JP4794956B2 - Scrambler - Google Patents

Description

  The present invention relates to a scramble device used for video distribution.

  A cable provider such as a CATV provider has realized a mechanism for receiving satellite broadcast and terrestrial broadcast and retransmitting it to its own transmission path. Encryption service is applied to a service called HITS (Headend In The Sky), in which a program for a satellite broadcast or a CATV provider is packaged in advance by a distributor. Depending on the service format, the CATV provider temporarily cancels encryption and newly performs CATV encryption processing called C-CAS, or multiplexes information necessary for decryption by a receiver. (For example, Patent Document 1) ensures confidentiality in the transmission path from the CATV station to the receiver.

  FIG. 5 shows the configuration of a repeater used in the conventional encryption system disclosed in Patent Document 1. In FIG. 5, the repeater 500 includes a receiving / decoding device 510 and a security module 520. The reception decoding device 510 includes a demultiplexer 511, a descrambler 512, and a decoder 513. The video signal and audio signal separated by the demultiplexer 511 are descrambled by the descrambler 512 and then decoded by the decoder 513. And output to the monitor 530. On the other hand, the security module 520 includes a program / individual information analysis unit 521 and a contract information storage unit 522.

The repeater 500 is provided with a demodulator 514 in the receiving / decoding device 510, a CATV program control unit 540, a program information encryption unit 550, a CATV customer management unit 560, an individual information encryption unit 570, a multiplexer 580, And a modulator 590 is provided.
The demodulator 514 demodulates the satellite broadcast signal transmitted via the satellite broadcast transmission path 501 and outputs it to the demultiplexer 511 as a digital signal.

  The CATV program control unit 540 generates CATV program information including a CATV program number corresponding to a program broadcast as a CATV broadcast set by a CATV broadcast provider, and outputs the CATV program information to the program information encryptor 550. The program information encryption unit 550 encrypts the scramble key input from the program / individual information analysis unit 521 and the CATV program information input from the CATV program control unit 540 with the work key input from the individual information encryption unit 570. And output to the multiplexer 580.

  The CATV customer management unit 560 includes contract information such as a viewable channel, an expiration date, and a charge amount contracted by each customer (viewer) who subscribes to the CATV broadcast, and all the viewers have. Individual keys corresponding to a CATV broadcast receiving apparatus (not shown) are stored and supplied to the individual information encryptor 570. The individual information encryptor 570 generates a work key and supplies it to the program information encryptor 550. The individual information encryptor 570 corresponds to each CATV broadcast receiving device with the CATV individual information including the work key and the contract information supplied from the CATV customer management unit 560. Encrypted with the individual key to be output to the multiplexer 580.

  Note that the work key generated by a satellite broadcast transmission apparatus (not shown) and the work key generated by the individual information encryptor 570 may be the same or different. Similarly to the work key, the individual key stored in the scramble control unit of the satellite broadcast transmission device and the individual key stored in the CATV customer management unit 560 may be the same as the individual key. And it can be different.

  Multiplexer 580 receives video and audio signals scrambled with a scramble key input from demultiplexer 511, CATV program information input from program information encryptor 550, and input from individual information encryptor 570. The CATV individual information is time-division multiplexed and output to the modulator 590.

Modulator 590 modulates the time-division multiplexed CATV broadcast signal input from multiplexer 580 and transmits it as a CATV broadcast signal to each CATV broadcast receiver via CATV broadcast transmission path 502.
JP 2001-339380 A

  However, the conventional processing described in Patent Document 1 has a problem that it cannot be recompressed because the encryption cannot be released even if the CATV station tries to recompress the video signal to secure the band. Moreover, since the encryption is once canceled in the HITS service, it can be recompressed. However, since encryption different from the broadcasting system is performed, there is a problem that the confidentiality intended by the broadcasting station cannot be ensured.

  In view of the above-described conventional problems, the present invention extracts encrypted information when releasing a broadcast-type encryption, and performs encryption with the extracted encryption information when transmitted to the network of the CATV station. An object of the present invention is to provide a scrambler that can ensure the confidentiality of the broadcasting station while enabling signal processing at the same time.

In order to solve the conventional problem, the scrambler of the present invention includes:
Receiving means for receiving an encrypted broadcast signal transmitted from the first network; and decrypting means for decoding part or all of the broadcast signal received by the receiving means;
Encrypted information extracting means for extracting encrypted information used for encryption from the broadcast signal;
To retransmit a broadcast signal transmitted from the first network, using the extracted encryption information in the encrypted information extracting unit, a broadcast signal decoded by said decoding means, with respect to the broadcast signal It is characterized by comprising an encryption process and at least an encryption means for encrypting by an encryption process using the same encryption method and encryption key .
With the above configuration, it becomes possible to extract the encrypted information of the decoded broadcast signal, re-encrypt it , and retransmit it.

  In the scramble apparatus of the present invention, it is preferable that the encrypted information includes information used for decryption by the decryption means. Similarly, the encryption performed by the encryption means is preferably the same as the encryption processed for the signal transmitted from the first network.

The scrambling apparatus of the present invention preferably further comprises a format conversion means for converting the output signal of the decryption means into another format and inputting it to the encryption means. The another format is preferably a format for retransmitting the output signal of the decoding means via a CATV network. Similarly, it is preferable to provide buffer means for temporarily storing a signal that is not subjected to format conversion by the format conversion means.

  The scrambler of the present invention preferably includes a multiplexing means for time division multiplexing the output of the format conversion means and the output of the buffer means, and the multiplexing means is extracted by the encrypted information extraction means. It is preferable to multiplex information.

  The present invention can also be realized as a program that can execute the function of the scrambler by a computer.

  According to the scramble apparatus of the present invention, it is possible to ensure the confidentiality intended by the broadcasting station while performing re-compression of the signal to ensure the band at the CATV station at the time of retransmitting the broadcast.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a retransmission system that performs transcoding processing in a CATV network in the embodiment of the present invention. In this embodiment, an example in which a digital broadcast is adopted as the first network and a CATV network is adopted as the second network will be described. However, the network form is not particularly limited to this and is configured on the Internet. It goes without saying that it is also good.

  In FIG. 1, a scrambler 100 includes a tuner unit 101 that receives a broadcast wave transmitted from a digital broadcast station 110 via a terrestrial digital network 120, and a TS (Transport Stream) signal that has been subjected to error correction processing by the tuner unit 101. TS decoder 102 that distributes video signals, audio signals, and other types, descrambler 103 that decrypts a signal encrypted by the MULTI2 method in digital broadcasting station 110, and TS TS output from TS decoder 102 Among the output TS signals of the TS decoding unit 102 and the buffer unit 104 that temporarily stores data such as voice and data that are not subjected to signal processing, and the TS decoding unit 102 output video signals. H.264 (hereinafter simply referred to as “H.264”) or the like, and an encryption that stores an ECM (Entire Control Message) packet that is information related to encryption among the output TS signals of the TS decoding unit 102. An information extraction unit 106 and a multiplexing unit that time-division-multiplexes the audio TS stored in the buffer unit 104, the video TS format-converted by the transcoding unit 105, the ECM packet stored in the encrypted information extraction unit 106, etc. 107, a re-scrambler 108 that encrypts the output of the multiplexer 107 with the encrypted information stored in the encrypted information extractor 106, and a modulator 109 that performs 64QAM modulation, via the CATV network 130 Then, the broadcast is retransmitted to the receiver STB 140.

  Next, the operation of the scrambler 100 will be described. When the tuner unit 101 receives a broadcast program, the tuner unit 101 performs demodulation, error correction processing, and the like to restore the TS packet. The TS decoder unit 102 extracts PAT (Program Association Table) and PMT (Program Map Table) packets, which are program information packets defined by MPEG2-SYSTEMS, from the TS packets restored by the tuner unit 101. Based on the PID and descriptor described in the extracted PMT, the video is divided into ECM packets that are video, audio, data, and encryption information and sent to the descrambling unit 103.

  FIG. 2 shows the data structure of the PMT. The ECM PID is described in the descriptor 203 defined by ARIB (Radio Industry Association) TR-B10. An ECM having a PID described in the descriptor 203 is effective for all the target PIDs for scrambling. When changing the ECM for each service, the ECM is described in the descriptor 204. In any case, the descriptor tag is 09 indicating CA_descriptor. The descrambling unit 103 identifies the ECM based on the PID of the ECM described in the descriptor 203.

  The descrambling unit 103 holds the work key Kw, which is information for decrypting the ECM input from a communication line (not shown) or an external device, and releases the ECM encryption with the work key Kw. . The ECM stores Ks which is a program key (scramble key) for releasing the encryption applied to the video and audio TS.

  The ECM is configured in a section format. The data structure of the ECM section is shown in FIG. There are two types of scramble keys Ks, odd and even. One is a key that scrambles the current broadcast, and the other is a scramble key to be used next. Which key is used for scrambled can be confirmed by the value of the transport_scrambled_control field in the header of the tonlas port stream packet. The encryption performed by the broadcasting station is decrypted using odd or even Ks indicated in the transport_scramble_control field. The work key Kw may be sent by the same broadcast wave as the ECM.

  The descrambling unit 103 sorts the TS packets by PID, which is the ID of the TS packet, based on the signal type information obtained from the PMT after the decryption. The stream type 201 of FIG. 2 is individually assigned to video, audio, etc., and is described in the PMT as a set with the corresponding type of PID 202. Information that does not modify the TS packet, such as voice information and data information, is stored in the buffer unit 104, and the encrypted ECM and the Ks of the odd and even program keys and the target PID are stored in the encrypted information extraction unit 106. The

  An example of the data configuration stored in the encrypted information extraction unit 106 is shown in FIG. The ECM 401, the Ks odd 402, the Ks even 403, and the scramble target PID 404 are stored as one group.

  The video TS is sent to the transcoding unit 105, and MPEG2 to H.264 is transmitted. H.264. The transcode unit 105 is set so that a TS is output with the same PID as the input TS. In the multiplexing unit 107, H.264 is used. The video TS converted to H.264 and the audio TS and data TS stored in the buffer unit 104 are time-division multiplexed. At this time, in order to synchronize video and audio, the reading from the buffer unit 104 is delayed in consideration of the processing time in the transcoding unit 105, and then PTS (Presentation_Time_Stamp) and DTS (DTS) defined by MPEG2-SYSTEMS Time information such as Decoding_Time_Stamp) and PCR (Program_Clock_Reference) is corrected.

  The multiplexing unit 107 also multiplexes the ECM that has been encrypted. The re-scramble unit 108 performs MULTI 2 encryption processing on the TS packet having the PID of the video or audio TS specified using Ks stored in the encryption information extraction unit 106.

  Prior to the encryption process with the scramble key Ks, the multiplexing unit 107 receives and multiplexes the ECM storing the Ks used for encryption from the encryption information extraction unit 106, performs 64QAM modulation by the modulator 109, and then performs the CATV network. It is transmitted to the STB 140 via 130.

  In this configuration, the ECM is once extracted and stored in the encrypted information extraction unit 106, and then the multiplexing unit 107 multiplexes the ECM at a period defined by ARIB, but a new ECM is transmitted from the digital broadcasting station 110. In this case, it is possible to adjust the key update timing by matching the new ECM multiplexing timing with the Ks update timing in the subsequent re-scrambler 108. As a result, the STB 140 can also decrypt the signal encrypted with Ks.

  Although the transcoding has been described as an example of the processing after decoding, it may be a transrate that converts the code rate in the same format, and is not particularly limited. When there is no change in the total data amount and there is no change in the data arrangement, such as data replacement, correction of time information in the multiplexing unit 107 is unnecessary.

  Further, the encryption has been described by taking the MULTI2 system as an example, but is not particularly limited. Further, the ECM stored in the encrypted information extraction unit 106 may remain decrypted. In this case, it is necessary to encrypt again with Kw before multiplexing by the multiplexing unit 107.

  The scrambler according to the present invention enables signal format conversion while ensuring the confidentiality of broadcast waves, and is useful for retransmission of broadcast waves to a communication network.

The block diagram which shows the structure of the retransmission system in embodiment of this invention The figure which shows the data structure of PMT in the embodiment The figure which shows the data structure of ECM in the embodiment The figure which shows an example of the data structure of the encryption information extraction part in the embodiment The block diagram which shows the structure of the repeater used for the conventional encryption system

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Scramble apparatus 110 Broadcast station 120 Broadcast network 101 Tuner part 102 TS decoding part 103 Descramble part 104 Buffer part 105 Transcoding part 106 Encryption information extraction part 107 Multiplexing part 108 Re-scramble part 109 Modulation part 130 CATV network 140 STB
201 stream type
202 PID
203, 204 descriptor
401 ECM
402 Scramble key Ks (odd)
403 Scramble key Ks (even)
404 PID group

Claims (8)

Receiving means for receiving an encrypted broadcast signal transmitted from the first network;
Decoding means for decoding part or all of the broadcast signal received by the receiving means;
Encrypted information extracting means for extracting encrypted information used for encryption from the broadcast signal;
To retransmit a broadcast signal transmitted from the first network, using the extracted encryption information in the encrypted information extracting means, a signal decoded by said decoding means, the encryption for the broadcast signal A scramble apparatus comprising: an encryption process; and an encryption unit that encrypts at least the encryption method and the encryption key with the same encryption process .   The scrambler according to claim 1, wherein the encrypted information includes information used for decryption by the decryption means. 3. The scramble apparatus according to claim 1, further comprising: a format conversion unit that converts an output signal of the decryption unit into another format and inputs the converted signal to the encryption unit. 4. A scrambler according to claim 3 , further comprising buffer means for temporarily storing a signal which is not subjected to format conversion by said format conversion means. 5. The scrambler according to claim 4 , further comprising multiplexing means for time division multiplexing the output of the format conversion means and the output of the buffer means. 6. The scramble apparatus according to claim 5 , wherein the multiplexing unit multiplexes the information extracted by the encrypted information extracting unit. The scrambler according to claim 3, wherein the another format is a format for retransmitting the output signal of the decoding means via a CATV network. A computer program for causing a computer to function as a scramble device that encrypts a received signal,
Receiving means for receiving an encrypted broadcast signal transmitted from the first network;
Decoding means for decoding part or all of the broadcast signal received by the receiving means;
Encrypted information extracting means for extracting encrypted information used for encryption from the broadcast signal;
To retransmit a broadcast signal transmitted from the first network, before SL using the encryption information extracted by the encryption information extracting means, a signal decoded by said decoding means, with respect to the broadcast signal A computer program that functions as an encryption means for performing encryption processing and at least encryption processing using the same encryption method and encryption key .

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