Abstract:
It is an object of this invention to protect a copyright for each of subcontents of a digital content. A computer system, comprising: a content providing server for providing a user terminal with a digital content obtained through digitization; and a copyright management server for managing copyright information on the digital content, wherein the content providing server is configured to: obtain copyright information set for each of subcontents included in the digital content from the copyright management server; associate the obtained copyright information with the each of the subcontents, and add the copyright information to the digital content; and transmit the digital content to which the copyright information is added to the user terminal.

Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims priority from Japanese patent application JP 2009-267212 filed on Nov. 25, 2009, the content of which is hereby incorporated by reference into this application. 
       BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to a system for managing copyright information on digital contents, and more particularly, to a technology of managing copyright information for each of subcontents contained in one file. 
         [0003]    In recent years, as typified by electronic books, various media have been converted into electronic data. A copyright is reserved for a book, and, when the book is converted into data, by adding copyright information on the book to a file of an electronic book, the copyright of the book is protected as disclosed in, for example, Japanese Patent Application Laid-open No. Hei 8-190545. 
         [0004]    In many cases, a book such as a novel has one copyright holder. However, a magazine may have different copyright holders for each of subcontents (such as documents, images, or music compositions) contained in the magazine. When such a magazine is converted into data, the copyright of the magazine converted into data is managed on a file basis, and thus management of copyright for each of subcontents contained in the magazine is not taken care of. 
         [0005]    Moreover, when information on all copyrights reserved for the magazine is contained in the copyright information added to the file, a subcontent contained in the magazine and the copyright information are not associated with each other, and thus the subcontent cannot be separated from the magazine. Further, when the magazine is divided into the subcontents, copyright information is not added to the divided subcontents, and the copyrights of the subcontents are not possibly protected properly. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of this invention to protect a copyright for each of subcontents of a digital content. 
         [0007]    According to one embodiment of the invention, there is therefore provided a computer system, comprising: a content providing server for providing a user terminal with a digital content obtained through digitization; and a copyright management server for managing copyright information on the digital content, wherein the content providing server is configured to: obtain copyright information set for each of subcontents included in the digital content from the copyright management server; associate the obtained copyright information with the each of the subcontents, and add the copyright information to the digital content; and transmit the digital content to which the copyright information is added to the user terminal. 
         [0008]    According to the representative aspect of this invention, a copyright of a digital content can be protected for each of subcontents, and, when the digital content is edited, a copyright of each of the subcontents can be inherited. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present invention can be appreciated by the description which follows in conjunction with the following figures, wherein: 
           [0010]      FIG. 1  is a block diagram illustrating a configuration of a computer system according to the embodiment of this invention; 
           [0011]      FIG. 2  is a block diagram illustrating a configuration of the digital content management server according to the embodiment of this invention; 
           [0012]      FIG. 3  is a diagram illustrating a configuration of the digital content database according to the embodiment of this invention; 
           [0013]      FIG. 4  is a diagram illustrating a configuration of the copyright information database according to the embodiment of this invention; 
           [0014]      FIG. 5  is a diagram illustrating a configuration of the content information database of the embodiment according to this invention; 
           [0015]      FIG. 6  is a diagram illustrating a configuration of the license information database of the embodiment according to this invention; 
           [0016]      FIG. 7  is a diagram illustrating an overview of processing of creating a file of a digital content according to the embodiment of this invention; 
           [0017]      FIG. 8  is sequence diagram of processing of newly registering a digital content by the terminal for digital content registration according to the embodiment of this invention; 
           [0018]      FIG. 9A  is a sequence diagram of processing of acquiring a digital content by the end-user terminal according to the embodiment of this invention; 
           [0019]      FIG. 9B  is a sequence diagram of processing of browsing a digital content by the end-user terminal according to the embodiment of this invention; 
           [0020]      FIG. 10  is a flowchart of processing of browsing a digital content according to the embodiment of this invention; and 
           [0021]      FIG. 11  is a flowchart of processing of printing a digital content according to the embodiment of this invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    An embodiment of this invention is detailed below referring to accompanying drawings. 
         [0023]      FIG. 1  is a block diagram illustrating a configuration of a computer system according to the embodiment of this invention. 
         [0024]    The computer system according to this embodiment includes a digital content management server  110 , a copyright management server  120 , a digital content providing server  130 , and a license authentication server  140 . Each of the servers is a computer including a processor, a memory, and an interface (refer to  FIG. 2 ), and is coupled to an intranet  102  via the interface. The digital content providing server  130  and the license authentication server  140  are also coupled to a global network  103 , are then coupled via a firewall  104  to the Internet  105 , and are thus accessible via the Internet  105  from an end-user terminal  106 . 
         [0025]    A registration terminal  101  is a computer including a processor, a memory, and an interface. The registration terminal  101  transmits, to the digital content management server  110 , request for newly registering a digital content, a request for browsing the digital content, and a request for editing the digital content. Moreover, the registration terminal  101  transmits, to the copyright management server  120 , a request for newly registering copyright information, a request for browsing the copyright information, and a request for editing the copyright information. 
         [0026]    The end-user terminal  106  is a computer including a processor, a memory, and an interface. The end-user terminal  106  makes a request for digital content acquisition to the digital content providing server  130 . Moreover, the end-user terminal  106 , when an acquired digital content is to be browsed, requests for authentication by the license authentication server  140 . 
         [0027]    Though, in  FIG. 1 , only the single registration terminal  101  and the single end-user terminal  106  are illustrated, a plurality of the terminals for digital content registration  101  and a plurality of the end-user terminals  106  may be provided. 
         [0028]      FIG. 2  is a block diagram illustrating a configuration of the digital content management server  110  according to the embodiment of this invention. 
         [0029]    In  FIG. 2 , the digital content management server  110  includes a processor (CPU)  113 , a memory controller  114 , a main memory  115 , a disk controller  116 , a network I/F  117 , and a storage device  118 . 
         [0030]    The processor  113  carries out various processing by executing programs stored in the main memory  115 , thereby controlling the main controller  114 , the disk controller  116 , and the network I/F  117 . The memory controller  114  controls an access to the main memory  115  according to an instruction received from the processor  113 . The main memory  115  stores the programs to be executed by the processor  113  (such as a digital content management program  111 ) and data required for the execution of the programs (such as digital content data). 
         [0031]    The disk controller  116  controls an access to the storage device  118  according to an instruction received from the processor  113 . The storage device  118  is constructed by a magnetic disk, a non-volatile semiconductor memory, or the like, and stores a digital content database  112  (refer to  FIG. 3 ) in a memory area. The network I/F  117  is coupled to the intranet  102 , and controls data communication with other devices. 
         [0032]    When the digital content management server  110  receives, from the registration terminal  101  via the intranet  102 , a request for registering a digital content or a request for acquiring a digital content, the digital content management program  111  registers the digital content to the digital content database  112 , or acquires the digital content from the digital content database  112 . 
         [0033]    Key information (such as a digital content ID) on the registered digital content is transmitted, via the intranet  102 , to the digital content providing server  130 . Moreover, when the digital content management server  110  receives, from the registration terminal  101  or the digital content providing server  130  via the intranet  102 , a request for referring to digital content information, the digital content management program  111  makes an inquiry to the digital content data base  112 , and transmits a result of the inquiry to the registration terminal  101  or the digital content providing server  130 , which is the source of the request. 
         [0034]    Though  FIG. 2  illustrates the configuration of the digital content management server  110 , other servers such as the copyright management server  120 , the digital content providing server  130 , and the license authentication server  140  have the same hardware configuration except for installed programs and data stored in the storage device  118 . 
         [0035]    The digital content management server  110 , the copyright management server  120 , the digital content providing server  130 , and the license authentication server  140  may be computers physically different from each other or virtual computers configured by logically dividing the same physical computer. 
         [0036]    A description is now given of differences in configuration and function among the copyright management server  120 , the digital content providing server  130 , the license authentication server  140 , and the digital content management server  110 . 
         [0037]    The copyright management server  120  has a copyright information database  122  (refer to  FIG. 4 ) stored in the storage device  118 , and a copyright management program stored in the main memory  115  for managing the copyright information database  122 . Moreover, the copyright management server  120  couples, via the network I/F  117 , to the intranet  102 . 
         [0038]    Moreover, when the copyright management server  120  receives a request for registering or updating copyright information via the intranet  102  from the registration terminal  101 , the copyright management program makes an access to the copyright information database  122 , and registers or updates the copyright information. 
         [0039]    Further, when the copyright management server  120  receives a request for referring to copyright information from the registration terminal  101  or the digital content providing server  130  via the intranet  102 , the copyright management program makes an inquiry to the copyright information database  122 , and transmits a result of the inquiry to the registration terminal  101  or the digital content providing server  130 , which is the source of the request. 
         [0040]    The digital content providing server  130  stores a content information database  132  (refer to  FIG. 5 ) in the storage device  118 , and stores a digital content providing program for managing the content information database  132  in the main memory  115 . Moreover, the digital content providing server  130  couples, via the network I/F  117 , to the intranet  102  and the global network  103 . 
         [0041]    When the digital content providing server  130  receives, from the user terminal  106  via the global network  103 , a request for acquiring a digital content, the digital content providing program makes an inquiry to the content information database  132 , and obtains key information (digital content ID) on the corresponding content. The acquired key information on the content is set to a request for digital content acquisition, and is sent to the digital content management server  110 . 
         [0042]    The license authentication server  140  stores a license information database  142  (refer to  FIG. 6 ) in the storage device  118 , and a digital license authentication program in the main memory  115  for managing the license information database  142 . Moreover, the license authentication server  140  couples, via the network I/F  117 , to the intranet  102  and the global network 
         [0043]    When the license authentication server  140  receives, from the end-user terminal  106  via the global network  103 , a request for user authentication, the license authentication program  141  makes an inquiry to the license information database  142 , and carries out authentication processing for a corresponding user. Then, the license authentication server  140  transmits an acquired content key via the intranet  102  to the end-user terminal  106 . 
         [0044]      FIG. 3  is a diagram illustrating a configuration of the digital content database  112  according to the embodiment of this invention. 
         [0045]    The digital content database  112  is held by the digital content management server  110 , and includes a digital content table  1101 , layout tables  1102 , and subcontent tables  1103 . If a new content is generated, a new record is to be registered to those tables. 
         [0046]    The digital content table  1101  is a parent table for managing generated contents, and includes digital content IDs, digital content names, publisher names, author names, abstracts, dates of publication, layout IDs, and the like. The digital content table  1101  is associated with the layout tables  1102  by the layout ID. In other words, a plurality of pieces of layout data corresponding to layouts (such as pages) contained in one digital content is associated with one piece of digital content data. 
         [0047]    The layout table  1102  is a child table of the digital content table  1101 , and is provided for each page, for example. The layout table  1102  is a table for managing information on the layout of subcontents, and includes data such as layout IDs, digital content IDs, subcontent IDs, content layout information, and page information. 
         [0048]    The subcontent table  1103  is a table for managing subcontents, and includes subcontent IDs, copyright IDs, data such as content type, and binary data of contents. It should be noted that a subcontent is the minimum unit for managing copyrights of documents, images, music compositions, and the like. Binary data contained in the subcontent table  1103  are not encrypted. 
         [0049]      FIG. 4  is a diagram illustrating a configuration of the copyright information database  122  according to the embodiment of this invention. 
         [0050]    The copyright information database  122  is held by the copyright management server  120 , and contains a copyright information table  1201  for managing all of the copyright information pieces registered to the computer system according to this embodiment. 
         [0051]    The copyright information table  1201  contains copyright IDs, copyright holder names, subcontent IDs, copyright protection terms, secondary distribution permission flags, print permission flags, and the like, and, when new copyright information is added, a new record is registered to the copyright information table  1201 . In the copyright protection term, the last day of protection by a copyright is recorded. This copyright protection term may be calculated based on a legal protection term, or a copyright holder may set a term shorter than the legal protection term. 
         [0052]      FIG. 5  is a diagram illustrating a configuration of the content information database  132  of the embodiment according to this invention. 
         [0053]    The content information database  132  is held by the digital content providing server  130 , and contains a content key information table  1301  and provided content tables  1302 . 
         [0054]    The content key information table  1301  manages key information used when the end-user terminal  106  searches for a digital content, and contains digital content IDs, digital content names, publisher names, author names, abstracts, dates of publication, and the like. 
         [0055]    The provided content table  1302  is a child table of the content key information table  1301 , and is associated with the content key information table  1301  by the digital content ID. 
         [0056]    The provided content table  1302  is a table for managing digital contents provided for end users, and contains provided content IDs, user IDs, digital content IDs, content keys, content binary data, and the like. The content binary data is an encrypted digital content provided for an end user, and the content key is information used for decrypting the encrypted digital content. 
         [0057]    When a digital content is generated, a new record is registered to the content key information table  1301 . Moreover, when a digital content is provided for the end-user terminal  106 , a new record is registered to the provided content table  1302 . It should be noted that a record registered to the provided content table  1302  may be deleted when a predetermined period has elapsed after a digital content was provided for an end user. 
         [0058]      FIG. 6  is a diagram illustrating a configuration of the license information database  142  of the embodiment according to this invention. 
         [0059]    The license information database  142  is held by the license authentication server  140 , and contains a license information table  1401  for managing user information. 
         [0060]    The license information table  1401  contains user IDs, passwords, user information, and the like. When an end user requests for user registration, a new record is added to the license information table  1401 . 
         [0061]      FIG. 7  is a diagram illustrating an overview of processing of creating a file of a digital content according to the embodiment of this invention. 
         [0062]    First, in a step ( 1 ), the registration terminal  101  converts, by means of an image processing device such as a scanner or an OCR, paper media (information printed on a paper sheet) into digital information, thereby generating a digital content  1 . Subcontents contained in the digital content  1  are encrypted, and written to a file, and information on a layout of the subcontents is written to the file without being subjected to encryption. 
         [0063]    Then, in a step ( 2 ), copyright information to be associated with the generated digital content  1  is selected. The copyright information selected on this occasion is managed by the copyright management server  120 , and is stored in the copyright information database  122 . 
         [0064]    Then, in a step ( 3 ), the selected copyright information is associated with each of the subcontents contained in the digital content  1 . Then, the copyright information associated with each of the subcontents is written to the subcontent  1  without being subjected to encryption. 
         [0065]    In the above-mentioned steps ( 1 ) to ( 3 ), the digital content  1  is generated, each subcontent of which the copyright information is associated with. 
         [0066]    Then, in a step ( 4 ), processing of combining a subcontent B extracted from the digital content  1  and a subcontent D extracted from another digital content into a digital content  2  is illustrated. 
         [0067]    The subcontent B extracted from the digital content  1  inherits the same subcontent ID. Moreover, in the digital content database  112 , a relationship between a subcontent and copyright information, namely a copyright ID corresponding to a subcontent ID is registered. Therefore, even when the subcontent B extracted from the digital content  1  is to be contained in another digital content, the same copyright is inherited. 
         [0068]    In the computer system according to this embodiment, copyright information is associated with each of subcontents, and thus even when subcontents extracted from different contents are combined, thereby generating a new digital content, copyright information originally associated with the subcontents is inherited. 
         [0069]      FIG. 8  is sequence diagram of processing of newly registering a digital content by the registration terminal  101  according to the embodiment of this invention. 
         [0070]    First, when a digital content registration program starts, the registration terminal  101  makes a request for copyright information acquisition to the copyright management server  120  (S 601 ). When the acquisition of the copyright information is requested, the copyright management server  120  transmits all of the copyright information pieces stored in the copyright information database  122  to the registration terminal  101  (S 602 ). 
         [0071]    Then, the registration terminal  101  digitizes a book or the like, thereby generating a digital content. A file of the generated digital content contains at least one subcontent, information on layouts for arranging the subcontents, and attribute information on the digital content (such as content keys). Then, one piece of the acquired copyright information is associated with each of subcontents contained in the digital content, and an ID of the associated copyright information is written to the file of the digital content. Then, the registration terminal  101  requests the copyright management server  120  to register the copyright information associated with the digital content (S 603 ). It should be noted that the registration terminal  101  may not select the copyright information acquired from the copyright information database  122 , but may input new copyright information, and may request for registration of the new copyright information. 
         [0072]    When the copyright management server  120  receives the request for registration of the copyright information from the registration terminal  101 , the copyright management server  120  registers the received copyright information to the copyright information database  122 , and returns a result of the registration to the registration terminal  101  (S 604 ). Then, the registration terminal  101  requests the digital content management server  110  to register the digital content associated with the copyright information (S 605 ). 
         [0073]    When the digital content management server  110  receives the request for registration of the digital content, the digital content management server  110  registers the received digital content to the digital content database  112 . Specifically, digital content data to be stored in the digital content table  1101 , layout data to be stored in the layout table  1102 , and subcontent data to be stored in the subcontent table  1103  are registered to the digital content database  112 . 
         [0074]    Then, the digital content management server  110  transmits key information on the received digital content (such as the digital content ID and the digital content name) to the digital content providing server  130  (S 606 ). The digital content providing server  130  registers the received key information on the digital content to the content information database  132  (content key information table  1301 ). 
         [0075]    After the digital content management server  110  transmits the key information to the digital content providing server  130 , the digital content management server  110  returns, to the registration terminal  101 , a reply indicating the completion of the processing (S 607 ). It should be noted that the digital content management server  110  may receive, from the digital content providing server  130 , a reply indicating completion of the registration of the key information on the digital content, and then may reply, to the registration terminal  101 , the completion of the processing. 
         [0076]      FIG. 9A  is a sequence diagram of processing of acquiring a digital content by the end-user terminal  106  according to the embodiment of this invention. 
         [0077]    When the digital content is acquired, first, the end-user terminal  106  makes a request for the digital content acquisition to the digital content providing server  130  (S 701 ). The request for digital content acquisition contains information for identifying or narrowing down the digital content to be acquired. The information used for identifying or narrowing down the digital content is information input by a user to the end-user terminal  106 , and may be information contained in the content key information table  1301  of the content information database  132 . 
         [0078]    Moreover, this request for digital content acquisition contains a user ID and a password input when the digital content acquisition is requested from the end-user terminal  106 . As the user ID and the password, a user ID and a password held in the end-user terminal  106  may be used. 
         [0079]    When the digital content providing server  130  receives the request for digital content acquisition, based on the information used for identifying or narrowing down the digital content contained in the request for digital content acquisition, the digital content providing server  130  searches the content key information table  1301 , thereby acquiring key content information (such as a digital content ID). Then, the digital content providing server  130  transmits a request for digital content acquisition containing the acquired content key information to the digital content management server  110  (S 702 ). 
         [0080]    When the digital content management server  110  receives the request for digital content acquisition, the digital content management server  110  searches the digital content database  112  by using the content key information contained in the received request for digital content acquisition. Specifically, the digital content management server  110  searches the digital content table  1101  by using the received digital content ID, thereby acquiring the ID of a layout of the content. Then, the digital content management server  110  searches the layout table  1102  by using the acquired layout ID, thereby acquiring IDs of subcontents contained in the layout. Then, the digital content management server  110  searches the subcontent table  1103  by using the acquired subcontents IDs, thereby acquiring subcontent data. Then, the digital content management server  110  returns the acquired layout data and subcontent data to the digital content providing server  130  (S 703 ). Each of the returned subcontents contains an ID of a copyright set to each of the pieces of the subcontent data. 
         [0081]    Then, the digital content providing server  130  transmits a request for copyright information acquisition containing the acquired copyright IDs to the copyright management server  120  (S 704 ). When the copyright management server  120  receives the request for copyright information acquisition, the copyright management server  120  searches the copyright information database  122  by using the copyright IDs contained in the received request for copyright information acquisition, and returns corresponding copyright information to the digital content providing server  130  (S 705 ). 
         [0082]    The digital content providing server  130  combines, according to the layout data acquired in S 703 , the pieces of the subcontent data acquired in S 703 , thereby generating the digital content to be provided for the end-user terminal  106 . The generated digital content is data of image for browsing which can be displayed on a dedicated viewer of the end-user terminal  106 . Then, the digital content providing server  130  encrypts the generated content. Moreover, the digital content providing server  130  registers the data of the generated digital content to the provided content table  1302 . Then, the digital content providing server  130  transmits a decryption key (content key) generated at the time of the encryption to the license authentication server  140  (S 706 ). 
         [0083]    When the license authentication server  140  receives the content key, the license authentication server  140  registers the received content key to the license information database  142 , and then returns a reply indicating that the content key has been registered to the digital content providing server  130  (S 707 ). 
         [0084]    When the digital content providing server  130  receives the reply from the license authentication server  140 , the digital content providing server  130  transmits the encrypted content to the end-user terminal  106  (S 708 ). 
         [0085]    The end-user terminal  106  stores the acquired digital content in the storage device. 
         [0086]      FIG. 9B  is a sequence diagram of processing of browsing a digital content by the end-user terminal  106  according to the embodiment of this invention. 
         [0087]    When the digital content is browsed, first, the end-user terminal  106  reads key information (provided content ID) from the digital content to be browsed. Though the content to be browsed provided by the digital content providing server  130  is encrypted, the key information is contained in the digital content so that the key information may be read without being subjected to decryption. 
         [0088]    Then, the end-user terminal  106  transmits a user ID, a password, and the read provided content ID to the license authentication server  140 , thereby requesting for license authentication (S 711 ). As the user ID and the password, a user ID and a password input by the user to the end-user terminal  106 , or a user ID and a password held by the end-user terminal  106  are used. 
         [0089]    When the license authentication server  140  receives the request for license authentication, the license authentication server  140  searches the license information database  142  by using the user ID and the password contained in the received request for license authentication. As a result, if the received user ID and password are recorded in the license information database  142 , the user using the end-user terminal  106  is a valid user, and the license authentication server  140  transmits the provided content ID and the user ID contained in the received request for license authentication to the digital content providing server  130 , thereby requesting for a content key (S 712 ). 
         [0090]    When the digital content providing server  130  receives the provided content ID and the user ID, the digital content providing server  130  searches the content information database  132 , identifies a content key corresponding to the provided content ID and the user ID, and returns the identified content key to the license authentication server  140  (S 713 ). 
         [0091]    When the license authentication server  140  receives the content key from the digital content providing server  130 , the license authentication server  140  transmits, to the end-user terminal  106  which has requested the license authentication, a response to the request for license authentication (S 714 ). The response to the request for license authentication contains the provided content ID of the digital content, the authentication of which the end-user terminal  106  has requested, and the content key acquired from the content providing server  130 . 
         [0092]    It should be noted that as a result of the search on the license information database  142  by using the user ID and the password contained in the received request for license authentication, if the received user ID and password are not recorded in the license information database  142 , the user using the end-user terminal  106  is not a valid user, and, without requesting for a content key from the digital content providing server  130 , the license authentication server  140  transmits a reply indicating that the authentication has failed to the end-user terminal  106  (S 714 ). 
         [0093]      FIG. 10  is a flowchart of processing of browsing a digital content according to the embodiment of this invention. 
         [0094]    The processing of browsing a digital content illustrated in  FIG. 10  is carried out by the end-user terminal  106 . When a digital content generated by the system according to this embodiment is browsed on the end-user terminal  106 , a dedicated viewer is used. User information (such as a user name and an area) is set to this dedicated viewer in advance. 
         [0095]    First, the processor of the end user terminal  106  starts the dedicated viewer (S 901 ). When the dedicated viewer starts, the dedicated viewer requests the user to input a user ID and a password. It should be noted that the user ID and the password may be set to the dedicated viewer in advance. 
         [0096]    Then, the processor reads the digital content acquired by the digital content acquisition processing ( FIG. 9A ) from the storage device  118  (S 902 ). The dedicated viewer may show a list of digital contents stored in the storage device  118 , and the user may select the digital content to be read from the list. Moreover, the dedicated viewer may request the user to input information on the digital content to be read. 
         [0097]    Then, the processor reads the provided content ID from the read digital content (S 903 ). It should be noted that the provided content ID is written in the digital content in the non-encrypted form as the attribute information on the digital content. 
         [0098]    Then, the processor requests the license authentication server  140  to carry out the license authentication (S 904 , S 711  in  FIG. 9B ). When the processor receives an authentication result from the license authentication server  140  (S 714  in  FIG. 9B ), the processor determines the authentication result transmitted from the license authentication server  140  (S 905 ). 
         [0099]    When the authentication by the license authentication server  140  fails, the processing proceeds to Step S 908 , shows the fact that the authentication has failed, and stops the started dedicated viewer. In this case, the digital content is not displayed. 
         [0100]    On the other hand, when the authentication by the license authentication server  140  is successful, the processor refers to a user ID in the provided content table  1302  of the content information database  132 , which is set to the digital content, and determines whether or not the digital content, the authentication of which is successful, is a primary distribution or a secondary distribution. Specifically, the processor compares the user ID in the provided content table  1302  of the content information database  132  and the user ID input when the dedicated viewer is started with each other, and if those two user IDs are the same, the user is a person who has generated the digital content identified by the provided content ID, and thus the processor can determine that the digital content is a primary distribution. Moreover, if those two user IDs are different from each other, the user is not the person who has generated this digital content, and thus the processor can determine that the digital content is a secondary distribution. 
         [0101]    As a result, if the processor determines that the digital content is a primary distribution, the processor decrypts, by using the content key transmitted from the license authentication server  140 , an encrypted portion of the digital content (S 906 ). 
         [0102]    Then, the processor displays the decrypted digital content on a display unit of the end-user terminal  106  (S 907 ). Then, by an operation of the user, the dedicated viewer is stopped (S 908 ). 
         [0103]    On the other hand, if the processor determines that the digital content is a secondary distribution, the processor refers to the secondary distribution permission flag of copyright information of a subcontent contained in the digital content to be displayed, and determines whether or not secondary distribution of the subcontent is permitted (S 909 ). As a result, if the secondary distribution is not permitted, the subcontent cannot be displayed as the secondary distribution, and the processor determines whether or not the secondary distribution of a next subcontent is permitted. It should be noted that if the secondary distribution is not permitted, an area for the subcontent may be masked after the subcontent is decrypted. 
         [0104]    On the other hand, the secondary distribution is permitted, the subcontent can be displayed as the second distribution, and the processor decrypts the encrypted portion of the digital content by using the content key transmitted from the license authentication server  140  (S 910 ). 
         [0105]    It should be noted that the processing from Step S 909  to Step S 910  is repeated as many times as the number of the subcontents contained in the digital content to be displayed. 
         [0106]      FIG. 11  is a flowchart of processing of printing a digital content according to the embodiment of this invention. 
         [0107]    First, the dedicated viewer running on the end user terminal  106  starts a print driver (S 1001 ). It should be noted that when the print drive starts, a digital content to be printed has been decrypted. 
         [0108]    Then, the processor of the end user terminal  106  reads copyright information on a subcontent contained in the digital content to be printed from the digital content (S 1002 ). Then, the processor determines, by referring to a copyright protection term of the read copyright information, whether or not protection of the subcontent by the copyright has expired (S 1003 ). As a result, if the protection term of the copyright has expired, the protection of the subcontent by the copyright is not necessary, and the processing proceeds to Step S 1005 . 
         [0109]    On the other hand, if the protection term of the copyright has not expired, the subcontent is protected by the copyright. Therefore, the processor refers to the print permission flag of the copyright information, thereby determining whether or not the subcontent can be printed (S 1004 ). As a result, if this subcontent can be printed, the processor sets the subcontent to a print form (S 1005 ). On the other hand, if the subcontent cannot be printed, the processing returns to Step S 1002 , and processes a next subcontent. When the printing is not permitted, an area for the subcontent may be masked after the subcontent is decrypted. 
         [0110]    It should be noted that the processing from Step S 1002  to Step S 1005  is repeated as many times as the number of the subcontents contained in the digital content to be printed. 
         [0111]    In other words, if the copyright protection term of the subcontent has not expired, and the printing of the subcontent is not permitted, the subcontent is not set to the print form, and a portion for this subcontent is blanked. Moreover, if the copyright protection term of the subcontent has expired, or the print of the subcontent is permitted, the subcontent is set to the print form, and is printed. 
         [0112]    When the determination of the copyright has made for all the subcontents (S 1002  to S 1005 ), in order to print the form to which the subcontents are set, print data is transmitted to a printer (S 1006 ). Then, the print driver stops (S 1007 ). 
         [0113]    As mentioned before, according to the embodiment of this invention, when a digital content (electronic book) is generated from a book, copyright information is associated with each of subcontents (documents and images contained in the book), and a file containing the copyright information is generated. The copyright information is independently associated with the subcontents, and according to each copyright policy, the print, the secondary distribution, and the like can be controlled. 
         [0114]    Moreover, when subcontents are extracted from a file, and, by combining the extracted subcontents, a new digital content is generated, a copyright set to each of the subcontents can be inherited. 
         [0115]    Further, when a file to which copyright information is added is to be browsed, the permission of the display is determined for each of the subcontents. Further, when the file to which copyright information is added is to be printed, the permission of the print is determined for each of the subcontents. 
         [0116]    Therefor, for each of the subcontents contained in the digital content, the copyright can be properly protected. Moreover, when the digital content is edited, the copyright set to each of the subcontents can be inherited, the digital content comes to be used more, and a wide variety of services using the digital content can be provided. 
         [0117]    While the present invention has been described in detail and pictorially in the accompanying drawings, the present invention is not limited to such detail but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims.