JPH10200877A - Transmitter of conditional access system for cable television and receiver thereof - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a conditional access system for digital cable television broadcasting and a transmission / reception apparatus therefor. SOLUTION: Content scrambling means 111 for calculating a part of the digital data 151 in the transport stream format and key data 152 for encrypting the data, and key information scrambling means 112 for encrypting the key data 152 are provided. The output data 158 of the content scrambler 111 is modulated by the 64-level QAM modulator 102 and transmitted, and the output data 155 of the first key information scrambler 112 is converted to the downlink signal modulation circuit 1.
In step 04, FSK is digitally modulated and transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a conditional access system for specifying a receiver of a television broadcast and permitting reception of the television broadcast, and particularly to a conditional access system for a digital cable television broadcast using a CATV (Cable Television) transmission line. The present invention relates to a method and a transmission / reception device.

[0002]

2. Description of the Related Art Conventionally, a CAT called a cable television
The conditional access system for television broadcasting using the V transmission path is described in "Introduction to Cable TV Technology", edited by the Cable Machinery Engineering Committee of the Electronic Machinery Manufacturers Association issued by Corona. According to the description, 1W
A system called an AY addressable system is described. In this method, the descrambling function in the home terminal on the receiving side is controlled by the FSK modulation downlink from the transmitting side. Although there is no detailed description of the scramble system, the method has changed while progressing in the following manner.

[0003] First, as a simple conditional access system, a popular name channel skip system for limiting channel selection of a CATV receiver by downlink control information transmitted by FSK modulation or the like in a band other than the channel transmitting the video signal. was there. In the channel skip method, a CATV receiver skips a receivable channel in accordance with downlink control information so that a receiver cannot receive a channel for which the receiver has not subscribed. Now being sold to users, they can no longer skip channels and no longer receive conditional access.

As another conditional access system, there is a scramble system of synchronous compression. In this system, the level of the horizontal synchronization signal of the NTSC video is transmitted at a reduced level, so that it cannot be reproduced even by a CATV channel compatible television receiver. In the CATV receiver, the receiver is controlled according to downlink control information. When a contracted channel is received, reproduction can be performed by extending the period of the horizontal synchronizing signal whose level has been reduced by compression and returning it to a normal level. The scramble system of the synchronous compression is generally used as a conditional access system for analog television broadcasting for transmitting NTSC video, but does not describe a conditional access system for digital cable television broadcasting.

[0005] Further, with the recent development of digital transmission technology and the like, a plurality of digitized images are going to be transmitted on one NTSC image transmission channel which is an analog signal. The digital transmission of this cable television is described in the technical report of the Institute of Television Engineers of Japan (vol. 19, No. 4) published on September 21, 1995.
2) It is shown in "Telecommunication Technology Council Provisional Digital Cable Television Broadcasting Transmission Experiment" on pages 19 to 24. According to this report, a data stream in a format called a transport stream in which digital data such as an image compressed by a digital image compression technique called mpeg2 (MPEG2) is multiplexed, and signal processing such as Reed-Solomon error correction is performed. The signal is modulated by a digital modulation technique called 64QAM (64-level quadrature amplitude modulation) and transmitted on a CATV transmission line. This report does not describe the conditional access system either.

On the other hand, there is digital satellite television broadcasting as a method of distributing multi-channel digitized video. The broadcasting is described in the article “Near 70 Multi-channels” on page 149 of Nikkei Electronics, September 2, 1996. This is realized by a combination of digital image compression technology and digital transmission technology, as described in "Japan's First Digital Satellite Broadcasting to Achieve." According to this paper, Japan's unique scramble system and IC
By performing descrambling using a card, a conditional access system that specifies a receiver and permits reception is realized. In this way, satellite television broadcasting does not have an uplink line for transmitting information from each home to the transmitting side for broadcasting via satellite,
The system uses an IC card and a telephone line.
In this paper, there is no description for adapting the scramble system and the conditional access system for descrambling by the IC card to other transmission systems such as digital cable television broadcasting.

[0007]

In the prior art, CA
There is no conditional access system for digital cable television broadcasting using a TV transmission path, and with a channel skip system like a conventional analog receiver, a digital cable television compatible TV receiver will be sold to general users. The conditional access function is lost. In digital cable television broadcasting, the signal to be transmitted is NTSC.
Since there is no horizontal synchronizing signal instead of video, the scrambling method of synchronous compression cannot be adopted. Under these circumstances, it is conceivable to adopt a conditional access system for digital satellite television broadcasting that transmits transport streams of the same format.However, specific methods such as techniques for adapting to cable television broadcasting are described. Not been.

An object of the present invention is to provide a conditional access system for digital cable television broadcasting in which digital data such as a compressed image is transmitted in a format called a transport stream, and a transmitting / receiving apparatus therefor.

[0009]

In order to solve the above-mentioned problems, the present invention calculates a part of digital data in a transport stream format and first key data for encrypting the data. Content scrambling means, first key information scrambling means for calculating first key data and second key data for encrypting the first key data, and output data of the content scrambling means. A first modulating means for digitally modulating such as multi-valued QAM such as 64 values, and / or a digital signal such as FSK by multiplexing output data of the first key information scrambling means and / or second key data. A second modulating means for modulating, and a signal combining means for frequency-multiplexing a plurality of modulated waves including the output of the first modulating means and the output of the second modulating means. Means, a first demodulating means for demodulating a digital modulated wave such as a multi-valued QAM such as 64 values which are frequency-multiplexed and transmitted, and a FSK or the like which is frequency-multiplexed and transmitted. A second demodulating means for demodulating the digital modulated wave, the scrambled first key information obtained by the second demodulating means, and the second demodulating means.
Key decoding means for decoding the first key data from the output data of the demodulation means or the second key data transmitted by another transmission method, and the first key data obtained by the key decoding means. Receiving means comprising descrambling means for obtaining transport stream digital data from the content scrambled data obtained by the demodulating means.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a configuration of a conditional access transmission apparatus for a cable television and an arrangement of the reception apparatus according to an embodiment of the present invention. First of the present invention
The conditional access system of the cable television according to the embodiment of the present invention includes a transmitting-side encrypted modulation device 100 and a transmitting-side video signal source device 200.
, A transmission-side key management device 300, a CATV transmission line 400, a reception-side terminal device 500, and a reception-side TV receiver 600.

[0011] The transmitting side encryption / modulation device 100 includes an encryption device 1
01, 64QAM (Quadrature Amplitude Modulation) modulation circuit 102, signal synthesis circuit 103, and downlink control line signal modulation circuit 104. The encryption device 101 includes a video / audio multiplexing / content scrambling circuit 111, a first key encryption circuit 112, and a second key encryption circuit 113.

The transmitting side video signal source device 200 transmits the video / audio data 151 to the video / audio multiplexing / content scrambling circuit 111. The video / audio multiplexing / content scrambling circuit 111 generates scrambled video / audio data 158.
To the 64QAM modulation circuit 102. Sender key management device 30
A value of 0 sends the first key data 152, the second key data 153, and the third key data 154 to the encryption device 101, and further sends the third key data 154 to the downlink control line signal modulation circuit 104. .

The 64QAM modulation circuit 102 sends the 64QAM digital modulated wave signal 159 and the downlink control line signal modulation circuit 104 sends the downlink control line modulated wave signal 157 to the signal synthesis circuit 103. The first key encryption circuit 112 generates the encrypted first key information 155
The second key encryption circuit 113 sends the encrypted second key information 156 to the downlink control line signal modulation circuit 104.

The receiving terminal device 500 includes a frequency division multiplexed signal separation circuit 501, a control microcomputer 502, and a 64QAM demodulation circuit 503.
, An error correction circuit 504, and a downlink control line signal demodulation circuit 505.
A second key decryption circuit 506, a first key decryption circuit 507,
A content descrambling circuit 508, an MPEG demultiplexing circuit 509, an MPEG video decoder 510, and an NTSC (National
levision System Committee) Video encoder 511,
And an audio decoder 512.

The frequency multiplexed signal separation circuit 501 sends the 64QAM modulated wave signal 552 to the 64QAM demodulation circuit 503 and the downlink control line modulated wave signal 554 to the downlink control line signal demodulation circuit 505. The control microcomputer 502 sends a control signal 551 for channel selection and the like to the frequency division multiplexed signal separation circuit 501. 64QAM demodulation circuit 50
3.The 64QAM demodulated digital data 553
Send to The error correction circuit 504 sends the digital data 555 after the error correction to the content descrambling circuit 508. The downlink control line signal demodulation circuit 505 sends the third key data 556 and the second key information 557 to the second key decryption circuit 506.
The first key information 558 is sent to the first key decryption circuit 507. The second key decryption circuit 506 sends the second key data 559 to the first key decryption circuit 507. First key decryption circuit 507 sends first key data 560 to content descrambling circuit 508.

The content descrambling circuit 508 converts the descrambling digital data 561 to the MPEG demultiplexing circuit 5.
Send to 09. The MPEG demultiplexer 509 sends the compressed video data 562 to the MPEG video decoder 510 and the compressed audio data 563 to the audio decoder 512. MPEG video decoder 510 converts video data 564 to NTSC video encoder
Send to 511. The NTSC video encoder 511 sends out the NTSC video signal 565 and the audio decoder 512 sends out the analog audio signal 566 to the TV receiver 600 on the receiving side.

The video / audio data 151 including video and audio data from the transmission side video signal source device 200 is digital data in an MPEG2 transport stream format or a format that can be converted into a transport stream. A part of the digital data in the transport stream format and the scrambled data which are input to the video / audio multiplexing / content scrambling circuit 111 and are encrypted by the first key data 152 from the transmission side key etc. management device 300. Video and audio data 158 is provided to 64QAM modulation circuit 102. The 64QAM modulation circuit 102 adds an error correction code to the scrambled video / audio data 158, performs interleave processing, energy diffusion processing, etc.
The signal is converted into an M digital modulated wave signal 159 and output to the CATV transmission path 400 via the signal synthesis circuit 103.

The first key data 152 for encrypting the video / audio data 151 into the scrambled video / audio data 158 is converted into the second key data 153 from the transmission side key etc. management device 300 by the first key encryption circuit 112. , And becomes the encrypted first key information 155. Further, the second key data 153 for encrypting the first key data 152 is encrypted by the second key encryption circuit 113 with the third key data 154 from the transmission side key etc. management device 300, and is encrypted. The converted second key information 156 is obtained. The encrypted first key information 155, the encrypted second key information 156, and the encrypted third key data 154 are transmitted to the downlink control line signal modulation circuit 104 by FSK (Frequency Shift Keying) or QSK.
The signal is digitally modulated such as PSK (Quadrature Phase Shift Keying), converted into a downlink control line modulated wave signal 157, and output to the CATV transmission path 400 via the signal synthesis circuit 103.

On the other hand, the receiving apparatus of the conditional access system of the cable television includes a receiving terminal device 500. The receiving terminal device 500 receives the 64QAM digital modulated wave signal and the downlink modulated wave signal transmitted by frequency multiplexing from the CATV transmission line 400, and controls the control signal from the control microcomputer 502 by the frequency multiplexing signal separation circuit 501. Tuning is performed according to 551, the 64QAM digital modulated wave signal 552 is sent to the 64QAM demodulation circuit 503, and the downlink control line modulated wave signal 554 is sent to the downlink control line signal demodulation circuit 5.
Entered in 05. The 64QAM modulated wave signal 552 is converted into 64QAM demodulated digital data 553 by a 64QAM demodulation circuit 503.
Further, the error of the data generated in the transmission path is corrected by the error correction circuit 504, and the corrected data is input to the content descrambling circuit 508 as digital data 555 after the error correction.
The error correction circuit 504 also performs decoding of data that has been subjected to the interleave processing and the energy diffusion processing.

In the downlink control line signal demodulation circuit 505, FSK or
Demodulates the digitally modulated downlink control line modulated wave signal 554 such as QPSK, and obtains third key data 556 and second key information.
557 and first key information 558 are obtained. The second key decryption circuit 506 uses the third key data 556 to generate the second key information 55
7, the second key data 559 is obtained by the first key decryption circuit 507.
Decrypts the encryption of the first key information 558 to obtain the first key data 560
Is obtained.

In the content descrambling circuit 508,
The error-corrected digital data 555 encrypted with the obtained first key data 560 is decrypted and returned to the descrambled digital data 561 in the MPEG2 transport stream format. The data is separated into data 562 and compressed audio data 563 and input to the MPEG video decoder 510 and the audio decoder 512. The compressed video data 562 is converted into video data 564 by an MPEG video decoder 510, and is converted into an NTSC video signal 565 by an NTSC video encoder 511. The compressed audio data 563 is converted into an analog audio signal 566 by the audio decoder 512. The NTSC video signal 565 and the analog audio signal 566 are input to a TV (TeleVision) receiver 600, and information such as video and audio displayed on the TV receiver 600 can be provided to a viewer.

As described above, when the viewer watches the contracted channel, the first key data 560 is obtained, so that the content-scrambled error-corrected digital data 555 is decoded, and the MPEG2 transformer is decoded. The data can be returned to the descrambled digital data 561 in the port stream format, and information such as displayed video and audio can be obtained. In the case of viewing a non-subscribed viewer or a non-subscribed channel, the first key data 56
Since 0 cannot be obtained, the error-corrected digital data 555 subjected to content scrambling cannot be decoded, and information cannot be obtained. That is, the conditional access system of digital cable television broadcasting is achieved.

In this embodiment, the encrypted video / audio data is transmitted as a 64QAM digital modulated wave signal,
Since three types of third key data are transmitted by the downlink control line modulated wave signal from the key data of the above, it is necessary to simultaneously decode the 64QAM digital modulated wave signal 552 and the downlink control line modulated wave signal 554, There is an advantage that it is hard to eavesdrop.

In this embodiment, the first key data to the third key data and the three types of key data are used. However, regardless of the number of keys, a conditional access system for digital cable television broadcasting is realized. it can. Generally, it is said that as the number of keys increases, eavesdropping becomes more difficult.

An example of the transmission signal form of the CATV transmission line 400 according to the present invention will be described with reference to FIG. 2 which is a conceptual diagram showing the frequency arrangement of the CATV transmission line. In the transmission signal of CATV transmission line 400,
The entire downlink signal band 2001 includes a 64QAM digital modulated wave signal 2002 for transmitting scrambled video and audio data, a downlink control line modulated wave signal 2003 for transmitting key information for descrambling, and an unscrambled video signal. A plurality of modulated wave signals such as a 64QAM digital modulated wave signal transmitting audio data and a modulated wave transmitting analog video / audio are frequency-multiplexed.

With reference to FIG. 3, the concept of the structure of the descrambling digital data 561 in the MPEG2 transport stream format of the receiving terminal device 500 according to the present invention will be described. M
The descrambled digital data 561 returned to the PEG2 transport stream format is a 1-byte synchronization signal 3001.
188 bytes of MPEG2 transport stream format data composed of 187 bytes of MPEG video data and MPEG audio data packets 3002, and a 16-byte Reed-Solomon (204,188) error correction code 3003 added Is done.

A second embodiment of the conditional access system transmitting apparatus and the receiving apparatus for a cable television according to the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a configuration of a transmitting apparatus of a conditional access system for a cable television according to a second embodiment of the present invention and a configuration of the receiving apparatus. In FIG. 4, the third key data 154 from the transmission-side key etc. management device 300 for encrypting the second key data 153 is separately distributed using another distribution path 700 such as an IC card, a semiconductor chip or a telephone line. In other respects, the same reference numerals as in FIG. 1 indicate the same functions. In this embodiment, the encryption device 101 of the transmission-side encryption modulation device 100 shown in FIG.
The third key data 154 from the transmission side key etc. management device 300 for encrypting 3 is performed by using another delivery path 700 such as an IC card, a semiconductor chip or a telephone line. In the receiving terminal device 500, the second key decryption circuit 506 decrypts the encryption of the second key information 557 with the distributed third key data 154 to obtain the second key data 559. The scrambled video / audio data encrypted by the content descramble circuit 508 can be decrypted.

The conditional access system according to the present embodiment uses scrambled video / audio data obtained by encrypting data in the MPEG2 transport stream format using a 64QAM digital modulated wave signal and key information for decryption using a downlink control line modulated wave signal. And the third key data 154 is distributed via an IC card, a semiconductor chip, a telephone line, or the like. Therefore, in order to release using the three types of signals, the three types of signals are used for eavesdropping. Simultaneous analysis is required, and there is an advantage that decoding is more difficult than digital satellite television broadcasting in which scrambled video / audio data obtained by encrypting data in the MPEG2 transport stream format is decrypted by an IC card.

A third embodiment of a conditional access system transmitting apparatus and a receiving apparatus for a cable television according to the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a configuration of a conditional access transmission device for a cable television according to a second embodiment of the present invention and a configuration of the reception device. In this embodiment, the scrambled video / audio data 158 from the video / audio multiplexing and content
First key information 155 from the key encryption circuit 112 of FIG.
Scrambled video and audio key data obtained by time-division multiplexing
A time-division multiplexing circuit 106 for transmitting 165 to the transmission-side encryption modulation apparatus 100 is provided, a time-division multiplexing / demultiplexing circuit 515 for obtaining separation key information 565 is provided on the reception-side terminal device 500, and a second key data 153 is further provided. It is characterized in that the third key data 154 from the transmission side key etc. management device 300 for encrypting the data is separately delivered using another delivery path 700 such as an IC card, a semiconductor chip or a telephone line. For the configuration of FIG.
The same reference numerals indicate the same functions.

Transmission side encryption / modulation apparatus 10 for cable television
At 0, the scrambled video / audio data 158 encrypted with the first key data 152 and the first key information 155 encrypted with the second key data 153 are time-division multiplexed by the time-division multiplexing circuit 106. The multiplexed scrambled video / audio key data 165 is provided to the 64QAM modulation circuit 102.

On the other hand, the receiving terminal device 50 of the cable television
In the case of 0, the time-division multiplexing / demultiplexing circuit 515 corrects the error-corrected digital data
The separated key information 565, which is the encrypted first key information 155 separated from the first key data 155, is applied to the first key decryption circuit 507, and is decrypted by the second key data 559 to obtain the first key data 560. .
The error-corrected digital data 555 encrypted with the obtained first key data 560 is decrypted by the content descramble circuit 508, and the descrambled digital data 561 in the MPEG2 transport stream format is obtained.

The contents descrambling circuit 508
In place of the encrypted error-corrected digital data 555 added to the digital data 555, the encrypted error-corrected digital data after the first key information encrypted by the time-division demultiplexing circuit 515 is separated. A similar function can be obtained by adding 555 to the content descrambling circuit 508.

In this embodiment, a part of the encrypted key information is time-division multiplexed and transmitted with the scrambled video / audio data of the 64QAM digital modulated wave signal, and the other key information is transmitted in the downlink control line modulated wave signal. Therefore, there is an advantage that the encryption is more difficult to be decrypted than in FIG.

Although FIG. 4 shows an example in which the time division multiplexing circuit 106 and the like are added to the configuration shown in FIG. 4, the configuration shown in FIG. Is also possible.

A fourth embodiment of a conditional access transmission apparatus and a reception apparatus for a cable television according to the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of a transmission apparatus of a conditional access system for a cable television according to a fourth embodiment of the present invention and a configuration of the reception apparatus. This embodiment is characterized in that a switching circuit 516 for obtaining the switching key information 567 is provided in the receiving terminal device 500, and the other components having the same reference numerals as those in FIG. 4 or 5 indicate the same functions. ing. In the receiving terminal device 500 of the cable TV,
The switching circuit 516 separates the demultiplexed key information 565, which is the encrypted first key information obtained by the time division multiplexing / demultiplexing circuit 515, or the encrypted first demodulated signal from the downlink control line modulated wave signal 554. When one of the key information 558 arrives, one of the key information 558 is selected and encrypted first key information 56
7 is applied to the first key decryption circuit 507 and decrypted by the second key data 559 to obtain the first key data 560. Since the switching circuit 516 switches digital signals, it can be easily configured with an OR circuit or the like.

Also, in the present embodiment, the separation key information 565, which is the encrypted first key information separated by the time division multiplexing / demultiplexing circuit 515, and the first modulated signal 554 obtained by demodulating the downlink control line modulated wave signal 554. When the first key information 155 is sent in any one of the key information 558, the first key information 155 is automatically taken in and the first key decryption circuit is sent.
Although described as being added to 507, the signal for switching the switching circuit 516 is time-division multiplexed from the transmitting side into the unscrambled information of the descrambled digital data 561 in the MPEG2 transport stream format, and downlink control is performed. The signal may be transmitted by a method of multiplexing with the line modulated wave signal 554.

In this embodiment, regardless of whether the first key information is transmitted in the form of FIG. 4 or the form of FIG. 5,
The switching circuit 516 automatically switches and adds the first key decryption circuit 507 to the first key decryption circuit 507, so that the transmission method of the first key data 152 of the transmission-side encryption / modulation device 100 of the cable television can be adapted to equipment having different transmission methods. This has the advantage that the receiving side can be shared. In the figure, the switching circuit is added to the configuration shown in FIG.
Although an example in which 516 is added has been described, it is also possible to combine the configuration shown in FIG.

A fifth embodiment of the transmission apparatus of the conditional access system for a cable television and the reception apparatus according to the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing a configuration of a transmitting apparatus of a conditional access system for a cable television according to a fifth embodiment of the present invention and a configuration of the receiving apparatus. This embodiment is characterized in that a multiplying circuit 517 is provided in the receiving-side terminal device 500, and the other components having the same reference numerals as those in FIG. 4 or 5 indicate the same functions.

Transmission-side encryption / modulation device 10 for cable television
At 0, the first key information 155 is transmitted by the time division multiplexing circuit 106 shown in FIG. 5 and also by the downlink control line signal modulation circuit 104 shown in FIG. In the receiving terminal device 500 of the cable television, the separation key information 565 which is the encrypted first key information obtained by the time division demultiplexing circuit 515
The first key decryption circuit 5 starts when both the encrypted first key information 558 demodulated by the downlink signal demodulation circuit 505 from the downlink control line modulated wave signal 554 reach the multiplication circuit 517.
In addition, the first key data 560 is obtained by decrypting the second key data 559 with the second key data 559. Note that the multiplying circuit 517 is a multiplication of digital signals, and therefore can be easily configured with an AND circuit or the like. In the present embodiment, the first key information is transmitted to both the scrambled video / audio data and the downlink control line and is added to the first key decryption circuit 507 only after receiving both, so that it is more difficult to decrypt the encryption. There is.

Although FIG. 4 shows an example in which a multiplying circuit 517 is added to the configuration shown in FIG. 4, it is also possible to combine the configuration shown in FIG.

A sixth embodiment of a conditional access system transmitting apparatus and a receiving apparatus for a cable television according to the present invention will be described with reference to FIG. FIG. 8 is a block diagram showing a configuration of a conditional access system transmitting apparatus for a cable television according to a sixth embodiment of the present invention and a configuration of the receiving apparatus.

In this embodiment, the uplink control line signal demodulation circuit 1 which receives the uplink control line modulated wave signal 161 and sends out the uplink control line data 162 to the transmission-side encrypted modulation apparatus 100
05, and an uplink control line signal modulation circuit 522 that receives the uplink control line data 571 and outputs an uplink control line modulated wave signal 572 to the receiving side terminal device 500, and transmits the uplink control line modulated wave signal 572 by CATV transmission. It is characterized in that a signal synthesizing circuit 521 for transmitting the signal to the path 400 is provided, and the other components having the same reference numerals as those in FIG. 1 indicate the same functions.

The uplink control line data 571 from the control microcomputer 502 of the receiving terminal device 500 of the cable television is supplied to an uplink control line modulated wave modulated by a digital modulation method such as FSK or QPSK by an uplink control line signal modulation circuit 522. Signal 57
2 and output to the CATV transmission path 400 via the signal synthesis circuit 521. Cable-TV transmitter-side encryption modulator 10
The 0 uplink control line signal demodulation circuit 105 demodulates the digitally modulated uplink control line modulated wave signal 161 such as FSK or QPSK, obtains uplink control line data 162, and sends it to the transmission side key etc. management device 300. Then, if the information can be confirmed against the information of the customer management, the key information is changed or the key information is generated.

The 64QAM digital modulated wave signal and the downlink modulated wave signal which are frequency-multiplexed and transmitted from the CATV transmission line 400 are subjected to frequency division multiplexing signal separation 573 as a downstream modulated wave signal 573 via a signal combining circuit 521. Applied to circuit 501.

In this embodiment, an uplink control line is used, and a key data generation request for encryption and a key change can be made in response to a request from a cable television receiving apparatus. Information such as passwords can be communicated when a request is made from the requester to the service provider, and key information etc. can be transmitted accordingly, making it effective for confirming information on both on-demand services such as video-on-demand and shopping It is.

Although the present embodiment is a form in which an uplink control line is added to FIG. 1, it is also possible to use an uplink control line in the embodiments shown in FIGS. 4, 5, 6, and 7. There is an advantage that is effective for both information confirmations as in the present embodiment.

Referring to FIG. 9, the concept of the frequency arrangement of the CATV transmission line in the embodiment shown in FIG. 8 will be described. As shown in FIG. 9, the CATV transmission path 400 has a downlink signal band 2001
And an uplink signal band 9001. The uplink signal band 9001 is configured to include the uplink control channel modulated wave signal 9002, and the downlink signal band 2001 is configured to be the same as the entire downlink signal band 2001 having the same code as in FIG. The figure shows the CA
This is an example of a transmission signal form of the TV transmission path 400. An uplink signal band 9001 includes a plurality of signals such as the uplink control line modulated wave signal 9002 described in FIG. 8 and another uplink control line modulated wave signal. Are frequency multiplexed.

The encryption algorithm of the transmission-side encryption modulation device 100 of the cable television and the reception-side terminal device 500 of the cable television shown in FIGS. 1, 4, 5, 6 and 7 of the embodiment of the present invention. Are the content scramble circuit 111 and the content descramble circuit 508 which are each pair of encryption circuits, the first key encryption circuit 112, the first key decryption circuit 507, the second key encryption circuit 113, and the second Key decryption circuits 506 need to use the same algorithm as each other, but the encryption algorithms of the content scramble, the first key encryption, and the second key encryption may be the same or different. . In the embodiment of the present invention, the key data is divided into three pieces from the first to third key data.
Although the type is used, the type and number of key data are not limited.

[0049]

According to the present invention, encrypted video and audio data is transmitted as a 64QAM digital modulated wave signal, and three types of key data from the first key data to the third key data are transmitted to the downlink control line modulated wave. Signal, modulated signal of upstream control line and IC
Since it can be distributed in various transmission forms such as a card, a semiconductor chip, or a telephone line, it is possible to provide a conditional access system in which there are many signals to be analyzed for eavesdropping and decoding is difficult.

As described above, the present invention is an extremely effective technique capable of providing a conditional access system for digital cable television broadcasting.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmitting apparatus of a conditional access system of a cable television according to a first embodiment of the present invention and a configuration of the receiving apparatus.

FIG. 2 is a view for explaining a first embodiment according to the present invention;
FIG. 3 is a conceptual diagram showing a frequency arrangement of a CATV transmission line.

FIG. 3 is a conceptual diagram showing a configuration for explaining a first embodiment according to the present invention.

FIG. 4 is a block diagram showing a configuration of a conditional access system transmitting apparatus and a receiving apparatus for a cable television according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conditional access system transmitting apparatus for a cable television according to a third embodiment of the present invention and a configuration of the receiving apparatus.

FIG. 6 is a block diagram showing a configuration of a transmission apparatus using a conditional access system of a cable television according to a fourth embodiment of the present invention and a configuration of the reception apparatus.

FIG. 7 is a block diagram illustrating a configuration of a conditional access transmission device for a cable television according to a fifth embodiment of the present invention and a configuration of the reception device.

FIG. 8 is a block diagram showing a configuration of a conditional access system transmitting apparatus for a cable television according to a seventh embodiment of the present invention and a configuration of the receiving apparatus.

FIG. 9 is a conceptual diagram showing a frequency arrangement of a CATV transmission line for explaining one embodiment of the present invention.

[Explanation of symbols]

 100 Transmission-side encryption / modulation device 200 Transmission-side video signal source device 300 Transmission-side key etc. management device 400 CATV transmission line 500 Receiving terminal device 600 Receiving-side TV receiver 101 Encryption device 111 Video / audio multiplexing and content scrambling circuit 112 First key encryption circuit 113 Second key encryption circuit 503 64QAM demodulation circuit 505 Downlink control line signal demodulation circuit 506 Second key decryption circuit 507 First key decryption circuit 508 Content descramble circuit

Claims (20)

[Claims] 1. Content scramble means for calculating a part of digital data in a transport stream format and first key data for encrypting the data, a first key data and a first key data thereof First key information scrambling means for calculating second key data for encrypting key data, and first key information scramble means for digitally modulating the output data stream of the content scramble means with multi-valued QAM such as 64 values. Modulating means; second modulating means for multiplexing output data and / or second key data of the first key information scrambling means and performing digital modulation such as FSK; and first modulating means And a signal synthesizing means for frequency-multiplexing a plurality of modulated waves including the output of the second modulating means and transmitting the multiplexed waves to a transmission path. Place. 2. Content scramble means for calculating a part of digital data in a transport stream format and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting the key data; time-division multiplexing of an output data stream of the content scrambling means and output data of the first key information scrambling means; Multiplexing means, a first modulating means for digitally modulating the output of the multiplexing means, such as multi-valued QAM such as 64 values, and an output data of the first key information scrambling means and a second key data. A second modulator for multiplexing both or one of them and performing digital modulation such as FSK; an output of the first modulator and the second modulator; A signal combining means for frequency-multiplexing a plurality of modulated waves including the output of the stage and transmitting the multiplexed waves to a transmission path. 3. Content scrambling means for calculating a part of digital data in a transport stream format and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting key data, second key data and third key data for encrypting the second key data, The second to calculate
Key information scrambling means, and an output data stream of the content scrambling means are multi-valued Q such as 64 values.
A first modulating means for digitally modulating AM or the like; an output data of the first key information scrambling means;
Second modulation means for multiplexing output data of the key information scrambling means and all three kinds of data of the third key data, or two kinds of data, or any one kind of data and digitally modulating the data by FSK or the like; A conditional access transmission device comprising: signal combining means for frequency-multiplexing a plurality of modulated waves including the output of the first modulation means and the output of the second modulation means and transmitting the multiplexed waves to a transmission path. 4. Content scrambling means for calculating a part of the digital data in the transport stream format and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting key data, second key data and third key data for encrypting the second key data, The second to calculate
Key data scrambling means, output data stream of the content scrambling means, output data of the output data of the first key information scrambling means and / or output data of the output data of the second key information scrambling means Multiplexing means for time-division multiplexing the data, and multi-valued Q
A first modulating means for digitally modulating AM or the like; an output data of the first key information scrambling means;
Second modulation means for multiplexing output data of the key information scrambling means and all three kinds of data of the third key data, or two kinds of data, or any one kind of data and digitally modulating the data by FSK or the like; A conditional access transmission device comprising: signal combining means for frequency-multiplexing a plurality of modulated waves including the output of the first modulation means and the output of the second modulation means and transmitting the multiplexed waves to a transmission path. 5. A first demodulator for demodulating a digital modulated wave such as a multi-level QAM such as a 64-level QAM transmitted by frequency multiplexing.
Demodulating means, second demodulating means for demodulating a frequency-multiplexed and transmitted digital modulated wave such as FSK, and scrambled first key information obtained by the second demodulating means. Key decryption means for decrypting the first key data from the output data of the second demodulation means or the second key data transmitted by another transmission method; and the first key data obtained by the key decryption means. A descrambling means for obtaining transport stream format digital data from the content scrambled data obtained by the first demodulation means. 6. A first demodulator for demodulating a digital modulated wave such as a multi-valued QAM such as a 64 value transmitted in a frequency multiplexed manner.
Demodulating means, second demodulating means for demodulating a frequency-multiplexed and transmitted digital modulated wave such as FSK, and scrambled data separated from the time-division multiplexed data of the first demodulating means. Time-division multiplexing / demultiplexing means for obtaining the first key information, scrambled first key information obtained by the time-division multiplexing / demultiplexing means, and transmission by the output data of the second demodulation means or another transmission method Key decryption means for decrypting the first key data from the obtained second key data;
The first key data obtained by the key decryption means
And a descrambler for obtaining digital data in a transport stream format from the content-scrambled data obtained by the demodulator or the time-division multiplexing / demultiplexer. 7. A first demodulator for demodulating a digital modulated wave such as a multi-valued QAM such as a 64 value transmitted in a frequency multiplexed manner.
Demodulating means, second demodulating means for demodulating a frequency-multiplexed and transmitted digital modulated wave such as FSK, second key information obtained by the second demodulating means, and the second demodulating means. Second key decryption means for decrypting the second key data from the output data of the means or the third key data transmitted by another transmission method, and the scrambled second key data obtained by the second demodulation means. A first key decryption unit that decrypts the first key data with the first key information and the second key data obtained by the second key decryption unit; and a second key decryption unit that decrypts the first key data obtained by the first key decryption unit. A descrambling unit for obtaining digital data in a transport stream format from the content-scrambled data obtained by the first demodulation unit using the first key data. 8. A first demodulator for demodulating a digital modulated wave such as a multi-valued QAM such as a 64 value transmitted in a frequency multiplexed manner.
Demodulating means, second demodulating means for demodulating a frequency-multiplexed and transmitted digital modulated wave such as FSK, and scrambled data separated from the time-division multiplexed data of the first demodulating means. Time-division multiplexing / demultiplexing means for obtaining the first key information, scrambled second key information obtained by the second demodulation means, and transmission by the output data of the second demodulation means or another transmission method Second key decryption means for decrypting the second key data from the obtained third key data, scrambled first key information obtained by the time division multiplexing / demultiplexing means, and the second key decryption First key decryption means for decrypting the first key data with the second key data obtained by the means, and first demodulation means using the first key data obtained by the first key decryption means. Obtained by the above time-division demultiplexing means Receiving device conditional access system and a descrambling means for obtaining digital data transport stream format from content scrambling of suffering data. 9. A first demodulator for demodulating a frequency-multiplexed digital modulated wave such as multi-level QAM such as 64-level QAM transmitted.
Demodulating means, second demodulating means for demodulating a digital modulated wave such as FSK transmitted in a frequency multiplexed manner, and a second demodulated data separated from the time division multiplexed data by the first demodulating means. 1 key information, a selection unit that passes one of the output of the second demodulation unit and the output of the time division demultiplexing unit, and the second demodulation unit. Second key decoding means for decoding the second key information from the scrambled second key information and the output data of the second demodulation means or the third key data transmitted by another transmission method; The first key information scrambled obtained by the selecting means and the second key data obtained by the second key decrypting means.
A first key decryption means for decrypting the key data of the first key decryption means, and a content scramble obtained by the first demodulation means or the time division demultiplexing means by the first key data obtained by the first key decryption means. And a descrambling means for obtaining transport stream digital data from the received data. 10. A first demodulation means for demodulating a digital modulated wave such as a multi-valued QAM such as 64-values transmitted in a frequency multiplexed manner, and a digital modulated wave demodulation such as FSK transmitted in a frequency multiplexed manner. A second demodulating means for performing the above operation, a time-division multiplexing / demultiplexing means for separating the time-division multiplexed data of the first demodulating means to obtain scrambled first key information, and a second demodulating means. Multiplication means for passing only information whose output coincides with the output of the time division demultiplexing means; scrambled second key information obtained by the second demodulation means; and output of the second demodulation means Second key decryption means for decrypting the second key data from the third key data transmitted by the data or another transmission method; the scrambled first key information obtained by the multiplication means; Second key First key decryption means for decrypting the first key data with the second key data obtained by the decryption means, and first demodulation means using the first key data obtained by the first key decryption means Or a descrambling means for obtaining digital data in a transport stream format from the content-scrambled data obtained by the time-division multiplexing / demultiplexing means. 11. Content scramble means for calculating a part of the digital data in the transport stream format and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting key data, and first key information scramble means for digitally modulating the output data stream of the content scramble means with multi-valued QAM such as 64 values. Modulating means; second modulating means for multiplexing output data and / or second key data of the first key information scrambling means and performing digital modulation such as FSK; and first modulating means Signal synthesizing means for frequency-multiplexing a plurality of modulated waves including the output of the second modulation means and the output of
Uplink demodulation means for demodulating uplink data, which is information from a receiving apparatus transmitted by digital modulation such as FSK, and the first key data and the first key data for encrypting at the request of the uplink demodulation means. 2. A conditional access transmission device comprising: key generation means for changing the occurrence time and / or information of both or one of the two key data. 12. Content scrambling means for calculating a part of digital data in a transport stream format and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting the key data; time-division multiplexing of an output data stream of the content scrambling means and output data of the first key information scrambling means; Multiplexing means, a first modulating means for digitally modulating the output of the multiplexing means, such as multi-valued QAM such as 64 values, and an output data of the first key information scrambling means and a second key data. A second modulating means for multiplexing both or one of them and performing digital modulation such as FSK; an output of the first modulating means and the second modulating means; Signal synthesizing means for frequency-multiplexing a plurality of modulated waves including the output of the means and transmitting the multiplexed waves to a transmission path;
Uplink demodulation means for demodulating uplink data which is information transmitted from the receiving apparatus by digital modulation such as K, the first key data for encrypting at the request of the uplink demodulation means, and the first key data. 2. A conditional access transmission device comprising: key generation means for changing the occurrence time and / or information of both or one of the two key data. 13. Content scramble means for calculating a part of transport stream format digital data and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting key data, second key data and third key data for encrypting the second key data, Second key information scrambling means for calculating the following equation, first modulation means for digitally modulating the output data stream of the content scrambling means, such as multi-valued QAM such as 64 values, and output of the first key information scrambling means. Data, output data of the second key information scrambler, and third key data, all or two types of data, or any one type of data. A second modulating means for multiplexing digital data such as FSK and a plurality of modulated waves including an output of the first modulating means and an output of the second modulating means. Signal synthesizing means for sending, FS
Uplink demodulation means for demodulating uplink data which is information transmitted from the receiving apparatus by digital modulation such as K, the first key data for encrypting at the request of the uplink demodulation means, and the first key data. Limited reception transmission including key generation means capable of changing the generation time and information of all or two types of key data of the second key data and the third key data or two types of key data or any one type of key data apparatus. 14. Content scramble means for calculating a part of transport stream format digital data and first key data for encrypting the data, a first key data and a first key data thereof. First key information scrambling means for calculating second key data for encrypting key data, second key data and third key data for encrypting the second key data, Second key information scramble means for calculating the output data stream of the content scramble means, the output data of the first key information scramble means and the output data of the second key information scramble means, or Multiplexing means for time-division multiplexing one of the output data; and a multi-valued Q such as 64-valued output data from the multiplexing means.
A first modulating means for digitally modulating AM or the like; an output data of the first key information scrambling means;
Second modulation means for multiplexing output data of the key information scrambling means and all three kinds of data of the third key data, or two kinds of data, or any one kind of data and digitally modulating the data by FSK or the like; Signal synthesizing means for frequency-multiplexing a plurality of modulated waves including the output of the first modulation means and the output of the second modulation means and transmitting the multiplexed waves to a transmission path;
Uplink demodulation means for demodulating uplink data, which is information from the receiving device transmitted by digital modulation such as,
All or two types of key data of the first key data, the second key data, and the third key data for encryption at the request of the uplink demodulation means, or any one of the key data A conditional access transmission device comprising: a key generation unit that can change the generation time and information of various types of key data. 15. A first demodulating means for demodulating a digital modulated wave such as multi-level QAM such as 64-values transmitted in a frequency multiplexed manner, and a demodulated digital modulated wave such as FSK transmitted in a frequency multiplexed manner. A second demodulating means, a scrambled first key information obtained by the second demodulating means, and a second key transmitted by the output data of the second demodulating means or another transmission method. Key decryption means for decrypting first key data from the data, and a transport stream format from the content-scrambled data obtained by the first demodulation means using the first key data obtained by the key decryption means. A descrambling means for obtaining digital data, and information generated by a service request operation such as image selection of a receiving apparatus by digital modulation such as FSK or the information generated by the operation. The key generation request or the second
And an uplink modulator for transmitting the key data as data to the transmitting device. 16. A first demodulating means for demodulating a digital modulated wave such as a multi-valued QAM such as 64 values transmitted in a frequency multiplexed manner, and a digital modulated wave demodulation such as FSK transmitted in a frequency multiplexed manner. A second demodulating means for performing the above operation, a time-division multiplexing / demultiplexing means for obtaining scrambled first key information by separating the data from the time-division multiplexed data of the first demodulating means, Key decryption means for decrypting the first key data from the obtained scrambled first key information and the output data of the second demodulation means or the second key data transmitted by another transmission method;
The first key data obtained by the key decryption means
Descrambling means for obtaining digital data in a transport stream format from the content-scrambled data obtained by the demodulation means or the time-division multiplexing / demultiplexing means, and a service request operation such as image selection of a receiving apparatus by digital modulation such as FSK. Generated by the above or a key generation request corresponding to the information or the second
And an uplink modulator for transmitting the key data as data to the transmitting device. 17. A first demodulating means for demodulating a digital modulated wave such as a multi-valued QAM such as 64-values transmitted in a frequency multiplexed manner, and a digital modulated wave demodulation such as FSK transmitted in a frequency multiplexed manner. A second demodulating unit that performs the second demodulation based on the second key information obtained by the second demodulating unit and the output data of the second demodulating unit or the third key data transmitted by another transmission method. Second key decryption means for decrypting the key data, scrambled first key information obtained by the second demodulation means, and second key data obtained by the second key decryption means. A first key decryption means for decrypting the first key data with the first key data obtained by the first key decryption means, and a content scrambled data obtained by the first demodulation means by the first demodulation means. Transport stream format data Descrambling means for obtaining digital data, information generated by a service request operation such as image selection of a receiving apparatus by digital modulation such as FSK, a key generation request corresponding to the information, or the third key data as data to a transmitting apparatus. A receiving apparatus of a conditional access system, comprising: an uplink modulation unit for transmitting. 18. A first demodulating means for demodulating a digital modulated wave such as a multi-valued QAM such as 64 values transmitted by frequency multiplexing, and a demodulated digital modulated wave such as FSK transmitted by frequency multiplexing. A second demodulating means, a time-division multiplexing / demultiplexing means for separating the time-division multiplexed data of the first demodulating means to obtain scrambled first key information, and a second demodulating means. Second key decryption for decrypting the second key data from the obtained scrambled second key information and the output data of the second demodulation means or the third key data transmitted by another transmission method. Means for decoding the first key data with the scrambled first key information obtained by the time division demultiplexing means and the second key data obtained by the second key decoding means. Key decryption means, and the first Descrambling means for obtaining digital data in a transport stream format from the content-scrambled data obtained by the first demodulation means or the time-division demultiplexing means by the first key data obtained by the key decoding means. And information generated by a service request operation such as image selection of a receiving device by digital modulation such as FSK, a key generation request corresponding to the information, or the above-mentioned third key data to a transmitting device as uplink data. A conditional access system receiving device. 19. A first demodulating means for demodulating a digital modulated wave such as a multi-valued QAM such as 64 values transmitted in a frequency multiplexed manner, and a digital modulated wave demodulation such as FSK transmitted in a frequency multiplexed manner. A second demodulating means for performing the above operation, a time-division multiplexing / demultiplexing means for separating the time-division multiplexed data of the first demodulating means to obtain scrambled first key information, and a second demodulating means. Selecting means for passing either the output or the output of the time division demultiplexing means, the scrambled second key information obtained by the second demodulating means, and the output data of the second demodulating means. Alternatively, second key decryption means for decrypting second key data from third key data transmitted by another transmission method, scrambled first key information obtained by the selection means and the second key data, 2 key decryption First key decryption means for decrypting the first key data with the second key data obtained by the means,
Descrambling means for obtaining digital data in a transport stream format from the content-scrambled data obtained by the first demodulation means or the time-division demultiplexing means by the first key data obtained by the key decoding means. And information generated by a service request operation such as image selection of a receiving device by digital modulation such as FSK, a key generation request corresponding to the information, or the above-mentioned third key data to a transmitting device as uplink data. A conditional access system receiving device. 20. A first demodulating means for demodulating a digital modulated wave such as a multi-valued QAM such as 64 values transmitted in a frequency multiplexed manner, and a demodulated digital modulated wave such as FSK transmitted in a frequency multiplexed manner. A second demodulating means for performing the above operation, a time-division multiplexing / demultiplexing means for separating the time-division multiplexed data of the first demodulating means to obtain scrambled first key information, and a second demodulating means. Multiplication means for passing only information whose output coincides with the output of the time division demultiplexing means; scrambled second key information obtained by the second demodulation means; and output of the second demodulation means Second key decryption means for decrypting the second key data from the third key data transmitted by the data or another transmission method; the scrambled first key information obtained by the multiplication means; Second key First key decryption means for decrypting the first key data with the second key data obtained by the decryption means, and first demodulation means using the first key data obtained by the first key decryption means Alternatively, it is generated by descrambling means for obtaining digital data in a transport stream format from the content-scrambled data obtained by the time division demultiplexing means, and by a service request operation such as image selection of a receiving apparatus by digital modulation such as FSK. A conditional access system receiving apparatus comprising: an uplink modulator for transmitting information or a key generation request corresponding to the information or the third key data to the transmitting apparatus as data.