JP2006203505A - Content distributing system, server, user terminal and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce load of a distribution server in a content distribution system where an animation or the like is distributed. <P>SOLUTION: When a distribution request of a content such as the animation is supplied to the distribution server 110 from one of user terminals 120 to 190, decoding key data for decoding ciphered content data is supplied to the user terminal from the distribution server 110, and a site list where other user terminals which previously down-load enciphered content data are listed is supplied. Content data is transmitted/received between the user terminals based on the site list. Thus, load of the distribution server 110 is reduced. A charging amount is discounted on the user terminal transmitting content data to the other user terminal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a content distribution system, a server, a user terminal, and a program suitable for use in distributing video and audio content.

  2. Description of the Related Art In recent years, content distribution systems that distribute video or audio content that a user wants to view via an IP network such as the Internet are known. Such a content distribution system has been realized by a one-to-many connection between a distribution server that mainly distributes content and a large number of user terminals that receive the content. However, for example, when distribution of content related to a popular movie becomes possible, distribution of the content may be requested from a huge number of user terminals in a short time, and the distribution server is overloaded. There was a problem. Patent Document 1 discloses a technique for providing a plurality of distribution servers and a server management unit that distributes distribution requests from user terminals to these distribution servers to prevent an overload state of the distribution servers.

  Patent Document 2 discloses a client / server processing system. Here, when there is a request from a certain client to execute a certain service from a certain client, it is determined whether or not there is room in the server for executing this service. If there is no room for resources, the requesting client is notified of the IP addresses of other clients that can execute the service. As a result, services can be provided between client computers. For this reason, a database listing services that can be provided by each client is stored in the server.

Japanese Patent Laid-Open No. 11-150723 JP 2001-337937 A

However, the technique described in Patent Document 1 has a problem that the service provider needs to prepare a large number of distribution servers corresponding to the load at the peak time, resulting in a large capital investment.
The technique of Patent Document 2 is executable because there is a high trust relationship between the server and the client in the network, and the server knows the state of each client. However, particularly in a content distribution system in which a general consumer owns a user terminal or borrows it from a service provider, the downloaded content may be deleted according to the convenience of each user. It is not even guaranteed that the power is on. For this reason, it was not feasible to completely delegate the function of the distribution server to the user terminal.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a content distribution system, a server, a user terminal, and a program that can reduce the processing load of the server with a low capital investment.

In order to solve the above problems, the present invention is characterized by having the following configuration. The parentheses are examples.
The content distribution system according to claim 1, comprising at least one server and a plurality of user terminals that communicate with each other via a network, wherein the servers respond to requests from the user terminals. In a content distribution system that enables the use of content in a terminal, when the server receives a distribution request designating specific content from any of the user terminals, the user terminal that has transmitted the distribution request, Decryption key data supply means (20, 18, SP74) for supplying decryption key data for decrypting encrypted encrypted content data, and information for specifying other user terminals that can supply the encrypted content data Site list transmission that supplies the site list that is enumerated to the user terminal that has transmitted the distribution request. Stage (20, 18, SP84), and each user terminal sends a delivery request to the server based on a user's operation for selecting the desired content to be provided (50, 48, SP2), download request means (50, 48, SP8) for requesting download of the encrypted content data to any of the other user terminals listed in the site list, and other user terminals An encrypted content data supply means (50, 48, SP34, SP40, SP42) for supplying the encrypted content data to the other user terminal when receiving the download request of the encrypted content data from It is characterized by having.
Furthermore, in the configuration according to claim 2, in the content distribution system according to claim 1, the server applies the upload target to at least some of the target user terminals of the plurality of user terminals. Regardless of whether or not a distribution request is received from the user terminal, it further comprises upload means (20, 18, SP54) for uploading the encrypted content data, and the site list transmitting means is adapted to specify the distribution request. The site list is generated by enumerating information for identifying upload target user terminals that have uploaded encrypted content data of the content.
Furthermore, in the configuration according to claim 3, in the content distribution system according to claim 2, the server includes a first user whose upload means (20, 18, SP54) is included in the upload target user terminal. After uploading the encrypted content data to the terminal, a pre-delivery site list including information for identifying the first user terminal with respect to another second user terminal included in the upload target user terminal And when each of the upload target user terminals receives the pre-delivery site list, the other user listed in the pre-delivery site list Pre-delivery download request means for requesting download of the encrypted content data to any of the terminals Characterized in that it has a modification (1)).
Furthermore, in the configuration according to claim 4, in the content distribution system according to claim 1, the server performs charging processing for each of the user terminals, and It further comprises discount means (20, 18, SP42) for discounting the billing amount to the user terminal that has supplied the encrypted content data.
The server (110) according to claim 5 is connected to a plurality of user terminals via a network, and can use contents in each user terminal in response to a request from each user terminal. And a server for decrypting the encrypted content data encrypted with respect to the user terminal that has transmitted the distribution request upon receiving a distribution request designating specific content from any of the user terminals. A site list formed by listing decryption key data supply means (20, 18, SP74) for supplying the decryption key data and information specifying other user terminals that can supply the encrypted content data is sent to the distribution request. It has site list transmission means (20, 18, SP84) to be supplied to the transmitted user terminal.
The user terminal according to claim 6 includes at least one server and a plurality of user terminals that communicate with each other via a network, and the server responds to a request from each user terminal. Distribution request transmission means for transmitting a distribution request to the server based on a user's operation of selecting content to be provided in one user terminal used in a content distribution system that enables the use of the content in the user terminal (50, 48, SP2), decryption key data receiving means (50, 48, SP4) for receiving, from the server, decryption key data for decrypting encrypted content data obtained by encrypting the content, A site list receiver that receives from the server a site list that lists information for identifying user terminals. (50, 48, SP7), download request means (50, 48, SP8) for requesting download of the encrypted content data to any of the other user terminals listed in the site list, and others Encrypted content data supply means (50, 48, SP34, SP40, etc.) for supplying the encrypted content data to the other user terminal when a request for downloading the encrypted content data is received from the user terminal SP42).
The program according to claim 7 is a server connected to a plurality of user terminals via a network and enabling use of contents in each user terminal in response to a request from each user terminal. A program to be executed, wherein the server receives a distribution request designating specific content from any of the user terminals (SP72); and the user terminal from which the server has transmitted the distribution request On the other hand, a decryption key data supply process (SP74) for supplying decryption key data for decrypting the encrypted content data encrypted, and another user terminal to which the server can supply the encrypted content data A site list transmission list for supplying a site list that lists information to be identified to the user terminal that has transmitted the distribution request. It characterized by having a (SP 84) and.
The program according to claim 8 includes at least one server and a plurality of user terminals that communicate with each other via a network, and the server responds to a request from each user terminal. In a program executed in one user terminal used in a content distribution system that enables use of content in a terminal, the one user terminal selects the content to be provided based on a user's operation. A distribution request transmission process (SP2) for transmitting a distribution request to the server, and a decryption key data received by the one user terminal for decrypting encrypted content data obtained by encrypting the content from the server Key data reception process (SP4), and the one user terminal displays information specifying another user terminal The site list reception process (SP7) for receiving the site list formed from the server and the one user terminal with respect to any of the other user terminals listed in the site list, the encrypted content Download request process (SP8) for requesting data download, and when the one user terminal receives a request for downloading the encrypted content data from another user terminal, the other user terminal And an encrypted content data supply process (SP40, SP42) for supplying encrypted content data.

  As described above, in the present invention, the server supplies the decryption key data to the user terminal that has transmitted the distribution request, and lists information specifying other user terminals that can supply the encrypted content data. Since the site list is supplied to the user terminal, the user terminal can download the encrypted content data from another user terminal. Thereby, compared with the case where a server transmits encryption content data directly with respect to each user terminal, the processing load of a server can be reduced significantly.

1． Hardware Configuration of Embodiment Next, the configuration of a content distribution system according to an embodiment of the present invention will be described with reference to FIG.
In the figure, reference numeral 100 denotes an IP network, which may be either the Internet or a private network. A distribution server 110 and a plurality of user terminals 120, 130,..., 190 are connected to the IP network 100. In the distribution server 110, reference numeral 2 denotes a hard disk, which stores an operating system, various distribution service programs operating on the operating system, content data, and various other data. Reference numeral 4 denotes a removable disk such as a CD-ROM or DVD-RAM, which stores the same information as the hard disk 2. Reference numeral 6 denotes a display that displays various types of information to the user (system administrator).

  Reference numeral 8 denotes an input device, which includes a keyboard, a mouse, and the like, and various information is input by the user. Reference numeral 18 denotes a network interface that exchanges information with each of the user terminals 120, 130,..., 190 through the IP network 100. A CPU 20 controls each unit in the distribution server 110 via the bus 14 based on the operating system and a distribution service program described later. A ROM 22 stores an initial program loader and the like. A RAM 24 is used as a work memory for the CPU 20.

  Next, in the user terminal 120, the constituent elements 32, 34, 36, 38, 44, 48, 50, 52, 54 are the constituent elements 2, 4, 6, 8, 14, 18, of the distribution server 110. The configuration is the same as 20, 22, and 24. Reference numeral 40 denotes a sound board, which synthesizes an analog audio signal based on the supplied audio data. The synthesized musical sound signal is generated through the sound system 42. The user terminals 130,..., 190 are configured in the same manner as the user terminal 120. However, since the user terminal is mainly a TV receiver, the input device 38 includes various keys, an infrared remote control device, and the like.

2． Operation of the embodiment
2.1. Pre-distribution When the IP network 100 is the Internet, generally, the IP address assigned to each user terminal often changes dynamically. Thus, when the IP address of the user terminal changes dynamically, an IP packet with a terminal ID (information that uniquely identifies the user terminal) is periodically transmitted from each user terminal to the distribution server 110. The Thereby, even when an IP address is dynamically assigned, the distribution server 110 can sequentially grasp the IP address of each user terminal.

  Further, in the distribution server 110, the encrypted content data is uploaded to each user terminal during a time period when the traffic of the IP network 100 is low, such as midnight. In the present specification, unless otherwise specified, content data refers to encrypted content data. Here, the uploaded content data is different for each user terminal. For example, if the number of user terminals to be uploaded is 1000 and there are 50 types of content, and if these are uploaded equally, the same content data is uploaded for every 20 user terminals. Will be. However, in practice, it is not necessary to make the number of user terminals to be uploaded uniform, and the number of user terminals to be uploaded may be increased or decreased according to the degree of popularity of content. The uploaded content data is stored in the hard disk 32 of each user terminal.

Hereinafter, pre-delivery processing executed in the delivery server 110 when automatically uploading content data in this way will be described with reference to FIG.
In the figure, when the process proceeds to step SP50, a user terminal list, a content list, and an uploaded list are created. Here, the user terminal list is a list in which IP addresses of user terminals that are permitted to upload content data are listed as elements. The content list is a list formed by listing, as elements, information obtained by combining a content ID that uniquely identifies each content and the number of user terminals to which the content is to be uploaded.

  Further, the uploaded list is a list composed of elements that are a combination of the terminal ID of the user terminal that uploaded the content data and the content ID of the uploaded content data. At this point, the list is an empty list. . Next, when the process proceeds to step SP52, “1” is substituted into a variable N for specifying an element in the user terminal list. Next, when the process proceeds to step SP53, one element included in the content list is selected, and the content data related to the selected element is selected as content data to be uploaded.

  Next, when the process proceeds to step SP54, upload of the selected content data is started to the Nth user terminal in the user terminal list. Next, when the process proceeds to step SP56, it is determined whether or not an upload timeout has occurred (that is, the upload is not completed even after a predetermined time has elapsed since the start of the upload). If "NO" is determined here, the process proceeds to a step SP58 to determine whether or not the upload of the content data is completed. If "NO" is determined here, the process returns to the step SP56. Thereafter, the loop of steps SP56 and SP58 is repeated.

  If a timeout occurs during execution of the loop, “YES” is determined in step SP56, and the process proceeds to step SP66. Here, the variable N is incremented by “1”, and the process returns to step SP53. Thereby, the process after step SP53 is similarly repeated with respect to the user terminal corresponding to this new variable N. On the other hand, if the upload ends before the timeout occurs, “YES” is determined in step SP58, and the process proceeds to step SP60. Here, an element composed of a set of the terminal ID of the Nth user terminal and the content ID of the uploaded content data is added to the uploaded list.

  Next, when the process proceeds to step SP62, the content list is updated. As described above, each element of the content list is composed of the content ID and the number of user terminals, but in step SP62, the number of user terminals in the element related to the content data that has been successfully uploaded is decremented by “1”. . When the number of user terminals becomes “0” as a result of the decrement, the element itself is deleted from the content list. Next, when the process proceeds to step SP64, it is determined whether or not the content list is an empty list. If "NO" is determined here, the process proceeds to step SP66, and the variable N is incremented by "1". And the process after step SP53 is repeated with respect to the Nth user terminal. Thereafter, by repeating the same processing, when the necessary content data is uploaded to the required number of user terminals, the content list becomes an empty list. When this is detected in step SP64, this routine ends.

2.2. Distribution request operation at user terminal When a predetermined operation is executed at each user terminal, a list of viewable contents is acquired from distribution server 110, and the contents (content name, content ID, etc.) are displayed on display 36. Is done. Then, the user can select content desired to be distributed by operating the input device 38. When content is selected in this way, a distribution request operation routine (FIG. 2) is started.

  When the process proceeds to step SP2 in FIG. 2, a distribution request is transmitted to the distribution server 110 with the content ID of the content. Next, when the process proceeds to step SP4, the process waits until the decryption key data is supplied from the distribution server 110. Here, the decryption key data is data for decrypting / decrypting the content data. For example, the decryption key data is valid only for one decryption, for example, one day or one week only for a user terminal having a specific terminal ID. Depending on the contract between the service provider and the user, such as those valid within a certain time limit and those that can be decrypted at any user terminal by performing authentication within a predetermined period There may be a form of decryption key data.

  When the decryption key data is received, the process proceeds to step SP5 to determine whether or not the selected content data has already been downloaded. For example, the content data itself may remain in the hard disk 32 if a new distribution request is made because the decryption key data has expired for content viewed in the past. Further, by executing the pre-distribution processing routine (FIG. 4), the content data may already be stored in the hard disk 32 even though the user has not requested the content in the past. If “YES” is determined here, the processing is immediately terminated. That is, since the user obtains encrypted content data and decryption key data, the user can view the content.

  On the other hand, if “NO” is determined in step SP5, the process proceeds to step SP6, and a site list request message is transmitted from the user terminal to the distribution server 110. In step SP7, the process waits until the site list is supplied. When the site list is received, the process proceeds to step SP8. Here, the site list is a list of IP addresses of sites presumed to have the requested content data. The “site” may include the distribution server 110 in addition to other user terminals. When the site list is received, the process proceeds to step SP8, and a download inquiry message is transmitted to the first site in the site list. Here, the “download inquiry message” is a message for applying to the destination site for downloading content data.

  Next, when the process proceeds to step SP10, it is determined whether or not a download timeout has occurred, that is, whether or not a predetermined time or more has elapsed since step SP8 was executed first. If "NO" is determined here, the process proceeds to step SP12, and it is determined whether or not a rejection notice that "cannot respond to download" is received from the download inquiry site. If "NO" is determined here, the process proceeds to step SP14, and it is determined whether or not a permission notice that "can respond to download" is received. If "NO" is determined here, the process returns to the step SP10. Thereafter, the loop of steps SP10 to SP14 is repeated until a timeout occurs or a rejection notification or permission notification is received.

  When this loop is being executed, if “YES” is determined in step SP10 or step SP12, the process proceeds to step SP22. In such a case, content data cannot be downloaded from the site at present. Therefore, in such a case, the site as the first element (that is, the site to which the download inquiry message is transmitted) is deleted from the site list. Next, when the process proceeds to step SP24, it is determined whether or not the site list is an empty list. If "NO" is determined here, the process returns to step SP8, a download inquiry message is transmitted to a new site that is positioned at the head of the site list, and the above-described process is repeated. Become. If the above process is repeated until the site list becomes empty, “YES” is determined in step SP24, and the process returns to step SP2. Thereby, the processing of this routine is repeated from the beginning.

  If a permission notice is received when the loop of steps SP10 to SP14 is repeated, “YES” is determined in step SP14, and the process proceeds to step SP16. Here, download of content data is started from the site. Next, when the process proceeds to step SP18, it is determined whether or not a timeout has occurred, that is, whether or not a predetermined time has elapsed since step SP16 was executed first. If "NO" is determined here, the process proceeds to step SP20 to determine whether or not the download is completed. If not completed, the process returns to step SP18, and the loop of steps SP18 and SP20 is repeated.

  When the download is completed during the execution of this loop, the processing of this routine ends. On the other hand, if a timeout occurs during downloading, the process proceeds to step SP22. In such a case, after all, content data could not be downloaded from the site, so the site as the first element is deleted from the site list. As described above, the process returns to step SP2 or SP8 via step SP24.

2.3. Distribution Request Reception Processing As described above, when step SP2 is executed at the user terminal that is the distribution request source, a distribution request is transmitted to the distribution server 110. In the distribution server 110, when the distribution request is received, a distribution request receiving routine shown in FIG. In the figure, when the process proceeds to step SP72, decryption key data for decrypting / decrypting the content data is created. Next, when the process proceeds to step SP74, the generated decryption key data is transmitted to the user terminal that is the distribution request source.

2.4. Site List Request Reception Processing When a site list request message is transmitted from the distribution request source user terminal to the distribution server 110 (step SP6), the distribution server 110 receives the site list request shown in FIG. The routine is invoked. In the figure, when the process proceeds to step SP82, a site list is created. That is, in the distribution server 110, as described above, an uploaded list, which is a list composed of elements obtained by combining the terminal ID of the user terminal that uploaded the content data and the content ID of the uploaded content data, is created. Yes. In addition, the IP address assigned to each user terminal is sequentially reported to the distribution server 110.

  Therefore, in the distribution server 110, when a site list request accompanied by the designation of the content ID is supplied, it is possible to obtain the IP addresses of all user terminals that uploaded the content related to the content ID. Therefore, the site list is created by listing these IP addresses as elements. Further, the IP address of the distribution server 110 itself may be added to the site list as an element at the end. This is because the distribution server 110 itself distributes the content data when any user terminal included in the site list cannot respond to the file transfer as a result. Whether or not the IP address of the distribution server 110 itself is included in the site list may be determined according to the load status in the distribution server 110.

2.5. Download Query Reception As described above, when step SP8 is executed at the user terminal that is the distribution request source, a download inquiry message is transmitted to one site (the distribution server 110 or another user terminal). At the site receiving this message, a download inquiry message processing routine shown in FIG. In the figure, when the process proceeds to step SP30, it is determined whether or not the content data related to the inquiry is held in the site.

  If "YES" is determined here, the process proceeds to step SP32 to determine whether or not the traffic of the own device (the data rate currently transmitted / received via the network interfaces 18 and 48) is less than a predetermined value. Is done. If "YES" is determined here, the process proceeds to step SP34, and a permission notice is transmitted to the user terminal that is the transmission source of the download inquiry message. On the other hand, if “NO” is determined in any one of steps SP30 and SP32, the process proceeds to step SP36, and a rejection notification is transmitted to the inquiring user terminal.

2.6. Download Request Reception Further, when step SP16 is executed in the user terminal that has received the permission notification, downloading of content data is started in the user terminal. At that time, a download request is transmitted from the user terminal to the download source site. Then, at the site that received the download request, a download request processing routine shown in FIG. In the figure, when the process proceeds to step SP40, the process waits until the file transfer of the content data is completed. The processing of the next step SP42 differs based on whether the site that performed the file transfer is the distribution server 110 or a user terminal.

  That is, when this routine (FIG. 3B) is executed in the distribution server 110, the download request source site is added to the uploaded list. On the other hand, when this routine (FIG. 3B) is executed in the user terminal, the content ID of the transferred content data, the terminal ID of the user terminal that performed the file transfer, and the user terminal that downloaded the content data The terminal ID is reported to the distribution server 110. Then, in the distribution server 110, for the user terminal (file transfer source terminal) that has transferred the content data file to other user terminals in this way, the number of times content data has been transferred, the amount of data transferred, and accordingly The discount amount determined in the above is recorded.

  Here, the discount of charges will be described in detail. First, in this embodiment, the service provider charges each user a monthly basic fee and a metered fee according to the number of downloaded content data and the amount of data. However, for a file transfer source terminal that has transmitted content data to another user terminal, the service charge for the file transfer source terminal is discounted as the number of transfers and the amount of data increase.

  This is because the operation in which content data is transmitted from the file transfer source terminal to another user terminal (file transfer destination terminal) is the file transfer source terminal that is supposed to execute the file transfer process that should be executed at the facility on the service provider side. This is because it is considered that the Therefore, the consideration for cooperation with the service provider is reduced by the “discount amount”. In this way, if there is an advantage that the fee is discounted, each user will positively hope that his / her own user terminal will be used as the file transfer source terminal. Transfer of content data is further promoted.

3． As described above, according to the present embodiment, each user terminal can serve as a server that distributes content data to other user terminals. In addition, since a plurality of user terminals capable of distributing content data can be designated on the site list, it is not necessary to increase the reliability required for each user terminal. Thereby, a transmission path for many-to-many content data between user terminals is formed, and the load for transmitting the content data can be distributed, so that the load on the distribution server 110 can be reduced. Thereby, it is not necessary to employ a large-scale distribution server as the distribution server 110, and even when a plurality of distribution servers 110 are provided, the number of these can be reduced, and the equipment investment of the service provider can be reduced. . Furthermore, according to the above embodiment, even if the number of user terminals increases, an increase in the load on the distribution server 110 can be suppressed.

Four. Modifications The present invention is not limited to the above-described embodiments, and various modifications can be made as follows, for example.
(1) In steps SP54 to SP58 in the above embodiment, the content data is directly uploaded from the distribution server 110 to the user terminal. However, the content data may be transmitted and received between the user terminals. That is, after the distribution server 110 uploads content data to at least one upload target user terminal, a site list (pre-distribution site list) of the uploaded user terminals is created, and the other upload target user terminals are Thus, it may be instructed to download the content data from the user terminal included in the pre-delivery site list.

  In the user terminal that has received such a command, processing similar to steps SP7 to SP24 in FIG. 2 is executed based on the pre-delivery site list. That is, in the user terminal that has received the pre-distribution site list, download requests for content data are sequentially transmitted to the other user terminals listed in the pre-distribution site list until the download is successful. If possible, the content data is transmitted from the transmitting user terminal to the receiving user terminal. As described above, in the present modification, content data is transmitted and received between user terminals, so that the load on the distribution server 110 can be significantly reduced even in the pre-distribution process.

(2) Further, in the above embodiment, various processes are performed by the programs operating on the distribution server 110 and the user terminals 120 to 190, but only this program is stored in a recording medium such as a CD-ROM or a flexible disk. It can also be distributed through a transmission line.
(3) In the above embodiment, encrypted content data is transmitted / received between user terminals. However, unencrypted free content data may be transmitted / received.

(4) Further, in the above embodiment, each user terminal employs a method of reproducing after the content data is completely downloaded, but a streaming reproduction method of reproducing while downloading the content data may be employed.
(5) In the case of adopting the streaming playback method in this way, control such as playback start, pause, and interruption can be performed between the transmission-side user terminal and the reception-side user terminal without mediating the distribution server 110. You may be able to do it.

(6) However, when such a streaming reproduction method is adopted, there is a possibility that streaming reproduction may be interrupted if a failure occurs in the transmission-side user terminal while viewing content on the reception-side user terminal. Therefore, in order to prevent such a situation, the receiving-side user terminal may download the same content data from a plurality of transmitting-side user terminals at the same time, and reproduce the content while selecting the normally received content data. However, if content data is always downloaded from a plurality of transmission-side user terminals, traffic on the network interface 480 may become excessive. In such a case, in order to receive content data from other user terminals when a problem occurs in the transmission-side user terminal, it is preferable to search in advance for a user terminal that can be the transmission-side user terminal.

(7) In the above embodiment, each user terminal also functions as a server capable of supplying content data to other user terminals, but does not supply content data to other user terminals. A user terminal may be provided in the content distribution system. For example, when a small device such as a cellular phone is used as a user terminal, it is preferable to use this reception-only terminal.

(8) In the pre-distribution processing routine (FIG. 4) of the above embodiment, content data is uploaded from the distribution server 110 to the user terminal via the IP network 100. Such uploading is performed via the IP network 100. It is not always necessary, and the content data may be uploaded via satellite broadcasting or digital broadcasting. Thereby, content data can be simultaneously uploaded to many user terminals.

(9) The content data in the above embodiment is not limited to a moving image, and the system of the above embodiment may be used for various data distribution such as audio data, performance information, game programs, and the like.
(10) In the above embodiment, the user terminal may be provided with a wireless / wired LAN router, and a plurality of user terminals may be provided in one household via the router.
(11) The user terminal is not limited to the TV receiver, and a video deck, a home game machine, a personal computer, a mobile phone, a terminal adapter, or the like may be used as the user terminal.

It is a block diagram of the content distribution system of one Example of this invention. It is a flowchart of the delivery request | requirement operation routine performed in each user terminal. It is a flowchart of a download inquiry message processing routine and a download request processing routine executed in each user terminal. 5 is a flowchart of a pre-distribution processing routine executed in the distribution server 110. 7 is a flowchart of a distribution request reception routine and a site list request reception routine executed in the distribution server 110.

Explanation of symbols

  2, 32: hard disk, 4, 34: removal disk, 6, 36: display, 8, 38: input device, 14, 44: bus, 18, 48: network interface, 20, 50: CPU, 22, 52: ROM, 24, 54: RAM, 40: Sound board, 42: Sound system, 100: IP network, 110: Distribution server, 120-190: User terminal.

Claims (8)

In a content distribution system comprising at least one server and a plurality of user terminals that communicate with each other via a network, wherein the server can use content in each user terminal in response to a request from each user terminal ,
The server
When a distribution request designating specific content is received from any of the user terminals, the decryption key data for decrypting the encrypted content data is supplied to the user terminal that has transmitted the distribution request. Decryption key data supply means;
Site list transmission means for supplying a site list that lists other user terminals that can supply the encrypted content data to a user terminal that has transmitted the distribution request; Is
Distribution request transmission means for transmitting the distribution request to the server based on a user's operation of selecting content to be provided;
Download request means for requesting download of the encrypted content data to any of the other user terminals listed in the site list;
And an encrypted content data supply means for supplying the encrypted content data to the other user terminal when a request for downloading the encrypted content data is received from another user terminal. Content distribution system. The server uploads the encrypted content data to at least some upload target user terminals of the plurality of user terminals regardless of whether a distribution request is received from the upload target user terminals. And further has an upload means,
2. The site list transmitting means generates the site list by listing information for specifying upload target user terminals that have uploaded encrypted content data of specific content related to the distribution request. Content distribution system. The server uploads the encrypted content data to the first user terminal included in the upload target user terminal after the upload unit uploads it to another second user terminal included in the upload target user terminal. On the other hand, it has an automatic transmission control means for transmitting a pre-delivery site list including information for specifying the first user terminal,
Upon receiving the pre-delivery site list, each upload target user terminal requests download of the encrypted content data from any of the other user terminals listed in the pre-delivery site list. The content distribution system according to claim 2, further comprising a download request means for advance distribution. The server performs billing processing for each user terminal,
The content distribution system according to claim 1, further comprising discount means for discounting a charge amount to a user terminal that has supplied the encrypted content data to another user terminal. A server that is connected to a plurality of user terminals via a network and enables use of content in each user terminal in response to a request from each user terminal,
When a distribution request designating specific content is received from any of the user terminals, the decryption key data for decrypting the encrypted content data is supplied to the user terminal that has transmitted the distribution request. Decryption key data supply means;
A site list transmitting means for supplying a site list that lists other user terminals that can supply the encrypted content data to a user terminal that has transmitted the distribution request. . A content distribution system comprising at least one server and a plurality of user terminals that communicate with each other via a network, wherein the server enables use of content in each user terminal in response to a request from each user terminal In one user terminal used,
Distribution request transmission means for transmitting a distribution request to the server based on a user's operation of selecting content to be provided;
Decryption key data receiving means for receiving, from the server, decryption key data for decrypting encrypted content data obtained by encrypting the content;
Site list receiving means for receiving from the server a site list that lists information for identifying other user terminals;
Download request means for requesting download of the encrypted content data to any of the other user terminals listed in the site list;
And an encrypted content data supply means for supplying the encrypted content data to the other user terminal when a request for downloading the encrypted content data is received from another user terminal. User terminal. A program that is connected to a plurality of user terminals via a network and that is executed in a server that enables use of content in each user terminal in response to a request from each user terminal,
A receiving process in which the server receives a distribution request designating specific content from any of the user terminals;
A decryption key data supply process in which the server supplies decryption key data for decrypting encrypted encrypted content data to the user terminal that has transmitted the distribution request;
The server includes a site list transmission step of supplying a site list in which information specifying other user terminals capable of supplying the encrypted content data is listed to the user terminal that has transmitted the distribution request. A featured program. A content distribution system comprising at least one server and a plurality of user terminals that communicate with each other via a network, wherein the server enables use of content in each user terminal in response to a request from each user terminal In a program executed on one user terminal used,
A distribution request transmission process in which the one user terminal transmits a distribution request to the server based on a user's operation of selecting content to be provided;
A decryption key data reception process in which the one user terminal receives decryption key data for decrypting encrypted content data obtained by encrypting the content;
A site list receiving process for receiving, from the server, a site list in which the one user terminal lists information identifying other user terminals;
A download request process in which the one user terminal requests download of the encrypted content data from any of the other user terminals listed in the site list;
An encrypted content data supply process for supplying the encrypted content data to the other user terminal when the one user terminal receives a request to download the encrypted content data from the other user terminal; The program characterized by having.

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