Abstract:
An apparatus, system and method for giving and taking an RO for a content between devices are provided. The provided method includes both a method for directly giving and taking the RO between devices and a method for giving and taking the RO through a network server. Accordingly, the apparatus, system and method provide the capability of giving and taking an RO between respective devices and improve the ability expand functions.

Description:
PRIORITY 
       [0001]    This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Industrial Property Office on Sep. 22, 2006 and assigned Serial No. 2006-0092438, the entire disclosure of which is hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a method, an apparatus and a system for managing a Digital Rights Management environment. More particularly, the present invention relates to a method, an apparatus, and a system for giving and taking a Rights Object (RO) for a content in an environment to which a Digital Rights Management (hereinafter, referred to as DRM) is applied. 
         [0004]    2. Description of the Related Art 
         [0005]    Content services have been gradually expanding to include charged services. When providing charged services, a content provider has provided content services based on initial copy protection technology. More recently however, a DRM technology based on the flexibility and convenience for user&#39;s RO has been introduced. 
         [0006]    Such DRM technology basically permits free distribution of encrypted content among users. However, a user is not allowed to execute the content until the user purchases an RO which contains information including authority to use the content. Such DRM technology, which is a representative security technique for content protection, defines an encrypted content and an authority to use the content. In one implementation, a domain for content sharing is created by grouping devices that intend to share their contents with each other on a network having one identical service provider. So configured, such a group can share an encryption key corresponding to the domain thereof and a member belonging to the domain is determined based on the shared encryption key. To this end, the service provider mainly manages registration or secession of terminals to or from the domain. 
         [0007]    A domain defined in OMA DRM v2.0 is used as a conventional construction for sharing contents among devices. Such a conventional DRM system is shown in  FIG. 1 . Hereinafter, a domain structure and a procedure of sharing contents based on common OMA DRM v2.0 will be described. As shown in  FIG. 1 , a plurality of devices  12  and  13  belong to one domain  14 , and a Rights Issuer (RI)  11  transmits a content and an RO for the content to the devices  12  and  13 . Entities playing a major role in an environment to which a DRM is applied include devices  12  and  13  for reproducing the content by using the RO, and the RI  11  (i.e. a service provider) for generating and issuing a usage RO for the content. Such devices  12  and  13  are registered in a specific domain through communication with the RI  11 . The devices  12  and  13 , having been registered in the domain, acquire a domain key and decrypt a domain RO through the acquired domain key, thereby using the content. 
       SUMMARY OF THE INVENTION 
       [0008]    As described above, in order to protect distributed contents, an authentication procedure is performed between a service provider and a terminal. Conventional related standards of such content protection methods include an OMA DRM v2.0. However, there has never been a detailed disclosed method with respect to a rights movement, or related standard technologies, between respective devices in an environment to which a DRM is applied. Therefore, it is not possible to apply a rule capable of giving and taking an RO between respective devices to a structure of the current standard. This causes a structural problem and thus may be a barrier to function expansion. 
         [0009]    An aspect of the present invention is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method, an apparatus, and a system for giving and taking an RO for a content between devices. 
         [0010]    In accordance with another aspect of the present invention, a method for transmitting and receiving a Rights Object (RO) for a content between one or more devices is provided. The method includes transmitting to at least one second device by a first device of the devices, a content list for a right to be transmitted, receiving an identifier for a content designated according to user&#39;s input from the second device, transmitting, by the first device, information of the right for the designated content based on the received identifier and, when the second device makes a request for a right as much as the second device wants to receive, transmitting, by the first device, the right as much as the second device wants to receive. 
         [0011]    In accordance with another aspect of the present invention, a method for transmitting and receiving an RO for a content between devices in a system including one or more devices and a Rights Issuer (RI) is provided. The method includes transmitting to the RI by a first device of the devices, information of a right to be transmitted, transmitting to the second device by the RI, a message asking if the second device will receive the information of the right and transmitting the information of the right to the second device by the RI when receiving an approval message with respect to transmission of the asking message. 
         [0012]    In accordance with another aspect of the present invention, a method for transmitting and receiving an RO for a content between devices in a system including one or more devices and an RI is provided. The method includes transmitting to the RI by a first device of the devices, information of a right to be transmitted, transmitting to the second device by the RI, a message requiring start of a process of acquiring the information of the right from the first device and bringing, by the second device, the right from the RI when receiving the message. 
         [0013]    In accordance with another aspect of the present invention, a method for transmitting and receiving an RO for a content between devices in a system including one or more devices and an RI is provided. The method includes transmitting to the RI by a first device of the devices, information of a right to be transmitted, transmitting to the second device by the first device, the information of the right to be transmitted, when receiving a confirmation message from the RI and transmitting, by the RI, the right to the second device, when an approval message is received from the second device. 
         [0014]    In accordance with another aspect of the present invention, a system for transmitting and receiving an RO for a content between devices is provided. The system includes a first device for transmitting information of a right to be transmitted, to an RI, the RI for transmitting a message, asking if a second device will receive the information of the right, to the second device when receiving the information of the right, and transmitting the information of the right to the second device when receiving an approval message from the second device and the second device for transmitting a response message, indicating approval or disapproval, to the RI when receiving the message, asking if the second device will receive the information of the right, from the RI, and receiving the right from the RI when transmitting an approval message indicating the reception of the information of the right. 
         [0015]    In accordance with another aspect of the present invention, an apparatus for transmitting and receiving an RO for a content is provided. The apparatus includes a move management module for transmitting a content list for a right to be transmitted to another device, transmitting information of the right for a corresponding content to said another device when an identifier for the content designated by said another device is received, and transmitting a right as much as said another device designates, a rights management module for forwarding information of a corresponding right based on the identifier to the move management module, generating an RO for the right as much as said another device designates to forward the generated RO to the move management module, and removing information of transmitted right when a confirmation message is received from said another device; and a secure storage module for storing a right for use at the time of the content reproduction. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above and other aspects, features and advantages of certain exemplary embodiments of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a diagram illustrating a structure of a conventional domain in a DRM system; 
           [0018]      FIG. 2  is a diagram illustrating how an RO is moved according to an exemplary embodiment of the present invention; 
           [0019]      FIG. 3  is a diagram illustrating an internal construction of a device according to an exemplary embodiment of the present invention; 
           [0020]      FIG. 4  is a flowchart illustrating an inter-device transmission/reception of a message for RO movement according to an exemplary embodiment of the present invention; 
           [0021]      FIG. 5  is a flowchart illustrating an inter-device transmission/reception of a message through an RI according to an exemplary embodiment of the present invention; 
           [0022]      FIG. 6  is a flowchart illustrating an inter-device transmission/reception of a message through an RI according to another exemplary embodiment of the present invention; 
           [0023]      FIG. 7  is a flowchart illustrating an inter-device transmission/reception of a message through an RI according to yet another exemplary embodiment of the present invention; 
           [0024]      FIG. 8  is a schematic diagram illustrating a procedure for generating an RO according to an exemplary embodiment of the present invention; and 
           [0025]      FIG. 9  is a view illustrating a generated RO according to an exemplary embodiment of the present invention. 
       
    
    
       [0026]    Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features and structures. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0027]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness. For convenience, the present invention uses names of entities that Open Mobile Alliance (OMA), i.e. a standard organization of a device application has been defining. However, it goes without saying that the standards and names do not limit the scope of the present invention which can be applied to a system having similar technical background. 
         [0028]    The present invention provides a method for giving and taking an RO between devices in an environment to which a DRM is applied. To this end, exemplary embodiments of the present invention provide two methods, which include a method for directly providing an RO between devices, and a method for providing an RO based on a network server, such as an RI. Therefore, since the RO can be mutually given and taken between devices, it is possible to freely reproduce a content between multiple devices. 
         [0029]    The methods will be described with reference to  FIG. 2 . The methods include a method for directly providing an RO between devices having the above-described function, and a method for providing an RO to another device through an RI. 
         [0030]      FIG. 2  is a diagram illustrating how the RO is moved according to an exemplary embodiment of the present invention. 
         [0031]      FIG. 2  shows a flowchart of a message for the RO provision, which is proposed based on a basic structure that an OMA DLDRM Sub-Working Group (SWG) has been discussing. 
         [0032]    First, in order to directly give and take an RO between devices, mutual authentication must be performed between the devices. A secure channel is established between a device- 1   10  and a device- 2   20  through such mutual authentication. If the secure channel is established through the mutual authentication, the device- 1   10  can separate information of the right from an RO for its own content and transmit an RO for the separated right to the device- 2   20 . The device- 2   20  transmits a confirmation message after receiving the RO for the separated right, so that the device- 2   20  can use the RO transferred from the device- 1   10 . 
         [0033]      FIG. 2  also shows a method for transferring an RO from the device- 1   10  to the device- 2   20  through the RI  30 . In order to give and take the RO between the device- 1   10  and the device- 2   20 , mutual authentication must be performed. According to a relay scheme through the RI, the RI  30  authenticates each of the device- 1   10  and the device- 2   20 , and forwards the RO from the device- 1   10  to the device- 2   20  after the mutual authentication. Through the above-described methods, which include a direct transmission method and a relay transmission method through the RI, it is possible to mutually give and take the RO between devices, that is, the RO can be transferred from the device- 1   10  to the device- 2   20  or the RO can be transferred from the device- 2   20  to the device- 1   10 . 
         [0034]    Hereinafter, a construction and an operation of a device having the above-described functions will be described with reference to  FIG. 3 .  FIG. 3  is a v diagram illustrating an internal construction of the device- 1   10  and the device- 2   20  according to an exemplary embodiment of the present invention. Referring to  FIG. 3 , the device- 1   10  includes an application module  100 , a registration module  110 , an authentication module  120 , a rights management module  130 , a content management module  140 , a move management module  150 , a crypto library module  160 , a secure storage module  170 , a communication module  180 , and a User Identity Module InterFace (UIM I/F) module  190 . 
         [0035]    In an exemplary implementation, the application module  100  includes a module as a media player for receiving a decrypted content and reproducing the received content. 
         [0036]    The registration module  110  performs resignation, service subscription, content usage management and the like. That is, the registration module  110  performs an operation according to the registration of a device and a service provider. The authentication module  120  manages authentication protocol execution of a UIM, such as a smart card including the user&#39;s identity, with a network, and generates and verifies a message by using its sub-module. The rights management module  130  manages the reproduction of the content according to a right within the device. The content management module  140  performs secure decryption of the content and interpretation of the content. The move management module  150  manages an RO to be moved to a counterpart device. 
         [0037]    The modules  100  to  150  interwork with the crypto library module  160  and perform encryption, decryption, electronic signature, etc. The secure storage module  170  stores an encryption key, and the UIM IF module  190  communicates with a user identification module. The communication module  180  transmits and receives data through a network. In particular, the communication module  180  receives a message from a network, and transmits a response message with respect to the received message. 
         [0038]    Hereinafter, the process of message transmission and reception between devices for RO movement according to an exemplary embodiment of the present invention will be described with reference to  FIG. 4 .  FIG. 4  illustrates a method of direct RO movement between the device- 1   10  and the device- 2   20 . In particular, an example of transferring an RO from the device- 1   10  to the device- 2   20  will be described. 
         [0039]    In step  200 , the device- 1   10  transmits a list of contents for an RO to be transmitted to the device- 2   20 . For example, the device- 1   10  transmits the names of content for a right to be transferred, to the device- 2   20 . 
         [0040]    Then, a user selects and designates desired contents to be received in the device- 2   20  from the list of contents. In step  210 , the device- 2   20  transmits an identifier (ID) for the designated content to the device- 1   10 . The above-described operations are performed in each move management module  150  constructed within the device- 1   10  and the device- 2   20 . 
         [0041]    The device- 1   10  receives the content ID designated by the device- 2   20 , thereby recognizing which content right to transfer. In step  220 , the device- 1   10  loads information of the right associated with the designated content into a message, and transmits the message to the device- 2   20 . Herein, the information of the right denotes information of the right included in the RO. For example, the device- 1   10  transmits information, indicating that the device- 1   10  possesses a right capable of playing an MP3 file ten times, to the device- 2   20 . In this case, the move management module  150  of the device- 1   10  receives information of the corresponding right from the rights management module  130 , generates the received information into a message constructed in the format as shown in Table 1 below, and forwards the generated message to the device- 2   20 . 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
             
               
                   
                 Permission X1 
                 Constraint Y1 
               
               
                   
                 Permission X2 
                 Constraint Y2 
               
               
                   
                 . . . 
                 . . . 
               
               
                   
                   
               
             
          
         
       
     
         [0042]    In Table 1, “permission” indicates a class of a usage right for a content and “constraint” indicates the amount of a right based on the usage right. A typical example of the permission includes “play” allowing the reproduction of the content, and “print” allowing printing of the content. A typical example of the constraint includes “count” indicating the number of usage permission, and “start time/end time” indicating time allowed for use of the content. 
         [0043]    When the device- 2   20  receives the message constructed in the format as shown in Table 1, the device- 2   20  transmits specified right information on a desired part selected by the user from among the entire right information to the device- 1   10  in step  230 . For example, when the device- 1   10  transmits information, indicating that the device- 1   10  possesses the right capable of playing a specific MP3 file ten times, to the device- 2   20  in step  220 , the device- 2   20  may transmit a message, which indicates that the device- 2   20  wants to obtain a right capable of playing the MP3 file five times from among the right capable of playing the MP3 files ten times, to the device- 1   10  in step  230 . In this case, the device- 2   20  appoints a value, indicating the amount of the right the device- 2   20  wants to receive, to a corresponding constraint of each permission and transmits the message including the appointed value. The response message transmitted from the device- 2   20  to the device- 1   10  as described above is constructed in the format as shown in Table 2 below. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
             
             
               
                   
                 Permission X1 
                 Constraint Y11 
               
               
                   
                 Permission X2 
                 Constraint Y21 
               
               
                   
                 . . . 
                 . . . 
               
               
                   
                   
               
             
          
         
       
     
         [0044]    Table 2 shows a case where a right as much as a constraint Y11 is set for the permission X1, and a right as much as a constraint Y21 is set for the permission X2. That is, the Y11 and the Y21 are values appointed by the device- 2   20 . As described above, the device- 2   20  can appoint a right as much as the device- 2   20  wants at the constraints according to a class of a usage right for a content. 
         [0045]    In step  240 , the device- 1   10  generates a right as much as the device- 2   20  designates in the form of an RO message, and transmits the generated message to the device- 2   20 . The message format forwarded to the device- 2   20  includes each field of Device- 1  ID (i.e. identity information of the device- 1   10 ), an RO containing a right, a TS (i.e. time stamp), and an electric signature. That is, when the rights management module  130  of the device- 1   10  generates as much RO as the device- 2   20  designates and forwards the generated RO to the move management module  150 , the move management module  150  forwards the RO to the device- 2   20  in the format of the message. 
         [0046]    After receiving the message, the device- 2   20  transmits a reception confirmation message to the device- 1   10  in step  250 . Then, the rights management module  130  of the device- 1   10  removes a permission and a constraint of the transferred right from its own right. That is, the device- 1   10  removes a permission and a constraint representing a right transferred to the device- 2   20 . For example, if the device- 1   10  transfers the right capable of playing a specific MP3 file five times to the device- 2   20 , the device- 1   10  removes the transferred right capable of playing a file five times from among its own right (i.e. an entire right) capable of playing a file ten times. 
         [0047]    Hereinafter, a method for giving and taking an RO between the device- 1   10  and the device- 2   20  through the RI relay will be described. Exemplary embodiments of the present invention will be separately described as follows. An exemplary embodiment of the present invention deals with a method for right transmission from the device- 1   10  to the device- 2   20  through the RI, another exemplary embodiment of the present invention deals with a method for right transmission through the RI based on the OMA DRM v2.0, and yet another exemplary embodiment of the present invention deals with a method by which the device- 2   20  receives the RO from the device- 1   10  based on a message that the device- 1   10  transmits to the RI. 
         [0048]      FIG. 5  is a flowchart of an inter-device transmission/reception of a message through the RI according to an exemplary embodiment of the present invention. 
         [0049]    Referring to  FIG. 5 , in step  300 , the device- 1   10  transmits a message to the RI  30 , the message including an ID of a content to be transmitted to the device- 2   20 , information of a right, an ID of the device- 1   10  (i.e. a transmitter), an ID of the device- 2   20  (i.e. a receiver), and a TS. In this case, the move management module  150  of the device- 1   10  obtains information of the corresponding right through the rights management module  130 . The above-described information of the right is constructed to have the same format as shown in Table 1. 
         [0050]    As such, if the device- 1   10  transmits information of a right in the form of a message, the RI  30  transmits a confirmation message with respect to the received message to the device- 1   10  in step  310 . In step  320 , the RI  30  forwards the message from the device- 1   10  to the device- 2   20 . 
         [0051]    If the device- 2   20  receives the message, the device- 2   20  notifies a user that the message is received. In step  330 , the device- 2   20  transmits a message indicating which content right to take. Herein, the right is designated according to the user selection. In this case, according to the user selection, the move management module  150  within the device- 2   20  transmits a response message indicating approval or disapproval for the right. If the device- 2   20  transmits a response message indicating disapproval for the right to the RI  30  (e.g. “No”), the RI  30  determines that the device- 2   20  denies the reception of the right, and thus terminates the processes according to a current protocol. 
         [0052]    In contrast, if the RI  30  receives a response message indicating approval for the right from the device- 2   20  (e.g. “Ok”), the RI  30  generates an RO based on the information of the right received from the device- 1   10 . In step  340 , the RI  30  forwards information including the generated RO, an ID of the device- 1   10 , an ID of the device- 2   20 , a TS, and data obtained by adding its own electric signature for such information, to the device- 2   20 . The move management module  150  of the device- 2   20  receives the message having the format as described above, and the move management module  150  forwards the RO included in the received message to the rights management module  130 . Therefore, the device- 2   20  stores the RO transferred from the device- 1   10  in the secure storage module  170  so as to use the stored RO at the time of content reproduction. 
         [0053]    In step  350 , the move management module  150  of the device- 2   20  transmits a confirmation message, indicating that the right has been safely received, to the RI  30 . In step  360 , the RI  30  transmits the confirmation message to the device- 1   10 . Then, the rights management module  130  of the device- 1   10  removes a permission and a constraint indicating the right transferred from its own right. 
         [0054]      FIG. 6  is a flowchart illustrating an inter-device transmission/reception of a message through an RI according to another exemplary embodiment of the present invention. 
         [0055]    Since steps  400  and  410  of  FIG. 6  are identical with steps  300  and  310  of  FIG. 5 , a detailed description thereof will be omitted. If the RI  30  obtains information of a right from the device- 1   10  through steps  400  and  410 , the RI  30  transmits an ROAP Trigger message, requiring the reception of an RO from the device- 1   10 , to the device- 2   20  based on the OMA DRM v2.0 in step  420 . That is, the ROAP Trigger message functions to make the device- 2   20  begin to acquire the RO of the device- 1   10 . 
         [0056]    In step  430 , the device- 2   20  having the received ROAP Trigger message recognizes that the device- 2   20  must bring the RO from the RI  30 , and thus transmits an RO request message to the RI  30  based on OMA RM v2.0. In step  440 , the RI  30  generates an RO based on the preliminarily received information of the right, and forwards the generated RO to the device- 2   20  by using the RO response message in the OMA DRM v2.0. In step  450 , the RI  30  transmits a confirmation message, indicating that the RI  30  has transferred the RO to the device- 2   20 , to the device- 1   10 . Therefore, the device- 1   10  removes a permission and a constraint indicating the right transferred from among its own right. 
         [0057]    Hereinafter, according to yet another exemplary embodiment of the present invention, a method by which the device- 2   20  receives the RO through the RI based on the message transmitted by the device- 1   10  will be described with reference to  FIG. 7 . 
         [0058]      FIG. 7  is a flowchart illustrating an inter-device transmission/reception of a message through the RI according to another exemplary embodiment of the present invention. Unlike the above-described exemplary embodiments, the exemplary embodiment illustrated in  FIG. 7  deals with a process by which the device- 2   20  receives the RO from the device- 1   10  based on the message transmitted by the device- 1   10 . 
         [0059]    Referring to  FIG. 7 , since steps  500  and  510  of  FIG. 7  are identical with steps  300  and  310  of  FIG. 5 , a detailed description thereof will be omitted. The RI  30  performs authentication in transmitting the information of the right from the device- 1   10  to the device- 2   20  through steps  500  and  510 . When the device- 1   10  successfully performs the authentication and receives the confirmation message from the RI  30 , the device- 1   10  directly transmits the information of the right together with the message to the device- 2   20  in step  520 . Herein, the information of the right is to be transferred, and the message includes an ID of the device- 1   10 , an ID of the device- 2   20  (i.e. a receiver), and a TS. In this case, the information of the right is constructed in the format as shown in Table 1 above. 
         [0060]    When the device- 2   20  receives the message, the device- 2   20  notifies a user that the message is received. In step  530 , the device- 2   20  transmits the message, indicating which content right to take. Herein, the right is designated according to the user&#39;s selection. In this case, the move management module  150  within the device- 2   20  transmits a response message indicating approval or disapproval for the right according to the user selection. If the device- 2   20  transmits a response message, indicating disapproval for the right (e.g. “No”), to the RI  30 , the RI  30  determines that the device- 2   20  denies the reception of the right, and thus terminates the processes based on a current protocol. 
         [0061]    In contrast, if the device- 2   20  transmits a response message indicating approval for the right (e.g. “Ok”), the RI  30  performs steps  540  to  560  similar to steps  340  to  360  of  FIG. 5 . Therefore, it is possible to give and take a right between the device- 1   10  and the device- 2   20 . When one user uses a plurality of devices, it is possible to share a right among them. It is also possible to conveniently reproduce a content at any time, even though any device may be used. 
         [0062]    In the above exemplary embodiments, one device separates a partial RO from an entire RO and then provides the separated partial RO to another device. However, according to another exemplary embodiment, the entire RO may include a separate transferable RO, so that the separate RO can be provided to another device. 
         [0063]      FIG. 8  is a schematic block diagram illustrating a procedure of generating the RO according to an exemplary embodiment of the present invention. In particular,  FIG. 8  shows a method for generating a separate RO. Referring to  FIG. 8 , a device corresponding to a host  600  includes a separate sub-RO within the entire RO, so that it is possible to separate only the sub-RO from the entire RO and provide the sub-RO to another device, such as a client device  610 , as indicated by reference numeral  620  in  FIG. 8 . 
         [0064]      FIG. 8  shows an entire RO including one sub-RO. However, the entire RO may include multiple sub-ROs as illustrated in  FIG. 9 . Therefore, when multiple sub-ROs are within the entire RO, it is also possible to transmit each of the sub-ROs to different devices. 
         [0065]    Exemplary embodiments of the present invention provide a method for giving and taking an RO between different devices, so that it is possible to freely reproduce a content among a plurality of devices based on the RO. 
         [0066]    While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.