JP2000332745A - Transmitter and receiver for definition reception system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the efficiency of multiplexing, when a plurality of information source coded bit string are set in packets, ciphered, multiplexed and transmitted. SOLUTION: This transmitter is configured with an information source coding section 1, a variable length packet assembling/scramble section 2, a priority multiplexer section 3, and an encipherment/priority multiplexing control section 4. The encipherment/priority multiplexing control section 4 controls the sections 3, 4 so that a multiplexed bit stream 104 has a scramble key updated at a larger time interval than a maximum multiplex delay time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for encoding and multiplexing digital data such as a video signal, an audio signal, and other data and transmitting the encoded data. The present invention relates to a conditional access system transmitting apparatus and a receiving apparatus in which only a specific receiver connected with the above can decode a scrambled signal.

[0002]

2. Description of the Related Art FIG. 10 shows, for example, "Multimedia Industrial Application Technology System" pp. FIG. 495-496 is a block diagram showing a configuration of a conventional conditional access transmission device shown in Fuji Techno System (1997).
FIG. 11 is a block diagram showing a configuration of a conventional conditional access receiving apparatus similarly shown in the above-mentioned document.

In FIG. 10, reference numeral 21 denotes an information source coding unit;
Reference numeral 22 denotes a fixed-length packetizing / scramble unit, 23 denotes a multiplexing unit, and 24 denotes a concealment / multiplexing control unit. Also, 40
1 is a content such as a video signal, an audio signal, various data, etc., 402 is an information source coded bit sequence, 403 is a fixed-length packet sequence, 404 is a multiplexed bit sequence, and 405 is concealment
This is a control signal for multiplexing. In the figure, arrows indicate transmission paths of the respective contents or the encoded bit streams. In the information source encoding unit 21 and the like, a plurality of contents or bit streams transmitted through the plurality of transmission paths are processed in parallel. Is done. In FIG. 11, 25 is a demultiplexer, 26 is a fixed-length packet
A descrambling unit 27 is an information source decoding unit.

Next, the operation will be described. First, processing in a conventional conditional access transmission apparatus will be described with reference to FIG. The information source encoding unit 21 outputs a video signal,
An information source encoding process is performed on a plurality of contents 401 such as audio signals, data, etc.
Generate 2. Fixed length packetization / scramble section 22
Generates a fixed-length packet by appropriately dividing each information source coded bit string 402 and storing the same in a payload of a fixed-length packet, and scrambling the payload of the fixed-length packet to conceal the payload of the fixed-length packet.
03 is generated. Further, the fixed-length packetizer / scrambler 22 adds confidential information such as a scramble key to the ECM in addition to a normal fixed-length packet in which the information source encoding bit string 402 for the content is stored in the payload.
(Entitlement Control Message) is stored in a fixed-length packet and output. The multiplexing unit 23 generates a multiplexed bit sequence 404 by multiplexing the fixed-length packet sequence 403 in fixed-length packet units. The concealment / multiplexing control unit 24 controls the update timing of the scramble key used for concealment, the multiplexing timing of the ECM, and the like.

[0005] Next, processing in a conventional conditional access receiving apparatus will be described with reference to FIG. The processing in the conventional conditional access receiving apparatus is the reverse of the processing in the transmitting apparatus. As shown in FIG. 11, the demultiplexing unit 25 separates the multiplexed bit sequence 404 for each content, and generates a plurality of fixed-length packet sequences 403 corresponding to each content. Fixed length packet decomposition
The descrambling unit 26 removes the confidential state of the fixed-length packet sequence 403 using the confidential information transmitted as the ECM, and decomposes the packet to generate the information source coded bit sequence 402. The information source decoding unit 27 decodes the information source coded bit string 402 and reproduces a content 401 such as a video signal, an audio signal, and various data.

Further, a description will be given of the multiplexing method of the transmission signal in the conventional conditional access system and the operation of the concealment / multiplexing control unit 24. FIG. 12 shows, for example, the transmission and operation conditions (ARIB S
TD-B20 1.0 version) "pp. 20-38 (199
FIG. 11 is a diagram illustrating a multiplexing method of a transmission signal in the conventional conditional access system shown on Nov. 6, 2008). Note that, regarding multiplexing, the processing in the transmitting apparatus and the processing in the receiving apparatus are the opposite processing, and therefore, the processing in the transmitting apparatus will be described here.

[0007] Each information source coded bit string 402 for each content (for each information source) is divided into fixed-length packets, the payload of the packets is scrambled, and the scrambled fixed-length packets are multiplexed in packet units. And a multiplexed bit string 404 is generated. The confidential information such as the scramble key is stored in a fixed-length packet as an ECM and multiplexed. The ECM can be specified for each content, or can be specified as common to a plurality of contents. The ECM is transmitted periodically (time interval: t). One ECM simultaneously carries two types of scrambling keys, which are called an odd key and an even key, respectively. The odd key and the even key stored in the ECM are not updated at the same time, but are updated one by one in order.

The concealment / non-concealment information as to whether or not concealment is performed, and the type (odd key / even key) of the scramble key used for concealment can be added in fixed length packet units. . The information on the concealment is stored in the header of the fixed-length packet.

An EC with updated settings related to concealment
If a packet subjected to scramble processing using the updated key is multiplexed and transmitted immediately after the packet storing M, the receiving side cannot receive the updated key in time and a descrambling error occurs. Sometimes.
Therefore, the packet storing the ECM with the updated content and the packet scrambled with the updated key are:
Normally, multiplexing is performed with a time interval in consideration of the key capture time on the receiving side. For example, the time at which the updated scramble key is sent by the ECM is Tecm, the time at which the updated scramble key is used at the receiver is Ts, the update period of the scramble key is Tt, and the receiver includes the transfer time without considering the multiplexing delay. Assuming that the key capture time is ΔT, it is necessary to satisfy at least Ts−2Tt−ΔT ≦ Tecm <Ts−ΔT (Equation 1). Here, 2Tt is
The use of an odd key or an even key on the receiving side is given as a valid period. That is, on the transmitting side,
The scramble key is updated from the odd key to the even key or from the even key to the odd key every update cycle Tt, and scramble processing is performed based on the updated scramble key.
However, updating from an odd key to the next odd key or updating from an even key to the next even key is performed with a cycle of 2Tt,
Since the type of the scramble key (odd key or even key) to be used is registered in each packet, the effective use period of the scramble key on the receiving side is 2Tt. Then, the concealment / multiplexing control unit 24 controls the update cycle of the scramble key, the update timing of the ECM, and the like so as to satisfy Expression 1.

[0010]

Since the conventional conditional access transmission apparatus and the like are configured as described above, when the information source coded bit string is divided and stored in the payload of the fixed length packet, It is necessary to insert a dummy byte in order to make the length of the multiplexing into a fixed length, and there is a problem that multiplexing efficiency is reduced.

[0011] In a conventional conditional access system transmission device or the like, when concealing an information source coded bit string given priority with respect to multiplexing and multiplexing and transmitting the same, the multiplexing delay time of a low priority packet is reduced. When the update period Tt of the scramble key is relatively small as compared with the case of (1), the packet cannot be decrypted on the receiving side because the packet scrambled with the old key and the packet scrambled with the new key arrive at the same time. was there.

[0012] In the conventional conditional access transmission apparatus, etc., the priority of concealment is not set according to the information source coding mode for each content. And cannot set flexible confidentiality characteristics. Here, the confidentiality characteristics include a period setting for concealing the content, a type of encryption used for concealment, and CBC (Cipher Block Chaining).
) Mode and OFB (Output Feed Back) mode and other attributes related to confidentiality such as encryption use modes. The information source encoding mode indicates an encoding method used when encoding each content.
Taking the G-2 video standard as an example, an intra prediction mode,
The forward prediction mode and the bidirectional prediction mode are provided as encoding modes.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and improves the efficiency of multiplexing when a plurality of information source coded bit strings are stored in a packet and are concealed and multiplexed for transmission. It is an object of the present invention to obtain a conditional access system transmitting device and a receiving device.

[0014] The present invention also provides a highly reliable conditional access transmission apparatus and a reception apparatus which prevent undecryption due to mixing of a packet scrambled with a new key and a packet scrambled with an old key. The purpose is to gain.

A further object of the present invention is to provide a transmitting apparatus and a receiving apparatus of a conditional access system capable of setting flexible confidential characteristics according to an information source coding mode for each content.

[0016]

According to the transmitting apparatus of the conditional access system according to the present invention, the concealment / priority multiplexing control means updates the scramble key in the multiplexed bit stream at a time interval larger than the maximum multiplexing delay time. Control so that the

In the transmitting apparatus of the conditional access system according to the present invention, the packetization / scramble means generates the variable length packet by storing the information source coded bit string in the payload of the variable length packet.

The conditional access system transmitting apparatus according to the present invention includes an ECM identification number for identifying an ECM that stores a scramble key used by the packetizer / scrambler for concealing a part of the packet. It is intended to be registered in.

In the receiving apparatus of the conditional access system according to the present invention, the packet disassembling / descrambling means specifies the scramble key used for concealing a part of the packet with reference to the ECM specifying number, and The concealment of the concealment part is released.

[0020] In the transmitting apparatus of the conditional access system according to the present invention, the concealment / priority multiplexing control means controls the concealment characteristics of the packet based on the concealment priority.

[0021] In the transmission apparatus of the conditional access system according to the present invention, the concealment / priority multiplexing control means controls the concealment characteristics of the packet based on the concealment priority set for each information source coding mode for each content. Is controlled.

[0022] In the transmitting apparatus of the conditional access system according to the present invention, the concealment / priority multiplexing control means controls the type of encryption, the CBC mode, the OFC, and the like based on the priority of concealment.
The encryption is changed by changing the use mode of the encryption such as the B mode.

In the transmitting apparatus of the conditional access system according to the present invention, the concealment / priority multiplexing control means controls the concealment period based on the priority of concealment.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of a conditional access system transmitting apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a configuration of a conditional access receiving apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 1 denotes an information source encoding unit (information source encoding means) for encoding various types of content information, and 2 denotes a variable length packetizer for performing variable length packetization and concealment. A scrambler (packetizing / scrambler), 3 is a priority multiplexer (priority multiplexer) for performing multiplexing according to priority, and 4 is a variable length packetizer / scrambler 2 and a priority multiplexer 3. A concealment / priority multiplexing control unit (concealment / priority multiplexing control means) to be controlled. Reference numeral 101 denotes a content such as a video signal, an audio signal, and various data; 102, an information source coded bit sequence; 103, a variable length packet sequence (packet sequence);
4 is a multiplexed bit string, and 105 is a control signal for concealment / priority multiplexing.

In FIG. 2, reference numeral 5 denotes a multiplexed bit sequence 104.
Multiplexing / separating unit (priority multiplexing / separating means) for separating the data into a variable length packet sequence 103 for each content; A descrambling unit (packet decomposition / descrambling means) 7 decodes the information source coded bit string 102 and
Is an information source decoding unit (information source decoding means) that reproduces.

Next, the operation will be described. First, the processing in the conditional access transmission apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. The information source encoding unit 1 performs an information source encoding process on a plurality of contents 101 such as a video signal, an audio signal, and data to generate an information source encoded bit sequence 102. When performing this encoding process, the source encoding of the video signal complies with the MPEG-2 video standard, and a coding unit called “picture” corresponding to a video frame, a video field, and the like is used as a unit. Intra prediction mode,
The source coding mode is selected from the forward prediction mode and the bidirectional prediction mode. On the other hand, for audio signals, various data, and the like, information source encoding processing is performed using a predetermined time length or a predetermined byte length as an encoding unit.

Next, the variable-length packetizer / scrambler 2 divides each information source coded bit string 102 into coding units and stores it in the payload of the variable-length packet to generate a variable-length packet. The payload of the variable-length packet is scrambled and concealed to generate a variable-length packet sequence 103.

FIG. 3 is a diagram showing a configuration of a variable length packet used in the first embodiment of the present invention. 201
Is a packet start code in which a unique word for identifying the head of a variable-length packet is stored, 202 is a packet identifier assigned with a different number for each content stored in the packet, 203 is concealment / non-concealment information, Odd / even key distinction information used for concealment, CBC or O
Confidential information for notifying the use mode of encryption such as FB, 2
04 notifies the value of the packet identifier of the variable length packet storing the ECM related to the concealment of the variable length packet.
CM identification number, 205 is a payload length indicating the payload length of the variable-length packet, 206 is assigned to prevent error emulation of the header portion of the variable-length packet and the packet start code 201 at the time of performing the scrambling process. CRC 207 is a variable length packet payload that stores the encoded bit string. In addition, a plurality of ECMs of different types are prepared according to the content or the information source encoding mode, and the like.
The ECM identification number 204 identifies the content of the packet or the type of ECM according to the information source coding mode.

At the time of concealment, the control signal 105 output from the concealment / priority multiplexing control unit 4 controls the concealment in accordance with the content contents or the information source coding mode of each coding unit. Type of encryption used for encryption, CB
The use modes of encryption such as C and OFB, concealment / non-concealment information, and the like are controlled for each variable-length packet, and these control information are written in the fields of the concealment information 203 of each variable-length packet.

For example, in the case of video contents,
The priority multiplexing control unit 4 controls the concealment based on the following priority Pca specified for the information source coding mode of the coding unit as follows. Pca = 1: All coding units are concealed. Pca = 2: Encoding units other than the intra prediction mode are concealed. Pca = 3: Only coding units in bidirectional prediction mode are concealed. Pca = 4: No concealment.

For concealment of audio contents and various data contents, the concealment / priority multiplexing control unit 4 sets a concealment period or a non-concealment period to an encoding unit according to the priority of concealment. Control in units. In addition, depending on the priority of concealment, the strength of concealment is controlled by changing the type of cipher to be used or changing the use mode of cipher such as CBC mode or OFB mode. Note that concealment-related information such as a scramble key that is not contained in the field of the concealment information 203 of each variable-length packet regarding concealment is stored as an ECM in the payload of the variable-length packet and sent.

Next, the preferential multiplexing unit 3 preferentially multiplexes the variable length packet sequence 103 for each content to generate a multiplexed bit sequence 104 at a fixed bit rate (CBR).
At this time, the multiplexing characteristic at the time of the preferential multiplexing is controlled by the control signal 105 based on the priority regarding the multiplexing delay given to each content. Regarding the priority regarding the multiplexing delay, the ECM and the control information have the highest priority. In addition, the priority for contents that require real-time transmission is increased, and the priority for contents that do not require real-time transmission is decreased. Furthermore, the same priority is given to a plurality of contents that need to be reproduced synchronously, as in the case of a video and audio accompanying the video.

The concealment / priority multiplexing control unit 4 controls the update timing of the scramble key used for concealment and multiplexes the ECM in addition to the control of the concealment priority for each variable-length packet. It outputs a control signal 105 for performing timing control, priority multiplexing control based on the priority regarding the multiplexing delay given to each content, and the like.

Second, processing in the conditional access receiving apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. As shown in FIG. 2, the priority demultiplexing unit 5 separates the multiplexed bit sequence 104 for each content with reference to the packet start code 201, the packet identifier 202, the payload length 205, and the CRC 206, and 103 is generated.

Next, the variable length packet disassembling / descrambling unit 6 deciphers the payload of the variable length packet with reference to the concealment information 203 and the ECM identified by the ECM identification number 204, and The packet is decomposed to generate an information source encoded bit string 102 for each content. Then, the information source decoding unit 7 decodes the information source coded bit string 102 to reproduce the content 101 such as a video signal, an audio signal, and various data.

Third, the multiplexing of transmission signals in the conditional access system according to Embodiment 1 of the present invention,
The operation of the priority multiplexing control unit 4 will be described. FIG.
FIG. 3 is a diagram illustrating a multiplexing method of a transmission signal in a conditional access system according to Embodiment 1 of the present invention. Note that, regarding multiplexing, the processing on the transmission side and the processing on the reception side are the reverse of each other, and therefore the description will be made based on the processing on the transmission side.

Each of the information source coding bit strings 102 for each content (for each information source) is stored in a variable-length packet for each coding unit, the payload of the packet is subjected to scramble processing, and given to each content. The variable length packets scrambled based on the priority regarding the multiplexing delay are multiplexed in packet units to generate a multiplexed bit string 104. The confidential information such as the scramble key is stored as an ECM in a variable length packet and multiplexed.

In the conditional access system according to the first embodiment of the present invention, the ECM can be specified for each content, or can be specified as common to a plurality of contents. The ECM is transmitted periodically (time interval: t). One ECM simultaneously carries two types of scramble keys, which are respectively referred to as odd-numbered keys and even-numbered keys. The odd key and the even key stored in the ECM are not updated at the same time, but are updated one by one in order.

The concealment / non-concealment information and the type (odd key / even key) of the scramble key used for concealment can be added in units of variable-length packets. These pieces of information regarding concealment are stored as concealment information 203 in the header of the variable-length packet.

In the conditional access system according to the first embodiment of the present invention, in order to perform preferential multiplexing with respect to multiplexing delay, a delay time (multiplexing delay) from generation of a packet to multiplexing is different for each content. Different. Therefore, on the receiving side, it is necessary to prevent the packet scrambled with the old key and the packet scrambled with the new key from being mixed. However, the concealment / priority multiplexing control unit 4 must satisfy equation (1). In, only controlling the update cycle of the scramble key and the update timing of the ECM may cause a descrambling error. Therefore, considering the maximum multiplexing delay Tdmx of the multiplexed bit string, the update period Tt of the scramble key is controlled so as to satisfy Tt> Tdmx (Equation 2).

As described above, the cycle of updating the scramble key from the odd key to the even key or from the even key to the odd key on the transmitting side is Tt, but the validity period of the odd or even key on the receiving side is Tt. Is 2Tt. Therefore, even if a packet scrambled by the scramble key immediately before updating on the transmitting side arrives at the receiving side with a delay due to multiplexing delay, if the delay time is within Tt, the descrambling process is performed on the receiving side. By controlling so as to satisfy Equations 1 and 2, it is possible to prevent a packet scrambled with the old key and a packet scrambled with the new key from being mixed on the receiving side.

As for Tdmx, a value estimated by priority multiplexing simulation or the like may be used.
The threshold control on the multiplexing delay may be performed so that the multiplexing delay of each packet does not exceed Tdmx.

As described above, according to the first embodiment of the present invention, the information source encoded bit sequence 102
Is converted into a variable-length packet and then multiplexed to generate a multiplexed bit string 104, so that the packet can be formed into a variable length and there is no need to insert dummy bytes as in a fixed-length packet. There is an effect that the efficiency of conversion can be improved.

Further, by setting the update period of the scramble key longer than the maximum multiplexing delay time of the bit string to be multiplexed, the packet scrambled with the old key and the packet scrambled with the new key are mixed on the receiving side. Therefore, it is possible to reliably perform decoding of the coded bit string, and to increase the reliability of the conditional access system.

The concealment / priority multiplexing control section 4 sets the priority of concealment according to the content or according to the information source coding mode for each content. Since a flexible concealment characteristic can be set according to each information source coding mode, there is an effect that a flexible concealment function can be realized according to the content and use of the content to be transmitted.

Further, since the concealment / priority multiplexing control unit 4 is configured to perform encryption by changing the type of encryption and the use mode of encryption based on the priority of concealment, the content of the content or the information source There is an effect that the strength of concealment can be adaptively controlled according to the encoding mode and the like.

Furthermore, since the concealment / priority multiplexing control unit 4 is configured to control the concealment period based on the concealment priority, the concealment / priority multiplexing control unit 4 can control the concealment period in accordance with the contents of the contents or the information source coding mode. During a certain period, it is possible to selectively perform decryption only by the contractor or decryption by all the recipients, so that the reception mode can be flexibly set. .

Embodiment 2 The transmitter and the receiver of the conditional access system according to the second embodiment of the present invention have basically the same structure as the transmitter and the receiver of the conditional access system according to the first embodiment. The configuration is likewise shown by FIG. 1 and the configuration of the receiving device is likewise shown by FIG. The second embodiment is different from the first embodiment.
The only difference from the above is that the configuration of the variable length packet is different.

FIG. 5 is a diagram showing a configuration of a variable length packet used in the second embodiment of the present invention. The difference from the variable length packet used in the first embodiment shown in FIG. 3 is that the packet has the ECM version number 208. The ECM version number (ECM identification number) 208 is the ECM identification number (ECM identification number) 20
4 is given as a version number for identifying each individual ECM that is given a predetermined concealment characteristic and is individualized, and the content of each type of ECM is identified in each type of ECM. If an update occurs, the ECM version number is incremented by one.

Next, the operation will be described. Since the basic operation is the same as that of the first embodiment, the differences from the first embodiment will be described here. First,
At the time of concealment, the control signal 105 output from the concealment / priority multiplexing control unit 4 uses the ECM to identify the type of the ECM related to the scrambling process applied in the same manner as in the first embodiment. In the field of the identification number 204, the individual EC storing the scramble key used for the scramble processing in the second embodiment is further described.
The version number for specifying M is written in the ECM version number 208 field.

Second, at the time of concealment release, the variable length packet disassembling / descrambling unit 6 uses the ECM identification number 20
By referring to the ECM specified by the ECM4 and the ECM version number 208 and the concealment information 203, the scramble key used for the scrambling process of the variable-length packet is specified, thereby concealing the payload of the variable-length packet. To release.

As described above, according to the second embodiment of the present invention, the effect of improving the multiplexing efficiency and realizing a flexible concealment function is achieved as in the first embodiment, and each variable length packet is By providing a field for storing the ECM version number in the header, the scramble key used for scrambling the variable-length packet can be specified, so that the packet scrambled with the old key and the packet scrambled with the new key Thus, even if the two are mixed on the receiving side, the decoding of the encoded bit string can be reliably performed, and the effect of improving the reliability in the conditional access system can be obtained.

Embodiment 3 FIG. 6 is a block diagram showing a configuration of a conditional access transmission apparatus according to Embodiment 3 of the present invention. FIG.
FIG. 7 is a block diagram showing a configuration of a conditional access receiving apparatus according to Embodiment 3 of the present invention. 6, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and a description thereof will not be repeated. Further, in FIG. 7, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts, and thus the description thereof will be omitted. Embodiment 3 is different from Embodiment 1 in that coding units are stored in fixed-length packets and multiplexed.

In FIG. 6, reference numeral 10 denotes a fixed-length packetization / scramble section (packetization / scramble means) for implementing fixed-length packetization and concealment, and 106 denotes a fixed-length packet sequence (packet sequence). In FIG. 7, reference numeral 11 denotes a fixed-length packet disassembling / descrambling unit (packet disassembling / descrambling means) for deciphering the secret and decomposing the fixed-length packet to generate the information source coded bit string 102.

Next, the operation will be described. First, a process in the conditional access receiving apparatus according to Embodiment 3 of the present invention will be described. In addition, the information source encoding unit 1,
The operations of the priority multiplexing unit 3 and the concealment / priority multiplexing control unit 4 are the same as those in the first embodiment, and a description thereof will be omitted.

Fixed length packetization / scramble section 10
Generates a fixed-length packet by dividing each information source coded bit string 102 for each coding unit and storing it in a fixed-length packet payload, and concealing the fixed-length packet payload by scrambling the fixed-length packet. Generate column 106. Information source encoded bit sequence 10
When 2 is stored in the payload of the fixed-length packet, processing is performed so that the head of the information source coding unit always coincides with the head of the payload of the fixed-length packet as shown in FIG. For this purpose, dummy bytes are inserted into the payload of the fixed-length packet.

FIG. 8 is a diagram showing a configuration of a fixed-length packet used according to the third embodiment of the present invention. 301
Is a packet start code indicating the beginning of a fixed-length packet, 302 is a packet identifier to which a different number is assigned to each content stored in the packet, and 303 is concealment /
Non-confidential information, odd / even key discrimination information used for concealment, concealment information for notifying the use mode of encryption such as CBC or OFB, etc., and 304 stores the ECM related to concealment of the fixed-length packet. ECM identification number for notifying the value of the packet identifier of the fixed-length packet to be transmitted, 305 is an effective byte length for distinguishing dummy bytes from content stored in the payload of the fixed-length packet, and 307 stores encoded content. This is a fixed-length packet payload.

Note that confidentiality-related information such as a scramble key not contained in the confidentiality information 303 field of each fixed-length packet regarding concealment is stored as an ECM in the payload of the fixed-length packet and sent.

Second, processing in the receiving apparatus using the conditional access system according to the third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 7, the priority demultiplexing unit 5 separates the multiplexed bit string 104 for each content by referring to the packet start code 301, the packet identifier 302, and the effective byte length 305, and Generate

Next, the fixed-length packet disassembly / descramble unit 11 confidentiality information 303 and ECM identification information 304
Concealing the payload of the fixed-length packet with reference to the ECM identified by, and decomposing the fixed-length packet to obtain an information source encoded bit string 102 for each content.
Generate Then, the information source decoding unit 7 decodes the information source coded bit string 102 to reproduce the content 101 such as a video signal, an audio signal, and various data.

The multiplexing method of the transmission signal in the conditional access system according to the third embodiment of the present invention and the operation of the concealment / priority multiplexing control unit 4 are the same as those in the first embodiment, and therefore will not be described. Omitted.

As described above, according to the third embodiment of the present invention, the scramble key is updated at a longer cycle than the maximum multiplexing delay time of the multiplexed bit string, so that the scramble with the old key is performed on the receiving side. It is possible to prevent the encoded packet and the packet scrambled by the new key from being mixed with each other, so that the encoded bit string can be reliably decoded and the reliability of the conditional access system can be improved.

Further, the concealment / priority multiplexing control unit 4 sets the priority of concealment according to the content or according to the information source coding mode for each content. Since a flexible concealment characteristic can be set according to each information source coding mode, there is an effect that a flexible concealment function can be realized according to the content and use of the content to be transmitted.

Embodiment 4 The transmitter and the receiver of the conditional access system according to the fourth embodiment of the present invention have basically the same structure as the transmitter and the receiver of the conditional access system according to the third embodiment. The configuration is likewise shown by FIG. 6, and the configuration of the receiving device is likewise shown by FIG. The fourth embodiment is different from the third embodiment.
The difference from the above is that only the configuration of the fixed-length packet is different.

FIG. 9 is a diagram showing a configuration of a fixed-length packet used according to the fourth embodiment of the present invention. Compared with the fixed-length packet used in the third embodiment shown in FIG. 8, the difference is that the packet has the ECM version number 308. ECM version number 308 is EC
ECM of each type identified by M identification number 304
Is given as a version number for specifying an individual ECM that has been provided with a predetermined concealment property and is individualized. When the content of each type of ECM is updated, the ECM version The number is incremented by one.

Next, the operation will be described. Since the basic operation is the same as that of the third embodiment, the differences from the third embodiment will be described here. First,
At the time of concealment, the control signal 105 output from the concealment / priority multiplexing control unit 4, as in the third embodiment,
A number for identifying the type of the ECM related to the applied scramble processing is written in the field of the ECM identification number 304. Further, in the fourth embodiment, the individual ECM storing the scramble key used for the scramble processing is stored.
The version number for specifying the CM is written in the field of the ECM version number 308.

Second, at the time of concealment release, the fixed-length packet disassembling / descrambling unit 11 uses the ECM identification number 3
By referring to the ECM specified by the ECM 04 and the ECM version number 308 and the concealment information 303, the scramble key used for the scrambling process of the fixed-length packet is specified, thereby concealing the payload of the fixed-length packet. To release.

As described above, according to the fourth embodiment of the present invention, similar to the third embodiment, the effect of improving the multiplexing efficiency and realizing a flexible concealment function is achieved, and each fixed-length packet is transmitted. By providing a field for storing the ECM version number in the header, the scramble key used for scrambling the fixed-length packet can be specified. Therefore, the packet scrambled with the old key and the packet scrambled with the new key can be specified. Thus, even if the two are mixed on the receiving side, the decoding of the encoded bit string can be reliably performed, and the effect of improving the reliability in the conditional access system can be obtained.

[0070]

As described above, according to the present invention, the concealment / priority multiplexing control means controls the scramble key to be updated at a time interval larger than the maximum multiplexing delay time in the multiplexed bit stream. Therefore, it is possible to prevent the packet scrambled with the old key and the packet scrambled with the new key from being mixed on the receiving side, so that the encoded bit string can be reliably decoded, and the The effect that the property can be improved is produced.

According to the present invention, the packetization / scramble means is configured to store the information source coded bit string in the payload of the variable length packet to generate the variable length packet. This eliminates the need to insert a symbol, thereby improving the multiplexing efficiency.

According to the present invention, an ECM for specifying an ECM that stores a scramble key used by a packetizer / scrambler to conceal a part of a packet is used.
Since the CM identification number is configured to be registered in the header of the packet, the scramble key used for the scramble processing of the packet can be identified. Therefore, the packet scrambled with the old key and the packet scrambled with the new key can be specified. Thus, even if the two are mixed on the receiving side, the decoding of the encoded bit string can be reliably performed, and the effect of improving the reliability in the conditional access system can be obtained.

According to the present invention, the packet disassembling / descrambling means specifies the scramble key used for concealing a part of the packet with reference to the ECM specifying number, and conceals the concealed part of the packet. Since it is configured to cancel, even if the packet scrambled with the old key and the packet scrambled with the new key coexist on the receiving side, the decoding of the coded bit string can be reliably performed, and the reliability in the conditional access system The effect that it can raise is produced.

According to the present invention, the concealment / priority multiplexing control means is configured to control the concealment characteristics of the packet based on the priority of the concealment. Since the flexible concealment characteristic can be set according to the information source coding mode, there is an effect that a flexible concealment function according to the content of the content to be transmitted or the information source coding mode can be realized.

According to the present invention, the concealment / priority multiplexing control means performs encryption by changing the type of encryption and the use mode of encryption such as CBC mode or OFB mode based on the priority of concealment. With such a configuration, it is possible to adaptively control the strength of concealment according to the content of the content or the information source coding mode.

According to the present invention, the concealment / priority multiplexing control means is configured to control the concealment period based on the priority of concealment. Accordingly, during a certain period, it is possible to selectively perform decryption only by the contractor or decryption by all the recipients, so that the reception form can be flexibly set. It works.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a transmitting apparatus using a conditional access system according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram showing a configuration of a conditional access receiving apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a diagram showing a configuration of a variable length packet used in the conditional access system according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a transmission signal multiplexing method in the conditional access system according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a variable length packet used in a conditional access system according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conditional access transmission apparatus according to Embodiment 3 of the present invention.

FIG. 7 is a block diagram showing a configuration of a conditional access receiving apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a diagram showing a configuration of a fixed-length packet used in a conditional access system according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a fixed-length packet used in a conditional access system according to a fourth embodiment of the present invention.

FIG. 10 is a block diagram illustrating a configuration of a conventional conditional access transmission device.

FIG. 11 is a block diagram showing a configuration of a conventional conditional access receiving apparatus.

FIG. 12 is a diagram illustrating a multiplexing method of a transmission signal in a conventional conditional access system.

[Explanation of symbols]

1 information source coding section (information source coding means), 2 variable length packetization / scramble section (packetization / scramble means), 3 priority multiplexing section (priority multiplexing means), 4
Concealment / priority multiplexing control unit (concealment / priority multiplexing control means), 5 priority multiplex separation unit (priority multiplex separation means), 6
Variable length packet decomposition / descrambling section (packet decomposition / descrambling means), 7 information source decoding section (information source decoding means), 10 fixed length packetization / scramble section (packetization / scrambling means), 11 fixed length packet decomposition A descrambling unit (packet decomposition / descrambling means), 101 contents, 102 information source coded bit sequence, 103 variable length packet sequence (packet sequence), 104 multiplexed bit sequence, 106 fixed length packet sequence (packet sequence), 204 ECM Identification number (ECM
Specific number), 208 ECM version number (ECM specific number).

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) H04N 7/167 H04N 7/167 Z F term (reference) 5C064 CA14 CC04 5J104 AA01 AA34 BA03 BA04 NA02 NA37 PA05 5K028 AA14 CC02 EE03 KK32 SS07 SS17 TT01 5K030 GA03 GA11 HA02 HC01 JA05 JT04 LD19

Claims (10)

[Claims] An information source encoding means for encoding various contents, an information source encoded bit string output from the information source encoding means is stored in a packet, and a part of the packet is concealed to form a packet string. And a packetization and scrambling means for generating a multiplexed bit stream by multiplexing a plurality of information source coded bit strings in packet units based on a priority based on a multiplexing delay given to each of the information source coded bit strings. A multiplexing means, and a concealment / priority multiplexing control means for controlling the packetization / scramble means and the priority multiplexing means, wherein the concealment / priority multiplexing control means is provided. Control the scramble key to be updated at a time interval greater than the maximum multiplexing delay time in the multiplexed bit string. Transmitting device conditional access system according to claim. 2. The transmitting apparatus according to claim 1, wherein the packetizing / scrambler generates the variable length packet by storing the information source coded bit string in the payload of the variable length packet. 3. An information source encoding means for encoding various contents, an information source encoded bit string output from the information source encoding means being stored in a packet, and a part of the packet being concealed to form a packet string. And a packetization and scrambling means for generating a multiplexed bit stream by multiplexing a plurality of information source coded bit strings in packet units based on a priority based on a multiplexing delay given to each of the information source coded bit strings. A multiplexing means, and a packetization / scramble means and a concealment / priority multiplexing control means for controlling the priority multiplexing means, wherein the packetization / scramble means comprises a packet. The ECM identification number for identifying the ECM that stores the scramble key used to conceal part of the Transmitting device conditional access system and registers the Tsu bets header. 4. The transmitting apparatus according to claim 3, wherein the packetizing / scrambler generates the variable length packet by storing the information source coded bit string in the payload of the variable length packet. 5. A priority multiplexing / demultiplexing means for separating a multiplexed bit sequence multiplexed according to a priority based on a multiplexing delay in packet units into a packet sequence for each content, and concealing a concealed portion in the packet sequence. And a packet disassembly / descrambling means for disassembling a packet to generate an information source encoded bit string, and an information source decoding means for decoding the information source encoded bit string and reproducing the content. In the receiving device, the packet disassembly / descrambling means refers to the ECM identification number, identifies the scramble key used to conceal a part of the packet, and releases the concealment of the concealment part of the packet. Characteristic reception method receiving device. 6. An information source encoding means for encoding various contents, and a packetization method for storing an information source encoded bit string output from the information source encoding means in a packet and concealing a part of the packet. Scrambling means, and priority multiplexing means for generating a multiplexed bit stream by multiplexing a plurality of information source coded bit strings in packet units based on a priority based on a multiplexing delay given to each of the information source coded bit strings And a concealment / priority multiplexing control unit that controls the packetization / scramble means and the priority multiplexing means, wherein the concealment / priority multiplexing control means Characterized in that the confidentiality of the packet is controlled based on the priority of the packet. 7. The concealment / priority multiplexing control means controls a concealment characteristic of a packet based on a concealment priority set for each information source coding mode for each content. Item 7. A conditional access receiving transmission device according to item 6. 8. The concealment / priority multiplexing control means, based on the priority of concealment, uses the type of encryption and CBC
The transmitting apparatus of the conditional access system according to claim 6 or 7, wherein encryption is performed by changing an encryption use mode such as a mode or an OFB mode. 9. The conditional access system according to claim 6, wherein the concealment / priority multiplexing control means controls the concealment period based on the concealment priority. apparatus. 10. The variable length packet according to claim 6, wherein the packetization / scramble means generates the variable length packet by storing the information source coded bit string in the payload of the variable length packet. A transmission device using a conditional access method according to claim 1.