Abstract:
It is unknown what information terminals and how many information terminals are connected to one contracted information terminal. Accordingly, contents licensed to use by only family members of one household may be used by other persons. In view of such a situation, it is necessary to create secure environments. The present invention manages subterminals registered in all main terminals in a subterminal management part of a host device, and confirms validity of registration and deregistration by contract-time personal authentication information managed in a main terminal contract management part. Thereby, contents can be delivered only to reliable home networks.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a contents delivery system for delivering contents to plural information terminals.  
           [0003]    2. Description of the Prior Art  
           [0004]    In recent years, with rapid development of the Internet in broadband transmission, video contents delivery services have been started to deliver high volumes of video contents via the Internet. In the contents delivery services, it is very important to set contents use limitations, and some services are proposed which deliver scrambled contents and descramble the scrambled video contents only for use conforming to use contracts. In these video contents delivery services, with plural information terminals connected to one host, a contract must have been made for each of the information terminals to use contracts.  
           [0005]    With the development of broadband transmission, an information terminal (STB, etc.) for receiving video contents is attached to each TV from one per household. As a result, plural information terminals exist within a household, and there is a demand to use contents contracted by a specified information terminal within a household in other information terminals as well.  
           [0006]    It is very convenient to users that contents contracted by one information terminal can be used in other information terminals as well. However, since it is unknown to contents deliverers what information terminals and how many information terminals are connected to one contracted information terminal, contents licensed to use by only family members of one household may be used by other persons. Such network environments cannot be said to be secure environments. Therefore, it has been necessary to manage connectable information terminals so that only reliable information terminals can use contents. Such environments require collective management of states of contents stored in plural information terminals within households and contents presentation understandable to users. There is a problem that it is difficult to procure contents having been delivered.  
           [0007]    From the standpoint of providers to deliver contents, as a service for collecting contractors, there is a demand for simple communication means among households holding contracts with the same service providers.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention has been made in view of the above problems, and provides an information terminal management method and a contents delivery system that enables collective management of states of contents stored in plural information terminals within households and contents presentation understandable to users, and simple communications with other households.  
           [0009]    To solve the problems, according to the present invention, first, a host device includes: a subterminal management part for managing information about subterminals using contents sent from main terminals; a main terminal contract management part for managing personal information of contractors of the main terminals; and a UI part for specifying main terminals and subterminals to be registered or deregistered, wherein the main terminals include: an authentication part, when registering or deregistering subterminals permitted to use contents sent from the main terminals, for querying the subterminal management part of the host device about whether to permit the registration or deregistration; and an authentication information management part for managing registered subterminals. Thereby, the host device manages subterminals registered in all main terminals and confirms validity of registration and deregistration by contract-time personal authentication information, whereby contents can be delivered only to reliable home networks. The setting of registration limitation conditions prevents malicious users from illegally increasing subterminals. An accounting system dependent on the configuration of subterminals can be built. When contents are delivered, since all contents of formats processable to a main terminal making a request for contents delivery and subterminals registered in the main terminal are sent, format conversion is unnecessary in receiving terminals. Only contents of formats processable to terminals permitted by contents license are delivered, thereby preventing the delivery of meaningless contents not used because of the lack of license.  
           [0010]    Second, the host device includes a main terminal list creation part for creating a list of main terminals or subterminals, and the main terminals or subterminals further include a UI part for enabling specification of other main terminals or subterminals registered in the main terminals as communication parties, and an inter-terminal communication part for communicating with other terminals. This realizes simple communication means among households holding contracts with the same service providers and makes it possible for service providers delivering contents to provide services for collecting contractors.  
           [0011]    Third, the subterminals include: a contents storage part for storing contents sent from the main terminals; and a takeout determination part for determining whether the subterminals can be taken out, and the main terminals include: a contents storage part for storing contents sent from the host terminal; and a contents storage information management part for managing contents storage information, whereby storage states in plural contents storage parts within a home network are collectively managed, and takeout limitations and reservations for the contents are enabled. Thereby, the states of storage devices of plural terminals within the home network can be shown in a form easily understandable to users because the storage devices appear to be one storage device.  
           [0012]    Fourth, the host device includes: a contents list management part for managing contents lists showing the correspondence between the main terminals and contents successfully stored by the individual main terminals, and sending the contents lists to the main terminals; a contents delivery history management part for collecting and managing contents delivery histories; and a delivery charge computation part for computing amounts to be paid to the users of the main terminals according to the contents delivery histories, wherein the main terminals include: a data receiving part for receiving a contents list sent from the contents list management part; an inter-terminal communication part for receiving contents sent from other main terminals; a UI part for showing a contents list to receive selection of contents; a contents storage part for storing contents; and a contents delivery history creation part for creating contents delivery histories containing information about main terminals to deliver contents from and sending the contents delivery histories to the host device, whereby contents lists are provided to the subterminals, and contents delivery from other home networks is enabled. Thereby, even contents having been delivered from the host device can be provided to users. Also, by compiling contents delivery histories and enabling charge computations according to the delivery histories, a business is established in which service providers managing contents and licenses and performing contents delivery pay charges for contents delivery operations to contractors of main terminals having performed contents delivery in place of the host device.  
           [0013]    As has been described above, according to the present invention, the host device manages subterminals registered in all main terminals and confirms validity of registration and deregistration by contract-time personal authentication information, whereby contents can be delivered only to reliable home networks. The setting of registration limitation conditions prevents malicious users from illegally increasing subterminals. An accounting system dependent on the configuration of subterminals can be built.  
           [0014]    When contents are delivered, since all contents of formats processable to a main terminal making a request for contents delivery and subterminals registered in the main terminal are sent, format conversion is unnecessary in receiving terminals.  
           [0015]    Only contents of formats processable to terminals permitted by contents license are delivered, thereby preventing the delivery of meaningless contents not used because of the lack of license.  
           [0016]    By realizing simple communication means among households holding contracts with the same service providers, providers to deliver contents can provide services for collecting contractors.  
           [0017]    Storage states in plural contents storage parts within a home network are collectively managed, and takeout limitations and reservations for the contents are enabled. Thereby, the states of storage devices of plural terminals within the home network can be shown in a form easily understandable to users because the storage devices appear to be one storage device.  
           [0018]    Contents lists are provided to the subterminals, and contents delivery from other home networks is enabled. Thereby, even contents having been delivered from the host device can be provided to users. Also, by compiling contents delivery histories and enabling charge computations according to the delivery histories, a business is established in which service providers managing contents and licenses and performing contents delivery pay charges for contents delivery operations to contractors of main terminals having performed contents delivery in place of the host device.  
           [0019]    Objects and advantages of the present invention as described above will be made more apparent from embodiments described below with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIG. 1 is a diagram showing a contents delivery system in a first embodiment of the present invention;  
         [0021]    [0021]FIG. 2 is a diagram showing a main terminal contract management table in the first embodiment;  
         [0022]    [0022]FIG. 3 is a diagram showing a subterminal management table in the first embodiment;  
         [0023]    [0023]FIG. 4 is a diagram showing a contents use status management table in the first embodiment;  
         [0024]    [0024]FIG. 5 is a diagram showing a contents license management table in the first embodiment;  
         [0025]    [0025]FIG. 6 is a diagram showing a contents management table in the first embodiment;  
         [0026]    [0026]FIG. 7 is a flowchart explaining a contents acquisition processing in the first embodiment;  
         [0027]    [0027]FIG. 8 is a diagram showing a contents use status management table in the first embodiment;  
         [0028]    [0028]FIG. 9 is a flowchart explaining a download processing of contents in a first embodiment;  
         [0029]    [0029]FIG. 10 is a flowchart explaining a registration processing of a subterminal to a main terminal in the first embodiment;  
         [0030]    [0030]FIG. 11 is a diagram showing a subterminal management table in the first embodiment;  
         [0031]    [0031]FIG. 12 is a diagram showing a subterminal management table in the first embodiment;  
         [0032]    [0032]FIG. 13 is a diagram showing a main terminal management table in the first embodiment;  
         [0033]    [0033]FIG. 14 is a flowchart showing processing for using contents of a main terminal in a subterminal in the first embodiment;  
         [0034]    [0034]FIG. 15 is a flowchart explaining contents use check processing in the first embodiment;  
         [0035]    [0035]FIG. 16 is a flowchart explaining processing for deregistering main terminals and subterminals from a host device in the first embodiment;  
         [0036]    [0036]FIG. 17 is a diagram showing a contents delivery system in a second embodiment of the present invention;  
         [0037]    [0037]FIG. 18 is a diagram showing a main terminal list in the second embodiment;  
         [0038]    [0038]FIG. 19 is a flowchart explaining processing of inter-terminal communication in the second embodiment;  
         [0039]    [0039]FIG. 20 is a diagram showing a subterminal management table in the second embodiment;  
         [0040]    [0040]FIG. 21 is a diagram showing conditions specific to terminals used in the second embodiment;  
         [0041]    [0041]FIG. 22 is diagram showing alternative search conditions in the second embodiment;  
         [0042]    [0042]FIG. 23 is a diagram showing a contents delivery system in a third embodiment of the present invention;  
         [0043]    [0043]FIG. 24 is a diagram showing contents storage information in the third embodiment;  
         [0044]    [0044]FIG. 25 is a diagram showing contents storage location decision conditions in the third embodiment;  
         [0045]    [0045]FIG. 26 is a flowchart explaining storage processing for delivered contents in the third embodiment;  
         [0046]    [0046]FIG. 27 is a diagram showing a presentation example in a UI part in the third embodiment;  
         [0047]    [0047]FIG. 28 is a diagram showing takeout determination criteria standard in the third embodiment;  
         [0048]    [0048]FIG. 29 is a diagram showing a contents delivery system in a fourth embodiment of the present invention;  
         [0049]    [0049]FIG. 30 is a diagram showing a contents list in the fourth embodiment;  
         [0050]    [0050]FIG. 31 is a diagram showing a contents list in the fourth embodiment;  
         [0051]    [0051]FIG. 32 is a diagram showing terminal selection conditions in the fourth embodiment;  
         [0052]    [0052]FIG. 33 is a diagram showing a contents delivery system in the fourth embodiment;  
         [0053]    [0053]FIG. 34 is a diagram showing contents list sending information in the fourth embodiment;  
         [0054]    [0054]FIG. 35 is a diagram showing circulation of contents lists in the fourth embodiment;  
         [0055]    [0055]FIG. 36 is a diagram showing a contents delivery history in the fourth embodiment;  
         [0056]    [0056]FIG. 37 is a diagram showing a contents list delivery history compilation table in the fourth embodiment; and  
         [0057]    [0057]FIG. 38 is a diagram showing a charge calculation result table in the fourth embodiment. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0058]    Hereinafter, a contents delivery system according to embodiments of the present invention will be described with reference to the drawings.  
         [0059]    (First Embodiment)  
         [0060]    As shown in FIG. 1, the contents delivery system has a host device  20  and plural information terminals, and delivers contents of the host device  20  to the information terminals through transmission lines (communication lines or data broadcasting). The information terminals fall into two categories: a main terminal  21  and subterminals  22 ,  23 , and  24 , which are managed as to their contents use state by the main terminal  21 . The number of subterminals is unlimited. Also, the number of main terminals is unlimited. Hereinafter, in this specification, a network which comprises one main terminal and subterminals connected thereto will be referred to as a home network.  
         [0061]    The host device comprises a contents management part  31 , a contents sending part  32 , a contents license generation part  33 , a license sending part  34 , a subterminal management part  35 , a main terminal contract management part  36 , and a UI (user interface) part  37 , and sends contents to the information terminals. Upon receipt of a request to use contents from the information terminals, the host device sends contents license to the information terminals.  
         [0062]    The contents management part  31  holds plural contents such as video contents, music contents, and games, and a contents management table in which contents names, contents details, and the like are managed by contents ID. The contents license generation part  33  has a contents license management table corresponding to the contents management table, and generates contents licenses from the contents license management table, in response to a request from the main terminal  21 . The contents sending part  32  and the license sending part  34  respectively send contents, and the contents management table and licenses to the information terminals. The main terminal contract management part  36  manages contents, the contents management table, personal information of contractors to receive licenses, and main terminal information which are sent from the host device  20 . Specifically, for example, as shown in FIG. 2, these items of information are managed by a main terminal contract management table consisting of contractor personal information containing main terminal ID, main terminal type, and authentication information, support format, the number of connectable subterminals, and the like. The subterminal management part  35  manages subterminals registered as terminals using contents received by the main terminal. Specifically, for example, as shown in FIG. 3, the subterminals are managed by a subterminal management table consisting of main terminal ID, the number of registered subterminals, registered subterminal ID, registered subterminal type, registered subterminal support format, and the like. The UI part  37  specifies subterminals to be registered or deregistered.  
         [0063]    The main terminal  21  will be described. The main terminal  21  includes a UI part  40 , a data receiving part  41 , an access control part  42 , an authentication part  43 , an inter-terminal communication part  44 , an authentication information management part  45 , a contents use status management part  46 , a contents license management part  48 , a contents storage part  49 , a contents reproduction and execution part  50 , a license acquisition part  51 , and a transportable recording medium  25 . The UI part  40  is connected with a TV and a remote controller used by a user to issue requests to the main terminal  21 . The authentication part  43  determines subterminals connectable to the main terminal  21  in consultation with the authentication information management part  45 . The authentication information management part  45  stores the terminal IDs of subterminals authorized to connect to the main terminal  21 .  
         [0064]    The contents use status management part  46  manages the use statuses of individual contents in the information terminals. Specifically, the use statuses of the contents are managed by a contents use status management table shown in FIG. 4. Use date, use terminal, and the like are recorded and managed for each of the contents versions of contents IDs.  
         [0065]    The contents license management part  48  manages contents licenses including use conditions for contents provided from the contents license generation part  33 . Specifically, contents are managed by a contents license management table shown in FIG. 5. For example, contents licenses are subjected to use limitation management by contents ID and contents version in terms of use count, use expiration, and use terminal.  
         [0066]    The access control part  42  compares contents licenses and contents use statuses described above, and determines whether to reproduce contents.  
         [0067]    The contents storage part  49  holds contents and a contents management table which were delivered from the host device  20 . The contents management table, as shown in FIG. 6, has a contents list containing contents producers, contents names, and the like, and is used for contents selection in the UI part. The contents management table may be described and delivered as contents having a format like normal menus. Alternatively, the contents management table, after being read by applications of terminals, may be displayed through GUI of each of the terminals. The contents storage part  49  is composed of a hard disk over, e.g., 60 gigabytes, e.g., 40 gigabytes of which are allocated to an area called a provider area, which can be updated by only the host device  20 . Contents delivered from the host device  20  are stored in the provider area. The contents storage part  49  may be not a hard disk but a memory. The contents reproduction and execution part  50  fetches contents from the contents storage part  49  to reproduce and execute them.  
         [0068]    The transportable recording medium  25  includes a contents storage part  52  and a main terminal information management part  38 . The contents storage part  52  stores contents delivered from the host device. The main terminal information management part  38  manages main terminal information (e.g., main terminal ID, etc.) for identifying the main terminal in which it is included.  
         [0069]    The subterminal  22  will be described. The subterminal  22  includes a UI part  55 , a contents reproduction and execution part  56 , and an inter-terminal communication part  57 . The subterminal  22  receives contents delivered from the main terminal  21  and reproduces the contents in the contents reproduction and execution part  56  of the subterminal  22 . The configurations of the subterminals  23  and  24 , which are omitted in FIG. 1, are identical with each other.  
         [0070]    The contents license management part  48  of the main terminal  21  manages contents licenses of the subterminals  22 ,  23 , and  24 , as well as contents licenses of the main terminal  21 . Thereby, contents delivered to the main terminal  21  can be shared in the subterminals  22 ,  23 , and  24 , as well as in the main terminal  21 . In this case, the contents licenses may be defined as “no subterminals are permitted”, “up to three subterminals are permitted”, and the like (see the contents license management table of FIG. 5). In the case where the subterminal  22  attempts to reproduce contents stored in the contents storage part  49 , there is no need to access the host device  20 , so that the load of access to the host device  20  can be reduced. Contents to be referred to are not limited to contents stored in the main terminal; the licenses can be shared even when contents are directly requested from the subterminals to the host device, or when contents stored in digital media such as DVD are reproduced and executed.  
         [0071]    Next, a detailed description will be made of contents acquisition operation of the contents delivery system with reference to a flowchart of FIG. 7.  
         [0072]    When contents are to be reproduced in the main terminal  21 , the user attempts to display the contents management table on a TV screen. Accordingly, the UI part  40  requests the contents management table from the access control part  42  (S 10 ). The access control part  42  obtains the contents management table from the contents storage part  49  (S 20 ). The access control part  42  passes the contents management table to the UI part  40  (S 30 ), and displays a contents list from the contents management table on a TV screen connected to the UI part  40  (S 40 ).  
         [0073]    The user selects contents to be used from the contents management table displayed on the TV screen, and the UI part  40  receives the request to use the contents desired by the user (S 50 ). The UI part  40  sends the contents use request to the access control part  42  (S 60 ), and the access control part  42  performs contents use checking. The contents use checking is a procedure for checking whether a contents license is given to contents requested for use, and whether current use conditions satisfy conditions for using the contents. The contents license management part  48  has a contents license management table (FIG. 5) for managing contents to which contents licenses are given. The contents use status management part  46  has a contents use status management table (see FIG. 4) for managing contents use statuses. Whether the contents can be used is determined by comparing the contents license management table with the contents use status management table. The contents use checking will be described in detail later.  
         [0074]    As a result of checking whether the contents can be used (S 80 ), if the use of the contents is permitted, the access control part  42  instructs the contents storage part  49  to reproduce and execute the contents (S 100 ). The contents storage part  49  sends the requested contents to the contents reproduction and execution part  50  (S 120 ). The contents reproduction and execution part  50  reproduces and executes the contents, and displays the contents on a TV screen of the UI part  40  (S 130 ). The access control part  42  sends reproduction and execution history to the contents use status management part  46  and updates the contents use status management table managed in the contents use status management part  46 . FIG. 8 shows the contents use status management table when version 2 of contents ID 10023 is used; it will be recognized that a line of use history is added.  
         [0075]    As a result of checking whether the contents can be used (S 80 ), if it is found that a license is not given and a license is required to use the contents, the access control part  42  issues a request to acquire a license to the license acquisition part  51  (S 150 ). The license acquisition part  51  issues a request to acquire a license for the contents to the license sending part  34  (S 160 ). The license sending part  34  acquires a license for the contents from the contents license generation part  33  and sends it to the license acquisition part  51  (S 170 ). The license acquisition part  51  sends a contents license to the contents license management part  48  and makes acquisition response to the access control part  42  (S 180 ). After a license to use the contents is set, the contents use checking is performed again (S 80 ) and the contents storage part  49  is instructed to reproduce and execute the contents.  
         [0076]    As a result of checking whether the contents can be used (S 80 ), if the contents cannot be used, use impossibility is reported to the UI part  40  (S 190 ) and information indicating use impossibility is displayed on the TV screen, and the processing terminates (S 90 ). However, when use impossibility is reported to the UI part, a license can be acquired again to reproduce the contents. The use impossibility referred to here occurs when although a license to use the contents is once set, the status of using the contents does not satisfy the contents license. An example that a license is not satisfied occurs when access is made from an unauthorized terminal, person, or age. This case is referred to as use impossibility.  
         [0077]    The above processing is performed for the contents management table and requested contents already downloaded into the contents storage part; processing for those not downloaded into the contents storage part will be described using a flowchart of FIG. 9.  
         [0078]    The UI part  40  requests the contents management table from the data receiving part  41  (S 300 ), which requests the contents management table from the contents sending part  32  (S 310 ). The contents sending part  32  acquires the contents management table from the contents management part  31  (S 320 ), and sends the contents management table to the data receiving part  41  (S 330 ). The data receiving part  41  sends the contents management table to UI part  40  (S 340 ), which displays a contents list from the contents management table on a TV screen (S 350 ).  
         [0079]    From the TV screen, the user selects contents to be used. As a result, the UI part  40  receives a contents storage request (S 360 ) and requests the data receiving part  41  to store the contents in the contents storage part  49  (S 370 ). The data receiving part  41  requests the contents sending part  32  to store the contents (S 380 ), and the contents sending part  32  acquires the contents from the contents management part  31  (S 390 ). The contents sending part  32  sends the contents to the data receiving part  41  (S 400 ), which outputs the contents to the contents storage part  49  for storage (S 410 ). If storage of the contents begins, as described above (S 60 ), a use request is issued to the access control part  42  to check the contents for use. Although an example of storage is shown here, contents may be directly acquired and displayed. Although, in this example, contents are acquired before being checked to see if the contents can be used, the contents may be acquired after being checked to see if the contents can be used and determined to be usable.  
         [0080]    The above description is made of the case where contents are used in only the main terminal  21 . Next, a description will be made of the case where contents are used in the subterminals  22  connected to the main terminal  21 .  
         [0081]    Before using contents of the main terminal  21 , the subterminal  22  must be registered in the main terminal  21 . The main terminal  21  beforehand makes a contract for receiving contents delivered from the host device  20 , and the contract contents are managed by a main terminal contract management table as shown in FIG. 2 in the main terminal contract management part  36 .  
         [0082]    To register the subterminal  22  in the main terminal  21 , as shown by a flowchart of FIG. 10, the subterminal  22  is connected to the main terminal  21  in their respective terminal communication parts (S 500 ). They may be connected through a wire or wirelessly. The UI part  55  of the subterminal  22  makes a request to the main terminal  44  for terminal registration (S 510 ). The terminal registration request is passed to the authentication part  43  of the main terminal via the inter-terminal communication part  57  of the subterminal  22  and the inter-terminal communication part  44  of the main terminal (S 520 ). The authentication part  43  outputs a registration request to the UI part  55 , and the UI part  40  displays the registration request on a TV screen (S 530 ). If the subterminal  22  may be registered in the main terminal  21 , the user of the main terminal registers the subterminal by use of an input means such as a remote control. The user of the main terminal inputs personal authentication information such as password and fingerprint information registered at the time of the contract (S 540 ). The UI part  40  receives registration permission and sends a registration request to the authentication part  43  (S 550 ). The authentication part  43  queries the subterminal management part  35  of the host device  20  about whether registration is permitted (S 560 ), along with a main terminal ID, personal authentication information, and the like. The subterminal management part  35  uses the main terminal ID, personal authentication information, the subterminal ID of a subterminal to be registered, and the like to make a request to the main terminal contract management part  36  for authentication, and the main terminal contract management part  36  performs authentication from the sent personal authentication information and main terminal contract management information (S 570 ). For example, if a registration request is sent from a main terminal with a main terminal ID of 10023, a check is made to see if sent personal authentication information matches personal authentication information of the main terminal ID 10023 registered in the main terminal management table. If they do not match, registration rejection is returned to the authentication part  43  through the subterminal management part  35 . If they match, the main terminal contract management part  36  returns authentication permission to the subterminal management part  35  along with the number of connectable subterminals, and the subterminal management part  35  determines whether the registration results in the number of connectable subterminals exceeding a limited value. For example, since the main terminal contract management table as shown in FIG. 2 shows that a main terminal with a main terminal ID of 10023 can register three subterminals, and the subterminal management table as shown in FIG. 3 shows that the number of registered subterminals is two, one more subterminal can be registered. On the other hand, in a main terminal with a main terminal ID of 9303, three subterminals, which is the number of connectable subterminals, have already been registered. Therefore, no more subterminals can be registered. If the number of connectable subterminals is not exceeded, registration permission is returned to the authentication part  43 , and the subterminal management part  35  registers terminal information (registration subterminal ID, registration subterminal type, registration subterminal support format, etc.) of the subterminal requested for registration (S 580 ). Upon receipt of the authentication permission, the authentication part  43  registers terminal information of the subterminal  22  in the authentication information management part  45 , and returns a result to the UI part  40  (S 590 ). Subterminals registered as connectable with the main terminal  21 , managed in the authentication information management part  45 , are managed by the subterminal management table as shown in FIG. 11. The subterminal management table contains terminal IDs permitted for connection, terminal type, reproduction capabilities, recording capacity, and the like. Newly adding terminal IDs increases items of the subterminal management table.  
         [0083]    By executing such a procedure, the main terminal  21  and the subterminal  22  form a home network which allows contents stored in the contents storage part  49  to be shared in the subterminal  22 . Sharable contents presuppose that a contents license is given to the subterminal  22 . Although, in the above-described procedure, the main terminal  21  and the subterminal were first connected, this is not mandatory, and all information of subterminals may be inputted in the UI part  40  of the main terminal  21 .  
         [0084]    In addition to the subterminal  22 , the subterminals  23  and  24  may be registered in the main terminal  21 . Not only terminals but also transportable recording media may be registered. In this case, in the above-described procedure, after registration permission is returned to the authentication part  43 , and information about the transportable recording medium  25  is registered as shown in FIG. 12 in the subterminal management table of the authentication information management part  45 , the main terminal management table managed by the main terminal information management part  38  of the transportable recording medium  25  becomes as shown in FIG. 13. Transportable recording media can be used only in main terminals described in main terminal information and subterminals registered in main terminals, and cannot be used in other terminals.  
         [0085]    Although only registration of subterminals is described in the above description, deregistration of subterminals is also performed in the same flow; addition information in the management tables is replaced by deletion processing.  
         [0086]    Next, a procedure for using contents in the contents storage part  49  of the main terminal  21  in the subterminal  22  will be described with reference to a flowchart of FIG. 14.  
         [0087]    The subterminal  22  is connected to the main terminal  21  by the respective inter-terminal communication parts  44  and  57  (S 600 ). The UI part  55  of the subterminal  22  directs the sending of a contents use request to the main terminal  21  (S 610 ). The contents use request is passed to the authentication part  43  of the main terminal  21  via the inter-terminal communication part  57  of the subterminal  22  and the inter-terminal communication part  44  of the main terminal  21  (S 620 ). The authentication part  43  checks whether the subterminal making a request for use is permitted for use by the authentication information management part  45 . As a result, if the subterminal is not permitted for use, the subterminal is notified that it is not permitted for use. Of course, the subterminal cannot use the contents (S 650 ). On the other hand, in the subterminal  22  permitted for use, contents are reproduced and executed (S 660 ). The reproduction and execution procedure is the same as that in the main terminal  21  (S 10  to S 180 ), except that the access control part  42  outputs contents not to the contents reproduction and execution part  50  of the main terminal  21  but to the contents reproduction and execution part  56  of the subterminal  22 .  
         [0088]    If no contents license is set and the contents do not exist in the contents storage part  49  of the main terminal  21 , like the main terminal  21 , according to a request from the subterminal  22 , the purchase of a contents license and contents storage can be made.  
         [0089]    In the case where the subterminal  22  directly uses contents of the host device  32 , for example, even in the case of the reproduction and execution of normal WWW contents, it is checked whether a license for the contents exists in the main terminal  21 , before performing reproduction and execution. Thereby, no matter where contents to be reproduced and executed exist, licenses can be shared.  
         [0090]    The above-described contents use checking (S 80  in the flowchart of FIG. 7) will be described in detail with reference to FIG. 15.  
         [0091]    In the contents use checking, it is checked whether a contents license is set for specified contents (S 200 ). Since contents licenses are recorded in the contents license management table (FIG. 5) of the contents license management part  48 , the contents management table is checked using the contents ID as key. If the contents ID does not exist in the contents license management table, it is determined that a license is required, and control proceeds to S 150  in FIG. 7. If the contents ID exists in the contents license management table, since a license is already set, it is checked whether the license is valid or not.  
         [0092]    It is checked whether the license has a count limitation (S 210 ). If there is a count limitation, a use count of the contents is extracted from the use status management table (S 220 ), and it is determined whether a limitation count set in the license exceeds the use count of the contents. If the use count is equal to or greater than the limitation count, the contents are determined to be unusable. A use period has two patterns: a period from a contract date, that is, an absolute date, and a period from a first viewing, that is, a relative date. FIG. 5 shows an example of the latter, a relative date.  
         [0093]    Next, if the use count is less than the limitation count, or the license has no count limitation, it is checked whether the license has an expiration limitation (S 240 ). If there is an expiration limitation, a period in which the use period of the contents expires is calculated from the use status management table (S 250 ), and it is checked whether the expiration limitation set in the license violates the use period of the contents (S 260 ). If so, the contents are determined to be unusable.  
         [0094]    If the expiration limitation is observed, or the license has no expiration limitation, it is checked whether the license has a limitation on available terminals (S 270 ). If there is a terminal limitation, it is checked whether the contents have a terminal limitation from the use status management table (S 280 ), and it is determined whether use is made in other than terminals to which the license is given. For use in terminals to which the license is not given, the contents are determined to be unusable.  
         [0095]    As a result of the above checking, if all the conditions are satisfied, the contents are determined to be usable and control proceeds to S 100  of FIG. 7. By performing the contents use checking in this way, various licenses can be set.  
         [0096]    Although the above description assumes a configuration in which contents can be shared between the main terminal and subterminals, if the contents use statuses of subsidiary subterminals connected to the subterminals can be managed in the main terminal and the contents licenses of the subsidiary subterminals can also be managed in the main terminal, contents can be shared among the main terminal, subterminals, and subsidiary terminals.  
         [0097]    The description is only an example and places no limitations on sequence, conditions, and the like. Licenses may be provided with various limitations such as use limitations for each individual, age, and sex, if an individual to use the system is identified.  
         [0098]    As has been described above, if the host device manages subterminals registered in all main terminals and checks validity of registration and deregistration by contract-time personal authentication information, contents can be delivered only to reliable home networks. Also, the setting of registration limitation conditions prevents malicious contractors from illegally increasing subterminals. An accounting system dependent on the configuration of subterminals can be built.  
         [0099]    The contents sending part  32  can deliver all contents of formats processable to a main terminal making a request for contents delivery and subterminals registered in the main terminal. For example, when a request for contents delivery is issued from a main terminal with a main terminal ID of 10023, since it is determined from the main terminal contract management table (FIG. 2) and the subterminal management table (FIG. 3) that a format supported by the main terminal is MPEG2, and formats supported by subterminals registered in the main terminal are Real Video and MPEG2, requested contents are delivered in the MPEG2 and Real Video formats. Similarly, when a request for contents delivery is issued from a main terminal with a main terminal ID of 9303, request contents are delivered in the MPEG2, MPEG4 and Real Video formats. This makes format conversion in receiving terminals unnecessary.  
         [0100]    Only contents of formats processable to terminals permitted by contents license can be delivered. For example, when a request to deliver contents with contents ID 9303 and version 30 is issued from a main terminal with a main terminal ID of 10023, if licenses are set as shown by the contents license management table shown in FIG. 5, although a format supported by the main terminal is MPEG2 and formats supported by a subterminal registered in the main terminal are Real Video and MPEG2, since use in only the main terminal is permitted, only contents of MPEG2 format may be delivered. This prevents the delivery of meaningless contents not used because of the lack of license.  
         [0101]    Next, an example of deregistering a main terminal and a subterminal specified in the host device  20  will be described with reference to the flowchart of FIG. 16. The UI part  37  of the host terminal  20  specifies terminals to be registered or deregistered and makes a request to the subterminal management part  35  for deregistration (S 1300 ). The terminals are specified with terminal IDs, terminal types, and the like.  
         [0102]    If a specified terminal is a main terminal, the subterminal management part  35  directs the main terminal to deregister all subterminals, and the authentication information management part  45  of the main terminal deregisters all subterminals (S 1340 ). The subterminal management part  35  deletes information relating to the subterminals of the main terminal from the subterminal management table (S 1350 ), and requests the main terminal contract management part  36  to delete information of the terminals. The main terminal contract management part  36  deletes information of the main terminal from the main terminal contract management table (S 1360 ). The deleted main terminal will be unable to enjoy contents delivery from the host device.  
         [0103]    If the specified terminal is a subterminal, the subterminal management part  35  issues a request to deregister the subterminal to the authentication part  43  of the main terminal  21  in which the subterminal is registered (S 1310 ). The authentication part  43  requests the authentication information management part  45  to deregister the subterminal (S 1320 ), and the authentication information management part  45 , according to the request, deletes information of the subterminal from the subterminal management table (S 1330 ). If a terminal type is specified for deregistration, all subterminals registered in all main terminals are scanned, and the above processing is performed for subterminals matching the specified terminal type. Although the above description has been made of deregistration, registration is performed according to the same flow as in deregistration, except that deletion processing is replaced by addition processing. In deletion processing with a main terminal specified, although all subterminals registered in the main terminal have been deregistered, if there occurs no contradiction at reregistration, the subterminals may be left intact. By thus registering and deregistering terminals specified in a host terminal, even if a problem arises in terminal security due to bugs or hacking, the problematic terminal can be quickly deregistered. If the problem has been solved as a result of bug correction, deregistered terminals can be quickly reregistered.  
         [0104]    (Second Embodiment)  
         [0105]    A second embodiment of the present invention will be described with reference to FIG. 17. Components in the second embodiment that are identical to components in the first embodiment are identified by the same reference numbers; descriptions of them are omitted. The second embodiment is characterized in that communication is enabled between main terminals and subterminals that receive contents delivered from the host device  20 . The flow of processing of inter-terminal communication in the second embodiment of the present invention will be described with reference to a flowchart of FIG. 19.  
         [0106]    A main terminal list creation part  39  of the host device  20  in FIG. 17 creates a main terminal list from the main terminal contract management information managed by the main terminal contract management part  36 . The main terminal contract management information contains main terminal IDs, home network names, and communication information for communicating with main terminals. The main terminal list, shown in FIG. 18, is used to select communication parties in main terminals and subterminals. When a main terminal (or subterminal) performs communication with terminals belonging to other home networks, the UI part  40  (UI part  55  in the case of subterminal) issues a request for the main terminal list to the inter-terminal communication part  44  (S 1400 ). A request from the UI part  55  of a subterminal is issued through the inter-terminal communication part  57 . The inter-terminal communication part  44  obtains the main terminal list from the main terminal list creation part  38  of the host device  20  and returns it to the UI part  40  (UI part  55  in the case of requests from a subterminal) (S 1420 ). The UI part  40  (or UI part  55 ) displays the main terminal list and the user selects a main terminal to be connected (S 1430 ). The inter-terminal communication part  44  (or inter-terminal communication part  57 ) communicates with a main terminal selected by communication information contained in the main terminal list (S 1430 ). If communication with a subterminal is requested, the UI part  40  (or UI part  55 ) obtains and displays a subterminal management table, which is a list of subterminals registered in a home network including the main terminal, from the authentication information management part  45  of the connected main terminal  21  through the inter-terminal communication part  44  (S 1440 ). The subterminal management table, as shown in FIG. 20, contains terminal IDs, terminal types, terminal names, and communication information for communicating with subterminals of interest. The user selects a subterminal from the displayed subterminal management table (S 1450 ). The inter-terminal communication part  44  (or the inter-terminal communication part  57 ) communicates with a terminal selected from communication information of the subterminal management table.  
         [0107]    In this example, connection is made to a desired main terminal of a home network, and then connection is made to a subterminal within the home network. However, alternatively, after the main terminal list creation part  39  of the host device  20  creates a list containing all subterminals within the home network from the main terminal management table and the subterminal management table respectively managed by the main terminal contract management part  36  and the subterminal management part  35 , the list may be sent to a main terminal or subterminal. This enables communication with a selected subterminal without communicating with a main terminal.  
         [0108]    When the UI part  40  (UI part  55 ) selects a main terminal, communication requests may be sent to the main terminal and all subterminals connected to the main terminal. In this case, communication is made with a terminal that responded earliest to the communication request. The authentication information management part  45  of the main terminal  21  beforehand may set terminals to which to send communication requests so that the communication requests are sent to one or more of the set terminals without sending the subterminal management table.  
         [0109]    In the case where users are managed by the subterminal management table as shown in FIG. 20, users, not terminals, may be selected as communication destinations. For example, in FIG. 20, a user “Gakuchan” may be selected. In the case where the user uses plural terminals, priority may be set. If “Gakuchan” is selected, communications with terminals having higher priorities (smaller numbers) are performed earlier. If communication fails for the reason of absence or the like, communication with a terminal having the next highest priority of the same user is tried. Other information exchange methods are possible: instead of setting priorities in advance in the subterminal management table, of terminals used by the individual, communication with a terminal having the shortest idol time is tried; terminals in which an IC card for identifying an individual is inserted are preferentially selected; and a query is made to all terminals within a network and communication is made with responding terminals. These conditions specific to terminals used are set in the inter-terminal communication part  44  (see FIG. 21), which attempts communication with individuals, based on the conditions.  
         [0110]    Considering the case where communication with a selected individual cannot be performed, alternative search conditions may be set in the inter-terminal communication part  44  (FIG. 22). In an example of FIG. 22, if communication with “Gakuchan” is impossible because “Message to mother” is set, connection is made with a terminal used by “mother” to pass a message. If “Cellular phone” is set, a call is issued to a phone number set in advance. If “Answerphone” is set, a message can be recorded. A mail address may be set so that mail is sent to the address.  
         [0111]    The abstract word “communication” in the above description specifically refers to phone, file transfer by telnet and ftp, and information exchange by chat. Conditions specific to terminals used and alternative search conditions may include conditions other than those described here, depending on information exchange methods.  
         [0112]    By thus achieving simple communication means between households holding contracts with one service provider, there can be provided services by which service providers undertaking contents delivery collect contractors.  
         [0113]    (Third Embodiment)  
         [0114]    A third embodiment of the present invention will be described with reference to FIG. 23. Components in the third embodiment that are identical to components in the first embodiment or second embodiment are identified by the same reference numbers; descriptions of them are omitted. The third embodiment is characterized in that a contents storage information management part  62  manages the storage statuses of plural contents storage parts within a home network.  
         [0115]    The third embodiment is the same as the first and second embodiments in that a subterminal management table containing the capacities of the respective storage devices of subterminals is managed by the authentication information management part  45 . For example, a subterminal management table as shown in FIG. 20 is held in the authentication information management part  45 . The contents storage information management part  62  manages a copy of information about terminal ID, terminal type, and capacity, storage states (the IDs, contents details, and contents capacities of stored contents, and available space) of individual terminals, and contents storage information about terminal takeout state (indicates whether the terminal can be accessed from within a home network). A takeout state is determined in such a way that the contents storage information management part  62  periodically checks all subterminals through the inter-terminal communication part  44 . Contents storage information is as shown in FIG. 24. Terminals can include transportable recording media. Available methods for determining whether access can be made from within a home network are to determine whether connection is made by cables, and whether wireless transmission speed is equal to or greater than a reference value.  
         [0116]    In such a configuration, referring to a flowchart of FIG. 26, a description will be made of the flow of processing of up to contents storage in the case where contents are delivered from a host terminal as shown in the first embodiment. The data receiving part  41  of the main terminal  21 , upon receiving data, queries the contents storage information management part  62  as to a subterminal (including transportable recording media) in which to store contents (S 1500 ). The contents storage information management part  62  holds contents storage location decision conditions as shown in FIG. 25 and decides a contents storage location according to the conditions (S 1510 ). Since FIG. 25 shows that a contents storage location decision condition is a terminal having a large available space, in the case where a query is issued from the data receiving part  41 , the contents storage information management part  62  refers to a contents storage management table of FIG. 24 and gives an indication to store contents in STB of ID 10000, which has the largest available space. The data receiving part  41  stores contents in the contents storage part of STB (S 1520 ).  
         [0117]    Although the flow of processing for reproducing contents is the same as that in the first embodiment, by displaying the contents management table in the UI part  40  (or UI part  55 ) along with contents management information held by the contents storage information management part  62 , whether access can be made to contents stored in terminals within a home network can be indicated to the user. This prevents the user from reproducing inaccessible contents. An example of presentation in the UI part  40  (or UI part  55 ) is shown in FIG. 27. Inaccessible contents can be reserved in the contents storage management information. For example, in the presentation example of FIG. 27, since “One day of Rikuchan” is stored in an electronic book taken out, it is appreciated that the contents cannot be accessed from the current home network. In such a case, a reservation is made in the UI part  40  (or UI part  55 ) and reservation details (reserved contents, a reserving terminal, etc.) are managed by the contents storage information management part  62 . The contents storage information management part  62 , when a taking-out terminal has become accessible, checks whether reservations are made for contents of the terminal, and if so, notifies the UI part  40  (or UI part  55 ) of a reserving terminal that the contents have become accessible.  
         [0118]    Although the above description has been made of the case where terminals are taken out of a home network, the following description will be made of a method for processing reproduction requests for contents stored in terminals taken out of a home network.  
         [0119]    When the subterminal  22  is to be taken out of the range of access to a home network, the user queries a takeout determination part  63  about whether the subterminal can be taken out, through the UI part  40 . The takeout determination part  63  queries the contents storage information management part  62  about whether the subterminal can be taken out, through the inter-terminal communication part  57  and the inter-terminal communication part  44 . The contents storage information management part  62  holds a takeout determination criterion as shown in FIG. 28 and determines whether the subterminal can be taken out, according to the takeout determination criterion. Only when the takeout determination criterion can be cleared, the contents storage information management part  62  issues takeout OK. Even in the case of takeout NG, when there is a strong desire to take out the subterminal, arrangements are made so that the takeout determination criterion can be cleared. For example, in the case where “there are no contents unique to the home network in the terminal” in the takeout determination criterion of FIG. 28 cannot be cleared, that is, contents existing in only the terminal exist, the contents are copied to another terminal such as a main terminal. Thereby, users of terminals other than the terminal taken out can satisfy their desire to reproduce the contents.  
         [0120]    As has been described above, by collectively managing storage states in plural contents storage parts within a home network and enabling takeout limitations and reservations for the contents, the states of storage devices of plural terminals within the home network can be shown in a form easily understandable to users because the storage devices appear to be one storage device.  
         [0121]    (Fourth Embodiment)  
         [0122]    A fourth embodiment of the present invention will be described with reference to FIG. 29. Components in the fourth embodiment that are identical to components in the first to third embodiments are identified by the same reference numbers; descriptions of them are omitted. The fourth embodiment is characterized in that a list of contents successfully stored by individual home networks is delivered to all (or part) of main terminals so that contents duplication and movement from other home networks are enabled.  
         [0123]    A contents list sending part  64  of the main terminal  21  creates a contents list from contents storage information managed by the contents storage information management part  62  and sends it to a contents list management part  65  of the host device  20 . In this case, the contents storage information may be added with list delivery conditions, contents delivery conditions, contents quality, and the like set by individual main terminals. The list delivery conditions are delivery levels of contents storage information by which setting can be made so that a contents list may be delivered to familiar associates and is not delivered to unfamiliar people. The contents delivery conditions, which are conditions for delivering contents to other home networks, may include time conditions such as all-day run and daytime run, and conditions for limiting home networks of delivery destinations. Contents quality refers to contents format and the like for users and terminals to determine whether to receive delivery. A contents list sent from the contents list sending part  64  to a contents list management part  65  is, for example, as shown in FIG. 30. Although, in the example, list delivery conditions and contents delivery conditions are grouped by home network, they may be grouped by contents.  
         [0124]    The contents list management part  65  collects contents storage information collected from plural host devices  20  and again sends it to the data receiving part  41  of all (or part) of main terminals  21 . A contents list delivered is as shown in FIG. 31. FIG. 31 shows merged contents lists from plural home networks, wherein the contents lists are delivered to only home networks meeting list delivery conditions. The UI part  40  of the main terminal  21  receives and displays a contents list from the data receiving part  41  (in the case of the UI part  55  of the subterminal, through the inter-terminal communication part  57  and the inter-terminal communication part  44 ), and the user selects necessary contents and receives the contents from a home network storing the contents.  
         [0125]    Although information exchange with other home networks is basically performed according to the method described in the second embodiment, if the same contents exist in plural home networks, home networks to receive delivery are selected according to terminal selection conditions as shown in FIG. 32 held in the inter-terminal communication part  44  (inter-terminal communication part  57 ).  
         [0126]    After receiving contents, the main terminal  21  receives a contents license from the host device  20  according to the method described in the first embodiment, so that the contents can be reproduced.  
         [0127]    Although the above description has been made of an example that the host device  20  collects and merges contents lists from the main terminal  21 , if, each time contents are sent from the host device  20 , it can be checked whether the contents have been successfully stored, contents lists do not need to be collected because the host device  20  can recognize storage states.  
         [0128]    A description will be made of an example of sharing contents lists among all (or some) of home networks by circulating the contents lists among main terminals. A configuration for achieving this is shown in FIG. 33. The contents list sending management part  66  of the main terminal  21  manages contents list sending information, which is information indicating the sending destinations of contents lists created by the contents list sending part  64 . An example of the contents list sending information is shown in FIG. 34. The contents list sending part  64  sends a contents list created by the to the inter-terminal communication part  44  of a main terminal  21  of a destination home network indicated by the contents list sending information. Upon receiving the contents list, the inter-terminal communication part  44  passes the contents list to the contents storage information management part  62 , and passes it to the contents list sending part  64  along with contents storage management information managed by itself. The contents list sending part  64  merges the received contents list and the contents storage management information to create a contents list and sends the contents list to the inter-terminal communication part  44  of a main terminal  21  of a sending destination home network indicated by the contents list sending information. Contents list sending destination-information is set so that contents lists are transferred in a wraparound form. In a second round or later, a contents list previously added by a relevant home network itself is corrected. The circulation of contents lists is shown in FIG. 35. This enables the same contents lists as shown in FIG. 31 to be shared among home networks; selection and subsequent operations in the UI part are as described in the above description.  
         [0129]    When contents are delivered from other home networks, they are created and managed as a contents delivery history in a contents delivery history creation part  67 . The contents delivery history, which is, for example, as shown in FIG. 36, consists of delivery date, delivery source home network (main terminal ID), contents ID, and the like. A contents delivery history management part  68  of the host device  20  collects contents delivery histories of individual main terminals and compiles them for each of delivery source home networks. A resultant contents delivery history compilation table is, for example, as shown in FIG. 37, and shows a history of contents deliveries from individual home networks (main terminals) to other home networks. A contents delivery charge computation part  69  decides charges paid for contents delivery operations of individual home networks from the contents delivery history compilation table. Decided charges are, for example, as shown in a computation result table of FIG. 38. Although, in an example of FIG. 38, charges are determined as 10 yen per contents delivery, charges may be decided for the total of sizes of delivered contents. Charge computations for contents delivery operations by the contents delivery history creation part  67 , the contents delivery history management part  68 , and the contents delivery charge computation part  69  are also applicable to the contents delivery system of FIG. 29.  
         [0130]    By thus offering contents lists to subterminals and enabling contents deliveries from other home networks, even contents having been delivered from the host device can be provided to users. Also, by compiling contents delivery histories and enabling charge computations according to the delivery histories, a business is established in which service providers managing contents and licenses and performing contents delivery pay charges for contents delivery operations to contractors of main terminals having performed contents delivery in place of the host device.  
         [0131]    Although the present invention has been described based on preferred embodiments shown in the drawings, it is apparent that those skilled in the art may easily change and modify the invention, and such modifications are also included within the scope of the invention.