JP2010087814A - Broadcast receiver, integrated circuit device, and method of canceling scramble of digital broadcast content signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable flexible viewing control by providing a reception limiting method under a new condition in addition to the conventional reception limiting method in the unit of a channel. <P>SOLUTION: A broadcast receiver 4 includes: an encrypted data-receiving section 42 for receiving encrypted data (Lock-p) encrypted by a first key in a public/private key pair including a first key (K1-p1) and a second key (K1-p2); key information acquisition sections 35, 36 for acquiring key information given as a second key; a common information-receiving section 41 for receiving common information including a cancel key (Ks-p) for canceling a scramble applied to a broadcast content signal; and a cancel key supply section 44 for extracting, from the common information, the cancel key for canceling the scramble applied to the broadcast content signal associated with the encrypted data received by the encrypted data receiving section 42, and supplying the extracted cancel key to a decoder 45 when the encrypted data can be rightly decoded by the key information acquired by the key information acquisition sections 35, 36. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a broadcast signal conditional access system. In particular, the present invention relates to a technique for controlling access by a user to a release key for releasing scramble applied to a broadcast content signal.

  A conditional access system is employed in broadcasting services that distribute scrambled broadcast content signals, such as general BS broadcasting systems and CS broadcasting systems. In the conditional access system, content that can be viewed in a viewing service contract concluded between a contractor who receives a viewing service and a broadcaster is specified. A set-top box provided at the contractor's home, so-called STB, releases the scramble applied to the content signal only for the content signal of the channel defined in the viewing service contract.

In the viewing service contract of the conventional conditional access system, the content that can be viewed is specified in units of channels, and the STB only scrambles the content of the channel for which the viewing service contract is concluded.
The descrambling by the STB is performed according to common information and individual information distributed together with the content signal from the broadcaster. The common signal may be called ECM (Entitlement Control Message), and the individual information may be called EMM (Management Control Massage).

Examples of common information and individual information used in a conditional access system in which content that can be viewed on a channel basis is specified are shown in FIGS. 1 and 2, respectively.
The common information is applied to the field storing channel information for specifying the channel number (1 to n to p) of each content signal included in the distribution signal distributed from the broadcaster and the content signal of each channel. And a field for storing descrambling keys (Ks-1 to Ks-n to Ks-p) for descrambling, and has a table structure for associating a corresponding descrambling key with each channel. For simplicity, the scramble release key may be simply referred to as “release key” in the following description.

  The individual information is “1” indicating a field for storing channel information for specifying a channel number of each content signal included in the distribution signal and whether or not a contractor using the STB can view the content of each channel. And a field for storing contract information designated by a value of “0”, and has a table structure for associating corresponding contract information with each channel. In the example of the individual information shown in FIG. 2, the contractor views the channels “2” and “8” whose contract information value is “1” and views the contents of these channels with the broadcaster. A service contract has been concluded, and for channels “1” and “3” whose contract information value is “0”, a viewing service contract for viewing content is not concluded.

  The STB extracts the release key only from the common information extracted from the distribution signal for the channel designated as the viewing service contract in the individual information, that is, the channel whose contract information value is “1”. The content signal is supplied to a decoder for releasing the scramble.

  It should be noted that attributed content including content and content attribute information is provided from the content distribution device to the television device, the television device stores the attributed content in the storage means, and storage control is performed when the program viewer 3 views the program. Proposed to select and read content that is strongly related to program content from a plurality of stored content by searching for content attribute information using keywords extracted from digital broadcast program data from broadcasting Has been.

  In addition, the company ID of the corporation between the plurality of second servers connected to the first server managed or owned by the corporation via the network and the shareholder client connected via the network to each of the second servers. , Shareholder ID of shareholders who own shares, number of shares held by shareholders, video descrambling key for displaying video received by the shareholder client, and participation ID created by encrypting the password described in the shareholder list And the shareholder password owned by the shareholder are transmitted from the shareholder client to the second server, and the first server analyzes the participation ID to analyze the company ID, the shareholder ID, the number of shares held, the video descramble key, and the name list. Get password, send video descrambling key back to shareholder client, scramble with video descrambling key and browse When the second server receives the voting instruction for the video information of the main meeting from the shareholder client, the second server counts the voting rights according to the number of shares held, and the voting rights of the shareholder client connected to the second server. A method for managing a general meeting of shareholders is proposed in which the total is transmitted to a first server.

Japanese Patent Laid-Open No. 2002-247472 Japanese Patent Laid-Open No. 2002-197251

As described above, in the conventional conditional access system, a viewing service contract is concluded for each channel. For this reason, permission and prohibition of viewing by the contractor cannot be flexibly controlled using conditions other than the channel.
It is an object of the disclosed system, apparatus, and method to provide more flexible viewing control by providing a reception limitation method based on new conditions in addition to the conventional reception limitation method for each channel.

  In the disclosed apparatus and method, the broadcast content signal content receiving apparatus scrambles the encrypted data encrypted by the first key of the public key private key pair including the first key and the second key. The content signal and the common information including the release key for releasing the scramble of the broadcast content signal are received from the broadcast station, the key information given as the second key is acquired, and the received encrypted data is correctly decrypted with the acquired key information. When the encrypted data can be correctly decrypted by determining whether or not it is possible, a release key for releasing the scramble applied to the broadcast content signal associated with the encrypted data is extracted from the common information, and the broadcast content is extracted with the extracted release key. Unscramble the signal.

  The disclosed integrated circuit device is subjected to the encrypted data encrypted by the first key of the public key private key pair including the first key and the second key, the key information given as the second key, and the broadcast content signal An input unit for inputting common information including a release key for descrambling from the outside, a determination unit for determining whether encrypted data can be correctly decrypted with the key information, and correctly decrypting the encrypted data with the key information When possible, a release key extracting unit is provided that extracts from the common information a release key for releasing the scramble applied to the broadcast content signal associated with the encrypted data.

  In addition to the conventional reception limiting method for each channel, a reception limiting method based on a new condition is provided, which enables more flexible viewing control.

Hereinafter, embodiments will be described with reference to the accompanying drawings. FIG. 3 is an overall configuration diagram of the first embodiment of the disclosed broadcast distribution system. In this embodiment, a person who has watched a specific program or CM is allowed to view a scrambled program in a specific time zone.
The broadcast distribution system 1 includes a device that distributes broadcast content signals that are audio and / or video stream signals provided in the first broadcast station 2 and the second broadcast station 3, and a public that is provided in the authentication station 7. The key database 8 and the authentication server 9, the communication network NT, and the STB 5 and the TV device 6 provided in the contractor's home 4 of the contractor A who has concluded the viewing service contract with the second broadcasting station 3 are provided. In each drawing attached to this specification, “database” may be denoted as “DB” for simplicity.

The public key database 8 receives the public key generated by the second broadcasting station 3 from the second broadcasting station 3 and manages it. In response to a public key transmission request transmitted from the contractor A's STB 5 via the communication network NT, the authentication server 9 generates a public key created by the second broadcasting station 3 and stored in the public key database 8. Send to STB5.
The public key stored in the public key database 8 corresponds to the second key of the public key private key pair recited in the claims. A pair of keys generated as a public key / private key pair may be used as a public key and a secret key to be described later, and either of the pair of keys may be used as a public key.
The communication network NT that establishes communication between the authentication server 9 and the STB 5 may be the Internet or a dedicated line.

  The STB 5 receives a broadcast content signal distributed from the first broadcast station 2 via the communication transmission path C1 and a broadcast content signal distributed from the second broadcast station 3 via the communication transmission path C2, The device 6 converts the signal into a viewable signal. The communication transmission paths C1 and C2 may be wireless communication lines used for BS broadcasting, CS broadcasting, or the like, or may be priority communication lines used for CATV or the like. The broadcast content signal may be a digital signal or an analog signal. The configuration and operation of the STB 5 will be described later.

  FIG. 4 is a diagram showing a configuration of a device provided in the second broadcasting station 3 shown in FIG. As shown, the second broadcasting station 3 includes a public key / private key pair management device 10, a content information supply device 14, a common information supply device 15, an individual information generation device 16, a broadcast signal transmission device 17, An individual contract information database 18 is provided.

The public key / private key pair management device 10 issues and manages a public key / private key pair including the public key. Therefore, the public key / private key pair management apparatus 10 includes a public key issuing unit 11, a public key / private key pair generation unit 12, and a secret key database 13.
The public key / private key pair generation unit 12 generates a public key / private key pair in accordance with an existing public key / private key pair generation method. The private key corresponds to the first key of the public key private key pair described in the claims. The private key is stored in the private key database 13, and the public key is transmitted to the public key database 8 of the certificate authority 7 by the public key issuing unit 11 and stored in the public key database 8.

  The content information supply device 14 supplies the broadcast content signal to the broadcast signal transmission device 17. The broadcast content signal supplied to the broadcast signal transmission device 17 is scrambled, and the common information supply device 15 transmits common information including a release key for releasing the scramble applied to the broadcast content signal, for example, ECM. Supply to device 17. The common information of this embodiment has the data configuration shown in FIG.

  The individual information generating device 16 creates individual information, for example, EMM, according to the contents of the viewing service contract with each contractor stored in the personal contract information database 18 and supplies it to the broadcast signal transmitting device 17. The individual information is generated for each contractor and includes information indicating whether or not each channel included in the distribution signal distributed from the broadcast signal transmission device 17 can be viewed. A method of generating individual information by the individual information generating device 16 of this embodiment and the data contents thereof will be described later.

  The broadcast signal transmission device 17 receives a broadcast content signal supplied from the content information supply device 14, common information supplied from the common information supply device 15, individual information supplied from the individual information generation device 16, and other additional information. The multiplexed distribution signal is distributed to the STB 5 of each subscriber home 4.

FIG. 5 is a block diagram showing a schematic configuration of the STB 5 provided in the contractor's house 4 shown in FIG. As illustrated, the STB 5 includes a CPU 30, a ROM 31, a volatile RAM 32, a nonvolatile RAM 33, an operation input / output unit 34, and a communication interface 35.
Further, the STB 5 includes a signal separation unit 40, a common signal detection unit 41, an individual signal detection unit 42, an additional signal detection unit 43, a CAS (Conditional Access System) control unit 44, a decoder 45, and a register 46. . Each component in the STB 5 is connected by a data bus 51 and a control bus 52.

  The signal separation unit 40 separates the multiplexed distribution signal transmitted from the broadcast signal transmission device 17 of the second broadcast station 3 into a broadcast content signal, common information, individual information, and additional information. The broadcast content signal is supplied to the decoder 45, and the common information, individual information, and additional information are detected by the common information detector 41, the individual information detector 42, and the additional information detector 43, respectively.

  The ROM 31 stores a control program for controlling the operation of the STB 5, and the control program is executed by the CPU 30. The volatile RAM 32 is used as a temporary data storage area used by the CPU 30 to execute the control program. The nonvolatile RAM 33 stores data necessary for the operation of the STB 5 such as public key information acquired by the STB 5 from the certificate authority 7 as will be described later.

The operation input unit 34 is a user interface that accepts an operation input of the STB 5 by the contractor A, and may be, for example, a remote control device for operating the STB 5 or an operation key provided in the STB 5 itself.
The communication interface 35 realizes a communication environment via the communication network NT. In this embodiment, the communication interface 35 establishes communication between the authentication server 9 of the certificate authority 7 and the STB 5.
The register 46 receives a channel selection signal indicating the channel selected in the TV device 6 from the TV device 6 and holds it.

The CPU 30 executes the control program to obtain the common information and individual information detected by the common information detection unit 41 and the individual information detection unit 42, and the public key information acquired from the certificate authority 7 and stored in the nonvolatile RAM 33. , Input to the CAS control unit 44.
The CAS control unit 44 extracts a release key for releasing the scramble applied to the broadcast content signal from the common information according to the individual information and the public key information, and supplies it to the decoder 45.
The decoder 45 releases the scramble applied to the broadcast content signal by the supplied release key, and outputs the obtained audio signal and / or video signal to the TV device 6.

  The common information detection unit 41, the individual information detection unit 42, and the CAS control unit 44 correspond to the common information reception unit, the encrypted data reception unit, and the release key supply unit described in the claims. The CAS control unit 44 can be realized as an integrated circuit. The CAS control unit 44 realized as an integrated circuit corresponds to the integrated circuit device described in the claims.

FIG. 6 is a block diagram of functions realized by the CPU 30 executing the control program stored in the ROM 31 shown in FIG. By executing the control program stored in the ROM 31, the CPU 30 includes a common information supply unit 60, an individual information supply unit 61, an additional information acquisition unit 62, a viewing history generation unit 63, and a viewing condition determination unit 64. The public key information acquisition unit 65 and the public key information supply unit 66 operate.
In the present embodiment, each of the above functions shown in FIG. 6 is realized by software processing by the CPU 30, but these functions may be realized by dedicated hardware.

The common information supply unit 60 supplies the common information detected by the common information detection unit 41 illustrated in FIG. 5 to the CAS control unit 44. The individual information supply unit 61 supplies the individual information detected by the individual information detection unit 42 illustrated in FIG. 5 to the CAS control unit 44.
The additional information acquisition unit 62 acquires additional information detected by the additional information detection unit 43 shown in FIG. The additional information detected by the additional information detection unit 43 may be update data of the control program stored in the ROM 31 or whether the contractor A can view a specific program distributed by the second broadcasting station 3. Viewing condition data indicating viewing conditions for determining whether or not is included. The additional information acquisition unit 62 stores program update data in the ROM 31, and stores viewing condition data in the nonvolatile RAM 33.

  The viewing history generation unit 63 receives a channel selection signal of the TV device 6 input from the TV device 6 and stored in the register 46, and generates viewing history information of content viewed by the TV device 6. The viewing history information may be, for example, information for recording a history of time zone information including channel information that identifies a viewed channel and a start time and an end time when the channel is viewed. The viewing history generation unit 63 stores the created viewing history information in the nonvolatile RAM 33.

  The viewing condition determining unit 64 includes viewing condition data acquired from the additional information by the additional information acquiring unit 62 and stored in the nonvolatile RAM 33, viewing history information generated by the viewing history generating unit 63 and stored in the nonvolatile RAM 33, An operation input to the STB 5 performed via the operation input unit 34 is input. The viewing condition determination unit 64 determines whether the viewing condition indicated by the viewing condition data is satisfied according to the viewing history information and the operation input. The viewing condition determination unit 64 notifies the public key information acquisition unit 65 of the determination result.

When the viewing condition is satisfied, the public key information acquisition unit 65 requests the authentication server 9 of the certificate authority 7 to issue public key information generated in advance for the specific program, and the public key information is released from the authentication server 9. Receive key information. The public key information acquisition unit 65 stores the received public key information in the nonvolatile RAM 33. The public key information acquisition unit 65 corresponds to the key information acquisition unit described in the claims.
The public key information supply unit 66 inputs the public key information currently stored in the nonvolatile RAM 33 to the CAS control unit 44.

  FIG. 7 is a block diagram showing a schematic configuration of the CAS control unit 44 shown in FIG. The CAS control unit 44 includes an individual information holding unit 71, a public key information holding unit 72, a common information holding unit 73, a time condition determination unit 74, a decryption availability determination unit 75, and a release key extraction unit 76.

The individual information holding unit 71, the public key information holding unit 72, and the common information holding unit 73 are connected to the individual information supply unit 61, the public key information supply unit shown in FIG. 66 and individual information, public key information, and common information respectively input from the common information supply unit 60 are temporarily stored.
When the CAS control unit 44 is realized as an integrated circuit device, an input circuit for inputting individual information, public key information, and common information from the data bus 51 corresponds to an input unit described in the claims.

The time condition determination unit 74 determines whether or not the current time satisfies the time condition indicated by the time zone information included in public key information described later, and notifies the release key extraction unit 76 of the determination result.
The decryption permission / prohibition determination unit 75 decrypts an encrypted contractor ID included in individual information, which will be described later, using a public key included in public key information, and the decrypted data is a contractor ID of the contractor A. It is determined whether or not the encrypted contractor ID can be correctly decrypted. The decryption propriety determination unit 75 notifies the determination result to the release key extraction unit 76.

  The release key extraction unit 76 refers to the contract information set for each channel in the individual information, determines whether or not the viewing service contract is concluded for each channel, and the viewing service contract is concluded. The channel release key is extracted from the common information and supplied to the decoder 45.

When the contract information set for a certain channel is an encrypted contractor ID, the release key extraction unit 76 performs the following processing. The release key extracting unit 76 receives the determination result from the decryption permission / non-permission determining unit 75 that determines whether or not the encrypted contractor ID can be correctly decrypted. In addition, the release key extraction unit 76 determines whether the current time satisfies the time condition indicated by the time zone information included in the public key information together with the decrypted public key. Receive.
When the encrypted contractor ID is correctly decrypted and the current time satisfies the time condition indicated by the time zone information, the release key extraction unit 76 sets the encrypted contractor ID in the contract information in the individual information. The channel release key is extracted from the common information and supplied to the decoder 45.

  Hereinafter, the operation of each component of the broadcast distribution system 1 will be described. FIG. 8 is a flowchart showing a method for registering public key information in the public key database 8 shown in FIG. 3 by the second broadcasting station 2. In step S10, the public key / private key pair generation unit 12 provided in the second broadcasting station 3 shown in FIG. 4 generates a public key / private key pair composed of the public key K1-p2 and the secret key K1-p1.

  In step S11, the public key / private key pair generation unit 12 determines a channel and a time zone in which content permitting viewing is distributed to the STB 5 that has acquired the public key K1-p2 generated in step S10. In the following description, content permitted to be viewed by the STB 5 that has acquired the public key K1-p2 may be referred to as “service content”. For example, when the public key / private key pair generation unit 12 sets a specific program as service content, the channel and time zone for distributing the program are determined in step S11.

  The public key / private key pair generation unit 12 registers the secret key K1-p1 generated in step S10 and the channel information and time zone information representing the channel and time zone for distributing the service content in the secret key database 13, respectively. . FIG. 9 is a diagram illustrating a configuration example of the data configuration of the secret key database 13. The private key database 13 includes a field for storing channel information and time zone information for designating a channel and a time zone for delivering service content, and a field for storing a private key K1-p1. The secret key database 13 has a table structure that associates channel information and time zone information of service content with the secret key K1-p1.

In step S12, the public key / private key pair generation unit 12 generates public key information that combines the public key K1-p2 generated in step S10 with the channel information and time zone information determined in step S11.
In step S <b> 13, the public key issuing unit 11 registers the public key information generated by the public key / private key pair generation unit 12 in the public key database 8 of the certificate authority 7.

  FIG. 10 is a diagram showing a configuration example of the data configuration of the public key database 8. The public key database 8 includes a field for storing channel information and time zone information for designating a channel and a time zone for delivering service content, and a field for storing the public key K1-p2. The public key database 8 has a table structure that associates channel information and time zone information of service content with the public key K1-p2.

  FIG. 11 is a flowchart showing a method of creating individual information by the second broadcasting station 3, and FIG. 12 is a diagram showing an example of data contents of the individual information. The individual information includes a field for storing channel information for specifying the channel number of each content signal included in the distribution signal, and contract information for specifying whether the contractor A has a viewing service contract for each channel. And a table structure for associating corresponding contract information with each channel. The contract information value “1” indicates that a viewing service contract is concluded for the corresponding channel, and the contract information value “0” indicates that a viewing service contract is not concluded.

  In step S <b> 21, the individual information generating device 16 provided in the second broadcasting station 3 refers to the personal contract information database 18 and acquires personal contract information regarding the contractor A. The personal contract information includes the contractor ID of the contractor A and the channel in which the viewing service contract is concluded with the contractor A among the channels included in the distribution signal distributed from the second broadcasting station 3. Contains information to specify.

  In step S <b> 22, the individual information generating device 16 refers to the secret key database 13. When a record relating to service content that is scheduled to be distributed soon or is currently distributed is registered in the private key database 13, the contractor A uses the private key K1-p1 stored in this record. The contractor ID is encrypted. The contractor ID of the contractor A encrypted with the secret key K1-p1 is denoted as Lock-p.

The individual information generation device 16 repeats the iterative loops S23 to S29 for each channel 1 to N included in the distribution signal distributed from the second broadcasting station 3. The number of the target channel in each of the processes repeated for each channel is indicated as “i”.
In step S24, the individual information generating apparatus 16 determines whether or not the channel i is a channel that has a viewing service contract with the contractor A. When the channel i is a channel that has a viewing service contract with the contractor A, the individual information generating device 16 sets the contract information value of the record provided for the channel i to “1” in step S25. Set and end the process for channel i.

If it is determined in step S24 that the channel i is not a channel that has a viewing service contract with the contractor A, the individual information generating device 16 moves the process to step S26.
In step S26, the individual information generating device 16 determines whether or not the channel i is a service channel. Here, the service channel refers to a channel through which service content is distributed. For example, the individual information generating device 16 determines whether or not the channel i is a service channel by determining whether or not the channel i is a channel that has created the subscriber ID (Lock-p) encrypted in step S22. Determine whether or not.

When the channel i is a service channel, the individual information generation device 16 sets the value of the contract information of the record provided for the channel i of the individual information to Lock-p in step S27, and ends the processing for the channel i. To do.
In the example of the individual information shown in FIG. 12, since the secret key K1-p1 is registered in the channel p in the secret key database 13 shown in FIG. 9, the individual information generating device 16 determines that the channel p is a service channel. judge. Then, the individual information generation device 16 uses the contractor ID (Lock-p) encrypted using the secret key K1-p1 as the value of the contract information corresponding to the channel p.

  If it is determined in step S26 that the channel i is not a service channel, the individual information generating device 16 moves the process to step S28. In step S28, the individual information generating device 16 sets the contract information value of the record provided for channel i of the individual information to “0”, and ends the process for channel i.

  FIG. 13 is a flowchart showing a first example of a descrambling method by STB5. In step S <b> 30, the viewing condition determination unit 64 illustrated in FIG. 6 acquires the viewing condition data acquired by the additional information acquisition unit 62 from the nonvolatile RAM 33. The viewing condition data indicates a condition for permitting the contractor A to view service content distributed by the second broadcasting station 3.

  For example, the viewing condition may be that a specific CM or a specific program is viewed. In order to determine that a specific CM or a specific program has been viewed, for example, it may be determined whether or not a password presented in the specific CM or the specific program has been input from the operation input unit 34 of the STB 5. In addition, in order to determine that a specific CM or a specific program has been viewed, the viewing history information for viewing the channel to which the specific CM or the specific program has been distributed in the distributed time zone is stored in the nonvolatile RAM 33. It may be determined whether or not. These specific determination conditions are also called viewing conditions.

  In the present embodiment, viewing history information for viewing a specific program distributed from the first broadcasting station 2 is stored in the nonvolatile RAM 33, and the password indicated by this specific program is input to the operation input unit of the STB 5 It is assumed that the input from 34 is a viewing condition. The specific program distributed from the first broadcasting station 2 may be scrambled content or non-scrambled content. The viewing condition data includes, for example, password information indicating a password indicated by a specific program distributed from the first broadcasting station 2, channel information indicating a channel and a time zone in which the program is distributed, and time zone information. is there.

In step S31, the viewing history generation unit 63 shown in FIG. 6 creates viewing history information. In the present embodiment, the viewing history information is, for example, history information including channel information that identifies a viewed channel, and time zone information that includes a start time and an end time when viewing of the channel is started.
In the flowchart shown in FIG. 13, the viewing history information creation process by the viewing history generation unit 63 is shown in the flowchart. However, in the present embodiment, the viewing history generation unit 63 periodically creates the viewing history information creation process. I do. FIG. 14 is a flowchart showing a method of creating viewing history information by the STB 5.

In step S40, the viewing history generating unit 63 periodically starts the following steps S41 to S44. In step S41, the viewing history generation unit 63 changes the time information of the end time of the latest record of the viewing history information currently stored in the nonvolatile RAM 33 to the current time.
In step S42, the viewing history generation unit 63 inputs a channel selection signal indicating the channel selected in the TV device 6 from the register 46, and whether or not the channel information of the latest record and the channel selection signal are the same. Determine.

  If the channel information of the latest record and the channel selection signal are the same, the viewing history generating unit 63 moves the process to step S44. If they are not the same, the viewing history generating unit 63 creates a new record of viewing history information in step S43, and the process proceeds to step S44. In step S44, the viewing history generating unit 63 sets a time for starting the next viewing history information creating process S31.

  In step S <b> 32 shown in FIG. 13, the input of the password indicated by the specific program distributed from the first broadcasting station 2 input by the contractor A through the operation input unit 34 is accepted. In step S <b> 33, the viewing condition determination unit 64 illustrated in FIG. 6 receives the input password from the operation input unit 34, and reads viewing history information and viewing condition data from the nonvolatile RAM 33.

  The viewing condition determination unit 64 sets the viewing condition data in the time zone indicated by the time zone information indicated by the time zone information included in the viewing condition data when the password input from the operation input unit 34 matches the password information included in the viewing condition data. When the viewing history information indicates that the channel of the included channel information has been viewed, the contractor A determines that the service content can be viewed. It is determined that viewing of the content is prohibited. The viewing condition determination unit 64 notifies the determination result to the public key information acquisition unit 65 shown in FIG.

  When it is determined in step S33 that the contractor A can view the service content, in step S34, the public key information acquisition unit 65 issues the public key information that enables viewing of the service content to the authentication server. 9 and the public key information is received from the authentication server 9. The public key information acquisition unit 65 stores the received public key information in the nonvolatile RAM 33. The public key information stored in the nonvolatile RAM 33 is supplied to the CAS control unit 44 in FIG. 7 by the public key information supply unit 66.

  When the authentication server 9 of the authentication station 7 receives the viewing condition data from the second broadcasting station 3, and the public key information acquisition unit 6 requests the public key information, the public key information acquisition unit 65 operates the operation input unit. The password information and viewing history information input from 34 may be transmitted to the authentication server 9, and the authentication server 9 may determine whether or not the public key information may be issued.

  In step S35, the CAS control unit 44 in FIG. 7 acquires a release key from the common information supplied from the common information supply unit 60 shown in FIG. In the flowchart shown in FIG. 13, the release key acquisition process by the CAS control unit 44 is shown in the flowchart. However, in this embodiment, the CAS control unit 44 actually acquires the release key periodically from the common information. FIG. 15 is a flowchart illustrating a method for acquiring a release key.

In step S50, the CAS control unit 44 periodically starts the following steps S51 to S62. The CAS control unit 44 repeats the iterative loops S <b> 51 to S <b> 61 for each channel 1 to N included in the distribution signal distributed from the second broadcasting station 3. The number of the target channel in each of the processes repeated for each channel is indicated as “i”.
In step S52, the release key extraction unit 76 shown in FIG. 7 is supplied from the individual information supply unit 61 shown in FIG. 6, and is associated with the channel i from the individual information held in the individual information holding unit 71 shown in FIG. Get contract information.

  In step S <b> 53, the release key extraction unit 76 determines whether the value of the contract information is “1” or the encrypted contractor ID (Lock-p). If the value of the contract information is not “1” or the encrypted contractor ID (Lock-p), the release key extracting unit 76 moves the process to S61 and ends the process for the channel i.

  In step S54, the release key extraction unit 76 determines whether or not the value of the contract information is an encrypted contractor ID (Lock-p). If it is not the encrypted contractor ID (Lock-p), the release key extraction unit 76 moves the process to step S59. In step S59, the release key extraction unit 76 releases the scramble applied to the content of the channel i from the common information supplied from the common information supply unit 60 shown in FIG. 6 and held in the common information holding unit 73 shown in FIG. The release key is acquired, and the release key is supplied to the decoder 45 in step S60, and the process for channel i is terminated.

  If it is determined in step S54 that the contract information value is the encrypted contractor ID (Lock-p), the time condition determination unit 74 is supplied from the public key information supply unit 66 and holds the public key information in step S55. The time zone information is acquired from the public key information created for the channel i held in the unit 72, and the decryption availability determination unit 75 acquires the public key K1-p2 from the public key information.

  In step S56, the decryption propriety determination unit 75 decrypts the encrypted contractor ID (Lock-p), which is the value of the contract information, using the public key K1-p2. In step S <b> 57, the decryption permission determination unit 75 determines whether the decrypted value is equal to the contractor ID of the contractor A, and outputs the determination result to the release key extraction unit 76. When the decrypted value is different from the contractor ID of the contractor A, the release key extracting unit 76 moves the process to S61 and ends the process for the channel i.

  In step S <b> 58, the time condition determination unit 74 determines whether or not the current time is within the time zone indicated by the time zone information obtained from the public key information, and outputs the determination result to the release key extraction unit 76. When there is no current time within the time zone indicated by the time zone information, the cancel key extraction unit 76 moves the process to S61 and ends the process for channel i.

In step S59, the release key extraction unit 76 releases the scramble applied to the content of the channel i from the common information supplied from the common information supply unit 60 shown in FIG. 6 and held in the common information holding unit 73 shown in FIG. The release key is acquired, and the release key is supplied to the decoder 45 in step S60, and the process for channel i is terminated.
In step 62, the CAS control unit 44 sets a time to start the next release key acquisition process.

  FIG. 16 is a first explanatory diagram of a release key acquisition method. As shown in the figure, in the individual information given to the STB 5, the value of the contract information of the record 101 created for the channel 2 is “1” indicating that there is a viewing service contract. Therefore, as a result of the determination in steps S53 and S54, the processing S59 and S60 are executed for the channel 2, and the release key Ks-2 stored in the common information record 102 for the channel 2 is input to the decoder 45.

  In the individual information, the contract information value of the record 105 created for the channel p is an encrypted contractor ID (Lock-p). Therefore, as a result of the determination in steps S53 and S54, processes S55 to S60 are executed for channel p. In S56, Lock-p is decrypted with the public key K1-p2 of the public key information indicated by reference numeral 104. In step S57, it is determined whether or not the decrypted value 106 is the same as the contractor ID 107. When they are the same, the release key Ks-p stored in the common information record 108 for the channel p is input to the decoder 45 in steps S59 and S60.

  In step S <b> 36 shown in FIG. 13, the decoder 45 releases the scramble applied to the content signal with the release key supplied from the CAS control unit 44.

  According to the conditional access system of the present embodiment, it becomes possible to control whether or not to give a release key for releasing the scramble of the broadcast content signal depending on whether or not to give a public key as appropriate. More flexible viewing control is possible than conventional viewing control determined semi-fixed according to the content.

  As in this embodiment, when a public key that allows the use of a release key is given, a public key usage condition, that is, a release key acquisition condition or a release key use condition is given along with the public key. Also good. These conditions may be a viewable channel or a time zone, for example. In this case, it becomes possible to control permission and prohibition of viewing by the contractor only for the content in a specific time zone, for example, only for a specific program.

  Further, as in the present embodiment, viewing control may be performed by determining whether or not to provide a public key according to predetermined viewing conditions. According to the conditional access system of the present embodiment, only those who have watched a specific program or CM can view scrambled content in a specific time zone.

Encrypting and decrypting the contractor ID with the public key / private key pair makes it more difficult to illegally scramble than when encrypting the contractor ID with the common key.
If the contractor ID is encrypted and decrypted with the common key, the certificate authority 7 distributes the common key to the contractor. For this reason, if a third party who intends to unscramble illegitimately obtains a common key, the encrypted contractor to be distributed from the second broadcasting station 3 for any contractor ID An ID (Lock-p) can be freely generated and given to the CAS control unit 44.
However, if the contractor ID is encrypted with the secret key, even if the third party illegally obtains the public key distributed from the certificate authority 7, the third party The encrypted contractor ID (Lock-p) to be distributed from the station 3 cannot be generated.
The second broadcasting station may limit the validity period of the public key issued from the certification authority 7 by periodically updating the public key / private key pair.

  FIG. 17 is an overall configuration diagram of a second embodiment of the disclosed broadcast distribution system. In this embodiment, a person who has purchased a prepaid card by paying a fee for a predetermined viewing time is permitted to view the scrambled content. In this embodiment, when the subscriber A concludes a viewing service contract for receiving content distribution by purchasing a prepaid card, and the subscriber A purchases the prepaid card. It is assumed that the subscriber A can view the scrambled content.

  The broadcast distribution system 1 includes a broadcasting station 80 having the same device as the second broadcasting station described with reference to FIG. 3, a public key database 83 and a prepaid card issuing device 84 provided in a prepaid card issuing station 81, It includes an STB 5 and a TV device 6 provided in the contractor's home 4 of the contractor A who has signed the viewing service contract.

The public key database 83 stores public key information having the same configuration as the public key database 8 described with reference to FIG. 10, and receives and manages the public key generated by the broadcast station 80 from the broadcast station 80. .
The prepaid card issuing device 84 registers the public key information stored in the public key database 83 in a storage medium in the prepaid card 82. The contractor A obtains the public key K1-p2 by purchasing the prepaid card 82 in which the public key information is registered at the prepaid card issuing office 81.

  The STB 5 receives a broadcast content signal distributed from the broadcasting station 80 via the communication transmission path C3 and converts it into a signal that can be viewed by the TV device 6. The communication transmission line C3 may be a wireless communication line used for BS broadcasting or CS broadcasting, or may be a priority communication line used for CATV or the like. The broadcast content signal may be a digital signal or an analog signal.

FIG. 18 is a block diagram showing a schematic configuration of the STB 5 provided in the contractor's house 4 shown in FIG. The STB 5 has a configuration similar to the STB described with reference to FIG. For this reason, the same reference numerals are assigned to the same components, and the description of the components having the same mechanism as the components of the STB shown in FIG. 5 is omitted.
The STB 5 shown in FIG. 18 includes a card reader / writer 36 that can read / write data from / to the prepaid card 82 issued at the prepaid card issuing station 81. The card reader / writer 36 corresponds to a recording medium access unit described in the claims.

  FIG. 19 is a block diagram of functions realized by the CPU 30 executing the program stored in the ROM 31 shown in FIG. By executing the control program stored in the ROM 31, the CPU 30 causes the common information supply unit, individual information supply unit, additional information acquisition unit, viewing history generation unit, and public key information supply unit described with reference to FIG. Operate as the common information supply unit 60, the individual information supply unit 61, the additional information acquisition unit 62, the viewing history generation unit 63, and the public key information supply unit 66, respectively.

Further, the CPU 30 operates as the public key information acquisition unit 65 by executing the control program stored in the ROM 31. The public key information acquisition unit 65 in this embodiment stores the public key information read from the prepaid card 82 via the card reader / writer 36 in the nonvolatile RAM 33.
The public key information acquisition unit 65 updates the viewable time information indicating the remaining viewable time recorded in the prepaid card 82 according to the time when the content is viewed. The public key information acquisition unit 65 corresponds to the viewable time update unit described in the claims.
In the present embodiment, the above functions shown in FIG. 19 are realized by software processing by the CPU 30, but these functions may be realized by dedicated hardware.

  FIG. 20 is a flowchart showing a method for registering public key information in the prepaid card 82 shown in FIG. The configuration of the apparatus provided in the broadcasting station 80 is the same as that shown in FIG. In step S70, the public key / private key pair generation unit 12 illustrated in FIG. 4 generates a public key / private key pair including the public key K1-p2 and the secret key K1-p1.

  In step S71, the public key / private key pair generation unit 12 determines a channel and a time zone that can be viewed by the contractor A who has purchased the prepaid card 82 in which the public key K1-p2 is registered. The public key / private key pair generation unit 12 registers the secret key K1-p1 generated in step S70 and the channel information and time zone information respectively representing the channel and time zone determined in step S71 in the secret key database 13. . The data structure of the secret key database 13 is the same as the data structure described with reference to FIG.

  In step S72, the public key / private key pair generation unit 12 generates public key information in which the public key K1-p2 generated in step S70 is combined with the channel information and time zone information determined in step S71. The public key issuing unit 11 registers the public key information generated by the public key / private key pair generation unit 12 in the public key database 83 of the prepaid card issuer 81. The data configuration of the public key database 83 is the same as the data configuration described with reference to FIG.

  In step S73, the prepaid card issuing device 84 uses the public key information registered in the public key database 83 and the viewable time information indicating the viewable time during which the contractor A who has purchased the prepaid card 82 can view the content. 82.

  FIG. 21 is a flowchart showing a method for creating individual information by the broadcasting station 80. In step S <b> 81, the individual information generation device 16 provided in the broadcasting station 80 refers to the personal contract information database 18 and acquires personal contract information regarding the contractor A. The personal contract information is information that designates a channel for which a viewing service contract is concluded with the contractor A among the channels included in the distribution signal distributed from the broadcast station 80 and the contractor ID of the contractor A. And information specifying channel p that subscriber A can view by purchasing prepaid card 82.

In step S82, the individual information generating apparatus 16 encrypts the contractor ID using the secret key registered in the secret key database 13.
In this embodiment, the contractor A has a viewing service contract for viewing the channel p by purchasing the prepaid card 82 with the broadcasting station 80, and the secret key K 1 associated with the channel p is stored in the secret key database 13. -P1 is registered. The individual information generating device 16 sets the contractor ID of the contractor A encrypted using the secret key K1-p1 as Lock-p.

The individual information generating device 16 repeats the iterative loops S83 to S89 for each channel 1 to N included in the distribution signal distributed from the broadcast station 80. The number of the target channel in each of the processes repeated for each channel is indicated as “i”.
In step S84, the individual information generating apparatus 16 determines whether or not the channel i is a channel that has a viewing service contract with the contractor A. When the channel i is a channel that has a viewing service contract with the contractor A, the individual information generating device 16 sets the contract information value of the record provided for the channel i to “1” in step S85. Set and end the process for channel i.

If it is determined in step S84 that the channel i is not a channel that has a viewing service contract with the contractor A, the individual information generating device 16 moves the process to step S86.
In step S86, the individual information generating device 16 determines whether or not the channel i is the channel p that can be viewed by purchasing the prepaid card 82.

  When the channel i is the channel p that can be viewed by the prepaid card 82, in step S87, the individual information generating device 16 sets the contract information value of the record provided for the channel i of the individual information to Lock-p, and the channel The process for i ends.

  If it is determined in step S86 that the channel i is not the channel p that can be viewed by the prepaid card 82, the individual information generating device 16 moves the process to step S88. In step S88, the individual information generating device 16 sets the contract information value of the record provided for the channel i of the individual information to “0”, and ends the process for the channel i.

  FIG. 22 is a flowchart showing a second example of the descrambling method by STB5. In step S90, the contractor A sets the prepaid card 82 in the STB 5 so that the card reader / writer 36 can read / write data from / to the prepaid card 82. The prepaid card 82 may be a contact card or a non-contact card.

  In step S <b> 91, the CPU 30 of the STB 5 acquires public key information from the prepaid card 82. In the flowchart shown in FIG. 22, the public key information acquisition process S91 by the CPU 30 is shown in the flowchart. However, in the present embodiment, the CPU 30 actually executes the process S91 periodically. FIG. 23 is a flowchart showing a method for acquiring public key information from the prepaid card 82.

In step S100, the CPU 30 starts the following steps S101 to S109 periodically. In step S101, the viewing history generation unit 63 shown in FIG. 19 changes the time information of the end time of the latest record of the viewing history information currently stored in the nonvolatile RAM 33 to the current time.
In step S102, the viewing history generation unit 63 inputs a channel selection signal indicating the channel selected in the TV device 6 from the register 46, and whether or not the channel information of the latest record and the channel selection signal are the same. Determine.

  If the channel information of the latest record and the channel selection signal are the same, the viewing history generation unit 63 moves the process to step S104. If they are not the same, in step S103, the viewing history generating unit 63 creates a new record of viewing history information, and the process proceeds to step S104.

In step S104, the public key information acquisition unit 65 shown in FIG. 19 refers to the viewable time information stored in the prepaid card 82 via the card reader / writer 34. When the remaining viewable time indicated by the viewable time information is greater than 0, the public key information acquisition unit 65 moves the process to step S105.
In step S <b> 105, the public key information acquisition unit 65 inputs a channel selection signal indicating the channel selected in the TV device 6 from the register 46, and uses the public key information stored in the prepaid card 82 via the card reader / writer 34. Read. When the channel information of the public key information and the channel selection signal are not equal, the public key information acquisition unit 65 moves the process to step S108.

  When the channel information of the public key information is equal to the channel selection signal in the determination of step S105, the public key information acquisition unit 65 moves the process to step S106. In step S106, the public key information acquisition unit 65 subtracts the period time during which the public key information acquisition process S91 is performed by the CPU 30 from the remaining viewable time indicated by the viewable time information currently stored in the prepaid card 82. Calculate the new viewable remaining time. The public key information acquisition unit 65 updates the viewable time information by writing a new viewable remaining time to the prepaid card 82 via the card reader / writer 34.

In step S107, the public key information acquisition unit 65 stores the public key information in the nonvolatile RAM 33, and then moves the process to step S108.
When the viewable remaining time indicated by the viewable time information is not greater than 0 in the determination in step S104, the public key information acquisition unit 65 deletes the public key information stored in the nonvolatile RAM 33 and performs the process in step S108. Move to.
In step S <b> 108, the CPU 30 sets a time for starting the next public key information acquisition S <b> 91.

  In step S92 shown in FIG. 22, the CAS control unit 44 shown in FIG. 18 acquires a release key from the common information supplied from the common information supply unit 60 shown in FIG. The release key acquisition process by the CAS control unit 44 is the same as the process described with reference to FIG. FIG. 24 is a second explanatory diagram of the release key acquisition method.

As shown in the figure, in the individual information given to the STB 5, the release key Ks-2 is input to the decoder 45 for the channel 2 for which a normal viewing service contract is made, as in the description of FIG.
In the individual information, the contract information value of the record 202 created for the channel p is an encrypted contractor ID (Lock-p), and the contract information value of the record 202 is the channel p. Indicates that the channel can be viewed by purchasing a prepaid card.

When the contractor purchases the prepaid card 82 and sets it in the STB 5, the public key information indicated by the reference numeral 201 is stored in the nonvolatile memory 33. As a result, Lock-p is decrypted with the public key K1-p2 of the public key information 201. Then, it is determined whether or not the decrypted value 203 is the same as the contractor ID 204. When the decrypted value 203 is the same, the release key Ks-p stored in the common information record 205 for the channel p is input to the decoder 45.
In step S <b> 93 shown in FIG. 22, the decoder 45 releases the scramble applied to the content signal with the release key supplied from the CAS control unit 44.

According to the conditional access system of this embodiment, whether or not to provide a public key is determined according to the condition of whether or not a prepaid card has been purchased, that is, viewing control is performed.
Further, according to the remaining viewable time recorded in the prepaid card, whether or not the public key can be used, that is, whether or not the release key can be acquired or whether or not the release key can be used is determined. In other words, the remaining viewable time becomes a public key use condition, that is, a release key acquisition condition or a release key use condition.
In this embodiment, only those who have purchased a prepaid card for a predetermined time can be allowed to view scrambled content by specifying a viewable time.

The following additional notes are further disclosed with respect to the embodiment including the above examples.
(Appendix 1)
An encrypted data receiving unit for receiving encrypted data encrypted by the first key of a public key / private key pair including a first key and a second key;
A key information acquisition unit for acquiring key information given as the second key;
A common information receiving unit for receiving common information including a release key for releasing the scramble applied to the broadcast content signal;
Release that cancels the scramble applied to the broadcast content signal associated with the encrypted data when the encrypted data received by the encrypted data receiving unit can be correctly decrypted with the key information acquired by the key information acquiring unit. A release key supply unit that extracts a key from the common information and supplies the key to a decoder of the broadcast content signal;
A broadcast receiving apparatus.

(Appendix 2)
The broadcast receiving device according to appendix 1, wherein the key information acquisition unit receives the key information from a key information issuing server that issues the key information via a communication network.

(Appendix 3)
The key information acquisition unit receives time zone information together with the key information from the key information issuing server,
The broadcast receiving apparatus according to supplementary note 2, wherein the release key supply unit supplies the release key when a current time is in a time zone indicated by the time zone information.

(Appendix 4)
The broadcast receiving apparatus according to appendix 1, wherein the key information acquisition unit includes a recording medium access unit that reads and writes data from and on the recording medium on which the key information is recorded.

(Appendix 5)
Viewable time information indicating the remaining viewable time is recorded on the recording medium,
The broadcast receiving apparatus according to appendix 4, wherein the release key supply unit supplies the release key when the remaining viewable time indicated by the viewable time information read by the recording medium access unit is not zero.

(Appendix 6)
A viewable time update unit that updates the viewable time information by subtracting the time of viewing the broadcast content signal from the remaining viewable time;
The broadcast receiving apparatus according to appendix 5, wherein the recording medium access unit records the updated viewable time information on the recording medium.

(Appendix 7)
Encrypted data encrypted by the first key of a public key / private key pair including the first key and the second key, key information given as the second key, and scramble applied to the broadcast content signal An input unit for inputting common information including a release key to be released from the outside,
A determination unit that determines whether or not the encrypted data can be correctly decrypted with the key information, and a broadcast associated with the encrypted data from the common information when the encrypted data can be correctly decrypted with the key information. An integrated circuit device comprising: a release key extraction unit that extracts a release key for releasing scramble applied to a content signal.

(Appendix 8)
The input unit inputs time zone information from outside,
The integrated circuit device according to appendix 7, wherein the release key extraction unit extracts the release key when the current time is in a time zone indicated by the time zone information.

(Appendix 9)
Broadcast content signal content receiver
Encrypted data encrypted by the first key of a public key private key pair including a first key and a second key, a scrambled broadcast content signal, and a release key for releasing the scramble of the broadcast content signal Receive common information from broadcast stations,
Obtaining key information given as the second key;
Determining whether the encrypted data received can be correctly decrypted with the acquired key information;
When the encrypted data can be correctly decrypted, a release key for releasing the scramble applied to the broadcast content signal associated with the encrypted data is extracted from the common information,
A descrambling method of a broadcast content signal, wherein the descrambling of the broadcast content signal is canceled with the extracted release key.

(Appendix 10)
The descrambling method according to appendix 9, wherein the content receiving apparatus acquires the key information by receiving the key information from a key information issuing server that issues the key information via a communication network.

(Appendix 11)
The content receiving device is
Receiving time zone information together with the key information from the key information issuing server;
The scramble release method according to supplementary note 10, wherein the release key is extracted from the common information when a current time is in a time zone indicated by the time zone information.

(Appendix 12)
The content receiving device is
Read the key information and viewable time information indicating the remaining viewable time from a predetermined recording medium,
The scrambling release method according to appendix 9, wherein the release key is extracted from the common information when the remaining viewable time indicated by the read viewable time information is not zero.

(Appendix 13)
The content receiving device is
Updating the viewable time information by subtracting the time of viewing the broadcast content signal from the viewable remaining time;
13. The descrambling method according to appendix 12, wherein the updated viewable time information is recorded on the recording medium.

It is a figure which shows the example of the common information used with a conditional access system. It is a figure which shows the example of the separate information used with a conditional access system. 1 is an overall configuration diagram of a first embodiment of a disclosed broadcast distribution system. It is a figure which shows the structure of the apparatus provided in the 2nd broadcasting station shown in FIG. It is a block diagram which shows schematic structure of STB provided in the contractor's house shown in FIG. It is a block diagram of the function implement | achieved by running the control program memorize | stored in ROM shown in FIG. 5 by CPU. It is a block diagram which shows schematic structure of the CAS control part shown in FIG. It is a flowchart which shows the registration method of the public key information to the public key database shown in FIG. It is a figure which shows the structural example of the data structure of a secret key database. It is a figure which shows the structural example of the data structure of a public key database. It is a flowchart which shows the 1st example of the preparation method of separate information. It is a figure which shows the example of the data content of individual information. It is a flowchart which shows the 1st example of the descrambling method by STB. It is a flowchart which shows the production method of viewing history information by STB. It is a flowchart which shows the acquisition method of a cancellation | release key. It is the 1st explanatory view of the acquisition method of a release key. It is a whole block diagram of 2nd Example of the broadcast delivery system of an indication. It is a block diagram which shows schematic structure of STB provided in the contractor's house shown in FIG. It is a block diagram of the function implement | achieved by running the program memorize | stored in ROM shown in FIG. 18 by CPU. It is a flowchart which shows the registration method of the public key information to the prepaid card shown in FIG. It is a flowchart which shows the 2nd example of the preparation method of separate information. It is a flowchart which shows the 2nd example of the descrambling method by STB. It is a flowchart which shows the acquisition method of the public key from a prepaid card. It is the 2nd explanatory view of the acquisition method of a release key.

Explanation of symbols

1 Broadcast distribution system 2, 3 Broadcasting station 4 Contractor's house 5 STB
6 TV device 7 Certification authority 8 Public key DB
9 Authentication server C1, C2 Communication transmission line NT Communication network

Claims (5)

An encrypted data receiving unit for receiving encrypted data encrypted by the first key of a public key / private key pair including a first key and a second key;
A key information acquisition unit for acquiring key information given as the second key;
A common information receiving unit for receiving common information including a release key for releasing the scramble applied to the broadcast content signal;
Release that cancels the scramble applied to the broadcast content signal associated with the encrypted data when the encrypted data received by the encrypted data receiving unit can be correctly decrypted with the key information acquired by the key information acquiring unit. A release key supply unit that extracts a key from the common information and supplies the key to a decoder of the broadcast content signal;
A broadcast receiving apparatus.   The broadcast receiving apparatus according to claim 1, wherein the key information acquisition unit receives the key information from a key information issuing server that issues the key information via a communication network.   The broadcast receiving apparatus according to claim 1, wherein the key information acquisition unit includes a recording medium access unit that reads / writes data from / to a recording medium in which the key information is recorded. Encrypted data encrypted by the first key of a public key / private key pair including the first key and the second key, key information given as the second key, and scramble applied to the broadcast content signal An input unit for inputting common information including a release key to be released from the outside,
A determination unit that determines whether or not the encrypted data can be correctly decrypted with the key information, and a broadcast associated with the encrypted data from the common information when the encrypted data can be correctly decrypted with the key information. An integrated circuit device comprising: a release key extraction unit that extracts a release key for releasing scramble applied to a content signal. Broadcast content signal content receiver
Encrypted data encrypted by the first key of a public key private key pair including a first key and a second key, a scrambled broadcast content signal, and a release key for releasing the scramble of the broadcast content signal Receive common information from broadcast stations,
Obtaining key information given as the second key;
Determining whether the encrypted data received can be correctly decrypted with the acquired key information;
When the encrypted data can be correctly decrypted, a release key for releasing the scramble applied to the broadcast content signal associated with the encrypted data is extracted from the common information,
A descrambling method of a broadcast content signal, wherein the descrambling of the broadcast content signal is canceled with the extracted release key.

Images