JPH08331542A - Descrambler, viewing history receiver, scramble broadcast system and scramble broadcast method - Google Patents

Abstract

PURPOSE: To easily prevent illegal clearing of a viewing history of a descrambled program. CONSTITUTION: A viewing history of a descrambled program is stored in a memory (not shown) by a reception terminal equipment 5, ciphered with a prescribed code and sent to a center station 1 via a public network 6. The center station 1 decodes information from the reception terminal equipment 5 into the viewing history and a prescribed code and the prescribed code is sent to the reception terminal equipment 5 via the public network 6 as a command code commanding clearing the viewing history stored in the memory. The the equipment terminal equipment 5 compares the command code sent from the center equipment 1 with the prescribed code sent by itself and clears the viewing history stored in the memory when the both are identical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a descrambling device,
The present invention relates to a viewing history receiving device, a scramble broadcasting system, and a scramble broadcasting method. In particular, the viewing history of the viewed program is encrypted and transmitted together with a predetermined code, and the viewing history is cleared only when the predetermined code is returned, so that the viewing history is illegally cleared. The present invention relates to a descrambling device, a viewing history receiving device, a scramble broadcasting system, and a scramble broadcasting method capable of easily preventing such a situation.

[0002]

2. Description of the Related Art In pay broadcasting, a so-called scramble broadcasting is often used.
In this scrambled broadcast, the original signal is intentionally disturbed on the broadcast station (center station) side by a predetermined method, so that even if a person who does not have a contract with the broadcast station receives the broadcast, a normal image or Voice and other data cannot be used. In addition, by giving a decoder that descrambles (descrambles) using a predetermined key to those who have contracted with the broadcasting station, by descramble the scrambled data to the original form, It is designed so that normal images, sounds and data can be obtained.

By the way, as a contract form (reception form) of scrambled broadcasting, there are those called a flat system and a pay-per-view system, for example. What is the flat method?
The pay-per-view method pays the reception fee on a channel basis, and the pay-per-view method pays the reception fee according to the program viewed.

Therefore, in the case of the flat system, the broadcasting station side may basically perform a fixed amount billing process.
In the pay-per-view system, when charging is performed after viewing the program, it is necessary to check the program viewed by the contractor and perform the charging process according to the program. For this reason, in the case of such a pay-per-view system, the receiving side stores the viewing history of the program viewed by the contractor in a storage medium such as a memory, and this is stored in a storage medium such as a telephone line (public network). , And the charging process is performed on the broadcast station side based on the viewing history.
After the billing process, the broadcasting station clears the memory by transmitting a clear signal to the receiving side to clear (delete) the viewing history stored in the receiving side memory. Is secured so that a new viewing history can be stored.

[0005]

By the way, in order to avoid the charge, it is conceivable that the receiving side may illegally clear the viewing history before it is transmitted to the broadcasting station side. Therefore, the clear signal is generated and processed in a procedure as complicated as possible (for example, the clear signal is subjected to double, triple, or higher encryption processing (eg, disclosed in Japanese Patent Publication No. 2-18783). It is necessary to prevent the clear signal from being illegally decrypted by performing a complex process (such as a process) and transmitting it.

However, when the clear signal is generated and processed in a complicated procedure, the procedure for decoding the signal becomes complicated on the receiving side, which causes a problem that the cost of the apparatus increases.

Therefore, as a method for preventing the illegal decoding of the clear signal, for example, a method of appropriately changing the clear signal on the broadcast station side can be considered. However, in this case, it is necessary for the receiving side to recognize that the clear signal has changed by some method, and if the device has such a configuration, the device becomes complicated.

The present invention has been made in view of such a situation, and makes it possible to easily prevent the viewing history from being illegally cleared.

[0009]

A descrambling device of the present invention includes a viewing history storage means for storing a viewing history of a descrambled program, a code generation means for generating a predetermined code, and a viewing history storage means. An encryption means for encrypting the stored viewing history and a predetermined code generated by the code generating means, and the output of the encryption means are transmitted to a predetermined center station, and as a result, the predetermined center station Communication means for receiving an instruction code for instructing clearing of the viewing history stored in the viewing history storage means, an instruction code received by the communication means, and a predetermined code generated by the code generating means And a clearing means for clearing the viewing history stored in the viewing history storage means based on the comparison result of the comparing means.

This descrambling device adds detection code generating means for generating a detection code for detecting whether or not the viewing history has been tampered with, and the detection code generated by the detection code generating means to the viewing history, Additional means for supplying the encryption means may be further provided. The code generation means can change the generated predetermined code at a predetermined timing.

The viewing history receiving apparatus of the present invention is characterized by comprising a transmitting means for transmitting the predetermined code to the descrambler when the viewing history is transmitted together with the predetermined code.

The viewing history receiving apparatus can further include a decrypting means for decrypting the encryption when the information transmitted from the descrambler is encrypted. Further, the viewing history receiving apparatus can further include a detection unit that detects whether or not the viewing history has been tampered with. In this case, the transmission unit may not have tampered with the viewing history by the detection unit. The predetermined code can be transmitted only when it is detected. further,
When the viewing history is transmitted together with the detection code for detecting whether the viewing history has been tampered with, the detecting means is caused to detect whether the viewing history has been tampered with based on the detection code. You can

In the scramble broadcasting system of the present invention, the receiving device stores in the viewing history storage means for storing the viewing history of the descrambled program, the code generation means for generating a predetermined code, and the viewing history storage means. The viewing history and the encrypting means for encrypting the predetermined code generated by the code generating means, and the output of the encrypting means are transmitted to the transmitting device, and as a result, transmitted from the transmitting device.
A communication means for receiving an instruction code for instructing to clear the viewing history stored in the viewing history storage means, a comparing means for comparing the instruction code received by the communication means with a predetermined code generated by the code generating means. And a clearing means for clearing the viewing history stored in the viewing history storing means based on the comparison result of the comparing means, and the transmitting device includes:
It has a decoding means for decoding the information transmitted from the communication means into a viewing history and a predetermined code, and a transmission means for transmitting the predetermined code output from the decoding means to the receiving device as an instruction code. Characterize.

In the scramble broadcasting method of the present invention, the viewing history of the descrambled program is
The viewing history stored in the storage means for storing information is encrypted together with a predetermined code and transmitted to the transmitting device, and the transmitting device transmits the information transmitted from the receiving device to the viewing history. And a predetermined code which is decoded, and the decoded predetermined code is transmitted to the receiving device as an instruction code for instructing to clear the viewing history stored in the storage means, and is transmitted from the transmitting device to the receiving device. The instruction code is received, the instruction code is compared with a predetermined code transmitted together with the viewing history, and the viewing history stored in the storage means is cleared based on the comparison result.

[0015]

In the descrambling apparatus of the present invention, the viewing history storage means stores the viewing history of the descrambled program, and the code generation means generates a predetermined code. The encryption means encrypts the viewing history stored in the viewing history storage means and a predetermined code generated by the code generation means, and the communication means transmits the output of the encryption means to a predetermined center station. As a result, an instruction code for instructing to clear the viewing history stored in the viewing history storage means is received from a predetermined center station. The comparison means compares the instruction code received by the communication means with a predetermined code generated by the code generation means, and the clear means is stored in the viewing history storage means based on the comparison result of the comparison means. It is designed to clear the viewing history.

In the viewing history receiving apparatus of the present invention, the transmitting means transmits the predetermined code to the descrambler when the viewing history is transmitted together with the predetermined code.

In the scramble broadcasting system of the present invention, the viewing history storage means stores the viewing history of the descrambled program, and the code generation means generates a predetermined code. The encryption means encrypts the viewing history stored in the viewing history storage means and a predetermined code generated by the code generation means, and the communication means transmits the output of the encryption means to the transmission device, As a result, the instruction code for instructing to clear the viewing history stored in the viewing history storage means is received from the transmitting device. The comparison means compares the instruction code received by the communication means with a predetermined code generated by the code generation means, and the clear means is stored in the viewing history storage means based on the comparison result of the comparison means. It is designed to clear the viewing history. The decoding means decodes the information transmitted from the communication means into a viewing history and a predetermined code, and the transmitting means transmits the predetermined code output from the decoding means to the receiving device as an instruction code. Has been done.

In the scramble broadcasting method of the present invention, the viewing history of the descrambled program is stored in the storage means for storing information, and the viewing history stored in the storage means is encrypted together with a predetermined code, The information transmitted to the transmission device and transmitted from the reception device is decoded into a viewing history and a predetermined code, and the decoded predetermined code is used as an instruction code for instructing to clear the viewing history stored in the storage means. , The instruction code transmitted from the transmitting device is received, the instruction code is compared with a predetermined code transmitted together with the viewing history, and stored in the storage means based on the comparison result. It is designed to clear the viewing history.

[0019]

EXAMPLES Examples of the present invention will be described below, but before that, in order to clarify the correspondence between each means of the invention described in the claims and the following embodiments, each means will be described. In parentheses after the, add the corresponding example (however, one example),
The features of the present invention will be described as follows.

That is, the descrambling device according to claim 1 is a descrambling device that descrambles a scrambled program, and selecting means for selecting a program to be viewed (for example, a selection button shown in FIG. 6). 49, etc.), a descrambler (eg, descrambler 44 shown in FIG. 6) that descrambles the program selected by the selector, and a viewing history that stores the viewing history of the program descrambled by the descrambler. Storage means (for example, memory 54 shown in FIG. 6), code generation means for generating a predetermined code (for example, clear code generation circuit 56 shown in FIG. 6), and viewing history stored in the viewing history storage means. And an encryption means for encrypting a predetermined code generated by the code generation means (for example, the encryption shown in FIG. 6). And the output of the encryption means to a predetermined center station, and as a result, an instruction to clear the viewing history stored in the viewing history storage means transmitted from the predetermined center station. A communication unit that receives the code (for example, the modem 48 shown in FIG. 6), a comparison unit that compares the instruction code received by the communication unit with a predetermined code generated by the code generation unit (for example, FIG. 6). And the clearing means for clearing the viewing history stored in the viewing history storage means based on the comparison result of the comparing means (for example, the clearing circuit 58 shown in FIG. 6). Characterize.

The descrambling device according to claim 2 is
The detection code generation means (for example, the detection code generation circuit 45 shown in FIG. 6) for generating a detection code for detecting whether or not the viewing history has been tampered with, and the detection code generated by the detection code generation means are viewed. It is characterized by further comprising an adding means (for example, an adding circuit 46 shown in FIG. 6) added to the history and supplied to the encryption means.

A viewing history receiving apparatus according to claim 4 is a viewing history receiving apparatus for receiving a viewing history of a program transmitted from a descrambler which descrambles a scrambled program. It is characterized by including a transmitting means (for example, the modem 21 shown in FIG. 2) for transmitting the predetermined code to the descrambler when the predetermined code is transmitted.

The viewing history receiving apparatus according to claim 5 is a decoding means (for example, the decoding device shown in FIG. 2) for decoding the encryption when the information transmitted from the descrambler is encrypted. 25) and the like).

The viewing history receiving apparatus according to claim 6 further comprises detection means for detecting whether or not the viewing history has been tampered with (for example, the detection circuit 27 shown in FIG. 2), and the transmission means detects it. The predetermined code is transmitted only when the means detects that the viewing history has not been tampered with.

A scramble broadcasting system according to claim 8 is a scramble broadcasting system comprising a transmitting device for scrambling and transmitting a program, and a receiving device for receiving and descrambles the program, wherein the receiving device comprises:
Selection means for selecting a program to be viewed (for example, the selection button 49 shown in FIG. 6) and descrambling means for descrambling the program selected by the selection means (for example,
The descrambler 44 shown in FIG. 6) and the viewing history storage means for storing the viewing history of the program descrambled by the descramble means (for example, the memory 5 shown in FIG. 6).
4) and code generating means for generating a predetermined code (for example, the clear code generating circuit 56 shown in FIG. 6).
And encryption means for encrypting the viewing history stored in the viewing history storage means and the predetermined code generated by the code generation means (for example, the encryption circuit 47 shown in FIG. 6).
And a communication means (for example, a communication means for transmitting the output of the encryption means to the transmission device, and as a result, receiving an instruction code for instructing to clear the viewing history stored in the viewing history storage means, which is transmitted from the transmission device (for example, , The modem 48 shown in FIG. 6, etc.)
And a comparison means (for example, the comparison circuit 57 shown in FIG. 6) for comparing the instruction code received by the communication means with a predetermined code generated by the code generation means, and based on the comparison result of the comparison means. , Clearing means for clearing the viewing history stored in the viewing history storage means (for example, the clear circuit 58 shown in FIG. 6), and the transmitting device stores the information transmitted from the communication means in the viewing history and Decoding means for decoding into a predetermined code (for example, the decoder 25 shown in FIG. 2) and transmitting means for transmitting a predetermined code output from the decoding means to the receiving device as an instruction code (for example, in FIG. 2). (Shown as a modem 21) and the like.

According to a ninth aspect of the scramble broadcasting method, a transmitter for scrambling a program and transmitting the scrambled program.
A scramble broadcasting method of a scramble broadcasting system comprising a receiving device for receiving and descrambles a program, wherein the receiving device selects a program to watch, descrambles the selected program, and descrambles the descrambled program. The viewing history is stored in a storage unit (for example,
The viewing history stored in the storage means is stored in the memory 54 shown in FIG. 6) and is encrypted together with a predetermined code. The encrypted viewing history is transmitted to the transmission device, and the transmission device transmits the information transmitted from the reception device. Decoding to a viewing history and a predetermined code, the decoded predetermined code as an instruction code for instructing to clear the viewing history stored in the storage means,
It transmits to the receiving device, the receiving device receives the instruction code transmitted from the transmitting device, compares the instruction code with a predetermined code transmitted together with the viewing history, and based on the comparison result, the storage means It is characterized by clearing the stored viewing history.

Of course, this description does not mean that each means is limited to the above.

FIG. 1 shows the configuration of an embodiment of a pay broadcasting system to which the present invention is applied. It should be noted that in this pay broadcasting system, a program consisting of, for example, image, sound, and other data is digitally and scrambled to be broadcast.

At the center station 1, the program is scrambled, further subjected to necessary processing, and transmitted as an electric wave from an antenna (parabolic antenna) 2. This radio wave is received by an antenna (parabolic antenna) 4 on the receiver side via a satellite (broadcast satellite or communication satellite) 3 and received by a receiving terminal 5. In the receiving terminal 5, the received signal (program) supplied from the antenna 4 is descrambled,
It is displayed on a monitor or output from a speaker (neither is shown). Further, in the receiving terminal 5, the descrambling program, that is, the viewing history of the viewed program is
It is stored in the memory 55 shown in FIG. 6 described later, and is transmitted to the center station 1 via the public network 6 at regular intervals, for example. In the center station 1, when the viewing history is received from the receiving terminal 5,
For example, charging processing is performed based on the viewing history.

Next, FIG. 2 shows a more detailed configuration example of the center station 1. Video, audio, and other data forming the program are input to the encoder 11 and digitized therein. Further, under the control of the program control system 12, the encoder 11 compresses the digitized data on a program-by-program basis (for example, compression processing conforming to the MPEG standard) and performs other necessary processing (for example, audio processing). Different processing is performed depending on whether the mode is the stereo mode or the bilingual mode, or different processing depending on whether or not there is an independent voice, and the result is output to the multiplexer 15 (hereinafter, encoder 11 as appropriate). Data that is output from the program data).

On the other hand, in the viewing information collection processing system 22, the individual key is read from the individual key storage section 24 and supplied to the scramble control system 13. Here, the individual key is a key peculiar to the receiving terminal 5 owned by the viewer who has subscribed for the reception.
Individual keys are stored for all receiving terminals that have subscribed.

Further, when the modem 21 receives a contract request from the viewer via the public network 6, the contract request is supplied to the viewing information collection processing system 22. In this case, in the viewing information collection processing system 22, the contract information generation unit 23 generates contract information according to the contract request from the viewer, and this is also supplied to the scramble control system 13. Here, the contract request includes information such as whether the contract form is a flat system or a pay-per-view system, and when the contract form is a flat system, which channel the viewing is contracted. The contract information generation unit 23 converts such information into contract information in a predetermined format.

In the scramble control system 13, individual information used by each receiving terminal is generated according to the contract status of each receiving terminal and is supplied to the multiplexer 15. When the contract information is supplied from the viewing information collection processing system 22, this individual information is updated according to the contract information.
Further, in the scramble control system 13, a work key for encrypting the scramble key is generated and output to the related information sending device 14. At the same time, this work key is encrypted using the individual key supplied from the viewing information collection processing system 22, is included in the above-mentioned individual information, and is supplied to the multiplexer 15. In addition to the above-mentioned information, the individual information also includes a decoder identification number or the like attached to the receiving terminal that uses the individual information, for identifying each receiving terminal.

The related information transmitting device 14 generates a scramble key for scrambling the program and supplies it to the scrambler 16. At the same time, this scramble key is encrypted using the work key supplied from the scramble control system 13 and included in the common information that is the information associated with each program. In addition to the work key from the scramble control system 13, the related information transmission device 14 is also supplied with a program number as a unique number for identifying the program processed by the encoder 11 from the program control system 12. Related information sending device 1
In 4, the program number is also included in the common information.
Further, the related information transmitting device 14 arranges other necessary information (for example, the current date and time (hereinafter, appropriately referred to as date and time)) in the common information, and the multiplexer 15
Output to.

In the multiplexer 15, the program data from the encoder 11, the individual information from the scramble control system 13, and the common information from the related information transmitting device 14 are stored.
Time division multiplexing is performed, and the multiplexed data is output to the scrambler 16 in the form of packets. The scrambler 16 scrambles the multiplexed data from the multiplexer 15 using the scramble key from the related information transmitting device 14, and outputs the scrambled data to the error correction unit 17. In addition,
In the present embodiment, the scrambler 16 can scramble only program data among the multiplexed data.

The error correction unit 17 adds an error correction code to the output of the scrambler 16 and supplies it to the modulator 18. In the modulator 18, the output of the error correction unit 17 is
For example, phase modulation (for example, 4-phase modulation) is performed, and the resulting modulation signal is output to the up converter 19. The up-converter 19 up-converts the frequency of the modulation signal to a predetermined frequency and outputs the up-converted signal to the power amplifier 20. In the power amplifier 20, the modulated signal from the up converter 19 is power-amplified and supplied to the antenna 2. Upconverter 19 from antenna 2
From the satellite, which is transmitted via satellite 3
It is sent to the recipient side.

The decoder 25, the separation circuit 26, the detection circuit 27, and the viewing information storage unit 28 which compose the viewing information collection processing system 22 will be described later.

Next, FIG. 3 shows a packet format of the individual information and the common information (hereinafter, both are appropriately referred to as related information) output from the multiplexer 15. In this embodiment, for example, MPE is output from the multiplexer 15.
A packet (transport packet) conforming to the G (Moving Picture Experts Group) 2 standard is output. That is, one packet is composed of 188 bytes, for example, as shown in FIG. 3, the first 4 bytes (32 bits) of which is a header, and the remaining 184
The byte is the data part.

The header is composed of a synchronization byte, a packet ID, and other information, and from the beginning, an 8-bit synchronization byte, three 1-bit information, a 13-bit packet ID, two 2-bit information, One 4-bit information is sequentially arranged. Information for synchronization on the receiving side is arranged in the synchronization byte, and the packet ID includes
Information is placed to identify whether the packet is of related information or otherwise. The packet of the program data output from the multiplexer 15 is also a packet similar to the format shown in FIG. 3, and when the packet is of the program data, the information for identifying it is It is placed in the packet ID of the header.

Here, in MPEG2, the transport stream is defined as shown in FIG. As shown in FIG. 9A, the transport stream is a transport packet (transport_packet ()).
And its details are defined as shown in FIG. Note that in FIG. 9B, sync_byte to the 11th line represent the definition of the header.

The above-mentioned information is appropriately arranged in the data section. That is, when the packet is of common information, for example, as shown in FIG. 5A, the data part includes a scramble key (encrypted using a work key), a program number, and a date / time. , Other information is placed. If the packet is for individual information, for example, as shown in FIG. 5B, the data section has a decoder identification number, a work key (encrypted using the individual key), and other information. Are placed.

Next, FIG. 6 shows a detailed configuration example of the receiving terminal 5. The receiving terminal 5 includes a tuner 30, a decoder 4
0 and a security module 50. The tuner 30 includes a demodulator 31 and an error correction unit 3
2, the decoder 40 includes a separation circuit 4
1, a descrambler 44, a detection code generation circuit 45, an additional circuit 46, an encryption circuit 47, a modem 48, and a selection button 49. The security module 50 also includes the decryptors 42 and 43 and the memories 51 to 5
5, a clear code generation circuit 56, a comparison circuit 57, a clear circuit 58, and a separation circuit 59. The security module 50 is attachable to and detachable from the receiving terminal 5 so that it can be replaced as needed.

Radio waves transmitted from the center station via the satellite 3 are received by the antenna 4, converted into a signal having a predetermined intermediate frequency (hereinafter, appropriately referred to as an IF signal), and supplied to the tuner 30. In the tuner 30, the demodulator 31 subjects the IF signal from the antenna 4 to down conversion and other necessary processing, and then demodulates the demodulated signal, which is output to the error correction unit 32. In the error correction unit 32, the demodulated signal from the demodulator 31 is subjected to error correction processing and supplied to the decoder 40.

In the decoder 40, the output (packet) from the error correction unit 32 is input to the separation circuit 41. In the separation circuit 41, whether the packet from the error correction unit 32 is a program data packet or a related information packet is identified by referring to its header (packet ID). Then, if the packet from the error correction unit 32 is a packet of program data, the packet is supplied to the descrambler 44.

The packet from the error correction unit 32 is
If it is a packet of related information, the separating circuit 41 sends the packet to the separating circuit 5 of the security module 50.
Output to 9. The separation circuit 59 refers to the type identification of its header (packet ID) to determine whether the related information packet supplied from the separation circuit 41 is the common information packet or the individual information packet. Identify. When the related information packet is the common information packet, the packet is output to the decoder 43. On the other hand, when the packet of the related information is the packet of the individual information, the separation circuit 59 reads the decoder ID unique to the receiving terminal 5 stored in the memory 51, and includes this decoder ID and the individual information. The decoder identification number.

Then, the separation circuit 59 outputs the individual information to the decoder 42 only when the decoder ID and the decoder identification number match. That is, only when the individual information is to be used by the receiving terminal 5, the individual information is
It is output to the decoder 42.

Upon receiving the individual information, the decoder 42 reads the master key from the memory 53. Here, this master key corresponds to the individual key stored in the individual key storage unit 24 of the center station 1. Therefore, according to the master key, the encrypted work key included in the individual information can be decrypted.

The decryptor 42 decrypts the work key included in the individual information by using the master key read from the memory 53, and outputs the work key to the memory 52 for storage.

When the viewer desires to view the program, he or she selects the program desired to be viewed by operating the selection button 49. When the selection button 49 is operated, an operation signal corresponding to the operation is output to the decoder 43. When the decoder 43 receives the operation signal from the selection button 49, it reads the work key from the memory 52, and uses this work key to write the encrypted scramble key included in the common information supplied from the separation circuit 59. The data is decrypted and output to the descrambler 44.

Upon receiving the scramble key from the decoder 43, the descrambler 44 uses the scramble key to descramble the program data supplied from the separation circuit 41. The descrambled program data is output to a circuit (not shown), subjected to necessary processing there, and then displayed on a monitor or output from a speaker as described in FIG.

Therefore, the viewer can watch the program he / she wants to watch by operating the selection button 49.

After the descrambler 44 starts the descramble, when the descrambled program ends or the selection button 49 is operated again, the decoder 43 causes the scramble key Stop decoding. As a result, the program becomes unviewable.

When the descrambler 44 starts descrambling, the decoder 43 extracts the program number of the descrambled program from the common information and supplies this to the memory 54 as viewing information for storage. Let Every time the viewer operates the selection button 49 to watch the program, the above-described processing is performed, whereby the history of the program watched by the viewer, that is, the viewing history is stored in the memory 54 as the program number. Are stored in the form of a list.

The viewing information (viewing history) stored in the memory 54 as described above is stored in the center station 1 periodically or when the data amount of the viewing information stored in the memory 54 reaches a predetermined value. Sent. That is, the viewing information is read from the memory 54 and supplied to the additional circuit 46.

At this time, the decoder 43 extracts the year / month / day / hour / minute from the common information and outputs it to the clear code generation circuit 56. When the clear code generation circuit 56 receives the date and time from the decoder 43, the clear code generation circuit 56 clears the memory 54 (the memory 54
That is, a clear code α, which is a trigger, is generated and output to the memory 55 for storage.
That is, the clear code generation circuit 56 has a built-in random number generation circuit, for example, and causes the random number generation circuit to generate a random number with the date supplied from the decoder 43 as the initial value.
The random number is used as the clear code α in the memory 5
Output to 5 and store. Therefore, in this case, the clear code α is changed every time the viewing information is transmitted.

When the memory 55 stores the clear code α, it reads it and outputs it to the addition circuit 46. When the viewing information and the clear code α are received, the addition circuit 46 causes the detection code generation circuit 45 to generate (calculate) a detection code for detecting that the viewing information has been tampered with, when the viewing information is tampered with. . Then, the additional circuit 46
Adds the clear code α and the detection code to the viewing information and outputs it to the encryption circuit 47.

As the detection code, for example, a code used for error detection (for example, CRC (Cyclic R
edundancy Check) code etc.) can be used.

In the encryption circuit 47, the output of the addition circuit 46 is encrypted. That is, as shown in FIG. 7, the encryption circuit 47 encrypts the viewing information to which the clear code α and the detection code (alteration detection code) are added so as not to be easily recognized. As an encryption algorithm in the encryption circuit 47, for example, DES (DataEn
Cryptography Standard) can be used.

The encrypted data (hereinafter, appropriately referred to as uploading data) is output to the modem 48. Upon receiving the uplink data, the modem 48 establishes a communication link with the modem 21 of the center station 1 (FIG. 2) via the public network 6. After establishing the communication link, the uplink data is transmitted (uplink) to the center station 1.

Since the output of the modem 48 is encrypted as described above, its contents, that is, viewing information,
It is possible to prevent the clear code α and the detection code from being easily recognized.

The modem 21 of the center station 1 (FIG. 2) receives the uplink data transmitted from the modem 48 via the public network 6. This uplink data is
It is supplied to the viewing information collection processing system 22. In the viewing information collection processing system 22, the uplink data is input to the decoder 25. In the decoder 25, the uplink data is decrypted, and the encryption is released. The output of the decoder 25 is supplied to a separation circuit 26, where it is separated into viewing information, a clear code α, and a detection code. Then, the clear code α and the detection code are output to the detection circuit 27.

The detection circuit 27 detects whether or not the viewing information has been tampered with by using the detection code, that is, the CRC code in this embodiment as described above. Then, only when it is detected that the viewing information has not been tampered with, the detection circuit 27 controls the separation circuit 26 to output the viewing information to the viewing information storage unit 28 for storage.

The uplink data includes the viewing information, the clear code α, and the detection code as well as the decoder ID stored in the memory 51 of the security module 50 (FIG. 6) and is transmitted from the receiving terminal 5. It is designed to come. Then, the viewing information storage unit 28
Then, the viewing information output from the separation circuit 26 is stored in association with the decoder ID so that it can be known from which receiving terminal 5 the viewing information is transmitted.

After the viewing information is stored in the viewing information storage unit 28, in a processing circuit (not shown) built in the viewing information collection processing system 22, based on the viewing information, for example, a billing process or a viewing rate Calculation processing and the like are performed.

Furthermore, when it is detected that the viewing information has not been tampered with, the detection circuit 27 causes the clear code α.
Is output to the modem 21. The modem 21 has a detection circuit 2
When the clear code α is received from 7, the clear code α is transmitted to the receiving terminal 5 via the public network 6 as an instruction code for instructing the clearing of the viewing information stored in the memory 54 of the receiving terminal 5.

If the detection circuit 27 detects that the viewing information has been tampered with, that is, if an error occurs during transmission of the uplink data, or if the viewing information is actually tampered with. If so, the detection circuit 27
Controls the modem 21, which causes the receiving terminal 5 to
Request retransmission of uplink data. Then, if it is detected that the viewing information has not been tampered with based on the uplink data retransmitted as a result, it is first detected that the viewing information has been tampered with is the uplink data. It is determined that an error has occurred during the transmission of, and the instruction code is transmitted.

On the other hand, when it is detected that the viewing information has been tampered with as a result of the uplink data retransmission request, the detection circuit 27 determines that the viewing information has been tampered with, and the detection information 27 The registration is not performed in the viewing information storage unit 28, and the instruction code is not output. Further, in this case, the viewing information storage unit 28 is registered to indicate that the information has been tampered with.

Returning to FIG. 6, in the receiving terminal 5, when the instruction code is transmitted via the public network 6, the instruction code is received by the modem 48. Upon receiving the instruction code, the modem 48 disconnects the line and outputs the instruction code to the comparison circuit 57. When the comparison circuit 57 receives the instruction code, it outputs the clear code α from the memory 55.
Is read and both are compared. If the instruction code and the clear code α match, the comparison circuit 57
A control signal is output to the clear circuit 58. Clear circuit 58
Receives the control signal from the comparison circuit 57, the memory 5
Clear 4 That is, as a result, the viewing information stored in the memory 54 is deleted.

Here, the clearing process of the memory 54 will be further described with reference to FIG. From the receiving terminal 5,
The clear code α and the detection code are added to the viewing information, which are encrypted and transmitted to the center station 1.
The center station 1 detects whether the viewing information transmitted from the receiving terminal 5 has been tampered with, and if it has not been tampered with, the transmitted clear code α is directly received as an instruction code. It is transmitted to the terminal 5. Then, in the receiving terminal 5, the received instruction code is collated with the transmitted clear code α, and the memory 54 is cleared only when both match.

In the modem 48, if the instruction code cannot be received even after a lapse of a predetermined time after sending the uplink data, it is determined that the viewing information has been tampered with, and the instruction is given again. Even if the code can be received, if the comparison circuit 57 determines that the instruction code and the clear code α do not match, it is determined that an invalid code has been input to the modem 48, and the memory 5
Clearing 4 is not done. Further, if necessary, processing for stopping the operation of the decoders 42, 43 or the descrambler 44 is performed in order to prevent unauthorized reception (this is because, for example, such control is performed on individual information). Can be done by including the information).

As described above, the viewing information is cleared only when the clear code is added to the viewing information, encrypted and transmitted, and the same instruction code as the clear code can be received. Therefore, even if the clear code is recognized, it is possible to prevent the viewing information from being illegally cleared by changing the clear code. Further, in this case, since the receiving terminal 5 changes the clear code, it is not necessary for the receiving terminal 5 to recognize the change, and it is possible to prevent the apparatus from becoming complicated.

Further, since the clear code α is generated in the security module 50, its illegal acquisition is
It can be strongly prevented.

Further, since the detection code for detecting whether the viewing information has been tampered with is added, it is possible to prevent the viewing information from being illegally cleared when the viewing information has been tampered with. be able to.

Further, since the viewing information clear processing algorithm is a simple one that is executed only when the clear code is transmitted and the same instruction code is received, the hardware and the hardware for realizing such an algorithm are used. The software can be easily designed.

In this embodiment, the satellite line is used to
Although the program data is transmitted, the program data can be transmitted not only through a satellite line but also through a transmission line such as a CATV network or the like. Furthermore, in this embodiment,
Although the public network 6 is used for transmitting the uplink data and the instruction code, these transmissions can also be performed using other transmission paths. That is, when a bidirectional transmission path such as a CATV network is used for transmitting program data, the uploading data and the instruction code can be transmitted via the CATV network.

Further, although the information is transmitted digitally in this embodiment, the present invention can be applied to an apparatus for transmitting information in analog.

Further, in the present embodiment, the security module 50 is provided with the five memories 51 to 55. However, the security module 50 is provided with only one memory and has five storage areas. It is also possible to divide and use.

Further, in this embodiment, as the detection code for tampering detection, an error detection code such as a CRC code is used, but other codes may be used.

Further, in the present embodiment, the encryption circuit 47 is designed to perform encryption in accordance with the DES standard, but other encryption algorithms can be adopted. However, if a complicated algorithm is adopted, it will lead to complexity of the device and increase in cost, so what kind of algorithm should be used?
It is desirable to decide so as to balance the confidentiality of encryption by the algorithm with the configuration and price of the device.

In this embodiment, random numbers are generated with the year, month, day, hour, and minutes as initial values, and this is used as the clear code. However, the clear code can be generated by other methods. However, it is desirable that the clear code has no reproducibility.

Further, in the present embodiment, the instruction code is transmitted from the center station 1 via the public network 6, but
Besides, the instruction code may be included in, for example, individual information and transmitted via the satellite 3. However, since the individual information is not so frequently transmitted, when transmitting the instruction code via the satellite 3,
It may take some time from when the receiving terminal 5 transmits the uplink data until it receives the instruction code.

Further, in the present embodiment, the received clear code α is sent back as the instruction code as it is in the center station 1, but in addition to this, the instruction code may be a predetermined code based on the clear code α, for example. It is possible to use the result of the calculation. However, in this case, it is necessary for the receiving terminal 5 to compare the clear code and the instruction code in consideration of the predetermined calculation.

Further, in the present embodiment, the individual key is stored in the individual key storage section 24 incorporated in the viewing information collection processing system 22, but the individual key is stored in the other, for example, the scramble control system 13. , It is possible to manage.

Further, in FIG. 6, the decoder 40 and the security module 50 are connected by a plurality of lines, but in addition, the decoder 40 and the security module 50 are physically connected by one line. It is possible to establish a connection and exchange data between them by, for example, half-duplex communication.

Further, in the present embodiment, the format of the packet output from the multiplexer 15 is adapted to comply with MPEG2, but the format of this packet is not limited to this.

[0086]

As described above, according to the descrambling apparatus of the present invention, the viewing history storage means stores the viewing history of the descrambled program, and the viewing history is encrypted together with a predetermined code. It is transmitted to a predetermined center station. After that, an instruction code for instructing to clear the viewing history stored in the viewing history storage means, which is transmitted from a predetermined center station, is received, and the instruction code is compared with the predetermined code. Then, based on the comparison result, the viewing history stored in the viewing history storage means is cleared. Therefore, it is possible to easily prevent unauthorized clearing of the viewing history.

According to the viewing history receiving apparatus of the present invention, when the viewing history is transmitted together with the predetermined code,
The predetermined code is transmitted to the descrambler.
Therefore, by clearing the viewing history on the basis of the predetermined code, it is possible to easily prevent the viewing history from being illegally cleared.

According to the scramble broadcasting system and the scramble broadcasting method of the present invention, in the receiving device, the viewing history of the descrambled program is stored in the storage means for storing information and is encrypted together with the predetermined code. , Transmitted to the transmitter. The transmitting device decodes the information transmitted from the receiving device into a viewing history and a predetermined code, and the decoded predetermined code is received as an instruction code for instructing to clear the viewing history stored in the storage means. Sent to the device. The receiving device receives the instruction code transmitted from the transmitting device, and compares the instruction code with the predetermined code transmitted together with the viewing history. Then, based on the comparison result, the viewing history stored in the storage means is cleared. Therefore, it is possible to easily prevent unauthorized clearing of the viewing history.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a pay broadcasting system to which the present invention is applied.

FIG. 2 is a block diagram showing a detailed configuration example of a center station 1 in FIG.

FIG. 3 is a diagram showing a packet format.

FIG. 4 is a diagram showing a transport stream and transport packets.

FIG. 5 is a diagram showing packets of common information and individual information.

6 is a block diagram showing an example of a detailed configuration of a receiving terminal 5 in FIG.

FIG. 7 is a diagram for explaining the processing of the encryption circuit 47 in FIG.

FIG. 8 is a diagram for explaining a procedure for clearing the memory 54 of FIG.

[Explanation of symbols]

 1 center station 2 parabolic antenna 3 satellite 4 parabolic antenna 5 receiving terminal 6 public network 11 encoder 12 program control system 13 scramble control system 14 related information sending device 15 multiplexer 16 scrambler 21 modem 22 viewing information collection processing system 25 decoder 26 Separation Circuit 27 Detection Circuit 28 Viewing Information Storage Unit 40 Decoder 41 Separation Circuit 42, 43 Decoder 44 Descrambler 45 Detection Code Generation Circuit 46 Addition Circuit 47 Encryption Circuit 48 Modem 49 Selection Button 50 Security Modules 51 to 55 Memory 56 Clear Code generation circuit 57 Comparison circuit 58 Clear circuit 59 Separation circuit

Claims (9)

[Claims] 1. A descrambling device for descrambling a scrambled program, comprising: selecting means for selecting the program to be viewed; descramble means for descrambling the program selected by the selecting means. A viewing history storage means for storing a viewing history of the program descrambled by the descrambling means, a code generating means for generating a predetermined code, the viewing history stored in the viewing history storage means, An encryption means for encrypting the predetermined code generated by the code generation means, and an output of the encryption means is transmitted to a predetermined center station, and as a result, is transmitted from the predetermined center station. A communication unit for receiving an instruction code for instructing to clear the viewing history stored in the viewing history storage unit; Comparing means for comparing the instruction code received by the receiving means with the predetermined code generated by the code generating means, and stored in the viewing history storage means based on the comparison result of the comparing means. A descrambling device comprising: a clearing unit that clears the viewing history. 2. A detection code generating means for generating a detection code for detecting whether or not the viewing history has been tampered with, and the detection code generated by the detection code generating means is added to the viewing history. The descrambling device according to claim 1, further comprising: an addition unit that supplies the encryption unit. 3. The descrambling device according to claim 1, wherein the code generating means changes the generated predetermined code at a predetermined timing. 4. A viewing history receiving apparatus for receiving a viewing history of the program transmitted from a descrambler descrambles the scrambled program, the viewing history being transmitted together with a predetermined code. The viewing history receiving apparatus, characterized in that it comprises a transmitting means for transmitting the predetermined code to the descrambling apparatus. 5. The viewing history receiving apparatus according to claim 4, further comprising a decryption unit that decrypts the code when the information transmitted from the descrambler is encrypted. . 6. The detection means for detecting whether or not the viewing history has been tampered with, wherein the transmitting means includes the detecting means only if the detecting means detects that the viewing history has not been tampered with. The viewing history receiving apparatus according to claim 4, wherein a predetermined code is transmitted. 7. The viewing history is transmitted together with a detection code for detecting whether the viewing history has been tampered with, and the detection means determines whether the viewing history has been tampered with based on the detection code. The viewing history receiving device according to claim 6, wherein the viewing history receiving device detects whether or not. 8. A scramble broadcasting system comprising a transmission device that scrambles and transmits a program and a reception device that receives and descrambles the program, wherein the reception device selects the program to be viewed. Selecting means, descrambling means for descrambling the program selected by the selecting means, viewing history storing means for storing a viewing history of the program descrambled by the descrambling means, and generating a predetermined code A code generating means, an encryption means for encrypting the viewing history stored in the viewing history storage means, and the predetermined code generated by the code generating means; and an output of the encryption means, Stored in the viewing history storage means, which is transmitted to the transmitting device and as a result is transmitted from the transmitting device. Communication means for receiving an instruction code for instructing clearing of the viewing history; comparison means for comparing the instruction code received by the communication means with the predetermined code generated by the code generating means; Clearing means for clearing the viewing history stored in the viewing history storage means based on the comparison result of the comparing means, wherein the transmitting device includes the information transmitted from the communication means as the viewing history. And a transmitting means for transmitting the predetermined code output from the decoding means to the receiving device as the instruction code, and a decoding means for decoding the predetermined code. 9. A scramble broadcasting method of a scramble broadcasting system, comprising: a transmitting device that scrambles a program and transmits the program; and a receiving device that receives and descrambles the program, wherein the receiving device performs viewing. Select a program, descramble the selected program, store a viewing history of the descrambled program in a storage unit that stores information, and view the program stored in the storage unit together with a predetermined code. The history is encrypted and transmitted to the transmission device, and in the transmission device, the information transmitted from the reception device is decrypted into the viewing history and a predetermined code, and the decrypted predetermined code is The receiving device is transmitted as an instruction code for instructing to clear the viewing history stored in the storage means, In, receiving the instruction code transmitted from the transmitting device, comparing the instruction code and the predetermined code transmitted together with the viewing history, based on the comparison result, stored in the storage means. A scrambled broadcasting method characterized by clearing the viewing history.