Abstract:
An apparatus for digital home domain management includes a home domain server which manages in one user domain all user terminals within a home group and provides each user terminal with a domain license in contents; and a DRM coupler which provides the contents and domain licenses converted to conform to a DRM type loaded in user terminals if contents sharing is requested among user terminals loaded with different DRMs within the home group.

Description:
CROSS-REFERENCE(S) TO RELATED APPLICATION(S) 
       [0001]    The present invention claims priority of Korean Patent Application No. 10-2008-0131777, filed on Dec. 22, 2008, which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to digital rights management (referred to as DRM hereinafter), and, more particularly, to a method and apparatus that manages a number of user terminals loaded with different DRM technologies under a domain, receives a domain license from a domain management server of a content provider and provides contents and the domain license converted in a form appropriate for individual user terminals by coupling with DRM. 
       BACKGROUND OF THE INVENTION 
       [0003]    In general, DRM technology is a technology that prevents illegal circulation of digital contents and promotes safe circulation of digital contents and, in order to construct such DRM system encryption and decryption techniques, charge, permission to use and public-key infrastructure techniques are employed. 
         [0004]    Domain management is a technique to share the contents among a number of terminals by managing the terminals possessed by one user in a bundled unit called a domain. In general, the domain management technique has been used to realize content sharing based on a domain among terminals loaded with an identical DRM technique. Conventional DRM-based domain management is carried out on the domain management server of a content provider (referred to as CP hereinafter) on which all the terminals on the domain are registered and managed. 
         [0005]    When a user needs to use contents provided by a variety of CPs, however, it is difficult to manage user terminals in a uniform and consistent manner because domain management servers of CPs are managed independent of each other and, therefore, the service is limited to use only the CP which supplies the same DRM as that chosen on the user&#39;s terminal. 
         [0006]      FIG. 1  shows a domain management method based on a conventional DRM. 
         [0007]    It is supposed that a home group denoted by user  10  has three terminals, terminal A  20 , terminal B  30  and terminal C  40 , and that DRM-A is loaded on the first two, terminal A  20  and terminal B  30 , whereas DRM-B is loaded on the last, terminal C  40 . 
         [0008]    In this case, the domain of user  10  that consists only of the two terminals, terminal A  20  and terminal B  30 , are managed on domain server  60  of content provider  50  (hereinafter, CP) which provides DRM-A and the other terminal, terminal C  40 , is not comprised in the domain since it employs DRM-B that is different from the one provided by CP  50 . 
         [0009]    If user  10  purchases contents from CP  50  using a terminal, say terminal A  20 , domain server  60 , issues a domain license to the terminal and, therefore, the contents can be used on terminal A thanks to the issued domain license. Any other terminals that comprise the domain can use the contents as well, since the domain license can be copied on them. A terminal, i.e., terminal C  40 , of user  10  that does not comprise the domain, however, cannot use the contents even if the contents and domain license are copied and transmitted to the terminal, because it is not allowed to use the copied domain license. Conventional domain management techniques have been designed under the assumption that CP and the user&#39;s terminals are loaded with an identical DRM, and hence it is impossible to share purchased contents among the terminals loaded with different DRMs. 
         [0010]    If there exists another CP which provides DRM-B, contents purchased from the CP could be used only on terminal C  40  with DRM-B but not on other terminals, terminal A and terminal B, loaded with DRM-A. In this case, a domain server of this CP would manage a domain that consists of terminal C  40 . Note that this domain is independent of the one managed by domain server  60  mentioned in the above. 
         [0011]    In conventional domain management techniques, different content providers comprise mutually independent domains and, hence, a user should employ separate management processes using respective CPs for domains of his terminals that are loaded with different DRM techniques. 
       SUMMARY OF THE INVENTION 
       [0012]    In view of the above, the present invention provides an apparatus and method for digital home domain management which allows sharing of license and contents among a number of user terminals loaded with different DRM techniques, wherein the domain license gets issued from the domain management server of a CP by managing in a domain all the user terminals that were subject to separate domain servers of various CPs and user terminals are supplied with the contents and domain licenses converted to conform to respective DRMs on them. 
         [0013]    In accordance with one aspect of the present invention, there is provided an apparatus for digital home domain management, including: 
         [0014]    a home domain server which manages in one user domain all user terminals within a home group and provides each user terminal with a domain license in contents; and 
         [0015]    a DRM coupler which provides the contents and domain licenses converted to conform to a DRM type loaded in user terminals if contents sharing is requested among user terminals loaded with different DRMs within the home group. 
         [0016]    In accordance with another aspect of the present invention, there is provided a method for digital home domain management, including: 
         [0017]    managing in one user domain all user terminals within a home group; 
         [0018]    converting a license in contents that was purchased for one of the user terminals in order to conform to each user terminal with a domain license issued for the user domain; 
         [0019]    converting the contents to conform to each DRM type if contents sharing is requested among user terminals loaded with different DRMs; and 
         [0020]    providing the converted domain license and contents for each user terminal within the home group. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The above features of the present invention will become apparent from the following description of an embodiment given in conjunction with the accompanying drawings, in which: 
           [0022]      FIG. 1  shows a block diagram of a conventional domain management system. 
           [0023]      FIG. 2  shows a block diagram of a domain management system in accordance with an embodiment of the present invention. 
           [0024]      FIG. 3  shows a detailed block diagram of a home domain server and DRM coupler in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0025]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0026]      FIG. 2  shows a block diagram of a domain management system in accordance with an embodiment of the present invention. In comparison with  FIG. 1 , the domain management system in  FIG. 2  in accordance with an embodiment of the present invention has a home domain server  100  and a DRM coupler in addition to the conventional domain management system depicted in  FIG. 1 . 
         [0027]    There are two important differences between the two domain management systems. First, it is home domain server  100  in the home group of user  10  that manages the domain of user  10  in an embodiment of the present invention, whereas it is domain server  60  in CP  50  in the conventional system. Second, while, in the conventional system, domain server  60  of CP  50  manages in a domain only those terminals, terminal A  20  and terminal B  30 , loaded with a DRM (DRM-A) identical to that chosen by CP  50 , in an embodiment of the present invention, all terminals, terminal A, terminal B and terminal C, of user  10  are managed in a user domain irrespective of the type of DRMs loaded on them. 
         [0028]    Suppose that user  10  purchases a content from CP  50  using terminal A  20 . Then a content with DRM-A applied is transmitted from CP  50  directly to terminal A  20  as before. However, a license for DRM-A is first issued to home domain server  100  from domain server  60  of CP  50 . Referring to the domain information of user  10 , home domain server  100  generates a domain license in accordance with DRM-A used on a terminal A  20  and issues it to terminal A  20 . 
         [0029]    When user  10  wants to share the content on terminal A  20  loaded with DRM-A on terminal B  30  with the same DRM-A, the content and domain license are copied and transmitted to terminal B  30 , and the transmitted content and license can be used without having to go through any modifications since they are of the same DRM. 
         [0030]    When user  10  wants to share the content on terminal A  20  loaded with DRM-A on terminal C  40  with a different DRM, say DRM-B, the content with DRM-A applied is converted to a content with DRM-B applied through DRM coupler  200  and then transmitted to terminal C  40 . Terminal C  40  requests home domain server  100  for the license in the content to be issued. Home domain server  100 , referring to the domain information of user  10 , generates a domain license in accord with DRM-B used on terminal C  40  and then issues it to terminal C  40 . Because the content and domain license transmitted to terminal C  40  has been converted to conform to DRM-B loaded on itself, terminal C  40  can use the content. 
         [0031]      FIG. 3  shows a detailed block diagram of a home domain server  100  and DRM coupler  200  in a digital home domain management system in accordance with an embodiment of the present invention. Home domain server  100  comprises a domain server register  110 , a domain license manager  120 , a domain manager  130 , a terminal manager  140  and a domain management information database  150 , whereas DRM coupler  200  comprises a license converter  210 , a content converter  220  and a DRM processor  230 . 
         [0032]    Respective components of home domain server  100  shall be explained in detail by referring to  FIG. 3 . 
         [0033]    Home domain server  100  consists of a terminal manager  140  that identifies, authenticates and manages terminals of the user, a domain manager  130  that determines the domain comprises of which terminals, a domain management information database  150  that stores information about the terminals and domain, a domain server register  110  that registers home domain server  100  on domain server  60 , and a license manager  120  that generates and issues a domain license to the terminals in the domain using the license issued from domain server  60  of CP  50 . 
         [0034]    Domain manager  140  identifies, authenticates and manages terminals of the user and extracts from the respective terminals information about the DRMs loaded on them to pass to domain manager  130 . 
         [0035]    Domain manager  130  generates, deletes and manages the user domain based on the terminal information passed from terminal manager  140  and records on domain management information database  150  the domain setting information including which terminal belongs to which domain and which DRMs are loaded on the respective terminals on the domain. 
         [0036]    Domain server register  110  registers home domain server  100  on domain server  60  of CP  50  to take over the role as the domain license issuer played by domain server  60  of conventional CP  50 . Once home domain server  100  is registered on domain server  60  of CP  50 , domain server  60  of CP  50  relegates the issuing service of domain licenses to home domain server  100 . 
         [0037]    Domain license manager  120  generates, using the license issued from domain server  60  of CP  50 , the domain license based on the domain information of the respective user terminals and the terminal information that reside on domain management information database  150  and then issues the domain license to the user terminals. Using domain management information database  150 , domain license manager  120  finds which type of the DRM is loaded on the user terminal for which the domain license is to be issued and license converter  210  of DRM coupler  200  is used to convert to a domain license that is appropriate for the terminal. 
         [0038]    On domain management information database  150  are stored and managed the information about identification, authentication and DRM of the terminals managed by terminal manager  140 , the information about the domain generated in domain manager  130  and the terminal information on the domain. It is also a storage where domain license manager  120  records the license issued from domain server  60  of CP  50 . 
         [0039]    Respective components of DRM coupler  200  shall be explained in detail by referring to  FIG. 3 . 
         [0040]    DRM coupler  200  consists of a content converter  220  that converts a content between different DRMs, a license converter  210  that converts a license between different DRMs and a DRM processor  230  that includes DRM modules necessary to apply and remove DRMs in various converters for content and license conversions. 
         [0041]    Content converter  220  is used to convert a content with DRM-A applied to that with DRM-B applied. Content converter  220  is given the content from user terminal A  20  on which DRM-A is loaded, releases DRM-A applied on the content using DRM processor  230 , applies DRM-B instead and delivers the content to user terminal C on which DRM-B is loaded. 
         [0042]    License converter  210  converts the license in conformance with the DRM of the user terminal to which the domain license is to be issued, when the license issued from domain server  60  of CP  50  needs to be issued in the form of a domain license to a user terminal using a DRM different from that in domain server  60 . 
         [0043]    License converter  210  receives the license information from domain license manager  120 , converts using DRM processor  230  and then returns the converted license information back to domain license manager  120 . Domain license manager  120  generates the domain license for the user terminal using the converted license information and passes to the user terminal. 
         [0044]    DRM processor  230  includes DRM packager and unpackager modules used in content converter  220  as well as a permission language conversion module. It provides all processing modules necessary for use in the course of DRM coupling. 
         [0045]    While the invention has been shown and described with respect to the embodiment, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.