Method for managing download of duplicate contents

[0001] This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for METHOD FOR MANAGING DUPLICATED DOWNLOADING THE IDENTICAL CONTENTS earlier filed in the Korean Intellectual Property Office on 7 Jan. 2005 and there duly assigned Ser. No. 2005-1871.

[0002] 1. Field of the Invention

[0003] The present invention relates to a method for managing download of contents in communication terminals such as portable telephones, and more particularly, to a method for managing download of the same contents as already-stored contents in communication terminals.

[0004] 2. Description of the Related Art

[0005] With the recent developments in the communications industry, services provided by mobile communication systems have evolved into a multicasting multimedia service which transfers large-sized data such as packet data, circuit data, and the like, as well as provides a voice service.

[0006] Recent communication terminals have functions and programs comparable to personal computers. Portability and improved functions of the communication terminals themselves promote the use of additional functions by users. Basically, the communication terminals are able to store a considerable amount of data, such as telephone numbers and personal schedules, and output and edit the data as necessary.

[0007] In recent years, the communication terminals have become able to store and provide large-sized multimedia data, such as music, games and movies. For example, the communication terminals have functions of downloading and replaying various bell sounds or music files, which are not stored by the manufacturers, via an external communication interface from external communication devices, such as computers, or sound providers. The present invention is directed to a method for managing download of and replaying various content data using a communication terminal.

[0008] A communication terminal generally includes a data storage memory for storing contents provided by content providers and a usage-right storage memory for storing information about a right to use downloaded contents. The usage-right storage memory is called a replay cache memory and is hereinafter referred to simply as a replay memory.

[0009] The following is an example of a conventional replay memory that stores information about a right to use downloaded contents.

[0010] Open mobile alliance (OMA) digital right management (DRM) v2.0 specification specifies that a communication terminal has a replay cache memory to prevent downloaded contents from being replayed a limitless number of times. Thus, the communication terminal manages a globally unique right object (RO) identifier (GUID) and a right issuer timestamp (RITS) of contents.

[0011] For this, prior to downloading the contents, the communication terminal constructs the globally unique right object identifier (GUID) and the right issuer timestamp (RITS), provided by the content provider, as a table having a tree format, and stores and manages the table.

[0012] For reference, right related information including the globally unique right object identifier (GUID) includes content right information and content encryption key (CEK) information for decrypting encrypted contents. The information is used to decode the downloaded contents at the communication terminal. The information is forwarded to the communication terminal prior to downloading the content.

[0013] Examples of the right information include permission and constraints for contents. The permission information includes play, display, execute, print, and export. Further, the constraints include count, time-count, date time, interval, accumulated, individual, and system.

[0014] Among the above information, a content play right will be described herein. However, the present invention is likewise applicable to the other information.

[0015] The following is an example of a conventional method for managing download of contents in a communication terminal using the replay memory.

[0016] First, a communication terminal receives a right object (RO) containing a right issuer timestamp (RITS). The communication terminal then compares a content provision time included in the right issuer timestamp (RIFS) to a current time set in the communication terminal plus 24 hours. Here, the current time set in the communication terminal plus 24 hours is a reference time set to determine whether the right object (RO) is wrong.

[0017] If the content provision time is determined to be more than the current time set in the communication terminal plus 24 hours, the communication terminal determines based on time information provided by a base station whether the current time set in the communication terminal is correct. If the set current time is determined to be incorrect, the communication terminal accurately synchronizes the current time with the time provided by the base station.

[0018] If it is determined in that the set current time is correct, the communication terminal ignores the received right object (RO) and does not download content corresponding to the right object (RO) destined to be provided by the content provider.

[0019] On the other hand, if it is determined that the content provision time is not more than the current time set in the communication terminal plus 24 hours, the communication terminal compares the received right object (RO) to an entry stored in the replay memory. Specifically, the communication terminal determines whether the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) exist as entries in the replay memory.

[0020] If the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) are determined to exist as the entries in the replay memory, the communication terminal ignores the received right object (RO) and does not download the content corresponding to the right object (RO) destined to be provided by the content provider.

[0021] If it is determined in that the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) do not exist as the entries in the replay memory, the communication terminal recognizes that there is no same content information in the replay memory and determines whether there is an empty space in the replay memory. If it is determined that there is an empty space in the replay memory, the communication terminal accepts the received right object (RO) and stores the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) in the replay memory.

[0022] On the other hand, if it is determined that there is no empty space in the replay memory, the communication terminal determines whether the right issuer timestamp (RITS) of the received right object (RO) is earlier than the oldest entry stored in the replay memory. If the right issuer timestamp (RITS) of the received right object (RO) is earlier than the oldest entry stored in the replay memory, the communication terminal ignores the received right object (RO) and does not download content corresponding to the right object (RO) destined to be provided by the content provider.

[0023] On the other hand, if it is determined in that the right issuer timestamp (RITS) of the received right object (RO) is not earlier than the oldest entry stored in the replay memory, the communication terminal deletes an entry having the oldest right issuer timestamp (RITS) stored in the replay memory. The communication terminal then accepts the received right object (RO) and stores the globally unique right object identifier (GUID) and the right issuer timestamp. (RITS) of the received right object (RO) in an empty space of the replay memory from which the entry having the oldest right issuer timestamp (RITS) has been deleted.

[0024] Although a right for content paid and used by a user is about to expire, i.e., when the content has been replayed nine times and only one replay remains, the user might like to replay and listen to the content more than just once more. Normally, the user is allowed to re-purchase the same content when there is no remaining available replay count. However, in some cases the user may like to purchase the content in advance even when an available replay count remains.

[0025] When the user makes a download request for the same content, the communication terminal refuses a received right object (RO) and does not download the content since the existing downloaded globally unique right object identifier (GUID) and right issuer timestamp (RITS) entries remain in the replay memory. Thus, there is a need for a scheme to newly update an existing allocated use right (e.g., replay time) so that the same content is downloaded in duplicate even though the right is not all used and there remains content right related information in the replay memory.

[0026] It is an object of the present invention to provide a method for managing download of contents in a communication terminal, wherein even though a right to use existing downloaded content remains, the same content is allowed to be downloaded and used in succession to the remaining usage right.

[0027] It is another object of the present invention to provide a method for managing download of contents in a communication terminal that allows a new usage right to be successively used without deleting existing right information when a content usage right is determined to remain based on a right object (RO) for existing downloaded and used content.

[0028] It is yet another object of the present invention to provide a technique for managing download of contents in a communication terminal, that accommodates a highly flexible control over the use of the contents that is easy to implement and cost effective.

[0029] According to an aspect of the present invention, there is provided a method for managing download of contents, including: comparing a right issuer timestamp (RITS) included in a right object (RO) of currently received content to a current time plus a set threshold value; when the right issuer timestamp (RITS) is less than the current time plus the set threshold value, determining whether a globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are already stored; when the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are already stored, separately storing the received right object (RO) in association with the globally unique right object identifier (GUID); and when the content right is determined to expire based on the already-stored globally unique right object identifier (GUID) and the right issuer timestamp (RITS), successively providing a usage right for the content according to the separately stored globally unique right object identifier (GUID) and right issuer timestamp (RITS) of the right object (RO).

[0030] The method may further include: when the right issuer timestamp (RITS) is more than the current time plus the set threshold value, determining whether the set current time is correct; and ignoring the right object (RO) of the currently received content when the set current time is correct, and synchronizing the set current time when the set current time is incorrect.

[0031] The method may include accepting the received right object (RO) and storing the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of-the right object (RO) when the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are not already stored.

[0032] The method may further include: determining whether there is an empty space to store the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) when the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are not stored; when there is no empty space to store the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO), deleting an entry having the oldest right issuer timestamp (RITS) of the already-stored content; and storing the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) in the empty space from which the entry is deleted.

[0033] The threshold value may be more than 24 hours.

[0034] According to another aspect of the present invention, there is provided a method for managing download of contents, including: providing a replay memory for storing a globally unique right object identifier (GUID) and a right issuer timestamp (RITS), and a duplication memory for storing a right object (RO) in downloading a duplicate of content that is already stored in the replay memory; comparing a right issuer timestamp (RITS) included in the right object (RO) of the currently received content to a current time plus a set threshold value; when the right issuer timestamp (RITS) is less than the current time plus the set threshold value, determining whether the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are already stored in the replay memory; when the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are already stored in the replay memory, separately storing the received right object (RO) in the duplication memory in association with the globally unique right object identifier (GUID); and when a content usage right is determined to expire based on the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) which are already stored in the replay memory, continuously providing the content usage right according to the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) stored in the duplication memory.

[0035] The step of storing may include: when the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are already stored in the replay memory, determining whether there is an empty space in the duplication memory; when there is an empty space in the duplication memory, separately storing the received right object (RO) in the duplication memory in association with the globally unique right object identifier (GUID); and storing, in the replay memory, storage address information of the duplication memory where the received right object (RO) is stored, so that a reference is made to the storage address information upon fetching the unique right object identifier (GUID) stored in the duplication memory.

[0036] Storing the storage address information may include storing the storage address information in an area having an entry format associated with the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) stored in the replay memory.

[0037] The method may further include: determining whether the set current time is correct when the right issuer timestamp (RITS) is more than the current time plus the set threshold value; and synchronizing the set current time when the set current time is correct, ignoring the right object (RO) of the currently received content and when the set current time is incorrect.

[0038] The method may further include: determining whether there is an empty space in the replay memory to store the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) when the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) are not stored in the replay memory; when there is an empty space in the replay memory, accepting the received right object (RO) and storing the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) in the replay memory; and setting the storage address information for the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the stored right object (RO) to NULL.

[0039] The method may further include: when there is no empty space in the replay memory to store the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO), deleting an entry having the oldest right issuer timestamp (RITS) for the already-stored content; storing the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) in the empty space of the replay memory from which the entry is deleted; and setting the storage address information for the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the stored right object (RO) to NULL.

[0040] The method may further include: determining whether the right issuer timestamp (RITS) of the right object (RO) is earlier than the oldest globally unique right object identifier (GUID) and right issuer timestamp (RITS) entries already stored in the replay memory when there is no empty space in the replay memory to store the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO); when the right issuer timestamp (RITS) of the right object (RO) is not earlier than the oldest entry already stored in the replay memory, deleting the oldest entry from the replay memory; storing the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the right object (RO) in the empty space of the replay memory from which the oldest entry is deleted; and setting storage address information for the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the stored right object (RO) to NULL.

[0041] In the content download method according to this embodiment, the replay memory and the duplication memory may be configured as one memory with divided storage areas. The threshold value may be set to 24 hours.

[0042] According to the present invention, when the right object (RO) of content for which a usage right remains is received, the received right object (RO) is separately stored and a storage address of the right object (RO) is updated such that when a usage right for existing downloaded content expires, the content is continuously downloaded and used according to the separately stored right object (RO), thereby enabling purchase of the same content in advance and thus continuous use of the content irrespective of an existing right.

[0043] In addition, when there is a request to replay the same content, use of the content is enabled according to a right stored in the replay memory and, when the right stored in the replay memory expires, use of the content is enabled through updating the replay memory with right information (object information) stored in the duplication memory. Thus, even when the usage right expires, a user is allowed to continuously use existing downloaded content without having to gain access to the content provider whenever the user would like to use the content.

[0050] Turning now to the drawings, FIG. 1 shows an example of a conventional replay memory that stores information about a right to use downloaded contents.

[0051] Open mobile alliance (OMA) digital right management (DRM) v2.0 specification specifies that a communication terminal has a replay cache memory 10 to prevent downloaded contents from being replayed a limitless number of times. Thus, the communication terminal manages a globally unique right object (RO) identifier (GUID) 12 and a right issuer timestamp (RITS) 14 of contents.

[0052] For this, prior to downloading the contents, the communication terminal constructs the globally unique right object identifier (GUID) 12 and the right issuer timestamp (RITS) 14, provided by the content provider, as a table having a tree format as shown in FIG. 1, and stores and manages the table.

[0053] For reference, right related information including the globally unique right object identifier (GUID) includes content right information and content encryption key (CEK) information for decrypting encrypted contents. The information is used to decode the downloaded contents at the communication terminal. The information is forwarded to the communication terminal prior to downloading the content.

[0054] Examples of the right information include permission and constraints for contents. The permission information includes play, display, execute, print, and export. Further, the constraints include count, time-count, date time, interval, accumulated, individual, and system.

[0055] Among the above information, a content play right will be described herein. However, the present invention is likewise applicable to the other information.

[0056] FIG. 2 is a flowchart showing an example of a conventional method for managing download of contents in a communication terminal using the replay memory 10 of FIG. 1.

[0057] First, a communication terminal receives a right object (RO) containing a right issuer timestamp (RITS) (S11). The communication terminal then compares a content provision time included in the right issuer timestamp (RITS) to a current time set in the communication terminal plus 24 hours (S13). Here, the current time set in the communication terminal plus 24 hours is a reference time set to determine whether the right object (RO) is wrong.

[0058] If the content provision time is determined to be more than the current time set in the communication terminal plus 24 hours, the communication terminal determines based on time information provided by a base station whether the current time set in the communication terminal is correct (S23). If the set current time is determined to be incorrect, the communication terminal accurately synchronizes the current time with the time provided by the base station (S25).

[0059] If it is determined in S23 that the set current time is correct, the communication terminal ignores the received right object (RO) and does not download content corresponding to the right object (RO) destined to be provided by the content provider (S31).

[0060] On the other hand, if it is determined in S13 that the content provision time is not more than the current time set in the communication terminal plus 24 hours, the communication terminal compares the received right object (RO) to an entry stored in the replay memory 10 (S15). Specifically, the communication terminal determines whether the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) exist as entries in the replay memory 10 (S17).

[0061] If the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) are determined to exist as the entries in the replay memory 10, the communication terminal ignores the received right object (RO) and does not download the content corresponding to the right object (RO) destined to be provided by the content provider (S31).

[0062] If it is determined in S17 that the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) do not exist as the entries in the replay memory 10, the communication terminal recognizes that there is no same content information in the replay memory 10 and determines whether there is an empty space in the replay memory 10 (S19). If it is determined that there is an empty space in the replay memory 10, the communication terminal accepts the received right object (RO) and stores the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) in the replay memory 10 (S21).

[0063] On the other hand, if it is determined in S19 that there is no empty space in the replay memory 10, the communication terminal determines whether the right issuer timestamp (RITS) of the received right object (RO) is earlier than the oldest entry stored in the replay memory 10 (S27). If the right issuer timestamp (RITS) of the received right object (RO) is earlier than the oldest entry stored in the replay memory 10, the communication terminal ignores the received right object (RO) and does not download content corresponding to the right object (RO) destined to be provided by the content provider (S31).

[0064] On the other hand, if it is determined in S27 that the right issuer timestamp (RITS) of the received right object (RO) is not earlier than the oldest entry stored in the replay memory 10, the communication terminal deletes an entry having the oldest right issuer timestamp (RITS) stored in the replay memory 10 (S29). The communication terminal then accepts the received right object (RO) and stores the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) in an empty space of the replay memory 10 from which the entry having the oldest right issuer timestamp (RITS) has been deleted (S21).

[0065] Although a right for content paid and used by a user is about to expire, i.e., when the content has been replayed nine times and only one replay remains, the user might like to replay and listen to the content more than just once more. Normally, the user is allowed to re-purchase the same content when there is no remaining available replay count. However, in some cases the user may like to purchase the content in advance even when an available replay count remains.

[0066] When the user makes a download request for the same content, the communication terminal refuses a received right object (RO) and does not download the content since the existing downloaded globally unique right object identifier (GUID) and right issuer timestamp (RITS) entries remain in the replay memory 10, as shown in FIG. 2. Thus, there is a need for a scheme to newly update an existing allocated use right (e.g., replay time) so that the same content is downloaded in duplicate even though the right is not all used and there remains content right related information in the replay memory 10.

[0067] The present invention will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

[0068] FIG. 3 shows a structure of a memory that stores information about a content usage right to download and manage duplicate content according to a preferred embodiment of the present invention.

[0069] The present invention includes a duplication memory 200, as well as a replay memory 100 that stores constraints which are not deleted because an existing usage right remains. The duplication memory 200 stores globally unique right object identifier (GUID) 210, 110 stored in the replay memory 100 and a right object (RO) 230 having the same value as a right issuer timestamp (RITS).

[0070] The replay memory 100 stores a globally unique right object identifier (GUID) 110, a right issuer timestamp 130, and storage address information 150 in the form of a table having a tree format. The globally unique right object identifier 110 is information about an object having a content usage right, the right issuer timestamp 130 is time information provided by a provider having a content right, and the storage address information 150 is information about an address of the duplication memory 200 where the right object (RO) 230 is stored according to the present invention.

[0071] The duplication memory 200 stores the globally unique right object identifier 210 and the right object (RO) 230. The globally unique right object identifier 210 is information about an object having a content usage right, and is the same globally unique right object identifier as the globally unique right object identifier (GUID) 110 already stored in the replay memory 100.

[0072] In the present invention, the communication terminal does not ignore a currently received right object (RO) and stores the right object (RO) in the duplication memory 200 when the communication terminal discovers globally unique right object identifier (GUID) 110 and right issuer timestamp (RITS) 130 entries in the replay memory 100 that are the same as the received right object (RO). Thereafter, if the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) that are the same as the received right object (RO), which are stored in the replay memory 100, are deleted due to usage expiration, the communication terminal automatically updates the replay memory 100 with the right object (RO) stored in the duplication memory 200. In the present invention, for the same content, only the right object (RO) rather than detailed content information is stored, which does not affect the use of the memory.

[0073] In the present invention, the replay memory 100 and the duplication memory 200 may be configured as different memories. Alternatively, they may be configured as different storage areas in one memory depending on information type.

[0074] FIG. 4 is a flowchart illustrating a method for managing download of the same content using a replay memory and a duplication memory in a communication terminal according to a preferred embodiment of the present invention.

[0075] First, the communication terminal receives a right object (RO) including a right issuer timestamp (RITS) (S110). The communication terminal then compares a content provision time included in the right issuer timestamp (RITS) to a current time set in the communication terminal plus a predetermined time, for example 24 hours (S120). Here, the current time set in the communication terminal plus 24 hours is a reference time set to determine whether the right object (RO) is wrong.

[0076] If the content provision time is determined to be more than the current time set in the communication terminal plus 24 hours, the communication terminal determines based on the time information provided by a base station whether the current time set in the communication terminal is correct (S210). If the set current time is determined to be incorrect, the communication terminal synchronizes the current time with the accurate time provided by the base station (S230).

[0077] If it is determined in S210 that the set current time is correct, the communication terminal ignores the received right object (RO) and does not download content corresponding to the right object (RO) destined to be provided by the content provider (S220).

[0078] On the other hand, if it is determined in S120 that the content provision time is not more than the current time set in the communication terminal plus 24 hours, the communication terminal compares the received right object (RO) to the entry stored in the replay memory 100 (S130). The communication terminal then determines whether the globally unique right object identifier (GUID) and right issuer timestamp (RITS) corresponding to the received right object (RO) exist as entries in the replay memory 100 (S140).

[0079] If the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) are determined to exist as the entries in the replay memory 100, the communication terminal determines whether there is an empty space in the duplication memory 200 (S250). If it is determined that there is no empty space in the duplication memory 200, the communication terminal ignores the received right object (RO) and does not download the content corresponding to the right object (RO) destined to be provided by the content provider (S220).

[0080] If it is determined in S250 that there is empty space in the duplication memory 200, the communication terminal stores the received right object (RO) in the duplication memory 200 (S260). At this time, the communication terminal updates a storage address (SA) (150) area of the replay memory 100 with an address of the duplication memory 200 where the received right object (RO) is stored (S270). Preferably, the communication terminal updates the storage address area of the entries of the replay memory 100 where the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) are stored, with the address information of the received right object (RO) stored in the duplication memory 200.

[0081] On the other hand, if it is determined in S140 that the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) corresponding to the received right object (RO) do not exist as the entries in the replay memory 100, the communication terminal recognizes that there is no same information as the received contents information in the replay memory 100 and determines whether there is an empty space in the replay memory 100 (S150). If it is determined that there is an empty space in the replay memory 100, the communication terminal accepts the received right object (RO) and stores the globally unique right object identifier (GUID) and right issuer timestamp (RITS) corresponding to the received right object (RO) in the replay memory 100 (S160). At this time, the communication terminal sets the storage address (SA) information as ‘NULL’ because it does not store the received right object (RO) in the duplication memory 200 (S170).

[0082] On the other hand, if it is determined in S150 that there is no empty space in the replay memory 100, the communication terminal determines whether the right issuer timestamp (RITS) of the received right object (RO) is earlier than the oldest entry stored in the replay memory 100 (S310). If the right issuer timestamp (RITS) of the received right object (RO) is determined to be earlier than the oldest entry stored in the replay memory 100, the communication terminal ignores the received right object (RO) and does not download the content corresponding to the right object (RO) destined to be provided by the content provider (S220).

[0083] On the other hand, if it is determined in S310 that the right issuer timestamp (RITS) of the received right object (RO) is not earlier than the oldest entry stored in the replay memory 100, the communication terminal deletes an entry having the oldest right issuer timestamp (RITS) stored in the replay memory 100 (S320). The communication terminal then accepts the received right object (RO) and stores the globally unique right object identifier (GUID) and the right issuer timestamp (RITS) of the received right object (RO) in the empty space of the replay memory 100 from which the entry having the oldest right issuer timestamp (RITS) has been deleted (S160). Further, the communication terminal sets the storage address (SA) information of the replay memory 100 to ‘NULL’ (S170).

[0084] Thus, when the right object (RO) of content for which a usage right remains is received, the received right object (RO) is separately stored and a storage address of the right object (RO) is updated such that when a usage right for existing downloaded content expires, the content is continuously downloaded and used according to the separately stored right object (RO), thereby enabling purchase of the same content in advance and thus continuous use of the content irrespective of an existing right.

[0085] FIG. 5 is a flowchart illustrating a process of replaying the same content using a method for managing download of the same content according to the present invention. This embodiment will be described by taking content such as music needing the play contained in the permission information as an example. The content is not limited to music as it is shown only as an example. The content can include a plurality of other forms such as video, text based data, multimedia content etc.

[0086] First, upon receipt of a request to replay downloaded content (S410), the communication terminal compares a content usage count (usage_count) to a count contained in the constraints (S420). The communication terminal then determines whether the content usage count (usage_count) is more than the count in the constraints (S430).

[0087] If the content usage count (usage_count) is not more than the count in the constraints, the communication terminal increments the content usage count (usage_count) by ‘1’ because the content usage right is not all used up (S440). It allows the communication terminal to replay the content in response to the request to replay the content (S450).

[0088] On the other hand, if it is determined in S430 that the content usage count (usage_count) is more than the count in the constraints, the communication terminal checks the replay memory 100, storage address (SA) information 150 of the entry of the content requested to be replayed (S460). The communication terminal then determines whether the storage address (SA) information 150 of the entry of the content requested to be replayed is ‘NULL’ (S470).

[0089] If the storage address (SA) information 150 of the entry of the content requested to be replayed is determined to be ‘NULL’, the communication terminal outputs a message via a user interface to indicate that replay of the content is impossible (S490). If it is determined in S470 that the storage address (SA) information 150 of the entry of the content requested to be replayed is not ‘NULL’, the communication terminal detects address information of the duplication memory 200 where the right object (RO) of the content requested to be replayed is stored and updates the replay memory 100 with the permission containing content count information (S510).

[0090] The communication terminal then sets the storage address (SA) information 150 of the entry of the content requested to be replayed as ‘NULL’ (S520). Further, the communication terminal resets the content usage count (usage_count) to ‘0’ (usage_count=0) (S530). Accordingly, the communication terminal raises the content usage count (usage_count) by ‘1’ increment to replay the content (S440). It allows the communication terminal to then replay the content in response to the request to replay the content (S450).

[0091] Thus, when there is a request to replay the same content, permission to use the content is granted depending on a right stored in the replay memory 100, and when the right stored in the replay memory 100 expires, use of the content is enabled by updating the replay memory 100 with right information (object information) stored in the duplication memory 200. Thus, even when the usage right expires, a user is allowed to continue using existing downloaded content without having to gain access to the content provider whenever the user would like to use the content.

[0092] According to the present invention, when the right object (RO) of content for which a usage right remains is received, the received right object (RO) is separately stored and a storage address of the right object (RO) is updated such that when a usage right for existing downloaded content expires, the content is continuously downloaded and used according to the separately stored right object (RO), thereby enabling purchase of the same content in advance and thus continuous use of the content irrespective of an existing right.

[0093] In addition, when there is a request to replay the same content, use of the content is enabled depending on a right stored in the replay memory, and when the right stored in the replay memory expires, use of the content is enabled by updating the replay memory with right information (object information) stored in the duplication memory. Thus, even when the usage right expires, the user is allowed to continuously use existing downloaded content without having to gain access to the content provider whenever the user would like to use the content.

[0094] The present invention can be realized as computer-executable instructions in computer_readable media. The computer_readable media includes all possible kinds of media in which computer_readable data is stored or included or can include any type of data that can be read by a computer or a processing unit. The computer_readable media include for example and not limited to storing media, such as magnetic storing media (e.g., ROMs, floppy disks, hard disk, and the like), optical reading media (e.g., CD_ROMs (compact disc-read-only memory), DVDs (digital versatile discs), re-writable versions of the optical discs, and the like), hybrid magnetic optical disks, organic disks, system memory (read-only memory, random access memory), non-volatile memory such as flash memory or any other volatile or non-volatile memory, other semiconductor media, electronic media, electromagnetic media, infrared, and other communication media such as carrier waves (e.g., transmission via the Internet or another computer). Communication media generally embodies computer-readable instructions, data structures, program modules or other data in a modulated signal such as the carrier waves or other transportable mechanism including any information delivery media. Computer-readable media such as communication media may include wireless media such as radio frequency, infrared microwaves, and wired media such as a wired network. Also, the computer_readable media can store and execute computer_readable codes that are distributed in computers connected via a network. The computer readable medium also includes cooperating or interconnected computer readable media that are in the processing system or are distributed among multiple processing systems that may be local or remote to the processing system. The present invention can include the computer-readable medium having stored thereon a data structure including a plurality of fields containing data representing the techniques of the present invention.

[0095] An example of a computer, but not limited to this example of the computer, that can read computer readable media that includes computer-executable instructions of the present invention includes a processor that controls the computer. The processor uses the system memory and a computer readable memory device that includes certain computer readable recording media. A system bus connects the processor to a network interface , modem or other interface that accommodates a connection to another computer or network such as the Internet. The system bus may also include an input and output interface that accommodates connection to a variety of other devices.

[0096] While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the present invention as defined by the following claims.