JP5887399B2 - Digital broadcast transmitter and digital broadcast receiver - Google Patents

Description

  The present invention relates to a digital broadcast transmitting apparatus that transmits a program related to access control of a broadcast program of a digital broadcast, and a digital broadcast receiving apparatus that receives the program.

In the current digital broadcasting, the copyright can be obtained by restricting the broadcast program (hereinafter referred to as “content”) only to the subscriber's receiving device, allowing the content to be received only by a legitimate receiving device, or performing copy restrictions. The function of performing protection is realized using CAS (Conditional Access System) which is an access control method.
Specifically, a function related to access control (for example, decryption of a key for decrypting encrypted content) is mounted on an IC card (CAS card) which is a tamper-resistant module, and the IC card and the receiving device are mounted. In combination, access is restricted.

  However, there is a possibility that security of this function related to access control may be broken due to outflow of keys held inside, analysis of algorithms, or the like. In such a case, a method of redistributing an IC card with increased security strength is conceivable. However, since it imposes a burden on the user such as IC card distribution costs and IC card replacement, it is practically difficult to implement. In addition to solving security problems, there is a desire to expand functions related to access control.

Therefore, a technique for accumulating functions related to access control mounted on an IC card as a CAS program in a receiving apparatus and updating the CAS program via a broadcast wave is disclosed (see Patent Document 1).
In the technology disclosed in Patent Document 1, an encrypted CAS program is arranged and distributed in ECM-RMP (ECM: Entitlement Control Message, RMP: Rights Management and Protection), which is common information related to content right protection. ing.
In the technique disclosed in Patent Document 1, a key for decrypting an encrypted CAS program is arranged and distributed in EMM-RMP (EMM: Entitlement Management Message), which is individual information related to content right protection. ing.
As a result, the receiving apparatus can store and update the CAS program by downloading and decrypting the encrypted CAS program distributed by ECM-RMP using the key distributed by EMM-RMP. Become.

JP 2009-267605 A

In the prior art disclosed in Patent Document 1, CAS program distribution is realized by using ECM (ECM-RMP) or EMM (EMM-RMP) having a role as a security parameter. Security parameters such as ECM and EMM must be processed as confidential information by a tamper resistant module or the like.
In general, since the tamper resistant module has a low processing speed, for example, the bit rate can be increased only to about 300 kbps. That is, in the prior art, the CAS program must be transmitted from the transmission side at a low bit rate.
For this reason, in the prior art, in order to reliably distribute the CAS program, it is necessary to continue broadcasting for a long period of time, and there is a problem that the broadcast band is compressed.

  The present invention has been made in view of the above problems, and a digital broadcast transmitting apparatus and digital broadcast capable of downloading a CAS program at high speed while ensuring safety against alteration of the CAS program and the like. It is an object to provide a receiving device.

In order to solve the above problems, a digital broadcast transmitting apparatus according to the present invention is a digital broadcast transmitting apparatus that transmits an access control program for controlling access to content transmitted via a broadcast wave to the digital broadcast receiving apparatus. And encrypting the access control program with a scramble key, generating distribution data scramble means for generating encrypted distribution data, and encrypting the scramble key with a transmission path protection key transmitted to the digital broadcast receiver, Individual information including common information generating means for generating ECM-RMP , which is common information including a scramble key, and the transmission path protection key encrypted with an encryption key common to the digital broadcast receiving apparatus, and including the transmission path protection key and the individual information generating means for generating an EMM-RMP is, send a broadcast to the access control program With the addition of an identifier indicating that the, the download table generating means for generating a download table containing identification information for identifying the access control program, and the encrypted delivery data, and the ECM-RMP, the EMM-RMP And a multiplexing unit that multiplexes the download table and generates a multiplexed signal to be transmitted to the digital broadcast receiving device, wherein the download table generating unit transmits the access control program via a communication line. The download table including an identifier indicating that it is acquired from the designated server is generated.

Further, the digital broadcast receiving apparatus according to the present invention is a digital broadcast receiving apparatus that performs access control to content transmitted via a broadcast wave by an access control program, and encrypts the access control program with a scramble key to transmit packet data. and was the form encrypted delivery data, and ECM-RMP is the common information encrypted in the transmission line protection key includes a scramble key is the individual information encrypted with the encryption key comprises the transmission path protection key Separating means for separating each information from a multiplexed signal including EMM-RMP , a download table including an identifier indicating that the access control program is transmitted by broadcast and identification information for identifying the access control program And the identifier described in the download table, And download table analyzing means determines that the access control program is sent in broadcast, decrypts the EMM-RMP and digital broadcast transmission apparatus in a common encryption key, individual information decoding to obtain the transmission path protection key Means for decoding the ECM-RMP with the transmission path protection key acquired by the individual information decoding means and acquiring the scramble key, and the access table is broadcasted by the download table analyzing means. Distribution data descrambling means for decrypting the encrypted distribution data with the scramble key after detecting transmission, and the download table specifies the access control program via a communication line An identifier indicating that it is acquired from the server is described, and the download table contains If the identifier indicating that obtains the access control program from the server is described, and the structure further includes a communication downloading means for acquiring the access control program from the server.

The present invention has the following excellent effects.
According to the present invention, an access control program (CAS program) is distributed by a data carousel from a digital broadcast transmission device to a digital broadcast reception device, and identification information, a key, and the like of the access control program are security information common information. And can be distributed as individual information. As a result, the present invention prevents falsification of the access control program and the like, can be distributed at a higher speed than the case where the access control program is distributed as a security parameter, and can suppress the compression of the broadcast band.
Further, according to the present invention, even when the security of the access control program is broken, the access control program can be updated at high speed. Further, the broadcaster can change the access control program according to the service desired to be provided.

  ADVANTAGE OF THE INVENTION According to this invention, delivery of an access control program can be switched and delivered by a broadcast wave or a communication line. As a result, after the access control program is distributed for a certain period by the data carousel, it can be switched to the distribution of the access control program through the communication line, and the broadcast band can be prevented from being compressed.

It is a schematic block diagram which shows the structure of the digital broadcasting system which concerns on embodiment of this invention. It is a block block diagram which shows the structure of the digital broadcast transmitter which concerns on embodiment of this invention. It is a block block diagram which shows the structure of the delivery data production | generation means of the digital broadcast transmitter which concerns on embodiment of this invention. It is a block block diagram which shows the structure of the digital broadcast receiver which concerns on embodiment of this invention. It is a data structure figure which shows the content of a DII message. It is a data structure figure which shows the content of a DDB message. It is a data structure figure which shows the content of a download table. It is a data structure figure which shows the content of a download content descriptor. It is a data structure figure which shows the content of a network download content descriptor. It is a flowchart which shows the delivery operation | movement of the access control program (CAS program) in the digital broadcast transmitter which concerns on embodiment of this invention. It is a flowchart which shows the reception operation | movement of the access control program (CAS program) in the digital broadcast receiver which concerns on embodiment of this invention. It is a flowchart which shows starting instruction | indication operation | movement of the access control program (CAS program) in the digital broadcast transmitter which concerns on embodiment of this invention. It is a flowchart which shows the starting operation | movement of the access control program (CAS program) in the digital broadcast receiver which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
[Outline of digital broadcasting system]
First, an overview of a digital broadcasting system according to an embodiment of the present invention will be described with reference to FIG.

  The digital broadcast system S is composed of a digital broadcast transmission device 1 owned by a broadcaster and digital broadcast reception devices 2, 2, 2,... Installed in each home. This is a system in which a content (broadcast program) transmitted by a broadcast wave W is received by a digital broadcast receiver 2 and viewed by a viewer. The broadcast wave W may be wireless or wired, such as terrestrial digital broadcast, satellite broadcast, and cable broadcast.

  The digital broadcast transmission device 1 transmits content to the digital broadcast reception device 2 via the broadcast wave W. The digital broadcast transmitting apparatus 1 transmits a CAS (Conditional Access System) program (access control program) having a function related to content access control via a broadcast wave W in a digital broadcast data carousel, and updates it. It has the function to do.

The digital broadcast receiving apparatus 2 receives content via the broadcast wave W. The digital broadcast receiving apparatus 2 has a function of receiving and updating a CAS program distributed by data carousel transmission from the digital broadcast transmitting apparatus 1.
That is, the digital broadcast system S is used when the security is broken, such as the leakage of the key of the CAS program used in the digital broadcast receiver 2, or when it is desired to update the CAS program used according to the service to be provided. This is a system in which a broadcaster distributes a new CAS program to the digital broadcast receiver 2 by the digital broadcast transmitter 1.

The data carousel repeatedly distributes the same data defined by STD-B24 of the Radio Industries Association (ARIB) for a certain period of time, so that the digital broadcast receiving apparatus 2 obtains necessary data at an arbitrary timing. It is a transmission method that enables
In the digital broadcast system S, the CAS program (CAS P _{1 to} P _n ) is repeatedly transmitted for a certain period, so that the CAS program is distributed to the digital broadcast receiver 2.
Further, the digital broadcasting system S has a function of distributing the CAS program via the communication line N in addition to the distribution of the CAS program by the data carousel.

  Here, the digital broadcast system S includes a server (CAS server 3) that stores the CAS program and transmits the CAS program via the communication line N, and the digital broadcast transmission apparatus 1 transmits the CAS program via the broadcast wave W. The digital broadcast receiver 2 is notified of the location of the program (URL: Uniform Resource Locator). Then, the digital broadcast receiving apparatus 2 acquires a CAS program from the CAS server 3 via the communication line N and updates it.

As described above, the digital broadcasting system S can transmit the CAS program at high speed by performing the data carousel transmission, and the period for distributing the CAS program can be shortened to, for example, about one week.
Further, the digital broadcast system S can distribute the CAS program via the communication line N even when the transmission period of the CAS program by the data carousel has ended. As a result, the digital broadcasting system S can reduce the compression of the broadcast band accompanying the distribution of the CAS program by the broadcast wave W.

  Hereinafter, in the digital broadcast system S, the configuration and operation of the digital broadcast transmission device 1 and the digital broadcast reception device 2 that can update the CAS program by increasing the safety in transmission of the CAS program will be described in detail. .

[Configuration of digital broadcasting transmitter]
First, referring to FIG. 2 (refer to FIG. 1 as appropriate), the configuration of the digital broadcast transmitting apparatus according to the embodiment of the present invention will be described. Here, the digital broadcast transmission apparatus 1 includes content scramble means 10, ECM-CAS generation means 11, EMM-CAS generation means 12, distribution data generation means 13, distribution data scramble means 14, and ECM-RMP generation. Means 15, EMM-RMP generation means 16, download table generation means 17, activation program designation means 18, and multiplexing means 19 are provided.

  In FIG. 2, a plurality of configurations of the A portion indicated by the broken line portion are provided for each CAS program. For example, when the CAS program to be distributed differs for each manufacturer of the digital broadcast receiving device 2, a plurality of A parts are provided for each manufacturer.

The content scramble means 10 scrambles (encrypts) input content (video, audio, data, etc.) Ct with a scramble key Ks1.
For the encryption with the scramble key Ks1, a common common key encryption algorithm may be used. For example, the encryption is performed by the MULTI2 encryption. The scrambled content (encrypted content Sct) is output to the multiplexing means 19.

  The scramble key Ks1 is updated according to time, and is updated about once every several seconds. Here, it is assumed that the scramble key Ks1 is stored in a storage unit (not shown) and is appropriately updated by inputting a new scramble key Ks1 from the outside.

The ECM-CAS generation unit 11 encrypts the scramble key Ks1 used in the content scramble unit 10 with the work key Kw, and generates common information including the encrypted scramble key Ks1. This common information is security information common to all digital broadcast receiving apparatuses 2.
A common common key encryption algorithm may be used for encryption with the work key Kw. Further, the ECM-CAS generation unit 11 generates the common information as a message having an ECM (Entitlement Control Message) structure defined by MPEG (Moving Picture Experts Group) -2 Systems. The common information (ECM-CAS) generated in this way is output to the multiplexing means 19.

  The work key Kw has a longer update time than the scramble key Ks, and is updated in about one month, for example. Here, it is assumed that the work key Kw is stored in a storage unit (not shown) and appropriately updated by inputting a new work key Kw from the outside.

  The EMM-CAS generation unit 12 encrypts the work key Kw used in the ECM-CAS generation unit 11 with the master key Km1, and generates individual information including the encrypted work key Kw. This individual information is individual security information for each digital broadcast receiver 2.

  A general common key encryption algorithm may be used for encryption using the master key Km1. Further, the EMM-CAS generation unit 12 generates the individual information as a message having an EMM (Entitlement Management Message) structure defined by MPEG-2 Systems. At this time, an identifier ID for identifying the individual digital broadcast receiving device 2 is added to the individual information (EMM-CAS). The individual information (EMM-CAS) generated in this way is output to the multiplexing means 19.

  The master key Km1 is an encryption key that is different for each digital broadcast receiving apparatus 2 and is distributed to each digital broadcast receiving apparatus 2 in advance. Here, it is assumed that the master key Km1 is stored in a storage unit (not shown).

  The common information (ECM-CAS) generated by the ECM-CAS generation unit 11 and the individual information (EMM-CAS) generated by the EMM-CAS generation unit 12 are scrambled only by the digital broadcast receiving apparatus 2 with which a reception contract is made. It is security information for limited reception that can be solved.

The distribution data generation means 13 converts the CAS program P distributed to the digital broadcast receiving apparatus 2 into a data carousel data format and generates data for distribution (distribution data). The distribution data generated by the distribution data generation unit 13 is output to the distribution data scramble unit 14.
Note that a new CAS program to be updated is input to the distribution data generation unit 13 via an input unit (not shown).

  Here, with reference to FIG. 3, the structure of the delivery data generation means 13 is demonstrated in detail. As shown in FIG. 3, the distribution data generating unit 13 includes a signature value calculating unit 13a, a dividing unit 13b, an encrypting unit 13c, and a data carousel data generating unit 13d.

  The signature value calculation means 13a calculates the signature value of the digital signature for the new CAS program P to be updated. That is, the signature value calculation unit 13a generates a hash value from the CAS program P in advance by using a hash function common to the digital broadcast receiving device 2. Then, the signature value calculation means 13a calculates the signature value by encrypting the hash value with the secret key Kps corresponding to the public key (verification key) of the digital broadcast receiving apparatus 2 in the public key cryptosystem. The signature value calculated in this way is output to the data carousel data generation means 13d. The signature value generated by the signature value calculation means 13a can be calculated by general DSA and RSA.

  A public key (verification key) for verifying the digital signature corresponding to the secret key Kps used for calculating the signature value by the signature value calculation means 13a is a root public key certificate RPKC (see FIG. 2), which will be described later. Then, the EMM-RMP generating means 16 performs distribution to the digital broadcast receiving apparatus 2 by EMM-RMP.

  The dividing means 13b divides a new CAS program P to be updated into a predetermined size. Here, the dividing means 13b divides the CAS program P by the block size of a DDB (Download Data Block) message when performing data carousel transmission. The data thus divided (divided data) is output to the encryption means 13c.

The encryption unit 13c encrypts the CAS program P (divided data) divided by the dividing unit 13b with the master secret key Kms. The encryption in the encryption means 13c may use a common common key encryption algorithm.
The master secret key Kms is a key common to all the digital broadcast receiving apparatuses 2 and is stored in a storage unit (not shown). The divided data thus encrypted (encrypted divided data) is output to the data carousel data generation means 13d.

  The data carousel data generation unit 13d generates data carousel data from the divided data (encrypted divided data) of the CAS program P encrypted by the encryption unit 13c. That is, the data carousel data generating unit 13d sections the encrypted divided data as a DDB message and sections the configuration information as a DII (Download Info Indication) message.

  Further, the data carousel data generation means 13d inputs the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P from the outside and arranges them inside the DII. Thereby, the identifier and version of the CAS program distributed by the data carousel can be notified to the digital broadcast receiving apparatus 2.

  The data carousel data generation unit 13d arranges the signature value of the CAS program P calculated by the signature value calculation unit 13a in the DII when sectioning the DII. As a result, the digital broadcast receiving apparatus 2 can verify whether or not the CAS program P received by the data carousel is a legitimate one using the digital signature.

  Here, with reference to FIGS. 5 and 6 (refer to FIGS. 2 and 3 as appropriate), examples of data structures of DII and DDB generated by the distribution data generation means 13 will be described. Note that the description of the data defined in the ARIB STD-B24 is omitted, and in the present invention, the data that particularly needs to be set will be described.

FIG. 5 shows an example of the data structure of the DII message when the CAS program is transmitted in the data carousel.
As shown in FIG. 5, the digital broadcast transmitting apparatus 1 arranges a compatibility descriptor in the DII message. This compatibility identifier describes the meta information of the CAS program P distributed by DDB. Here, the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P are described in the compatibility descriptor (“CAS_version” area in FIG. 5). The identifier (CAS-ID) and version (CAS-Ver) are information input from the outside when the CAS program P is downloaded and written by the data carousel data generation means 13d.

  Further, as shown in FIG. 5, the digital broadcast transmitting apparatus 1 places the signature value of the CAS program P in the DII message (“CAS_digital_signature” area). The signature value is information generated by the signature value calculation unit 13a of the distribution data generation unit 13 and written by the data carousel data generation unit 13d.

FIG. 6 shows an example of the data structure of the DDB message when the CAS program P is transmitted in the data carousel.
As shown in FIG. 6, the digital broadcast transmitting apparatus 1 arranges the divided and encrypted CAS program P in the DDB message (“blockDataByte” area; payload area). The data in the payload area is information that is encrypted by the encryption unit 13c of the distribution data generation unit 13 and written by the data carousel data generation unit 13d.

Also, the digital broadcast transmitting apparatus 1 arranges a number (block number) indicating the order of the blocks of the CAS program P divided in the DDB message (here, “blockNumber” area). The block number is information that is sequentially incremented and written for each block by the data carousel data generation unit 13d of the distribution data generation unit 13.
As a result, the digital broadcast receiving apparatus 2 can reconstruct the encrypted CAS program with the DDB message after obtaining the DII message.
Returning to FIG. 2, the description of the configuration of the digital broadcast transmitting apparatus 1 will be continued.

The distribution data scramble means 14 scrambles (encrypts) the distribution data (DII, DDB), which is data for the data carousel generated by the distribution data generation means 13, with the scramble key Ks2.
For the encryption with the scramble key Ks2, a common common key encryption algorithm may be used. For example, the encryption is performed with the MULTI2 encryption. The scrambled data (encrypted distribution data Scas) is output to the multiplexing means 19.

  Note that, as with the scramble key Ks1, the scramble key Ks2 is updated with time, and is updated about once every few seconds. The scramble key Ks2 may be the same as the scramble key Ks1, but it is desirable to manage the scramble key Ks2 as another key, for example, by making the key length longer than the scramble key Ks1 in order to increase the security of the CAS program. . Here, it is assumed that the scramble key Ks2 is stored in a storage unit (not shown) and is appropriately updated by inputting a new scramble key Ks2 from the outside.

  The ECM-RMP generating means (common information generating means) 15 encrypts the scramble key Ks2 used in the distribution data scramble means 14 with the transmission path protection key Kp, and generates common information including the encrypted scramble key Ks2. It is. This common information is security information common to all digital broadcast receiving apparatuses 2.

A common common key encryption algorithm may be used for encryption using the transmission path protection key Kp. Further, the ECM-RMP generation unit 15 generates common information as a message having an ECM structure defined by MPEG-2 Systems. The common information (ECM-RMP) generated in this way is output to the multiplexing means 19.
The transmission path protection key Kp is a key that is delivered to the regular digital broadcast receiving apparatus 2 regardless of the reception contract. Here, it is assumed that the transmission path protection key Kp is stored in a storage unit (not shown) and is appropriately updated when a new transmission path protection key Kp is input from the outside.

  Further, the ECM-RMP generation means 15 specifies the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P delivered by PSI / SI when the CAS program to be started is specified by the start program specifying means 18 described later. ) And the hash value (CAS-H) of the CAS program P is added to the common information (ECM-RMP). This hash value is a value calculated using a hash function common to the digital broadcast receiving apparatus 2.

  As a result, the digital broadcast receiving apparatus 2 prevents malfunction caused by alteration of the identifier (CAS-ID) or version (CAS-Ver) of the CAS program P delivered by PSI / SI, or stores it in the digital broadcast receiving apparatus 2. It is possible to prevent malfunctions by detecting inconsistencies in the hash values of the CAS program P.

  The EMM-RMP generation means (individual information generation means) 16 encrypts the transmission path protection key Kp used in the ECM-RMP generation means 15 with the master key Km2, and stores the individual information including the encrypted transmission path protection key Kp. Is to be generated. This individual information is security information common to the digital broadcast receiving apparatus 2.

For encryption with the master key Km2, a common common key encryption algorithm may be used. Further, the EMM-RMP generation unit 16 generates the individual information as an EMM-RMP having an EMM structure defined by MPEG-2 Systems. In this EMM-RMP, the digital signature of the certificate authority is preliminarily added to the public key (verification key) corresponding to the secret key Kps (see FIG. 3) used when the distribution data generation means 13 generates the signature value. The added root public key certificate RPKC is added.
The common information (ECM-RMP) generated in this way is output to the multiplexing means 19.

  The master key Km2 used by the EMM-RMP generating unit 16 is an encryption key common to the digital broadcast receiving device 2 and is distributed to each digital broadcast receiving device 2 in advance. In this way, by making the master key Km2 common to the digital broadcast receiving apparatus 2, it is possible to reduce the amount of EMM-RMP that is individual information. Of course, the master key Km2 may be a different encryption key for each digital broadcast receiving apparatus 2. In this case, the same master key Km2 as the master key Km1 may be used. However, in order to increase the safety of the CAS program, the key length is made longer than that of the master key Km1, and security is increased. It is desirable to manage as Here, it is assumed that the master key Km2 is stored in a storage unit (not shown).

The common information (ECM-RMP) generated by the ECM-RMP generating unit 15 and the individual information (EMM-RMP) generated by the EMM-RMP generating unit 16 are all scrambled by the authorized digital broadcast receiving device 2. Security information that can be
The common information (ECM-RMP) and individual information (EMM-RMP) have a role as information used for cryptographic delivery of the CAS program P.

The download table generating means 17 inputs control information (download control information Dc) indicating various information when the digital broadcast receiving apparatus 2 downloads the CAS program P through an input means (not shown), It is generated as a table (download table).
Here, the download control information Dc is identification information for specifying the CAS program P to be distributed. For example, the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P.

  Here, the download control information Dc further includes information for identifying whether the CAS program P is distributed by broadcasting or the CAS program P is distributed by communication. For example, when the CAS program P is distributed by broadcasting (data carousel), the number of DII / DDB modules, module identification, module size, etc. are included, and when the CAS program P is distributed by communication, the CAS program P is held. The URL, IP address, etc. of the existing CAS server 3 are included.

  Note that whether the CAS program P is distributed by broadcasting or the CAS program P is distributed by communication is appropriately switched by an operator (broadcaster). For example, when a CAS program is newly distributed, the CAS program is distributed all at once by broadcasting, and after a certain period (for example, one week) has elapsed, the distribution is switched to communication. As a result, it is not necessary to continue sending the CAP program over a long period of time, and pressure on the broadcast band can be reduced.

  Here, an example of the data structure of the download table generated by the download table generation means 17 will be described with reference to FIGS. 7 to 9 (refer to FIG. 2 as appropriate). The download table, download content descriptor, and network download content descriptor shown in FIGS. 7 to 9 are examples of tables and descriptors in which data is arranged in accordance with the section format used in the existing digital broadcasting. Show. Therefore, only the data directly related to the present invention will be described here.

As shown in FIG. 7, a “target_version (target version)” area is provided in the download table, and the download table generation unit 17 sets the version of the CAS program to be updated. As a result, the digital broadcast receiving apparatus 2 can determine whether or not the CAS program held by itself is an update target, and can download the CAS program as necessary.
In addition, a “new_version (new version)” area is provided in the download table, and the download table generation unit 17 sets the version of the CAS program to be updated this time. As a result, the digital broadcast receiving apparatus 2 that has downloaded the CAS program can manage the version of the CAS program held by itself. Note that the version of the CAS program is the same value as the version (CAS-Ver) set by the distribution data generation means 13.

  Further, a “download_level (download level)” area may be provided in the download table, and the digital broadcast receiving apparatus 2 may be controlled to forcibly or arbitrarily update. For example, when the value of “download level” is “01”, the digital broadcast receiving apparatus 2 that holds the CAS program of “update target version” always updates the CAS program. On the other hand, when the value of “download level” is “00”, the digital broadcast receiving apparatus 2 holding the CAS program of “update target version” arbitrarily updates the CAS program.

  In addition, a “version_indication (version display)” area may be provided in the download table, and the CAS program to be updated may be controlled by version. For example, when the value of “version display” is “00”, designation of “target version” is invalidated, and all versions of the CAS program are to be updated. When the value of “version display” is “01”, the CAS program after the version specified by “target version” is set as the update target. When the value of “version display” is “02”, the CAS program before the version specified by “target version” is set as the update target. When the value of “version display” is “03”, only the CAS program of the version specified by “target version” is to be updated.

  Further, as shown in FIG. 7, when a “descriptor () (descriptor)” area is provided in the download table, and the download table generating means 17 distributes the CAS program P by broadcasting (data carousel), this descriptor “Download content descriptor” is placed in the area. Further, when the CAS program P is distributed by communication, a “network download content descriptor” is arranged in this descriptor area.

Thus, by arranging the “download content descriptor” in the descriptor area, the digital broadcast receiving apparatus 2 acquires the CAS program P by broadcasting (data carousel) and arranges the “network download content descriptor”. Thus, the digital broadcast receiving apparatus 2 acquires the CAS program P from the CAS server 3 (see FIG. 1) by communication.
Hereinafter, the “download content descriptor” and the “network download content descriptor” will be described.

  First, an example of the data structure of the download content descriptor will be described with reference to FIG. As shown in FIG. 8, the download content descriptor is a descriptor in which various information necessary for receiving the CAS program by the data carousel is set. For example, the number of DII / DDB modules of the data carousel that transmits the CAS program, module identification, module size, and the like. Further, here, the same compatibility descriptor as that arranged in the DII message (see FIG. 5) is arranged in the download content descriptor. As shown in FIG. 5, this compatibility descriptor includes the CAS program identifier (CAS-ID) and version (CAS-Ver). Can be controlled not to be downloaded.

Next, an example of the data structure of the network download identifier will be described with reference to FIG. As shown in FIG. 9, the network download content descriptor is a descriptor in which various information necessary for receiving the CAS program via the network is set. For example, the URL or IP address of a communication server (CAS server) that provides a CAS program. Here, the network download content descriptor is arranged with the same compatibility descriptor as that arranged in the DII message (see FIG. 5), like the download content descriptor. Accordingly, the digital broadcast receiving apparatus 2 can control not to acquire the CAS program from the server if the target CAS program has already been accumulated.
Returning to FIG. 2, the description of the configuration of the digital broadcast transmitting apparatus 1 will be continued.

  The activation program designating means 18 is for designating a CAS program to be activated in the digital broadcast receiving apparatus 2. The activation program designation means 18 adds information (program designation information) for designating a CAS program to be activated in the digital broadcast receiving apparatus 2 to PSI / SI (program arrangement information). This program designation information is an identifier (CAS-ID) of a CAS program and its version (CAS-Ver). As a result, the digital broadcast transmitting apparatus 1 can activate the designated CAS program in the digital broadcast receiving apparatus 2.

The activation program specifying means 18 arranges the program specifying information in a PSI / SI CAT (Conditional Access Table) or PMT (Program Map Table). Here, it is determined in advance whether to arrange in the CAT or the PMT.
In this CAT or PMT, for example, a compatibility descriptor (see FIG. 5) including an identifier (CAS-ID) of a CAS program and its version (CAS-Ver) is arranged in the descriptor area of each table. .
In this way, the PSI / SI to which the program designation information is added is output to the multiplexing means 19.

  The multiplexing unit 19 includes the encrypted content Sct generated by the content scramble unit 10, common information (ECM-CAS) generated by the ECM-CAS generation unit 11, and individual information (EMM generated by the EMM-CAS generation unit 12). -CAS), encrypted distribution data (DII, DDB) Scas generated by the distribution data scramble means 14, common information (ECM-RMP) generated by the ECM-RMP generation means 15, and EMM-RMP generation means 16 The generated individual information (EMM-RMP), the download table Td generated by the download table generating means 17, and the PSI / SI to which the program specifying information is added by the activation program specifying means 18 are multiplexed, and a multiplexed signal is obtained. Is to be generated.

  Here, it is assumed that the multiplexing means 19 multiplexes each input information into a TS (transport stream) format (MPEG-2 TS) defined by MPEG-2 Systems. The multiplexed multiplexed signal (MPEG-2 TS) is distributed to the digital broadcast receiving apparatus 2 via a broadcast wave by a transmission apparatus (not shown).

  By configuring the digital broadcast transmitting apparatus 1 in this way, the CAS program P can be distributed to the digital broadcast receiving apparatus 2 by a data carousel. At this time, since the information for decrypting and verifying the CAS program P and the information for verification are distributed to the digital broadcast receiving apparatus 2 by ECM-RMP or EMM-RMP, the safety of the CAS program P is improved. Can be delivered.

Further, the digital broadcast transmitting apparatus 1 can switch the distribution of the CAS program P from the data carousel transmission by broadcasting to the distribution by communication using the CAS server 3. As a result, the digital broadcast transmitting apparatus 1 can prevent wasteful use of the broadcast band over a long period of time.
The digital broadcast transmission apparatus 1 can be operated by a program (CAS program transmission program) that causes a general computer to function as each of the above-described means.

[Configuration of digital broadcast receiver]
Next, referring to FIG. 4 (refer to FIG. 1 as appropriate), the configuration of the digital broadcast receiving apparatus according to the embodiment of the present invention will be described. Here, the digital broadcast receiving apparatus 2 includes a separating unit 20, a program executing unit 21, a download table analyzing unit 22, a distribution data separating unit 23, a program decoding unit 24, a storage unit 25, and an activation program specifying unit. 26, a program starting unit 27, and a communication downloading unit 28.

The separating unit 20 separates the digital broadcast (multiplexed signal; MPEG-2 TS) transmitted from the digital broadcast transmitting apparatus 1. This separation means 20 is used to encrypt encrypted content Sct, individual information (EMM-CAS) and common information (ECM-CAS) including information for limited reception, and encrypted transmission of CAS programs from MPEG-2 TS. Separate information (EMM-RMP) and common information (ECM-RMP) including information, data carousel data (encrypted distribution data Scas), download table Td, and PSI / SI CAT or PMT To do.
Further, the separation unit 20 separates the data carousel data (DII, DDB) from the MPEG-2 TS when the download table analysis unit 22 is notified of an instruction to separate the data carousel data.

The program execution means 21 decrypts the encrypted content Sct and the encrypted delivery data Scas separated by the separation means 20.
The program execution means 21 is the substance of the CAS program distributed from the digital broadcast transmission apparatus 1 and is executed by the program activation means 27 described later. The program execution means 21 may be a programmable device such as an FPGA (Field Programmable Gate Array), or a virtual machine that operates with middleware on an OS (Operating System), such as a Java (registered trademark) virtual machine. You may comprise with a machine (Java Virtual Machine, Java VM) etc.

  When the program execution means 21 is configured by a programmable device, the CAS program is configured by circuit information. Further, when the program execution means 21 is configured as software operating on the OS, the CAS program is configured as a binary program.

  Here, the program execution unit 21 includes an EMM-CAS decoding unit 21a, an ECM-CAS decoding unit 21b, a content descrambling unit 21c, an EMM-RMP decoding unit 21d, an ECM-RMP decoding unit 21e, and distribution data. Descrambling means 21f.

The EMM-CAS decrypting means 21a decrypts the individual information (EMM-CAS) separated by the separating means 20 with the master key Km1. The EMM-CAS decrypting means 21a is used when the identifier for identifying the digital broadcast receiving device 2 included in the non-encrypted area of the EMM-CAS matches the identifier stored in the storage means 25 in advance. Only the master key Km1 stored in advance in the storage means 25 is used to decrypt the EMM-CAS encryption area and extract the work key Kw. As a result, the work key Kw can be decrypted only by the receiving apparatus with which a regular contract is made.
The work key Kw decrypted by the EMM-CAS decrypting unit 21a is output to the ECM-CAS decrypting unit 21b.

The ECM-CAS decrypting unit 21b decrypts the common information (ECM-CAS) separated by the separating unit 20 with the work key Kw decrypted by the EMM-CAS decrypting unit 21a. This ECM-CAS includes the scramble key Ks1 used when the encrypted content Sct is scrambled, and the ECM-CAS decrypting means 21b extracts the scramble key Ks1 by decrypting the ECM-CAS. .
The scramble key Ks1 decrypted by the ECM-CAS decrypting unit 21b is output to the content descrambling unit 21c.

  The content descrambling unit 21c descrambles (decrypts) the encrypted content Sct separated by the separating unit 20 with the scramble key Ks1 decrypted by the ECM-CAS decrypting unit 21b. The content Ct descrambled by the content descrambling means 21c is decoded (encoded) by a video / audio decoding means (not shown) and output to a display device (not shown).

The EMM-RMP decryption means (individual information decryption means) 21d decrypts the individual information (EMM-RMP) separated by the separation means 20 using the master key Km2. The EMM-RMP decrypting means 21d is used when the identifier for identifying the digital broadcast receiving device 2 included in the non-encrypted area of EMM-RMP matches the identifier stored in the storage means 25 in advance. Only, the EMM-RMP encryption area is decrypted with the master key Km2 stored in advance in the storage means 25, and the transmission path protection key Kp is extracted.
The transmission path protection key Kp decrypted by the EMM-RMP decrypting means 21d is output to the ECM-RMP decrypting means 21e.

  The EMM-RMP decrypting unit 21d extracts the root public key certificate RPKC when the EMM-RMP includes the root public key certificate RPKC, and stores it in the storage unit 25 or the tamper-resistant module not shown. Keep it.

  The ECM-RMP decrypting means (common information decrypting means) 21e decrypts the common information (ECM-RMP) separated by the separating means 20 with the transmission path protection key Kp decrypted by the EMM-RMP decrypting means 21d. is there. The ECM-RMP includes a scramble key Ks2 used when the distribution data (DII, DDB) is scrambled, and the ECM-RMP decrypting unit 21e decrypts the ECM-RMP to obtain a scramble key Ks2. To extract.

The scramble key Ks2 decrypted by the ECM-RMP decrypting means 21e is output to the distribution data descrambling means 21f.
Note that the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P delivered by PSI / SI and the hash value (CAS-H) of the CAS program P are added to the ECM-RMP. In this case, the ECM-RMP decoding unit 21e outputs these identification information (CAS-ID, CAS-Ver, CAS-H) to the program starting unit 27.

  The distribution data descrambling means 21f descrambles (decrypts) the data carousel data (encrypted distribution data Scas) separated by the separation means 20 with the scramble key Ks2 decrypted by the ECM-RMP decryption means 21e. is there. The distribution data (DII, DDB) cas descrambled by the distribution data descrambling means 21 f is output to the distribution data separating means 23.

The download table analysis means 22 analyzes the section format download table Td separated by the separation means 20, and determines whether the CAS program P is downloaded by broadcasting or communication.
Specifically, the download table analysis means 22 is a download content descriptor (see FIG. 8) indicating that download is performed by broadcasting in the “descriptor () (descriptor)” area in the download table described in FIG. Whether a network download content descriptor (see FIG. 9) indicating that download is performed by communication is described based on the value of the descriptor tag.

  Here, when the download content descriptor is described in the download table Td, the download table analysis unit 22 performs filtering by the packet identification (PID) of the data carousel arranged in the PMT in the separation unit 20, An instruction is given to output the data in the data carousel to the distribution data descrambling means 21f. As a result, the separating means 20 separates and extracts the data carousel data (DII, DDB) from the MPEG-2 TS and outputs them to the distribution data descrambling means 21f.

  On the other hand, when the network download content descriptor is described in the download table Td, the download table analysis unit 22 includes the URL or IP address of the communication server (CAS server 3) described in the network download content descriptor, and The identifier (CAS-ID) and version (CAS-Ver) of the CAS program described in the compatibility descriptor are output to the communication download means 28. As a result, the communication download means 28 starts downloading the CAS program P via the network (communication line N).

Note that the download table analysis means 22 has the CAS program P corresponding to the identifier (CAS-ID) and version (CAS-Ver) described in the download table Td already stored in the storage means 25. Do not execute the download. Thereby, an unnecessary download operation can be eliminated.
Further, as described in FIG. 7, the download table analysis unit 22 performs “target_version (target version)”, “new_version (new version)”, “download_level (download level)”, “version_indication (version display) of the download table Td. ) ", And whether or not download is possible may be determined.

The distribution data separation means 23 separates and extracts the CAS program P (encrypted CAS program P) from the data carousel data (distribution data cas) descrambled by the distribution data descrambling means 21f. .
That is, the distribution data separation means 23 is encrypted by concatenating data included in the DDB message from the DII message of the distribution data cas to the next DII message (data in the “blockDataByte” area in FIG. 6). The CAS program P is separated and extracted.

Further, the distribution data separating means 23 extracts the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P in the compatibility descriptor (“CAS_version” area in FIG. 5) in the DII message. , The signature value of the CAS program P in the DII message ("CAS_digital_signature" area in FIG. 5) is extracted.
The distribution data separating unit 23 outputs the separated and extracted encrypted CAS program P, identifier (CAS-ID), version (CAS-Ver), and signature value to the program decrypting unit 24.

  The program decryption means 24 decrypts the encrypted CAS program P separated and extracted by the distribution data separation means 23 or the encrypted CAS program P downloaded via the communication download means 28. Here, the program decryption unit 24 includes an encryption / decryption unit 24a, a signature verification unit 24b, and a writing unit 24c.

The encryption / decryption means 24a decrypts the encrypted CAS program P input from the distribution data separation means 23 or the communication download means 28 with the master secret key Kms. The master secret key Kms is the same key as that obtained by encrypting the CAS program P in the digital broadcast transmitting apparatus 1, and is stored in advance in the storage means 25 or a tamper resistant module not shown.
The decrypted CAS program P is output to the signature verification unit 24b.

The signature verification unit 24b verifies the digital signature added to the CAS program P input from the distribution data separation unit 23 or the communication download unit 28.
That is, the signature verification unit 24b generates a hash value of the CAS program P by a hash function common to the signature value calculation unit 13a (see FIG. 3). Then, the signature verification unit 24b decrypts the signature value of the CAS program P with the public key (verification key) Kpp included in the root public key certificate RPKC stored in the storage unit 25 or the tamper-resistant module (not shown). . If the decrypted value matches the hash value of the CAS program P, the signature verification unit 24b determines that the downloaded CAS program P is a genuine one that has not been tampered with.
The signature verification unit 24b outputs only the regular CAS program P to the writing unit 24c by verifying the downloaded CAS program P.

The writing unit 24c corresponds to the CAS program P input from the signature verification unit 24b with the identifier (CAS-ID) and version (CAS-Ver) of the CAS program P input from the distribution data separation unit 23 or the communication download unit 28. In addition, it is written in the storage means 25.
In this way, the program decryption means 24 writes and accumulates only the CAS program P that has not been tampered with in the storage means 25 by verifying the signature of the downloaded CAS program P.

The storage unit 25 stores a plurality of CAS programs P in association with an identifier (CAS-ID) and a version (CAS-Ver). For example, the storage unit 25 is a general storage medium such as a nonvolatile memory.
In this storage means 25, the CAS program P is written in association with the identifier (CAS-ID) and the version (CAS-Ver) by the writing means 24c of the program decoding means 24, and the program starting means 27 described later The CAS program P is retrieved and read using the identifier (CAS-ID) and version (CAS-Ver) as keys.
The storage means 25 stores at least one CAS program P in advance and downloads another CAS program.

The activation program specifying unit 26 determines the identifier (CAS-ID) of the CAS program P, which is program designation information, and its version (CAS-Ver) from the CAT or PMT of the PSI / SI (program arrangement information) separated by the separation unit 20. ) To identify the CAS program P to be started.
The identifier (CAS-ID) and version (CAS-Ver) of the extracted CAS program P are output to the program starting means 27.

The program starting unit 27 reads the CAS program P specified by the starting program specifying unit 26 from the storage unit 25 and executes it.
The program starting unit 27 searches the storage unit 25 using the identifier (CAS-ID) and the version (CAS-Ver) notified from the starting program specifying unit 26 as keys, and reads the corresponding CAS program P. Then, the program activation unit 27 activates the read CAS program P as the program execution unit 21.
Note that the program activation unit 27 activates the CAS program P stored in advance in the storage unit 25 at the initial activation, that is, in a state where the CAS program P has not yet been downloaded.

Further, the program starting unit 27 includes an identifier (CAS-ID) and version (CAS-Ver) notified from the ECM-RMP decoding unit 21e, and an identifier (CAS-ID) and version notified from the starting program specifying unit 26. It is determined whether or not (CAS-Ver) matches. If they do not match, the CAS program is not started.
As a result, the program starting unit 27 uses the identifier (CAS-ID) and version (CAS-Ver) distributed by PSI / SI, and the identifier (CAS-ID) and version (CAS-Ver) transmitted by ECM-RMP. ), The identifier (CAS-ID) and version (CAS-Ver) distributed by PSI / SI are falsified, and it is possible to prevent the CAS program P from malfunctioning.

  Further, the program starting unit 27 calculates the hash value of the read CAS program P, and the hash value matches the hash value (CAS-H) of the CAS program P notified from the ECM-RMP decoding unit 21e. If it does not match, the CAS program P is not started. As a result, it is possible to prevent the unauthorized CAS program P from being activated. Note that the hash function for calculating the hash value of the program activation unit 27 is the same as that on the transmission side of the CAS program P.

  The communication download unit 28 downloads the CAS program P from the communication server notified from the download table analysis unit 22 via the network (communication line N). The communication download means 28 is based on the URL or IP address of the communication server (CAS server 3) notified from the download table analysis means 22, and the identifier (CAS-ID) and version (CAS-Ver) of the CAS program. The CAS program is downloaded from the designated communication server (CAS server 3).

  The communication download means 28 outputs the downloaded encrypted CAS program P and the identifier (CAS-ID) and version (CAS-Ver) notified from the download table analysis means 22 to the program decryption means 24. . A signature value is added to the CAS program P downloaded from the communication server (CAS server 3), and the communication download means 28 also outputs this signature value to the program decryption means 24.

By configuring the digital broadcast receiving apparatus 2 in this way, the digital broadcast receiving apparatus 2 can download the CAS program P by data carousel transmission. Further, even if the distribution of the CAS program P by the data carousel is completed, the CAS program P can be downloaded via the network (communication line N).
The digital broadcast receiving apparatus 2 can be operated by a program (CAS program receiving program) that causes a general computer to function as each means described above.

[Operation of digital broadcasting system]
Next, the operation of the digital broadcast system S according to the embodiment of the present invention will be described. Since the content distribution operation by the conditional access method is the same as that of the prior art, the description is omitted here, and the CAS program distribution / reception operation and the CAS program start operation are mainly described.

(CAS program distribution operation: digital broadcast transmitter)
First, with reference to FIG. 10 (refer to FIG. 2 and FIG. 3 as appropriate for the configuration), the operation of the digital broadcast transmitting apparatus 1 when the CAS program is distributed will be described.

First, the digital broadcast transmitting apparatus 1 uses the distribution data generation means 13 to convert the CAS program P transmitted by data carousel transmission into the data format of the data carousel, and generates distribution data (DII, DDB).
That is, the digital broadcast transmission apparatus 1 inputs the CAS program P from the outside by the signature value calculation unit 13a of the distribution data generation unit 13, and calculates the signature value of the digital signature of the CAS program P using the secret key Kps. (Step S1).

  Further, the digital broadcast transmitting apparatus 1 divides the CAS program P by the block size of the DDB message used when performing the data carousel transmission by the dividing unit 13b (step S2). Then, the digital broadcast transmitting apparatus 1 encrypts the divided data divided in step S2 by the encryption unit 13c with the master secret key Kms common to the digital broadcast receiving apparatus 2 (step S3).

  Thereafter, the digital broadcast transmitting apparatus 1 arranges the signature value calculated in step S1, the identifier (CAS-ID) and the version (CAS-Ver) of the CAS program input from the outside, and the DII message (FIG. 5) and at the same time, the encrypted divided data encrypted in step S3 is arranged and a DDB message (see FIG. 6) is generated to generate data carousel data (distribution data) (step S4).

The digital broadcast transmitting apparatus 1 then scrambles (encrypts) the data carousel data generated in step S4 with the scramble key Ks2 by the distribution data scramble means 14 (step S5).
Then, the digital broadcast transmitting apparatus 1 encrypts the scramble key Ks2 used in step S5 with the transmission path protection key Kp by the ECM-RMP generating means 15, and common information (ECM common to all the digital broadcast receiving apparatuses 2). -RMP) is generated (step S6).

  Further, the digital broadcast transmitting apparatus 1 uses the EMM-RMP generating means 16 to verify the digital signature corresponding to the transmission path protection key Kp used in step S6 and the private key Kps used in step S1 (verification key). ) Including the root public key certificate RPKC including the master key Km2 to generate individual information (EMM-RMP) for each digital broadcast receiving apparatus 2 (step S7).

  In addition, the digital broadcast transmitting apparatus 1 uses the download table generation means 17 to download a table Td (see FIG. 7) that is a section format table from information (download control information Dc) for specifying the CAS program P to be distributed. Is generated (step S8). Here, the CAS program is distributed by broadcasting, and a download descriptor (see FIG. 8) indicating that the CAS program by broadcasting is distributed is arranged in the download table Td.

Then, the digital broadcast transmitting apparatus 1 uses the multiplexing means 19 to scramble the data carousel data (encrypted distribution data) in step S5, the ECM-RMP generated in step S6, and the data generated in step S7. The EMM-RMP and the download table Td generated in step S8 are multiplexed to generate a multiplexed signal (MPEG-2 TS) and transmit it (step S9).
Through the above operation, the digital broadcast transmitting apparatus 1 can distribute the CAS program P by the data carousel.

(Receiving operation of CAS program: digital broadcast receiving device)
Next, with reference to FIG. 11 (refer to FIG. 4 as appropriate for the configuration), the operation of the digital broadcast receiving apparatus 2 when the CAS program is distributed will be described. Note that the digital broadcast receiving apparatus 2 stores at least one CAS program P in the storage unit 25 in advance even if the CAS program P is not downloaded. It is assumed that the program is started by the program starting unit 27 and is operating as the program executing unit 21.

  In this state, the digital broadcast receiving apparatus 2 receives the multiplexed signal (MPEG-2 TS) transmitted from the digital broadcast transmitting apparatus 1 and separates it into each signal by the separating means 20 (step S11).

  Then, the digital broadcast receiving apparatus 2 decrypts the EMM-RMP (individual information) separated by the separating means 20 by the EMM-RMP decrypting means 21d with the master key Km2, and the transmission path protection key Kp and the route public key The certificate RPKC is extracted (step S12).

  Further, the digital broadcast receiving apparatus 2 decrypts the ECM-RMP (common information) separated by the separating means 20 with the transmission path protection key Kp decrypted (extracted) in step S12 by the ECM-RMP decrypting means 21e. Then, the scramble key Ks2 is extracted (step S13).

  Thereafter, the digital broadcast receiving apparatus 2 analyzes the download table Td in the section format separated by the separating unit 20 by the download table analyzing unit 22 (step S14), and download content descriptor ( It is determined whether or not a network download content descriptor (see FIG. 9) is described (see FIG. 8) (step S15).

  In step S15, when the download content descriptor is described in the descriptor area (“broadcast”), the digital broadcast receiving apparatus 2 performs the data carousel by the separating means 20 in accordance with an instruction from the download table analyzing means 22. Data (encrypted distribution data) is separated and extracted (step S16).

  Then, the digital broadcast receiving apparatus 2 uses the distribution data descrambling means 21f to separate the data carousel data (encrypted distribution data; DII, DDB) extracted in step S16 with the scramble key Ks2 extracted in step S13. Descrambling (decoding) is performed (step S17).

  Then, the digital broadcast receiving apparatus 2 separates and extracts the CAS program P (encrypted CAS program P) from the data carousel data descrambled in step S17 by the distribution data separating means 23 (step S18). ). That is, in this step S18, the distribution data separating means 23 reconstructs the encrypted CAS program P by concatenating the data of each block of the DDB message. At this time, the distribution data separating means 23 acquires the signature value, identifier (CAS-ID) and version (CAS-Ver) of the CAS program P from the DII message.

  On the other hand, in step S15, when the network download content descriptor is described in the descriptor area (“communication”), the digital broadcast receiving device 2 is described in the network download content descriptor by the communication download means 28. The encrypted CAS program P is acquired from the existing communication server (CAS server 3) via the communication line N (step S19). It is assumed that a signature (signature value), an identifier (CAS-ID), and a version (CAS-Ver) are added to the CAS program P acquired from the CAS server 3.

  Then, the digital broadcast receiving apparatus 2 converts the (encrypted) CAS program separated and extracted in step S18 or the (encrypted) CAS program acquired in step S19 by the encryption / decryption unit 24a of the program decryption unit 24 into the master secret. Decryption is performed with the key Kms (step S20).

  Further, the digital broadcast receiving apparatus 2 performs signature verification of the CAS program decrypted in step S20 by the signature verification unit 24b (step S21). That is, the signature verification unit 24b decrypts the signature value added to the CAS program with the public key (verification key) Kpp included in the root public key certificate RPKC extracted in step S12, and matches the hash value of the CAS program. The CAS program is verified depending on whether or not to do so.

If there is no problem in the verification result in step S21, the digital broadcast receiving apparatus 2 stores the CAS program P decrypted in step S20 by the writing unit 24c in the storage unit 25 with the identifier (CAS-ID) and the version. It is written and stored in association with (CAS-Ver) (step S22).
Through the above-described operation, the digital broadcast receiving apparatus 2 can download the CAS program P in an encrypted and digitally signed state, and can prevent fraud with respect to the CAS program.

(CAS program start instruction operation: digital broadcast transmitter)
Next, referring to FIG. 12 (refer to FIG. 2 as appropriate for the configuration), the operation of the digital broadcast transmitting apparatus 1 for starting up the CAS program P designated by the digital broadcast receiving apparatus 2 will be described.

  First, the digital broadcast transmitting apparatus 1 uses the ECM-RMP generating means 15 to identify the CAS program P to be activated (CAS-ID), the version (CAS-Ver), and the hash value (CAS-H) of the CAS program P. Is encrypted with the transmission path protection key Kp, and common information (ECM-RMP) common to all the digital broadcast receiving apparatuses 2 is generated (step S31).

  In addition, the digital broadcast transmission device 1 encrypts the transmission path protection key Kp used in step S31 by the EMM-RMP generation unit 16 with the master key Km2, and stores individual information (EMM-RMP) for each digital broadcast reception device 2. ) Is generated (step S32).

Further, the digital broadcast transmitting apparatus 1 uses the activation program designating means 18 as information (program designation information) for designating the CAS program P to be activated, as an identifier (CAS-ID) and version (CAS-ID) of the CAS program P. Ver) is placed in the PSI / SI CAT or PMT (step S33).
Then, the digital broadcast transmission device 1 uses the multiplexing means 19 to generate the ECM-RMP generated in step S31, the EMM-RMP generated in step S32, and the PSI / SI in which the identifier and the like are arranged in step S33. Are multiplexed and a multiplexed signal (MPEG-2 TS) is generated and transmitted (step S34).

  Through the above operation, the digital broadcast transmitting apparatus 1 can specify the CAS program P to be started by the program specifying information arranged in the PSI / SI. Also, the digital broadcast transmitting apparatus 1 uses the ECM-P for the CAS program P identifier (CAS-ID) and version (CAS-Ver) designated by the program designation information and the hash value (CAS-H) of the CAS program P. By transmitting to the digital broadcast receiver 2 by RMP, it is possible to verify the consistency of the identifier (CAS-ID) and version (CAS-Ver) and the validity of the CAS program P in the digital broadcast receiver 2. become.

(CAS program start-up operation: digital broadcast receiver)
Next, referring to FIG. 13 (refer to FIG. 4 as appropriate for the configuration), the operation of the digital broadcast receiving apparatus 2 that activates the CAS program P designated by the digital broadcast transmitting apparatus 1 will be described.

First, the digital broadcast receiving apparatus 2 receives the multiplexed signal (MPEG-2 TS) transmitted from the digital broadcast transmitting apparatus 1, and separates it into each signal by the separating means 20 (step S41).
Then, the digital broadcast receiving apparatus 2 uses the activation program specifying means 26 to determine the CAS program P identifier (CAS-ID) and its version (CAS) from the CAT or PMT of PSI / SI (program sequence information). -Ver) is extracted (step S42).

  Then, the digital broadcast receiving apparatus 2 uses the EMM-RMP decrypting unit 21d to decrypt the EMM-RMP (individual information) separated in step S41 with the master key Km2 and extract the transmission path protection key Kp (step S43). ).

  Further, the digital broadcast receiving apparatus 2 uses the ECM-RMP decrypting unit 21e to decrypt the ECM-RMP (common information) separated in step S41 with the transmission path protection key Kp decrypted (extracted) in step S43, and to create a CAS program. The identifier (CAS-ID) and version (CAS-Ver) and the hash value (CAS-H) of the CAS program are extracted (step S44).

Then, the digital broadcast receiving apparatus 2 uses the program starting unit 27 to identify the identifier (CAS-ID) and version (CAS-Ver) extracted in step S42 and the identifier (CAS-ID) and version (CAS) extracted in step S44. -Ver) are determined to match each other (step S45).
Here, when the identifier (CAS-ID) and the version (CAS-Ver) do not match (No in step S45), the digital broadcast receiving device 2 ends the activation operation of the instructed CAS program P.

  On the other hand, when the identifier (CAS-ID) and the version (CAS-Ver) match (Yes in step S45), the digital broadcast receiving apparatus 2 instructs the activation stored in the storage unit 25 by the program activation unit 27. The hash value of the CAS program P thus obtained is calculated (step S46), and it is determined whether or not it matches the hash value (CAS-H) of the CAS program P extracted in step S44 (step S47).

Here, if the hash values do not match (No in step S47), the digital broadcast receiving device 2 ends the activation operation of the instructed CAS program P.
On the other hand, if the hash values match (Yes in step S47), the digital broadcast receiving apparatus 2 reads the designated CAS program P from the storage unit 25 by the program activation unit 27 and activates it as the program execution unit 21. (Step S48).

  Through the above operation, the digital broadcast receiving device 2 can activate the CAS program P designated by the digital broadcast transmitting device 1. At this time, the digital broadcast receiving apparatus 2 uses the identifier (CAS-ID), version (CAS-Ver), and hash value (CAS-H) of the CAS program P notified by ECM-RMP (common information). It is possible to start only a regular CAS program that is in the specified correct version and has not been tampered with.

As described above, according to the present invention, the CAS program P can be distributed from the digital broadcast transmitting apparatus 1 to the digital broadcast receiving apparatus 2 at high speed by data carousel transmission. As a result, even if the security of the function related to access control in the CAS program P is broken, the CAS program P with the changed security function can be distributed, so that the influence when the security is broken is minimized. Can be suppressed.
Further, according to the present invention, even when the distribution of the CAS program P by broadcasting is completed, the CAS program P can be distributed through the communication line, and the use of the broadcast band can be completed in a short period of time. Can do.

Further, according to the present invention, when the CAS program P is distributed in the data carousel, the CAS program P can be prevented from being falsified by the verification. Further, according to the present invention, when the digital broadcast transmitting apparatus 1 specifies the CAS program P to be activated, the digital broadcast receiving apparatus 2 can check the consistency of the version and the like, and the activated CAS is activated. Since the validity of the program P can be checked by the hash value, fraud with respect to the CAS program P to be started can be prevented.
Further, according to the present invention, the CAS program P to be activated can be switched from the digital broadcast transmitting apparatus 1 by PSI / SI, and the broadcaster can select the CAS program P according to the service provided. It becomes possible.

S Digital Broadcasting System 1 Digital Broadcasting Transmitter 10 Content Scrambling Unit 11 ECM-CAS Generation Unit 12 EMM-CAS Generation Unit 13 Distribution Data Generation Unit 13a Signature Value Calculation Unit 13b Division Unit 13c Encryption Unit 13d Data Carousel Data Generation Unit 14 Distribution data scramble means 15 ECM-RMP generation means (common information generation means)
16 EMM-RMP generation means (individual information generation means)
17 download table generation means 18 start program designation means 19 multiplexing means 2 digital broadcast receiver 20 separation means 21 program execution means 21a EMM-CAS decoding means 21b ECM-CAS decoding means 21c content descrambling means 21d EMM-RMP decoding means ( Individual information decoding means)
21e ECM-RMP decoding means (common information decoding means)
21f Distribution data descrambling means 22 Download table analysis means 23 Distribution data separation means 24 Program decryption means 24a Encryption / decryption means 24b Signature verification means 24c Writing means 25 Storage means 26 Startup program specifying means 27 Program starting means 28 Communication downloading means

Claims (2)

A digital broadcast transmitting apparatus that transmits an access control program for controlling access to content transmitted via a broadcast wave to a digital broadcast receiving apparatus,
A delivery data scramble means for encrypting the access control program with a scramble key and generating encrypted delivery data;
Common information generating means for encrypting the scramble key with a transmission path protection key transmitted to the digital broadcast receiver, and generating ECM-RMP which is common information including the scramble key;
Individual information generating means for encrypting the transmission path protection key with an encryption key common to the digital broadcast receiving apparatus and generating EMM-RMP which is individual information including the transmission path protection key;
A download table generating unit that adds an identifier indicating that the access control program is transmitted by broadcasting and generates a download table including identification information for identifying the access control program;
Multiplexing means for multiplexing the encrypted delivery data, the ECM-RMP, the EMM-RMP, and the download table to generate a multiplexed signal to be transmitted to the digital broadcast receiver;
The digital broadcast transmitting apparatus, wherein the download table generating means generates the download table including an identifier indicating that the access control program is acquired from a server designated via a communication line. In a digital broadcast receiving apparatus that performs access control to content transmitted via broadcast waves by an access control program,
Encrypted distribution data encrypted in a packet data format by encrypting the access control program with a scramble key, ECM-RMP, which is common information encrypted with a transmission path protection key including the scramble key, and the transmission path protection key Including an EMM-RMP that is individual information encrypted with an encryption key, an identifier indicating that the access control program is transmitted by broadcast, and a download table including identification information for identifying the access control program Separating means for separating each information from the multiplexed signal;
Download table analysis means for determining that the access control program is transmitted by broadcasting by means of an identifier described in the download table;
Digital broadcast transmitting apparatus and to decode the common of the EMM-RMP with the encryption key, and the individual information decoding means for acquiring the transmission path protection key,
Common information decryption means for decrypting the ECM-RMP with the transmission path protection key obtained by the individual information decryption means and obtaining the scramble key;
Distribution data descrambling means for decrypting the encrypted distribution data with the scramble key after the download table analysis means detects that the access control program is transmitted by broadcasting,
In the download table, an identifier indicating that the access control program is acquired from a server designated via a communication line is described.
Digital broadcasting further comprising communication download means for acquiring the access control program from the server when an identifier indicating that the access control program is acquired from the server is described in the download table Receiver device.

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