrambled, the content is sent to the descrambling unit 17 (S17).

The content packet sent to the descrambling unit 17 is processed according to the processing algorithm shown in FIG.

First, the descrambling unit 17 reads the channel key identifier from the content packet and requests the channel key storage unit 18 to output the channel key having the channel identifier. Channel key output section 1
At 9, the channel key storage 18 is searched and the channel key is output (S18, S19). If the channel key is not output at this time, it means that there is no permission to view the channel, that is, there is no right to view the channel, and the process related to the packet ends. When the channel key is output, the content packet is descrambled using the output channel key (S20), and the broadcast content is output to the external playback device C (S21).

Next, the processing of the part for receiving the channel key from the descramble key generation apparatus B will be described based on the processing algorithm shown in FIG.

The broadcast receiver A is an interface (I) for electrically connecting with the descramble key generator B.
/ O) 21. The descramble key generation device B
At the time when the channel key of the viewing channel is required, the pre-registered channel key is autonomously output. The broadcast receiving apparatus A receives this, and through the following processing, stores the channel key in question in the channel key storage unit 1.
Store in 8.

That is, in the broadcast receiving apparatus A, the descramble key generating apparatus B is connected through the interface 21, and the channel key packet receiving section 22 sends the channel key as shown in FIG. The packet is received (S22). At this time,
The master key authentication unit 23 refers to the master key identifier contained in the channel key packet, and refers to the master key storage unit 24 in the receiving device A to determine whether or not the master key identifiers match each other ( S23). If they do not match, it means that the descramble key generation device B is a borrowed item, and the processing of the packet is ended. If they match, the master key storage unit 24 outputs the master key, and the channel key packet decoding unit 25 decodes the channel key packet (S2).
4). Extract the channel key, channel key identifier, and channel identifier from the decrypted channel key packet,
The data is stored in the channel key storage unit 18 (S25). In this way, a series of processes related to the channel key packet is completed.

Next, the configuration and processing flow of the descramble key generation apparatus B of this embodiment will be described. An overall configuration diagram of the descramble key generation device B is shown in FIG. 8, a processing algorithm is shown in FIG. 9, and the processing algorithm will be described below with reference to the overall configuration diagram.

Descramble key generation device B of this embodiment
Then, the control unit 31 becomes the center of the process. The control unit 31 first reads the current time from the clock counter 32 (S31) and sets the channel counter i to 0 (S3).
2). Next, the contract information is read by referring to the contract information storage unit 33, and it is checked whether or not the i-th channel can be viewed (S33). If it is not viewable, i is incremented by 1 (S34) and the contract status of the next channel is checked.
Here, it is determined whether i is the total number of channels N or more (S35), and i
Is equal to or more than the total number of channels N, it means that the channel key output process has completed one cycle, so the process returns to the time reading process (S31) and the channel key output is continued.

Here, when the i-th channel is available for viewing, it is determined whether or not it is time to output the channel key by referring to the read time and the output time of the channel key in the contract information storage unit 33. Yes (S36). If it is not time to output the channel key, i is incremented by 1 (S34), and the same processing as described above is performed. If it is the output time of the channel key, the time information and the channel identifier are input to the pseudo-random number generation unit 34 (S37), and the channel key calculated by the calculation formula predetermined for each channel is obtained (S38). This is the channel key for the i-th channel. Similarly, the time information and the channel identifier are also input to the channel key identifier generation unit 35 (S39), and the channel key identifier of the channel key is obtained by an algorithm predetermined for each channel (S4).
0).

Next, the packet generator 36 receives the channel identifier, the channel key identifier, and the channel key obtained above.
Send to. In the packet generation unit 36, the master key storage unit 3
3 from the master key identifier read from FIG.
A channel key packet as shown in (4) is generated.
1). The generated channel key packet is encrypted by the encryption unit 38.
Then, the master key is read from the master key storage unit 37 (S42), and the channel key portion from the channel identifier is encrypted with the master key (S43). The encrypted channel key packet is output from the channel key packet output unit 39 to the conditional access chip of the broadcast receiving apparatus A (S44).

As is clear from the above description of the configuration and the flow of processing, by constructing a broadcast receiving system using the broadcast receiving apparatus and the descramble key generating apparatus of this embodiment, it corresponds to a conventional channel key. By distributing the descramble key of the content in the form of an IC card or the like only to the subscriber, it becomes possible to view and listen according to the contract channel and contract period. Therefore, it is not necessary to transmit the individual information for receiving the limited broadcast, and the transmission efficiency can be dramatically improved. Moreover, since the descramble key is generated by being encrypted with the encryption key unique to the receiving device, it cannot be viewed by other receiving devices, which is also effective in preventing unauthorized viewing.

Next, another embodiment of the present invention will be described.

First, in the above embodiment, a clock counter is provided in the descrambling key generation device to use for timekeeping, but the internal clock may be out of order, and it is not always possible to output the channel key at an accurate time. Not necessarily. In order to solve this problem, a configuration in which the time information is input from the receiving device main body to the descramble key generation device may be considered.
With this configuration, for example, time information transmitted by a broadcast wave can be referred to, so that more accurate limited broadcast reception can be realized. With respect to the configuration, it is sufficient to replace the clock counter 32 shown in FIG. 8 with a time reading unit that reads the time from the receiving device body, and the processing algorithm can be changed obviously.

Further, in the above embodiment, the descramble key generation device always encrypts the channel key packet with the master key and outputs it, but this is not always necessary. This is because it is difficult for the descrambling key generation device itself to imitate, and it is unlikely that a single descramble key generation device is copied and many viewers can view it for free. Rather, when one person has several receiving devices, there is an advantage that the same broadcast service can be received by any receiving device by replacing the descramble key generating device with each receiving device. .

Further, in the above-described embodiment, the descramble key generation device is provided in the reception device. However, when the frequency of changing the channel key is not so great, or when the channel key is viewed only for a short time, the generation is performed. Instead of using the device, write the channel key packet corresponding to the viewing period on the magnetic card for sale, and the viewer reads the magnetic card (from a card reader etc.) instead of inserting the descramble key generation device. Can realize a similar system. With such a configuration, since it can be realized at low cost, there is an effect that the range of application is further expanded.

[0048]

As described above, according to the present invention, it is not necessary to transmit the individual information for receiving the limited broadcast, and the limited broadcast receiving device, the descramble key generating device, and the limited broadcast which are effective for preventing unauthorized viewing. A reception method can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a key configuration adopted in a broadcast receiving system according to an embodiment of the present invention.

FIG. 2 is an exemplary view showing a format of a content packet received by the receiving apparatus of the embodiment.

FIG. 3 is an exemplary view showing a format of a channel key packet received by the receiving device of the embodiment.

FIG. 4 is a block diagram showing an overall configuration of a broadcast receiving system of the same embodiment.

FIG. 5 is a flowchart showing a processing algorithm from reception to channel selection in the broadcast receiving apparatus of the embodiment.

FIG. 6 is a flowchart showing a processing algorithm when a limited broadcast is received in the broadcast receiving apparatus of the embodiment.

FIG. 7 is a flowchart showing a processing algorithm when receiving a channel key in the broadcast receiving device of the embodiment.

FIG. 8 is a block diagram showing a configuration of a descramble key generation device of the same embodiment.

FIG. 9 is an exemplary flowchart showing a processing flow of the descramble key generation device of the embodiment.

[Explanation of symbols]

A: Broadcast receiver B ... Descramble key generation device C ... Content playback device 11 ... Receiver 12 ... A / D converter 13 ... Error detection / correction unit 14 ... Channel selection unit 15 ... Filter section 16 ... Channel selection I / F (interface) section 17 ... Descramble section 18 ... Channel key storage 19 ... Channel key output section 21 ... Interface (I / O) 22 ... Channel key packet receiver 23 ... Master key authentication unit 24 ... Master key storage 25 ... Channel key packet decoding unit 31 ... Control unit 32 ... Clock counter 33 ... Contract information storage unit 34 ... Pseudo-random number generator 35 ... Channel key identifier generation unit 36 ... Packet generator 37 ... Master key storage 38 ... Encryption unit 39 ... Channel key packet output unit

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Claims (10)

[Claims] 1. A scramble key generation device that changes a pattern at a predetermined cycle to generate a scramble key, scrambles content information with the scramble key generated by the device, and broadcasts it to a subscriber. In a broadcast receiving device used for a broadcast system including limited broadcasting and receiving the content information to be broadcast-distributed, a descramble key generation device for generating a descramble key having the same pattern as the scramble key generation device is connected. And a descrambler that descrambles the received content information with the descramble key provided from the descramble key generation device through the interface when the received content information is scrambled with the scramble key. Broadcast receiving apparatus characterized by comprising and. 2. When the descramble key generation device encrypts the descramble key with a master key individually assigned to each receiving device and outputs the encrypted descramble key, the master key that is individually assigned is stored. 3. A master key storage means, and a descramble key decryption means for decrypting an encrypted descramble key fetched from the interface with a master key stored in the master key storage means. The broadcast receiving device described. 3. The limited broadcast system changes a scramble key according to at least one of a channel and a period, and the descramble key generation device has a descramble key that matches at least one of a specific channel and a period. 2. The descrambling processing means reproduces and outputs only the content information of the channel and the period that match the descramble key generated by the descramble key generation device.
The broadcast receiving device described. 4. When the descrambling key generation device generates a plurality of descramble keys according to a channel and a period, a descrambling key storage means for storing the plurality of descrambling keys, and a channel selection input The broadcast receiving apparatus according to claim 3, further comprising: a descramble key search unit that searches the descramble key storage unit for a corresponding descramble key. 5. A scramble key generation device that changes a pattern at a predetermined cycle to generate a scramble key, scrambles content information with the scramble key generated by the device, and broadcasts it to a subscriber. A descramble key generation device that is used for a limited broadcast reception device that receives a limited broadcast and that provides a descramble key for descramble received scramble content information, the same as the scramble key generation device at the same timing. A descramble key generation device, which generates a descramble key of a pattern. 6. The descramble key generation apparatus according to claim 5, further comprising an encryption unit that encrypts and outputs the descramble key with a master key individually assigned to each of the limited broadcast receiving apparatuses. 7. A descramble key that matches at least one of a specific channel and period is generated when the limited broadcast changes a scramble key according to at least one of a channel and a period. The descramble key generation device according to claim 5. 8. The descramble key to be generated is changed at the same timing as the scramble key based on the time information from the broadcast receiving device.
The descramble key generation device described. 9. The descramble key generation device according to claim 7, wherein a plurality of the descramble keys are generated according to a designated channel or period. 10. A scramble key generation device for generating a scramble key by changing a pattern at a predetermined cycle,
Limited broadcast of a broadcast receiving device used for a broadcast system including a limited broadcast in which content information is scrambled by a scramble key generated by the device and broadcast-delivered to a subscriber. In the receiving method, a descramble key generation device that generates a descramble key of the same pattern at the same timing as the scramble key generation device is detachably and electrically connected, and the received content information is scrambled with the scramble key. A limited broadcast receiving method for a broadcast receiving apparatus, wherein received content information is descrambled with a descramble key provided from the descramble key generating apparatus.