JP3682785B2 - Descrambling apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a descrambling apparatus and method, and more particularly, to a descrambling apparatus and method that suppresses an inadvertent use of a scramble key that is inadvertently decoded.
[0002]
[Prior art]
In pay broadcasting, a broadcasting system called scramble broadcasting is often used. In this scrambled broadcasting, the original signal is intentionally disturbed (scrambled) by a predetermined method on the broadcast station side, so that even if a person who is not contracted with the broadcast station receives the broadcast, normal images and sound are transmitted. , And data cannot be used.
[0003]
That is, the decoder of the person who has contracted with the broadcasting station is given a key signal for canceling this scramble, and the decoder scrambles the data scrambled to the original form by this key signal so that a normal image can be obtained. , Voice, data and so on.
[0004]
Of the contracts for viewing pay broadcasts, the contract for each channel is called flat, and the charge for the program viewed is called pay-per-view. Among pay-per-views, when viewers suddenly want to watch a given program, those that do not require prior contact, which can be viewed simply by performing a predetermined operation, are called impulse pay-per-view, and advance contact is required. This is called call-ahead pay-per-view.
[0005]
[Problems to be solved by the invention]
As described above, in order to descramble scrambled broadcasting, a key signal is required. However, in a conventional scramble device, this key is obtained illegally, and a person who does not have a viewing contract illegally scrambles broadcast. There was a risk of watching.
[0006]
The present invention has been made in view of such a situation, and suppresses unauthorized viewing of a program that has not been subscribed to.
[0007]
[Means for Solving the Problems]
Descrambling apparatus according to claim 1, the extraction means, the scramble key, a unique ID to the extraction means, and at least one of the ID of the ID for identifying the conditional access system to scramble means and encrypted by using a key comprises an encryption means for supplying, the descrambling means, the scramble key encrypted by the encryption means, the extracting means using as a key the at least one ID of ID that identifies the unique ID and the conditional access system, Decoding means for decoding is provided.
[0008]
Descrambling method according to claim 2, in the extraction means, the scramble key, the scrambling means is encrypted using at least one of the ID of the ID that identifies the unique ID and the conditional access system, said means as a key supplied, the descrambling means, the scramble key is encrypted, characterized in that decoded using a unique ID to the extraction means, and at least one of the ID of the ID for identifying the conditional access system as a key.
[0009]
In the descrambling apparatus according to claim 1, the extraction means, the scramble key, a unique ID to the extraction means, and at least one of the ID scrambler encrypts using as a key ID that identifies the conditional access system comprises an encryption means for supplying, descrambling means using the scramble key encrypted by the encryption means, a unique ID to the extraction means, and at least one of the ID of the ID for identifying the conditional access system as a key comprises decoding means for decoding Te.
[0010]
In the descrambling method according to claim 2, in the extraction means, the scramble key, a unique ID to the extraction means scrambling means and encrypted by using a key at least one of the ID of the ID for identifying, and conditional access system supplying, in the descrambling means, decoded using a scramble key encrypted unique ID to the extraction means, and at least one of the ID of the ID for identifying the conditional access system as a key.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a configuration of an embodiment of a pay broadcast system to which the present invention is applied. The encoder 1 (1A to 1E) of the transmission side system 21 digitizes and compresses video signals and audio signals for five channels. The multiplexer 2 packetizes the outputs of a plurality of (for five channels) encoders 1 and a plurality of related information, and performs time division multiplexing. Here, the related information is “common information (program information)” including information related to the program and a scramble key for descrambling, contract information for each subscriber (viewer) (for example, contract form such as flat or pay-per-view) And “individual information” including a contract key for decrypting the encryption of the common information.
[0012]
The scrambler 3 selectively scrambles a predetermined output signal of the multiplexer 2 with a scramble key from the related information transmission device 4.
[0013]
The scramble control system 6 supplies a contract key (work key) to the related information transmitting apparatus 4 and encrypts the contract key with an individual key (stored in the scramble control system 6) unique to the receiving terminal 22 The information is supplied to the multiplexer 2 as part of the information.
[0014]
The related information transmission device 4 supplies the scramble key to the scrambler 3 and encrypts the scramble key with the contract key supplied from the scramble control system 6, and the multiplexer 2 as a part of the common information (program information). It is made to supply to.
[0015]
The program control system 5 generates a predetermined control signal and controls the encoder 1 according to the program. That is, it controls the digitization and compression method. Also, the program ID of the program encoded by the encoder 1 and the channel ID (service-id) of the corresponding channel are generated and supplied to the related information transmitting device 4. The viewing information collection processing system 7 receives viewing information (for example, viewed program ID, corresponding channel ID, viewing time, etc.) uploaded from a number of receiving terminals 22 via the telephone line 24, and contracts from viewers. The request is processed and supplied to the scramble control system 6 as contract information.
[0016]
On the other hand, the decoder 31 (descrambling means) of the receiving terminal 22 converts the scrambled signal into the original signal by the scramble key supplied from the security module 32 (extraction means) by the built-in descrambler 41 (FIG. 4). It is designed to be descrambled. Also, individual information and program information added to the program are extracted and output.
[0017]
The security module 32 is configured by, for example, an IC card that is detachably attached to the decoder 31, and stores an individual key unique to the receiving terminal 22 in the built-in EEPROM 53 (FIG. 4). When the unscrambled individual information is supplied, the individual information is decrypted using the individual key, and the contract key and the contract information are respectively extracted and stored. Also, common information accompanying the program supplied via the decoder 31 is fetched, the common information is decrypted with the contract key, the scramble key is extracted, encrypted, and then supplied to the decoder 31.
[0018]
Next, the operation will be described. First, an operation when individual information is transmitted from the transmission-side system 21 to the reception terminal 22 will be described. As shown in FIG. 2, the individual information includes a contract key number corresponding to the contract key, a contract key, a channel ID (service-id) corresponding to the contracted channel, a contract type, and the like. The individual information also includes the ID number (Card ID) of the receiving terminal 22 as the transmission destination.
[0019]
The contract key is transmitted together with, for example, an 8-bit contract key number so that a plurality of contract keys can be used properly. The contracted channel ID is represented by, for example, 16-bit Service_id. The contract type can identify flat, pay-per-view, and special contract, and is 4 bits, for example.
[0020]
This individual information is encrypted in the scramble control system 6 by using an individual key specific to the receiving terminal 22 to which the individual information is to be transmitted. The scramble control system 6 stores an individual key unique to the receiving terminal 22 in association with the ID number (Card ID) of the receiving terminal 22 for all the receiving terminals 22, and the ID number of the receiving terminal 22 of the transmission destination The individual key can be searched from. Therefore, the individual key corresponding to the ID number of the receiving terminal 22 as the transmission destination is searched, and the individual information is encrypted based on the individual key. The encrypted individual information is supplied to the multiplexer 2.
[0021]
In the multiplexer 2, the digitized and compressed video signal and audio signal corresponding to the predetermined program supplied from the encoder 1 and the individual information supplied from the scramble control system 6 are packetized, and time-divisionally performed. After being multiplexed, it is supplied to the scrambler 3. The digital signal supplied to the scrambler 3 is scrambled only for the program part (video data and audio data) using the scramble key supplied from the related information transmitting device 4, and the individual information part is not scrambled, and the transmission path 23.
[0022]
The transmission of the individual information to the receiving terminal 22 is performed as needed when the individual information needs to be updated. This individual information includes the contract information described above.
[0023]
Next, an operation when a normal program and program information (components of common information) added thereto are transmitted from the transmission system 21 to the reception terminal 22 will be described.
[0024]
For example, as shown in FIG. 3, the program information includes a contract type, a contract key number indicating a contract key number, a scramble key, a Service_id corresponding to a channel ID, a program ID for identifying a program, and the like. Of these, the scramble key is encrypted with a contract key (work key) supplied from the scramble control system 6. Further, the contract type includes a flag for identifying whether or not the program is a special program.
[0025]
The predetermined program information having the above-described configuration generated in the related information transmitting device 4 is supplied to the multiplexer 2. In the multiplexer 2, the digitized and compressed video signal and audio signal corresponding to the predetermined program supplied from the encoder 1 and the program information supplied from the related information sending device 4 are packetized, The signals are divided and multiplexed and supplied to the scrambler 3.
[0026]
The scrambler 3 packetizes a compressed video signal or audio signal and program information constituting a program and inputs a time-division multiplexed digital signal. Of these, a program portion (video signal and audio signal) is input. ) Is scrambled by the scramble key supplied from the related information sending device 4, and the program information part is sent to the transmission line 23 without being scrambled.
[0027]
In this way, a predetermined program and program information associated therewith are transmitted from the transmission side system 21 to the reception terminal 22.
[0028]
Next, the operation on the receiving terminal 22 side will be described.
[0029]
FIG. 4 is a diagram for explaining a principle operation in the case where viewing permission control is performed in the receiving terminal 22. The decoder 31 is composed of, for example, a descrambler 41 and a decoder 42 (decryption means), and the security module 32 is composed of decryptors 51 and 52, an EEPROM 53 and an encryptor 54 (encryption means).
[0030]
The individual information is transmitted to the receiving terminal 22 of the viewer who has formally contracted. A digital signal in which a predetermined scrambled program transmitted through the transmission path 23 and individual information not scrambled is time-division multiplexed is received by a tuner (not shown) of the receiving terminal 22 from the transmission side system 21. Then, a digital signal corresponding to the scrambled program is supplied to the descrambler 41.
[0031]
On the other hand, the ID number (Card ID) of the receiving terminal 22 added to the non-scrambled non-scrambled individual information, and the ID number (Card ID) of the receiving terminal 22 stored in advance in the EEPROM 53 of the security module 32 Are compared with each other, the individual information is taken in (that is, individual information addressed to itself) and supplied to the decoder 51.
[0032]
Of the individual information supplied to the decryptor 51, the encrypted part is decrypted with the individual key unique to the receiving terminal 22 stored in the EEPROM 53, and the contract key and the contract information are taken out and stored in the EEPROM 53. Supplied and stored. This contract key is used for decoding program information. The contract information is used when determining whether or not the received program is a contracted program.
[0033]
When the viewer is watching the program at the receiving terminal 22, the receiving terminal 22 receives the scrambled predetermined program transmitted through the transmission path 23 and the program information associated therewith. The digital signal corresponding to the scrambled predetermined program is supplied to the descrambler 41, and the program information associated therewith is supplied to the decoder 52.
[0034]
When the contract key corresponding to the channel of the predetermined program has already been decrypted by the decoder 51 and stored in the EEPROM 53 as described above, the decoder 52 operates and the contract key supplied from the EEPROM 53 is used. The encrypted part of the program information is decrypted. Thereby, the scramble key included in the program information is extracted.
[0035]
The scramble key decrypted by the decryptor 52 is input to the encryptor 54 and encrypted. For this encryption, at least one of Card ID and Ca_System_ID (which will be described later) stored in the EEPROM 53 is used.
[0036]
In this case, encryption can be performed by using at least one of Card ID and Ca_System_ID as a key for encryption as it is or performing a predetermined calculation.
[0037]
Next, the program information is checked against the contract information already stored in the EEPROM 53. As a result of the collation, when it is recognized that the program to which the program information is added is a contracted program, the scramble key (encrypted) obtained in the encryptor 54 is decrypted by the decoder 31 from the security module 32. Is supplied to the vessel 42.
[0038]
On the decoder 31 side, the decoder 42 decrypts the input encrypted scramble key. As described above, this decryption requires the Card ID or Ca_System_ID used for encryption in the encryptor 54 of the security module 32. As will be described later with reference to FIG. When the security module 32 is attached to the decoder 31, it is supplied from the security module 32 to the decoder 31 and stored on the decoder 31 side.
[0039]
The decryptor 42 supplies the decrypted scramble key to the descrambler 41. In the descrambler 41, the digital signal of the scrambled predetermined program is descrambled by the scramble key (decoded) supplied from the decoder 42, and returned to the original signal that can be normally viewed. Then output.
[0040]
When the encryption unit 54 and the decryption unit 42 in the embodiment of FIG. 4 are omitted, when the security module 32 is driven by another device and the output is taken into a memory or the like, the scramble key is illegal to a third party. May be acquired and misused. However, if the scramble key is output in a state encrypted by the encryptor 54 as in the embodiment, the scramble key is encrypted only by fetching the scramble key output from the security module 32. Therefore, it cannot be used as it is. Therefore, the scramble key can be prevented from being stolen.
[0041]
The decoder 31 is configured such that when this is disassembled, the internal circuit does not operate normally, or when it is disassembled, the disassembly is stored in the EEPROM 53 as viewing information and further stored in the viewing information collection processing system 7. Since it is configured to be transferred, the possibility of the scramble key being stolen by the decomposition of the decoder 31 is suppressed.
[0042]
Next, with reference to FIG. 5, an operation performed when the security module 32 composed of an IC card is attached to the decoder 31 will be described.
[0043]
The security module 32 has only a function of returning a predetermined response in response to a command from the decoder 31 without performing any operation independently.
[0044]
When the security module 32 is attached, the decoder 31 first generates a Reset signal and outputs it to the security module 32. The security module 32 performs a reset operation when the Reset signal is input, and outputs an Answer To Reset signal to the decoder 31 when the reset operation is completed.
[0045]
When the decoder 31 receives the Answer To Reset signal and detects that the reset of the security module 32 is completed, it next outputs an ID Request signal to the security module 32. The security module 32 outputs the Card ID and Ca_System_ID stored in the EEPROM 53 to the decoder 31 when receiving the input of the ID Request signal.
[0046]
This Card ID is an ID unique to the security module 32 given to the security module 32 individually. The security module 32 uses this Card ID to determine whether or not the received individual information is individual information to be taken into the EEPROM 53 as its own individual information.
[0047]
On the other hand, Ca (Conditional access) _System_ID is an identifier for identifying each receiving system when a plurality of conditional access systems coexist.
[0048]
When this Card ID and Ca_System_ID are supplied, the decoder 31 stores them in the RAM. Then, as described above, these are used as a decryption key in the decryptor 42.
[0049]
Next, the decoder 31 outputs the received individual information (EMM: Entity Management Message) to the security module 32. When receiving the individual information (EMM), the security module 32 extracts the one corresponding to the Card ID and returns the corresponding Response to the decoder 31.
[0050]
Further, the decoder 31 outputs program information (ECM) to the security module 32. As described above, the security module 32 decrypts the scramble key Ks from the supplied program information, further encrypts it, and outputs it to the decoder 31.
[0051]
In addition to the scramble key Ks, the security module 32 outputs Copy Right and Finger Printing to the decoder 31. This Copy Right is a flag indicating whether or not copying of the corresponding program is permitted. Also, Finger Printing is a flag indicating whether or not the Card ID corresponding to the program is forcibly displayed on the monitor.
[0052]
Hereinafter, when the individual information (EMM) is supplied from the decoder 31, the security module 32 returns a corresponding message, and when the program information (ECM) is supplied from the decoder 31, the security module 32 The operation of returning the message to be performed is appropriately performed.
[0053]
In the above embodiment, the transmission path 23 is described as being a broadcast wave.
[0054]
As a key used in the encryptor 54 and the decryptor 42, a key other than Card ID or Ca_System_ID may be used. However, if these are used, these are always transmitted first from the security module 32 to the decoder 31, so that it is not necessary to add a new sequence for transmitting the key as in the case of setting another key. .
[0055]
【The invention's effect】
According to the descrambling apparatus according to claim 1 and the descrambling method according to claim 2, in the extraction unit, the scramble key is an ID unique to the extraction unit , and at least one of an ID for identifying the conditional access system . is supplied to the descrambling unit and encrypted using the ID as a key, the descrambling means, the scramble key encrypted unique ID to the extraction means, and at least one of the ID of the ID for identifying the conditional access system Since the decryption is performed using the key, it is possible to prevent the scramble key from being accidentally decrypted and misused.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a pay broadcasting system to which the present invention is applied.
FIG. 2 is a diagram showing a part of individual information.
FIG. 3 is a diagram showing a part of program information.
4 is a diagram for explaining the principle of operation of the receiving terminal 22 of FIG. 1; FIG.
5 is a diagram for explaining transmission and reception of signals between the decoder 31 and the security module 32 of FIG. 1; FIG.
[Explanation of symbols]
1, 1A to 1E Encoder 2 Multiplexer 3 Scrambler 4 Related information sending device 5 Program control system 6 Scramble control system 7 Viewing information collection processing system 21 Transmission side system 22 Reception terminal 23 Transmission path 24 Telephone line 31 Decoder 32 Security module 41 Descrambler 42, 51, 52 Decoder 53 EEPROM
54 Encryption

Claims (2)

A descrambling means for separating a plurality of broadcasted information and descrambling information of a program of a predetermined scrambled channel;
A descrambling device comprising: an extraction unit that is attached to and detached from the descrambling unit and extracts a scramble key for releasing the scramble from broadcast information, and supplies the scramble key to the descrambling unit.
Said extraction means, said scramble key comprises an encryption means for supplying said scrambling means is encrypted using at least one of the ID of the ID that identifies the unique ID and the conditional access system, as the key to the extraction means ,
Said descrambling means, decoding for decoding using the scramble key encrypted by said encryption means, at least one of the ID of the ID that identifies the unique ID and the conditional access system, said extraction means as a key A descrambling device comprising: a converting means. A descrambling means for separating a plurality of broadcasted information and descrambling information of a program of a predetermined scrambled channel;
In a descrambling method for a descrambling apparatus, comprising: an extracting means for extracting the scramble key for releasing the scramble from information that has been attached to and detached from the descramble means and that has been broadcast, and supplies the descramble means to the descramble means.
In the extraction means, said scramble key, encrypts supplied to the scrambling means using at least one of the ID of the ID that identifies the unique ID and the conditional access system, the extraction unit as a key,
In the descrambling means, de, characterized in that decoding using the scrambling key that is encrypted, at least one of the ID of the ID that identifies the unique ID and the conditional access system, said extraction means as a key Scramble method.

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