JP2006287769A - Distribution system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize restricted reproduction corresponding to contents of a plurality of kinds in a server type broadcast. <P>SOLUTION: A restricted reproducing system and a server type CAS module can be realized corresponding not only to distribution of contents by the broadcast from a transmitter 1, but also to download contents and streaming contents through communication with a content server 9. Accordingly, a hybrid type charging can also be realized in the distribution profile of various contents. Moreover, a plurality of receivers provided in each household can use in common various contents. Meanwhile, it is possible for the receivers outside of household that contents cannot be used even under the same service contract, if contents are copied. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a distribution system, and more particularly, to a corresponding distribution system that enables limited reproduction that can support a plurality of forms of content distribution in server-type broadcasting.

  Server-type broadcasting has been proposed as one broadcasting form that can be viewed at any time when a viewer wants to view a program that the viewer wants to view.

  Examples of content handled by server-type broadcasting include type 1 content that stores and uses normal television broadcasts and type 2 content that stores and uses content of dedicated storage services.

  By the way, in the server type broadcasting, the use of content is limited by the contract contents of the viewer, but conventionally, the type 1 content and the type 2 content are greatly different in the limited reception method for the reproduction limitation. It was. For this reason, for example, the load of reception / reproduction processing in the receiver on the viewer side is heavy.

  In addition, content can be shared by multiple receivers in the home, but there is a service request that other home receivers copy the content so that it cannot be used in other homes even if there is the same viewing contract. It was not satisfied.

  Furthermore, it was not a system that considered not only server-type broadcasting but also content distribution by communication.

  The distribution system of the present invention has a distribution device that distributes content by broadcasting or communication, and when the content is received and further stored in a storage medium, and this usage right is held and the usage conditions are satisfied A group management device that manages group information and generates and manages a unique key for each group so that the reception device that reproduces the data only and the reception device are grouped so that only the reception devices in the same group can use the group A key management device that manages a key unique to each receiving device, and a sending device that encrypts a group-specific key with a key unique to the receiving device and sends this as broadcast key as group key information. The management apparatus is characterized in that it communicates with the receiving apparatus based on the receiver-specific key and transfers the group-specific key.

  The receiving device can be provided with means for receiving the broadcast or decrypting the group key information with a key unique to the receiver by communication, and extracting and holding the group key.

  Means for acquiring and holding a main license including a work key indicating the existence of a right to use a plurality of contents from broadcasting or communication, a content encrypted with the content key, a content key, and content usage condition information Means for receiving from a broadcast or communication channel a sublicense encrypted with a work key, means for encrypting the sublicense with a group key, means for storing the sublicense encrypted with the group key in a storage device And means for decrypting the sublicense encrypted with the group key with the group key, further decrypting with the work key to extract information including the content key and the content usage condition information, and determining the content usage condition information when using the content A means for outputting a content key only when the condition is satisfied, and a content key Means for decrypting the cipher, means for receiving and storing the information obtained by encrypting the key for each part with the content key together with the content, and the key for each part. It is possible to provide means for decrypting the information encrypted with the content key with the content key output from the means for outputting the content key during reproduction, and means for decrypting the content with the key for each part.

  The distribution device for distributing content by broadcasting or communication according to the second aspect of the present invention, and when the content is received and further stored in a storage medium, the usage right is held and the usage conditions are satisfied In a distribution system consisting of a receiving device that reproduces the content only, the receiving device broadcasts including an EMM in which a main license including a work key indicating the existence of a right to use a plurality of contents is encrypted with a key unique to the receiving device. Means for receiving the signal, means for decrypting the received EMM with the key unique to the receiving device and extracting the main license, and communicating with the device on the communication network, both the receiving device and the device on the specific communication network Based on the key unique to the receiving device held in the communication device, a communication means for performing settings for mutual authentication and communication data concealment, and a plurality of codes transmitted through the communication means. Means for taking out received the main license including a work key indicating the presence of a right to use the Ceiling, characterized in that it comprises a means for holding the main license.

  A device on a specific communication network that holds a key unique to the receiving device when communicating with a device on the communication network that holds a main license including a work key indicating the existence of a right to use a plurality of contents to the receiving device; A license that performs settings for mutual authentication and concealment of communication data based on a key unique to the receiving device held by both receiving devices, and transmits the main license from the device on the communication network to the receiver via the communication network Both transmission methods can be used.

  The receiving device belongs to a plurality of receiving device groups, and the receiving device can acquire and hold a plurality of group keys.

  Means for acquiring and holding a plurality of group keys belonging to a plurality of receiver groups in the receiving device; means for receiving information specifying a specific group key together with a sublicense from broadcast or communication; and the received group key Means for selecting one of the stored group keys from the information for identifying the information, means for encrypting the sublicense with the selected group key, and decrypting the encrypted sublicense with the selected group key Means can be further provided.

  ADVANTAGE OF THE INVENTION According to this invention, it can respond | correspond so that the limited reproduction | regeneration which can respond to a some form of content delivery can be performed in server type | mold broadcast.

(1) Server type broadcast Server type broadcast related to the present invention will be described. Normal broadcasting is premised on a form in which video signals, audio signals, and the like are continuously transmitted in broadcast waves, which are continuously received by a receiver, reproduced immediately, and viewed by a viewer. That is, the viewer can view the program at the time when the program is broadcast. On the other hand, in the server-type broadcast, the viewer can watch a program (content) that he / she wants to watch at his / her desired time.

  In order to realize this viewing mode, the receiver first needs to have a storage medium.

  As one operational form of server-type broadcasting, viewers do not watch immediately when broadcasting waves are transmitted, but are stored in storage media as content for each program when receiving broadcast waves at the receiver, and viewers later like There is a form to watch at the timing.

  Further, as an advanced form of this operation form, there is a form in which content stored in the storage medium is downloaded not only from the broadcast but also via communication. The target content in this operation mode is type 2 content.

  Ordinary broadcasts are stored as content in units of programs and viewed later at a timing that the viewer likes, but unlike so-called recording, they are stored as content and viewed in the same viewing mode as type 2 content. As a result, for example, it is possible to consider a service in which, for example, a recording-prohibited program is accumulated and then paid viewing is performed under specific conditions. The target content in this operation mode is type 1 content.

  Further, there is a form in which a viewer requests a server on a communication network at a timing when the viewer wants to view and receives the content to be viewed by a so-called streaming transmission method and immediately views the content.

  Common to these operation modes is that the viewer obtains viewing rights for content that is a single program unit by paying a fee, etc., and then views the content within the range of usage conditions for each content. As a technology common to these operations, there is a technology related to the processing from data generation to consumption, which is a license that expresses usage rights and usage conditions. In connection with this license, there is a need for a technique for protecting content from unauthorized use and enabling reproduction only when the correct license is used. Such a technique is called a limited reproduction technique.

  The present invention relates to a limited reproduction technique in server type broadcasting.

(2) Server type broadcast system FIG. 1 shows an example of the configuration of a server type broadcast system to which the present invention is applied.

  The broadcasting station 1 produces type 1 content and type 2 content, and transmits them as broadcast waves by a transmission method defined by applying necessary encryption.

  The broadcast station 1 transmits an individual license for each receiver 2, and an EMM (Entitlement Management Message) generated by the Kms management server 13 and encrypted with the server type master key Kms for each receiver 2. (Individual information for each subscriber) is transmitted.

  Each of the receiver 2-1, the receiver 2-2, and the receiver 2-3 (hereinafter referred to simply as the receiver 2 when there is no need to distinguish them individually. The same applies in other cases). This is a server-type broadcast-compatible receiver that includes storage media 31-1, 31-2, and 31-3. The receivers 2-1 and 2-2 belong to the same home, and the receiver 2-3 belongs to another home.

  The receivers 2-1 and 2-2 are connected to each other via the home network 4 so that the contents can be mutually used.

  Each home receiver 2 is connected to the broadband network 8 via the gateway 5 or 6 and can communicate with the content server 9 to the domain management server 12 on the broadband network 8 as necessary.

  The content server 9 supplies content to the receiver 2 via the broadband network 8 (provides content separately from broadcasting). As a method for supplying this content, there are a method of temporarily downloading to the storage medium 31 of each receiver 2 and a method of directly reproducing by streaming.

  The license server 10 supplies the license to the receiver 2 when an operation is performed in which the license is acquired through the communication path when the receiver 2 is necessary.

  The shop / settlement server 11 has a function as a Web server that performs navigation for a viewer to purchase content from the receiver 2 using BML or the like, and a function that performs billing / settlement.

  The domain management server 12 manages information about which receiver 2 belongs to which domain in order to properly operate the domain. In server-type broadcasting, basically, the domain for each home is managed, and the license for using the content is granted to the domain. Thus, for example, the receivers 2-1 and 2-2 can use content with a common license, but the receiver 2-3 is in a different domain, so the receivers 2-1 and 2-2 Requires a separate license.

  The domain management server 12 also generates and manages a domain key, and acquires the domain key by broadcasting or direct communication so that each receiver 2 can appropriately perform domain control.

  The Kms management server 13 manages the server type master key Kms embedded in the receiver 2 individually. The server type master key Kms is used for encryption of a license or the like as necessary for the security of the entire server type broadcasting system, or a security base when license transmission is performed between the license server 10 and the receiver 2. Used as

(3) Server type broadcast compatible receiver FIG. 2 shows a configuration example of the receiver 2. The receiver 2 also has a normal digital broadcast receiving function.

  When a normal broadcast is received, a data stream (hereinafter abbreviated as TS) including a channel to be selected is extracted by a tuner 22 from a broadcast wave input 21 of an intermediate frequency. When the scramble is applied in pay broadcasting or the like, the scramble is decrypted by the descrambler 23 which is judged to be viewable by the B-CAS card 24 by the descrambler 23 and inputted to the demultiplexer 25. In the demultiplexer 25, signals such as video, audio, and data broadcast signals constituting the channel to be selected are filtered, the video signal is the video decoder 26, the audio signal is the audio decoder 27, and the data broadcast signal is the BML browser 28. Are respectively input and decoded. Finally, the video output 29 and the audio output 30 are presented to the viewer.

  When a server-type broadcast is received, a stream to be serviced is extracted from the broadcast wave input 21 by the tuner 22 in the same manner as when a normal broadcast is received, but the descrambler 23 does not perform descrambling. The stream is input to the demultiplexer 25 as it is.

  The demultiplexer 25 extracts data to be stored as content, and the extracted content is stored as a content file group in the storage medium 31 based on the storage control information included in the stream.

  When the server type broadcast is received, the license is input to the server type CAS module 33 by broadcast or communication prior to the reproduction of the content, so that the license can be used. As license forms, there are a one-tier license and a two-tier license.

  In the case of a one-tier license, the license is transmitted by communication and directly input to the server type CAS module 33 from the communication input / output 34 via the communication interface 35.

  The two-tier license is composed of a main license and a sub license. The main license indicating the viewer's right to use is assumed to be used for both broadcast transmission and communication transmission.

  When transmitted by broadcast, the main license is embedded in the broadcast stream as an EMM packet independently of the content transmission, extracted from the broadcast wave input 21 by the demultiplexer 25 via the tuner 22, and the server type CAS module 33. Is input.

  When the data is transmitted by communication, it is directly input to the server type CAS module 33 from the communication input / output 34 via the communication interface 35 as in the case of the one-tier license.

  Since the sublicense is transmitted as a part of the content, the sublicense is stored in the storage medium 31 according to the above-described flow. However, the sublicense is input to the server type CAS module 33 before the content is reproduced.

  After a license is entered for a one-tier license, both a main license and a sub-license are entered for a two-tier license, and before the content is played, the license is made available on the server type CAS client and included in the license The content key included in the license is output from the server type CAS module 33 and set in the encryption / decryption device 32. As a result, the encryption / decryption device 32 can decrypt the encryption of the content read from the storage medium 31, so that the content can be reproduced.

  The content is assumed to be in the form of a stream including video and audio, and in the form of a file such as a BML document file or JPEG file. In the former case, the stream is supplied from the encryption / decryption device 32 to the demultiplexer 25, Therefore, the video and audio are separated, and the video is decoded by the video decoder 26 and the audio is decoded by the audio decoder 27 and presented to the viewer as a video output 29 and an audio output 30.

  In the latter case, the file is supplied from the encryption / decryption device 32 to the BML browser 28, where it is played back in multimedia, and finally presented as a video output 29 together with the video.

  Note that the demultiplexer 25 through the BML browser 28 and the encryption / decryption device 32 that perform content reproduction processing will be appropriately referred to as a renderer 36 hereinafter. In the following description of the present invention, the detailed module configuration of content playback is not directly related to the limited playback function, and therefore will be described as processing of the renderer 36.

(4) Limited Playback Processing in Type 1 Content The limited playback function realized in the present invention for each content and operation variation assumed in server type broadcasting will be described.

  First, the limited reproduction process for type 1 content will be described. Type 1 content is such that limited playback control is performed after a normal broadcast program is stored as content. Two service models are assumed.

  One is a free broadcast but scrambled for copyright protection. In addition to recording, it is stored as type 1 content to allow advanced use such as digest playback using segment metadata. It is a service model to let you. The other is a service model in which a premium program such as PPV is prohibited from recording, but is stored as content and permitted to be played only once for a fee.

  The former free program can be realized by the two-tier license model shown in FIG. The limited reproduction process in this case will be described. The numbers in FIG. 3 correspond to the order of this limited reproduction process.

  First, as a process corresponding to the number 1 in FIG. 3, it corresponds to a range of type 1 content flat tier subscribers such as viewers who have made a contract for a high level of use, and the like. The main license including the server type work key Kws and the usage conditions GroupRMPI related to the entire contract is encrypted with the server type master key Kms specific to the server type CAS module 33 of the receiver 2 used by the viewer, and broadcast station 1 as EMM. Is broadcast for a certain period of time. The viewer operates the receiver 2 to receive it, whereby the main license is input to the server-type CAS module 33 and decrypted with the server-type master key Kms and held.

  Next, as a process corresponding to the number 2, as a content of each program as shown in FIG. 3, an ordinary TV program stream that can be received and reproduced by a normal receiver that is not compatible with the server type is transmitted from the broadcasting station 1. Key Kc and its usage conditions EachRMPI encrypted with server type work key Kws Kc distribution ECM and scramble key Ksi of program AV signal packet updated every few seconds (i = 1,2, ..., n , N + 1,...), Two types of packets of ECM-Kc in which the content key Kc is encrypted are added and broadcast. The Kc distribution ECM is information that functions as a sublicense. In the receiver 2, the stream for one program that remains scrambled is stored in the storage medium 31 as content in the form of a file.

  Next, as processing corresponding to the number 3, when the reproduction of the content stored in the storage medium 31 of the receiver 2 is activated, the sublicense Kc distribution ECM is extracted and stored in the server-type CAS module 33. The server type work key Kws included in the main license (the process corresponding to number 1) input and held in the server type CAS module 33 is decrypted, and the sub license content key Kc and the main license The merged RMPI of the sub-licenses is set to a usable state in the server type CAS module 33.

  Next, as processing corresponding to the number 4, when the content reproduction is started, the renderer 36 makes a reproduction start permission request to the server type CAS module 33, and the ECM-Kc that first appears in the content stream is the server type CAS module 33. Is input. At that time, the RMPI usage condition is determined by the server-type CAS module 33. If it can be used, the ECM-Kc is decrypted with Kc, and the scramble key Ks is output to the renderer 36.

  The renderer 36 uses the scramble key Ks to unscramble the AV stream packet from the storage medium 31 and reproduce it. Thereafter, every time the ECM-Kc is updated, this is input to the server-type CAS module 33 to determine whether or not RMPI is used, and if it is available, the scramble key Ks is output to the renderer 36. Unscramble and play (playback continues).

  The latter pay program of the service model of type 1 content (a service such that premium programs such as PPV are prohibited from recording, but are allowed to be stored as content and limited playback is allowed once for a fee. Model) can be realized with the one-tier license model shown in FIG. The limited reproduction process in this case will be described. The numbers in FIG. 4 correspond to the order of this limited reproduction process.

  First, as a process corresponding to number 1 in FIG. 4, an AV signal of a program that is updated every few seconds as shown in FIG. 4 to a stream of a PPV TV program that can be received and reproduced by a normal receiver that is not server-type compatible. An ECM-Kc obtained by encrypting a scramble key Ks of a packet with a content key Kc included in an individual license, which will be described later, is added and broadcast from the broadcast station 1. In the receiver 2, the stream for one program that remains scrambled is stored in the storage medium 31 as content in the form of a file.

  Next, as processing corresponding to the number 2, the viewer communicates with the shop / payment server 11 (FIG. 1 and the like) to view the contents of the premium program stored in the storage medium 31, and performs a purchase operation. I do. As a result, the shop / settlement server 11 performs settlement, and as a result, the license server 10 generates an individual license corresponding to this content for the receiver 2 of the corresponding viewer. The server-type CAS module 33 of the receiver 2 acquires and holds the generated individual license through secure communication with the license server 10 based on mutual authentication.

  Next, as processing corresponding to the number 3, when the reproduction of the content stored in the storage medium 31 of the receiver 2 is activated, the individual license held in the server CAS module 33 is converted into the server master key Kms. Thus, the encryption is broken and the content key Kc and RMPI are set to be usable.

  Next, as processing corresponding to the number 4, when the content reproduction is started, the renderer 36 makes a reproduction start permission request to the server type CAS module 33, and the ECM-Kc that first appears in the content stream is the server type CAS module. 33. At that time, the RMPI usage condition is determined by the server-type CAS module 33. If it can be used, the ECM-Kc is decrypted with Kc, and the scramble key Ks is output to the renderer 36.

  The renderer 36 uses the scramble key Ks to unscramble the AV stream packet from the storage medium 31 and reproduce it. Thereafter, every time the ECM-Kc is updated, this is input to the server-type CAS module 33 to determine whether or not RMPI is used, and if it is available, the scramble key Ks is output to the renderer 36. Unscramble and play (continue playback).

(5) Limited playback method for type 2 content Next, a limited playback method for type 2 content will be described. Type 2 content consists of a single program as a file group, broadcasted and transmitted as a storage-only service that cannot be viewed immediately upon reception, and received and stored as content by the receiver 2, and then subject to limited playback control. It is played with. Therefore, it is assumed that transmission by broadcast is sent over a time different from the reproduction time.

  As a service model of type 2 content, it is assumed that a program is basically stored in the storage medium 31 of the receiver 2 as content and is viewed on demand for a fee. As a method, two types of operation are assumed, that is, a flat-rate billing based on a monthly contract (flat-tier billing) and a method of charging individual contents (pay-per-use billing), and the limited playback method differs depending on the two types of billing methods.

  In the former flat-tier billing operation, the two-tier license model shown in FIG. 5 is considered suitable. The limited reproduction process in this case will be described. The numbers in FIG. 5 correspond to the order of this limited reproduction process.

  First, as a process corresponding to number 1 in FIG. 5, the viewer contracts an on-demand service for type 2 content that allows viewing of a plurality of contents on a monthly basis. The contract is assumed to be online by communication between the shop / payment server 11 (FIG. 1 and the like) and the receiver 2 or offline where the viewer contracts by telephone or the like. For the flat tier usage contract, the main license including the server type work key Kws corresponding to the scope and the usage condition GroupRMPI related to the entire contract is unique to the server type CAS module 33 of the receiver 2 used by the viewer. It is encrypted with the server type master key Kms and sent as EMM from the broadcast station 1 by broadcasting for a certain period. The viewer operates the receiver 2 so as to receive it, whereby the main license is input to the server-type CAS module 33 and is decrypted and held with the key Kms.

  Next, as a process corresponding to the number 2, the business operator creates contents to be broadcast in a specific time zone using the storage service as a file group to be stored in the receiver 2. For example, in the case of video content such as a movie, a file obtained by encrypting data obtained by multiplexing a video signal and an audio signal for two hours in the MPEG2-TS format with a content key Kc is generated. In the case of multimedia content, it is assumed that a plurality of files encrypted with the content key Kc are configured. In addition to the content body file group, a sublicense file in which information including the content key Kc and the content usage condition EachRMPI is encrypted with the server-type work key Kws corresponding to the flat tier contract (hereinafter referred to as ACI, as appropriate) Is also generated. All these files are broadcast from the broadcast station 1 as a broadcast stream in a data carousel system suitable for broadcasting the files. In the receiver 2, these files are extracted from the received storage service and stored on the storage medium 31. At this time, accumulation control is performed based on information included in the data carousel so that a file group is generated with a directory configuration designated on the accumulation medium 31.

  Next, as a process corresponding to the number 3, when the reproduction of the content stored in the storage medium 31 of the receiver 2 is activated, a sublicense (ACI) file is input to the server type CAS module 33, and the server type The sub-license is decrypted with the server-type work key Kws included in the main license held in the CAS module 33, and the ACI content key Kc and the RMPI obtained by merging the main license and sub-license are the server-type CAS module. 33 is set to a usable state.

  Next, as a process corresponding to the number 4, when the content reproduction is started, the renderer 36 makes a reproduction start permission request to the server CAS module 33, and at that time, the use condition determination by RMPI is performed in the server CAS module 33. If available, the content key Kc is transferred to the renderer 36. The renderer 36 sets this in the encryption / decryption device 32 (FIG. 2), reads the content main body file, and decrypts the encryption to reproduce the content.

  The latter pay-per-use billing of type 2 billing operation can be realized by the one-tier license model shown in FIG. The limited reproduction process in this case will be described. The numbers in FIG. 6 correspond to the order of this limited reproduction process.

  First, in response to the number 1 in FIG. 6, the business operator produces content broadcasted in a specific time zone using the storage-type service as a file group to be stored in the receiver 2. For example, in the case of video content such as a movie, a file obtained by encrypting data obtained by multiplexing a video signal and an audio signal for two hours in the MPEG2-TS format with a content key Kc is generated. In the case of multimedia content, it is assumed that a plurality of files encrypted with the content key Kc are generated. These files are broadcast as a broadcast stream by the data carousel method. The receiver 2 extracts these files from the received storage service and stores them on the storage medium 31. At this time, accumulation control is performed based on information included in the data carousel so that a file group is generated with a directory configuration designated on the accumulation medium 31.

  Next, as a process corresponding to the number 2, the viewer communicates with the shop / payment server 11 to perform a purchase operation in order to view the content stored in the storage medium 31. As a result, the shop / settlement server 11 performs settlement, and as a result, the license server 10 generates an individual license corresponding to this content for the receiver 2 of the corresponding viewer. The server-type CAS module 33 of the receiver 2 acquires and holds the generated individual license through secure communication with the license server 10 based on mutual authentication.

  Next, as a process corresponding to the number 3, when the reproduction of the content stored in the storage medium 31 is started, the encryption of the individual license held in the server type CAS module 33 is decrypted with the key Kms. The content key Kc and RMPI are set to be usable.

  Next, as processing corresponding to number 4, at the time of content playback, the renderer 36 makes a request for permission to start playback to the server type CAS module 33, and at that time, the server type CAS module 33 makes use condition determination by RMPI. If available, the content key Kc is transferred to the renderer 36. The renderer 36 sets this in the encryption / decryption device 32, reads the content main body file, and decrypts the encryption to reproduce the content.

(6) Limited Playback Method for Downloaded Content by Communication Next, a limited playback method for downloaded content by communication will be described. A file group constituting the content is downloaded to the receiver 2 from the content server 9 via the communication network 8, and the receiver 2 stores this as content in the storage medium 31, and then performs limited playback control. Basically, only the content transmission form is different, and a limited reproduction method similar to that of type 2 content in broadcasting can be applied.

  As a service model, it is assumed that the content is downloaded from the content server 9 and stored in the storage medium 31 so that it can be viewed on-demand for a fee. The operation form to be used automatically is also assumed. As with Type 2 content, two types of operation are envisaged as a billing method for viewers: flat-rate billing based on monthly contracts (flat tier billing) and billing for individual content (pay per-use billing). The appropriate limited playback method differs depending on the two types of billing methods.

  In the former flat tier billing operation, the two-tier license model shown in FIG. 7 is considered suitable. The limited reproduction process in this case will be described. The numbers in FIG. 7 correspond to the order of this limited reproduction process.

  First, as a process corresponding to number 1 in FIG. 7, the viewer contracts an on-demand service for downloading content that allows viewing of a plurality of contents on a monthly basis. It is assumed that the contract is made online by communication between the shop / payment server 11 (FIG. 1 and the like) and the receiver 2, and as a result, the license server 10 downloads to the receiver 2 of the corresponding viewer. A main license including a server type work key Kws corresponding to a content flat tier usage contract and a usage condition GroupRMPI related to the entire contract is generated. The server type CAS module 33 of the receiver 2 acquires and holds the generated main license through secure communication with the license server 10 based on mutual authentication.

  Next, as a process corresponding to the number 2, the business operator creates each content constituting the service as a file group to be accumulated in the receiver 2. For example, in the case of video content such as a movie, a file obtained by encrypting data obtained by multiplexing a video signal and an audio signal for two hours in the MPEG2-TS format with a content key Kc is generated. In the case of multimedia content, it is assumed that a plurality of files encrypted with the content key Kc are generated. In addition to the content body file group, a sublicense file (hereinafter referred to as ACI, as appropriate) is obtained by encrypting information including the content key Kc and the content usage condition EachRMPI with a server type work key Kws corresponding to the flat tier contract. ) Is also generated. All these files are placed on the content server 9.

  The viewer connects the receiver 2 to the shop / settlement server 11, selects content included in the contract, and performs a download instruction operation, whereby the receiver 2 stores the content file group on the content server 9. They are accessed, downloaded in order, and stored in the storage medium 31 of the receiver 2.

  Next, as processing corresponding to the number 3, at the time of starting playback of the content stored in the storage medium 31 of the receiver 2, a sublicense (ACI) file is input to the server type CAS module 33, and the server type CAS The sub-license is decrypted with the server-type work key Kws included in the main license held in the module 33 and the content key Kc and the RMPI obtained by merging the main license and the sub-license are stored in the server-type CAS module 33. Set to available state.

  Next, as processing corresponding to the number 4, when the content is played back, the renderer 36 makes a playback start permission request to the server type CAS module 33, and at that time, the use type determination by RMPI is performed in the server type CAS module 33. If available, the content key Kc is transferred to the renderer 36. The renderer 36 sets this in the encryption / decryption device 32 (FIG. 2), reads the file of the content body, and reproduces the content by decrypting the encryption.

  The latter pay-per-use billing for content download billing by communication can be realized by the one-tier license model shown in FIG. The limited reproduction process in this case will be described. The numbers in FIG. 8 correspond to the order of this limited reproduction process.

  First, as a process of number 1 in FIG. 8, the business operator creates contents for download service as a file group to be stored in the receiver 2. For example, in the case of video content such as a movie, a file obtained by encrypting data obtained by multiplexing a video signal and an audio signal for two hours in the MPEG2-TS format with a content key Kc is generated. In the case of multimedia content, it is assumed that a plurality of files encrypted with the content key Kc are generated. All these files are placed on the content server 9. The viewer connects the receiver 2 to the shop / settlement server 11, selects specific content, and performs a download instruction operation, so that the receiver 2 accesses a file group of content on the content server 9. These are downloaded in order and stored in the storage medium 31.

  Next, as a process corresponding to the number 2, the viewer communicates with the shop / payment server 11 and performs a purchase operation in order to view the content stored in the storage medium 31 of the receiver 2. As a result, the shop / settlement server 11 performs settlement, and as a result, the license server 10 generates an individual license corresponding to this content for the receiver 2 of the corresponding viewer. The server-type CAS module 33 of the receiver 2 acquires and holds the generated individual license through secure communication with the license server 10 based on mutual authentication.

  Next, as a process corresponding to the number 3, the content key Kc and the RMPI included in the individual license in the server type CAS module 33 can be used when the content stored in the storage medium 31 is activated. Set to

  Next, as processing corresponding to the number 4, when the content is played back, the renderer 36 makes a playback start permission request to the server type CAS module 33, and at that time, the use type determination by RMPI is performed in the server type CAS module 33. If available, the content key Kc is transferred to the renderer 36. The renderer 36 sets this in the encryption / decryption device 32, reads the content main body file, and decrypts the encryption to reproduce the content.

(7) Limited playback processing in streaming content by communication Finally, limited playback processing in streaming content by communication will be described. Content is streamed from the content server 9 via the communication network 8, and playback control limited to when the content is received and played back in real time is performed. In this case, storage in the storage medium 31 of the receiver 2 is not assumed, but type 2 content and download content stored on the storage medium 31 are stored in the content server 9 on the communication network 8 and reproduced from the storage medium 31. However, if it is assumed that the content is reproduced from the external content server 9, the limited reproduction process similar to the type 2 content or download in broadcasting can be applied. As a service model, it is assumed that the content is directly viewed on demand from the content server 9 for a fee, but this is also a flat-rate billing based on a monthly contract as a billing method for the viewer as with type 2 content. Two types of operation are assumed, namely (flat tier charging) and a method of charging contents individually (pay-per-use charging), and an appropriate limited reproduction method is different from the charging method.

  In the former flat tier billing operation, the two-tier license model shown in FIG. 9 is considered suitable. The limited reproduction process in this case will be described. The numbers in FIG. 9 correspond to the order of this limited reproduction process.

  First, as processing corresponding to number 1 in FIG. 9, the viewer contracts an on-demand service that allows viewing of a plurality of contents on a monthly basis. Although it is assumed that the contract is made online by communication between the shop / payment server 11 and the receiver 2, as a result, the license server 10 sends a flat tier of download content to the receiver 2 of the corresponding viewer. A main license is generated that includes the server-type work key Kws corresponding to the usage contract and the usage conditions GroupRMPI related to the entire contract. The server type CAS module 33 of the receiver 2 acquires and holds the generated main license through secure communication with the license server 10 based on mutual authentication.

  Next, as the processing of number 2, the business operator produces each content for streaming constituting the service. For example, in the case of video content such as a movie, a file obtained by encrypting data obtained by multiplexing a video signal and an audio signal for two hours in the MPEG2-TS format with a content key Kc is generated. In the case of multimedia content, it is assumed that a plurality of files encrypted with the content key Kc are generated. In addition to the content body file group, a sublicense file (hereinafter referred to as ACI, as appropriate) is encrypted with the server key work key Kws corresponding to the flat tier contract and the information including the content key Kc and the usage condition of this content. Is also generated. All these files are placed on the content server 9.

  The viewer connects the receiver 2 to the shop / payment server 11, selects the content included in the contract, and operates the playback instruction to start streaming the content. The receiver 2 first acquires the ACI from the content server 9 and inputs it to the server-type CAS module 33, and decrypts the sub-license with the server-type work key Kws included in the held main license. The key Kc and the RMPI obtained by merging the main license and the sublicense are set to be usable in the server type CAS module 33.

  Next, as processing corresponding to number 3, when the content main body starts streaming, the renderer 36 requests the server type CAS module 33 to start reproduction, and at that time, the server type CAS module 33 uses the RMPI to determine the use condition. If it can be used, the content key Kc is transferred to the renderer 36. The renderer 36 sets this in the encryption / decryption device 32. The receiver 2 accesses the content body on the content server 9 and starts streaming. The receiver 2 sequentially receives the streaming, transfers it to the renderer 36, decrypts the encryption of the content, and reproduces the content.

  The latter pay-per-use billing for content streaming billing by communication can be realized by the one-tier license model shown in FIG. The limited reproduction process in this case will be described. The numbers in FIG. 10 correspond to the order of this limited reproduction process.

  First, as a process corresponding to number 1 in FIG. 10, the viewer communicates with the shop / payment server 11 to select the content and perform a purchase operation in order to view the on-demand content. As a result, the shop / settlement server 11 performs settlement, and as a result, the license server 10 generates an individual license corresponding to this content for the receiver 2 of the corresponding viewer. The server-type CAS module 33 of the receiver 2 acquires and holds the generated individual license through secure communication with the license server 10 based on mutual authentication.

  Next, as a process corresponding to number 2, the business operator produces each content for streaming that constitutes the service. For example, in the case of video content such as a movie, a file obtained by encrypting data obtained by multiplexing a video signal and an audio signal for two hours in the MPEG2-TS format with a content key Kc is generated. In the case of multimedia content, it is assumed that a plurality of files encrypted with the content key Kc are generated. All these files are placed on the content server 9. The viewer performs a reproduction instruction operation in the shop / payment server 11 following the purchase operation in the process of number 1. At this point, the content key Kc and RMPI included in the individual license in the server-type CAS module 33 are set in a usable state.

  Next, as processing corresponding to number 3, when the content main body starts streaming, the renderer 36 requests the server type CAS module 33 to start reproduction, and at that time, the server type CAS module 33 uses the RMPI to determine the use condition. If it can be used, the content key Kc is transferred to the renderer 36. The renderer 36 sets this in the encryption / decryption device 32. The receiver 2 accesses the content body on the content server 9 and starts streaming. The receiver 2 sequentially receives the streaming, transfers it to the renderer 36, decrypts the encryption of the content, and reproduces the content.

(8) Realization of security in license acquisition by communication In the limited playback process described above, a license is acquired by communication in the case of a one-layer license or communication content. It is necessary to fully consider the protection of In the present invention, in order to efficiently cope with both license acquisition from broadcasting and license acquisition from communication in one server-type CAS module 33, the source of security of EMM transmission of broadcasting is also used in license acquisition in communication. The server type master key Kms unique to the server type CAS module 33 is used. The key Kms is centrally managed by the Kms management server 13 that is firmly protected, and secure communication is realized between the server-type CAS module 33 of the receiver 2 and the license server 10 based on this key Kms by the following method. To do. This process will be described with reference to FIG.

  When the server-type CAS module 33 of the receiver 2 tries to acquire a license from a specific license server 10, the server-type CAS module 33 first connects to the license server 10 of the designated URL (S1). The client ID embedded in the server type CAS module 33 is sent (S2).

  The license server 10 temporarily stores the sent client ID and then sends its own server ID (S3). Then, the server type CAS module 33 confirms whether or not the SAC key Ksac corresponding to the server ID from the license server 10 is held (S4). If the SAC key Ksac is not held, the server type CAS module 33 issues a license request for obtaining the SAC key Ksac. The data is sent to the server 10 (S5).

  The license server 10 generates the SAC key Ksac corresponding to the client ID (S6), and transfers the client ID (S1) sent thereto to the Kms management server 13 (S7).

  The kms management server 13 associates the client ID transmitted from the license server 10 with the server type master key Kms (S8), encrypts the SAC key Ksac with the server type master key Kms associated with the client ID, Is transmitted to the license server 10 (S9).

  The license server 10 transfers the SAC key Ksac encrypted with the server type master key Kms transmitted from the Kms management server 13 to the server type CAS module 33 of the receiver 2 (S10).

  The server type CAS module 33 of the receiver 2 holds the SAC key Ksac encrypted with the server type master key Kms transferred from the license server 10 in association with the server ID (Ksac is held in S4). (S11). The server type CAS module 33 also generates a random number Rb (S12) and transfers it to the license server 10 (S13).

  The license server 10 generates a random number Ra (S14), encrypts the pair of the random number Ra and the random number Rb with the key Ksac, and transfers this to the server type CAS module 33 of the receiver 2 (S15). The server-type CAS module 33 of the receiver 2 decrypts the cipher with the same key Ksac, verifies whether Ra sent by itself is correct, and if it is correct, generates a random number Text (S16), and generates a random number Ra, a random number Rb. And the random number Text are encrypted with the key Ksac and transferred to the license server 10 (S17).

  The license server 10 decrypts the cipher with the key Ksac and verifies whether the Rb sent by the license server 10 is correct (S18). After that, the server type CAS module 33 and the license server 10 send a message using the random number Text as the session key. Encrypt and communicate.

  With the secure communication path secured in this way, the server-type CAS module 33 of the receiver 2 requests the license server 10 to acquire a specific license. Is transferred to the type CAS module 33.

(9) Domain registration and domain control Although the concept of domain has been introduced in server-type broadcasting, as described above, one domain basically corresponds to one household, and the receiver 2 in the same domain requires a license. Can be shared. In FIG. 1, since the receiver 2-1 and the receiver 2-2 belong to the same domain A, when the receiver 2-1 purchases content or makes a service contract, the receiver 2-1 acquires it. The same license can also be obtained by the receiver 2-2. On the other hand, since the receiver 2-3 belongs to another domain B, the licenses of the receivers 2-1 and 2-2 cannot be acquired.

  In order to enable such operation, the viewer needs to register the receiver 2 that he / she owns. Therefore, the viewer performs domain registration when the receiver 2 is held. Domain registration is performed with respect to the domain management server 12 (FIG. 1). Although it is assumed that the receiver 2 connects to the domain management server 12 and performs online domain registration, it is also possible to perform an operation in which the viewer communicates by telephone or postcard offline.

  Here, information to be transmitted at the time of registration is minimum personal information (for example, name, address, telephone number, etc.) of the viewer and ID information corresponding to the server type CAS module 33. The domain management server 12 manages the link between personal information and receiver information. At the time of content purchase or service contract, the license server 10 or the broadcasting station 1 accesses the domain management server 12 and issues a license to all receivers 2 corresponding to a specific individual.

  In the domain concept, there is a case where not only a range as a usage right, that is, a license sharing range but also a limitation of the sharing range of the content body is required. In a flat tier contract, a license to use content comprehensively is issued, but if the same contract is accidentally concluded in multiple domains (homes) and the same main license is held, content including sub-licenses Is copied from the storage medium 31 of the receiver 2 to the storage medium 31 of another receiver 2 between the domains, the reproduction can be performed by the limited reproduction described so far. In particular, in the case of type 1 content applied to free broadcasting, since it is assumed that everyone holds the same main license, it is impossible to perform actual copy control, and proper operation cannot be performed. This is also true for paid flat tier billing. Therefore, in the flat tier operation, it is necessary to keep the content movement within the domain.

  In the case of pay-per-use billing, the content can be viewed by purchasing the target content and acquiring a one-tier license. In this case, there is no problem even if the content moves beyond the domain.

  In order to perform such domain control, the following processing can be incorporated in addition to the limited playback processing described above.

(A) At the time of domain registration, the domain management server 12 issues a domain key Kd to the domain and manages it in association with the domain. At the same time, the domain management server 12 securely transfers this domain key Kd to the server-type CAS module 33 of the target receiver 2 by broadcasting or communication. Here, when the domain key Kd is transmitted by broadcasting, it is transmitted from the broadcasting station 1 as the domain key distribution EMM 41 in which the domain key Kd is encrypted with the server type master key Kms40 unique to each server type CAS client in FIG. . When the domain key Kd is sent by communication, mutual authentication and concealment based on the key Kms is performed between the domain management server 12 and the server type CAS module 33 in the same manner as the secure communication method at the time of license acquisition described in (8). The domain key Kd is sent securely by the means. In either case, the server type CAS module 33 holds the acquired domain key Kd semi-permanently. However, when it is discovered that the domain key Kd has been illegally used by others by some unauthorized means, the domain management server 12 updates the target domain key Kd and responds again with the above means. The domain key Kd is transferred to the server-type CAS module 33 of all receivers 2 in the domain, and each server-type CAS module 33 updates the held domain key Kd.

(B) On the premise that the domain key is held in the server-type CAS module 33, the limited reproduction process for type 1 content in the case of a flat tier contract will be described. The main license 42 of FIG. 12 is transmitted by broadcast EMM or the like, and the receiver 2 holds it in the server-type CAS module 33 (in the case of EMM, it is decrypted and held by the key Kms). When TS 43 is received as type 1 content by receiver 2, Kc distribution ECM 44 is extracted from the TS 43, and is input once to server-type CAS module 33 and encrypted with domain key Kd 41 held here. It is taken out above and stored in the storage medium 31 together with other data of the TS 43 in the form of a sub-license 45 at the time of storage.

  When reproducing type 1 content, the storage sublicense 45 is first input to the server-type CAS module 33 again, first decrypted with the domain key Kd41 in the server-type CAS module 33, and then the server type included in the main license. By decrypting with the work key Kws, a naked sublicense is taken out, and the content key Kc and RMPI included therein are extracted and can be used.

  The receiver 2 sequentially reads the TS43 file on the storage medium 31 from the top, but extracts and inputs it to the server-type CAS module 33 every time ECM-Kc is updated. For example, when the ECM-Kc 46 is input to the server-type CAS module 33, the RMPI usage condition is determined at that time. If the ECM-Kc 46 is available, the scramble key Ks1 that is included after the ECM-Kc is decrypted with the Kc is rendered. It is output to 36 descramblers 25. Then, the descrambling of the subsequent video / audio packet 49 is executed, and this portion is reproduced. Furthermore, if an update to the ECM-Kc 47 is detected during this playback, this is processed in the server-type CAS module 33 in the same manner as described above, and if available, a new scramble key Ks2 is set in the descrambler. The video / audio packet 50 is descrambled and the video / audio packet 50 is continuously reproduced from the video / audio packet 49.

(C) On the premise that the domain key Kd is held in the server-type CAS module 33, the limited reproduction process for type 2 content in the case of a flat tier contract will be described with reference to FIG. The main license 60 is transmitted by broadcast EMM or the like, and is held in the server-type CAS module 33 in the receiver 2 (in the case of EMM, it is decrypted and held by the key Kms). When the type 2 content is received by the receiver 2, the ACI file 61 is temporarily input to the server type CAS module 33, extracted after being encrypted with the domain key Kd41 held therein, and stored. The sublicense 62 is stored in the storage medium 31 together with the files of the content body 63 and the like.

  At the time of type 2 content playback, the storage sub-license 62 is first input to the server-type CAS module 33 again, first decrypted with the domain key Kd41 in the server-type CAS module 33, and then the server-type work included in the main license. By decrypting with the key Kws, a naked sublicense is extracted, and the content key Kc and RMPI included therein are extracted and made available. The receiver 2 issues a reproduction permission request to the server type CAS module 33 at the start of reproduction of the file of the content main body 63. The server type CAS module 33 makes a use condition determination based on RMPI, and if usable, the content key Kc is rendered. It is output to 36 encryption / decryption devices 32. Thereafter, when the data in the content body 63 is decrypted by the encryption / decryption device 32, the content is reproduced.

(D) Consider a case in which a file group of content including a sublicense is copied to another receiver 2 when the content is stored in the type 1 content and the type 2 content. If the receiver 2 is in the same domain, it can be decrypted with the same domain key Kd in the server-type CAS module 33 at the time of reproduction. Therefore, as long as the main license has already been acquired, as described in (b) and (c) It can be played in a simple flow. If copied to the receiver 2 in a different domain, the sublicense cannot be decrypted because the domain key Kd is different in the server type CAS module 33 at the time of playback, and even if the same main license has already been acquired as a result Cannot be played. In this way, the above domain control is realized.

(10) Domain control in the operator domain The domain described in (9) is basically assumed to be one household, but apart from this, a domain set by a service operator in a wider range is considered. Yes.

  One objective is to allow specific content (eg, educational content) of a specific broadcaster to be shared by a wider community (eg, school and student homes) than the home. In this case, for example, the educational content contracted at the school and accumulated in the school receiver 2 can be used at the home of each student through the network.

  In order to realize the above services, the concept of business domain is introduced. FIG. 14 shows a conceptual diagram thereof.

  Each service provider registers one provider domain for a specific purpose. It is assumed that there are a plurality of such operator domains.

  Each viewer who owns the receiver 2 registers the receiver 2 in the corresponding provider domain under a contract with a specific provider. Each viewer registers his / her receiver 2 in a domain for each home (hereinafter referred to as a private domain).

  In the example of FIG. 14, the receiver 2-11 belongs only to the private domain I, the receiver 2-12 belongs to the private domain C and the operator domain of the operator A, and the receiver 2-13 is the private domain D. It also belongs to the respective operator domains of the operator A and the operator B.

  Belonging to both the provider domain and the private domain means that the domain ID and domain key Kd of the provider domain can also be obtained from broadcasting or communication, and can be held in the server type CAS client of the receiver 2. That is, the receiver 2 performs domain sharing control of the provider domain and the private domain by using information of a plurality of domain IDs and domain keys Kd held in the server type CAS client. How the provider domain sharing control in one service example is realized will be described with reference to FIG.

  FIG. 15 shows the domain control method including the operator domain, but in this case, basically, the same as the limited playback processing in the type 2 content in the case of the flat tier contract shown in FIG. Processing is performed.

  It is assumed that the receiver 2 is registered in the two operator domains of the operator A and the operator B and is also registered in its own private domain. As a result, the server type CAS client of the receiver 2 holds the set 41, 64, 65 of three domain IDs and domain keys Kd.

  Here, it is assumed that the specific content of the business operator A is transmitted on the assumption that the business domain of the business operator A is shared. In the content designated as the sharing target, it is assumed that the domain ID of the operator domain is added as information outside the sublicense in the ECM for Kc distribution for the type 1 content and in the ACI for the type 2 content. Since FIG. 15 shows the case of type 2 content, a domain ID is added to the ACI 61.

  When receiving the ACI 61 (in the case of type 1 content, ECM for Kc distribution), the receiver 2 inputs these to the server type CAS client. When a specific domain ID is specified in the ACI 61, the server type CAS client has a corresponding domain key if the selector 66 has a matching domain ID in the domain key Kd and the domain ID held by the selector 66. Encrypts the sublicense entered by Kd and outputs it. The receiver 2 stores this together with the content body in the storage medium 31 as a sub-license 62 during storage.

  At the time of content reproduction, the receiver 2 inputs the sub-license 62 at the time of storage to the CAS client, and performs encryption / decryption with the domain key Kd corresponding to the domain ID added to the sub-license 62 at the time of storage as described above. Take out the license. Furthermore, if the main license 60 is acquired, reproduction is possible.

  Since the domain key Kd corresponding to the domain ID specified here is the domain key Kd of the operator domain, the stored content is transferred to another receiver 2 belonging to the same operator domain and played. In this case, since the sublicense can be restored with the same domain key Kd, it can be reproduced.

  If the ACI 61 (or ECM for Kc distribution) does not specify the operator domain and the server type CAS client holds multiple domain IDs and domain keys Kd, or if the operator domain is specified If there is no domain key Kd for the provider domain, the sublicense is encrypted with the domain key Kd for the private domain. In this case, only the receiver 2 in the home can be shared.

(11) Integrated Server Type CAS System and Integrated Server Type CAS Module FIG. 16 shows an integrated server type CAS system that realizes the limited playback processing of various contents described so far with one server type module.

  The square frame number 1 and number 4 are ECM and EMM for limited broadcast reception, respectively, which are independent of other server-type CAS-related data as distribution routes. In the cage receiver 2, processing is performed by the B-CAS card 24 independent of the server type CAS module 33.

  The domain key Kd is distributed regardless of the content type. When the domain key Kd is distributed by broadcasting, it is transmitted as EMM (Kd) through the route of number 6, encrypted at the broadcasting station 1 side with the key Kms at symbol E6, and on the receiver 2 side, the server type CAS module 33 Thus, the symbol D6 is decrypted with the key Kms and held as the domain key Kd. When the domain key Kd is distributed by communication, the domain key Kd is transferred through a secure communication path based on the key Kms of both the license server 10 and the server type CAS client via the path number 9 and the server type CAS module 33. Stored as a domain key Kd.

  In the distribution of the main license of the two-tier license, it can be handled without distinction between content types such as type 1 content and type 2 content. In broadcasting, it is transmitted as EMM (Kws) on the route of number 5, encrypted on the broadcast station 1 side with the key Kms at symbol E5, and on the receiver 2 side, decrypted with the key Kms at symbol D5 by the server type CAS module 33. Held as the main license. When the main license is distributed by communication, it is transferred through a secure communication path based on the key Kms of both the license server 10 and the server type CAS client through the route number 8 and is held as the main license in the server type CAS module 33. .

  Also, distribution of individual licenses of one-tier licenses can be handled without distinction between content types. It is transferred through a secure communication path based on the key Kms of both the license server 10 and the server type CAS client through the path of number 7, and is held as an individual license in the server type CAS module 33. The individual license specified at the time of reproducing the content is set in a state where it can be used as a usage license.

  The sublicense is a path of number 3 in the figure, and is common in the processing that the information including the content key Kc is encrypted with the key Kws in the symbol E3 on the provider system side, but in the type 1 content, Kc The distribution ECM and other contents are broadcast as an ACI file or transmitted through a communication path, so the paths are various. However, after being acquired by the receiver 2, the following processing is common.

  When the sublicense is input to the server type CAS module 33, it is encrypted with the domain key Kd at the symbol E7 and is output. When it is input to the server-type CAS module 33 at the time of reproduction again, the domain key Kd is decrypted with the symbol D7 and further decrypted with the key Kws of the main license with the symbol D3, and the contained content key Kc and RMPI can be used as a usage license. Is set to the correct state.

  As data specific to type 1 content, the ECM-Kc transmits a frequently updated scramble key Ks as data encrypted with the key Kc at the symbol E2 as a packet in the type 1 content. If it is stored in the storage medium 31 as part of the type 1 content as it is in the receiver 2, it is input to the server-type CAS module 33 at the time of playback and can be used in the usage determination based on the RMPI of the usage license. The symbol K2 is decrypted with the key Kc and the key Ks is output and set in the descrambler 23.

  In the case of type 2 content, download content, etc., the usage determination of the usage license in the server type CAS module is performed at the start of playback, and if it can be used, the content key Kc is output and the content is decrypted. Is called.

  The effects of the system shown in FIG. 1 are summarized as follows.

  A limited playback system and a server-type CAS module that can handle not only broadcast content distribution but also communication downloaded content and streaming content can be realized. This also makes it possible to perform hybrid charging operations for various content distribution forms.

  It is possible to realize a server-type CAS module in the receiver that enables an efficient operation system and efficient processing integrated for various content distribution forms.

  An independent operation system and server-type CAS module can be realized with various conditional access systems for digital broadcasting currently in operation. As a result, the server-type broadcast service can be applied to various digital broadcast systems.

  The service requirement that content can be shared by multiple receivers in the home, while the content is copied to receivers outside the home, even if the same viewing contract is made, is satisfied. It is a method.

  A series of processing such as the feature word extraction processing described above can be executed by dedicated hardware or can be executed by software.

  In the present specification, the steps described in the flowcharts are executed in parallel or individually even if they are not necessarily processed in time series, as well as processes performed in time series in the described order. It also includes processing.

Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

It is a figure which shows the structural example of the server type | mold broadcast system to which this invention is applied. It is a block diagram which shows the structural example of the receiver 2 of FIG. It is a figure explaining limited reproduction processing. It is a figure explaining other limited reproduction processes. It is a figure explaining other limited reproduction processes. It is a figure explaining other limited reproduction processes. It is a figure explaining other limited reproduction processes. It is a figure explaining other limited reproduction processes. It is a figure explaining other limited reproduction processes. It is a figure explaining other limited reproduction processes. It is a timing chart explaining a mutual authentication process. It is a figure explaining a domain control process. It is a figure explaining other domain control processing. It is a figure explaining a provider domain. It is a figure explaining other domain control processing. It is a figure which shows the data path | route of the comprehensive server type CAS system to which this invention is applied.

Explanation of symbols

1 broadcast station 2 receiver 9 content server 10 license server
11 shop / payment server, 12 domain management server, 31 storage media,
33 server type CAS module, 36 renderer

Claims (7)

A distribution device for distributing content by broadcast or communication;
A receiving device that receives the content, and in some cases, stores the content in a storage medium and then plays the content only when the usage right is held and the usage conditions are satisfied;
A group management device for grouping the receiving devices and managing the group information and generating and managing a unique key for each group in order to allow only the receiving devices in the same group to be used;
A key management device for managing a key unique to each of the receiving devices;
A distribution system comprising: a transmission device that encrypts a group-specific key with a key specific to the reception device and transmits the encrypted key as group key information by broadcast waves;
The group management device
The distribution system, wherein the key unique to the group is transferred by communicating with the receiving device based on the key unique to the receiver. The receiving device is:
The distribution system according to claim 1, further comprising means for receiving the broadcast or decoding the group key information with a key unique to the receiver and extracting and holding the group key. The receiving device is:
Means for acquiring and holding a main license including a work key indicating the existence of a right to use a plurality of contents from broadcasting or communication;
Means for receiving, from a broadcast or communication channel, a content encrypted with a content key, and a sublicense obtained by encrypting information including the content key and content usage condition information with the work key;
Means for encrypting the sublicense with the group key;
Means for storing a sublicense encrypted with the group key in a storage device;
Means for decrypting the sublicense encrypted with the group key with a group key, further decrypting with the work key, and extracting information including a content key and content usage condition information;
Means for determining the content usage condition information when using the content and outputting the content key only when the condition is satisfied;
Means for decrypting the content encryption with the content key;
If the content is encrypted with a key for each part, means for receiving and storing information obtained by encrypting the key for each part with the content key together with the content;
Means for decrypting the information obtained by encrypting the key for each part with a content key with the content key output from the means for outputting the content key during reproduction;
The distribution system according to claim 1, further comprising: means for decrypting the content with a key for each part. A distribution device for distributing content by broadcast or communication;
In a distribution system comprising a receiving device that receives the content, and in some cases, stores the content in a storage medium, and plays back the content only when the usage right is held and the usage conditions are satisfied,
The receiving device is:
Means for receiving a broadcast signal including an EMM obtained by encrypting a main license including a work key indicating the existence of a right to use a plurality of contents with a key unique to the receiving device;
Means for decrypting the received EMM with the key unique to the receiving device and extracting the main license;
Communication means for communicating with a device on a communication network and performing settings for mutual authentication and communication data concealment based on a key unique to the receiving device held by both the receiving device and a device on a specific communication network When,
Means for receiving and retrieving a main license including a work key indicating the presence of a right to use the plurality of contents transmitted through the communication means;
A distribution system comprising: means for holding a main license. The receiving device is:
A device on a specific communication network holding a key unique to the receiving device and the receiving device when communicating with a device on a communication network holding a main license including a work key indicating the existence of a right to use a plurality of contents Based on the key unique to the receiving device held by both, the setting for mutual authentication and communication data concealment is performed, and the main license is transmitted from the device on the communication network to the receiver via the communication network. The distribution system according to claim 4, wherein both of the license transmission methods are used. The distribution system according to claim 2, wherein the receiving device belongs to a plurality of receiving device groups, and acquires and holds the plurality of group keys. The receiving device is:
Means for belonging to a plurality of receiver groups and obtaining and holding the plurality of group keys;
Means for receiving information identifying a specific group key together with the sublicense from broadcast or communication;
Means for selecting one of the held group keys from the received information identifying the group key;
Means for encrypting a sublicense with the selected group key;
The distribution system according to claim 3, further comprising: means for encrypting and decrypting the encrypted sublicense with the selected group key.

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