KR20060082807A - Method for consuming rights object having inherit structure in distributed device circumstance and device for the same - Google Patents

Abstract

The present invention relates to digital rights management. A master device according to an embodiment of the present invention is a storage module for storing a rights object having an inheritance structure, a search module for searching for a rights object required to play a predetermined content object in the storage module, and the search module searches for the content object. A message generation module for generating a rights object request message for requesting an undiscovered rights object when the rights object required for playback is not found; transmitting the rights object request message to a slave device, and requesting the rights object from the slave device. A device interface module for receiving a rights object according to a message, and a playback module for playing the content object using at least one of the rights object retrieved by the search module and the rights object received by the device interface module.

DRM, rights object, inheritance

Description

Method for consuming rights object having inherit structure in distributed device circumstance and device for the same}

1 is a view for explaining the DRM concept according to the prior art.

2 is a diagram illustrating a DRM system according to an embodiment of the present invention.

3 is a flowchart illustrating a mutual authentication process according to an embodiment of the present invention.

4 is a flowchart illustrating a process of acquiring a rights object according to an embodiment of the present invention.

5 is a flowchart illustrating a process of acquiring an auxiliary right object according to an embodiment of the present invention.

6 is a view showing a secondary rights object according to an embodiment of the present invention.

7 is a view showing a child rights object according to an embodiment of the present invention.

8 is a block diagram illustrating a master device according to an embodiment of the present invention.

9 is a block diagram illustrating a slave device according to an embodiment of the present invention.

10 is a flowchart illustrating a method for consuming a rights object according to an embodiment of the present invention.

11 is a flowchart illustrating a process of providing a rights object of a slave device according to an embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>

110: device interface module 120: encryption / decryption module

130: storage module 140: search module

150: message generation module 160: playback module

170: control module

The present invention relates to digital rights management, and more particularly, to a method and a device for consuming a rights object in a distributed device environment in which a rights object having an inheritance structure is stored in different devices.

Recently, researches on digital rights management (hereinafter referred to as "DRM") have been actively conducted, and commercial services using DRM have been introduced or are being introduced. DRM is a technology concept for protecting digital content that is easy to copy and distribute.

Efforts to protect digital content have been made in the past, but the prior art focused on preventing unauthorized access to digital content. For example, access to digital content was allowed only to users who paid for it, and users who did not pay for it could not access digital content. However, due to the nature of digital data, digital content can be easily reused, processed, copied, and distributed. Therefore, if a user who pays for and accesses the digital content is copied or distributed without permission, the digital content can be used by the user who has not paid.

To solve this problem, DRM encrypts and distributes digital content and requires a right object (RO) license to use encrypted digital content.

Referring to FIG. 1, the device 10 may obtain digital content from the content provider 20. At this time, the digital content supplied by the content provider 20 is in an encrypted state, and a rights object is required to use the encrypted digital content.

The device 10 may obtain a rights object including a right to use the encrypted digital content from the rights object issuer 30. For this purpose, the user must pay a certain price. The rights object contains a key that can decrypt the encrypted digital content.

The rights object issuing agency 30 reports the rights object issuance history to the content provider 20, and in some cases, the rights object issuing agency 30 and the content provider 20 may be the same subject.

The device 10 acquiring the rights object may use the encrypted digital content by consuming the rights object.

Meanwhile, the encrypted digital content may be freely copied and distributed to other devices (not shown). However, since the rights object contains limited information such as the number and duration of use of the encrypted digital content, and the number of times the rights object can be copied, the rights object is restricted from reuse or duplication. do. This DRM technology can effectively protect digital content.

In the recent DRM technology, a content object reproduction service applying a concept of subscription is provided by reproducing a content object using a plurality of rights objects having an inheritance structure. In other words, in order to use an encrypted content object, the device needs two or more rights objects with mutual inheritance. However, since the number of rights objects required to use one encrypted content object is plural, a plurality of rights objects may be stored in different devices, and in such a case, a technology for consuming rights objects more effectively is required. do.

In particular, in order to simplify storage and distribution of encrypted digital contents or rights objects, a technology for managing rights objects through a portable storage device such as a memory stick or a multi-media card (MMC) has been attempted. . In the case of the portable storage device, the computing power is very low compared to the device that plays digital content. Therefore, when the device consumes the right object having the inheritance structure stored in the portable storage device, the computing load of the portable storage device can be reduced. Skill is needed.

It is an object of the present invention to more effectively consume a rights object in an environment in which the rights object having an inheritance structure is distributed to a plurality of devices.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a master device according to an embodiment of the present invention is a storage module for storing a rights object having an inheritance structure, a search module for searching for a rights object required to play a predetermined content object in the storage module, A message generation module for generating a rights object request message for requesting an unsearched rights object if the search module fails to search for the rights object required to play the content object, and transmits the rights object request message to a slave device; A device interface module for receiving a rights object according to the rights object request message from a slave device, and at least one of a rights object retrieved by the search module and a rights object received by the device interface module to play the content object. play Contains modules

In order to achieve the above object, a method for consuming a rights object according to an embodiment of the present invention includes obtaining a rights object having a predetermined inheritance structure from a slave device, and playing a predetermined content object using the obtained rights object. It includes the steps to make.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

First, a general description of the terms used in the present invention. The description of terms is intended to help the understanding of the present invention. Therefore, it should be noted that the terms described below are not used to limit the technical spirit of the present invention unless explicitly limited in the detailed description of the present invention.

Master device

The master device may be connected to a slave device, and refers to an apparatus capable of playing back a content object by using a plurality of rights objects having mutual inheritance structures. The master device may be a portable content playback device such as a mobile phone, PDA, MP3 player, or the like, or a fixed content playback device such as a desktop computer or a digital TV.

-Slave device

The slave device refers to a storage device including a nonvolatile memory having a property of reading, writing, and erasing data, such as a flash memory, having a predetermined computing power on data, and easily connecting / disconnecting from a master device. . Preferably the slave device may be a portable storage device such as smart media, memory stick, CF card, XD card, multimedia card and the like. However, the present invention is not limited thereto, and the slave device may be an apparatus of a type similar to that of the master device.

-Content object

The content object is digital content in encrypted state. The digital content is not limited to video, still images, audio, games, text, and the like.

Rights Object (RO)

A rights object is a license that has a right to use a content object. The rights object includes at least one of a content encryption key, restriction information, and permission information. In the present invention, a rights object may be divided into a parent rights object (parent RO) and a child rights object (child RO), which have an inheritance structure. The sub-rights object includes at least one of restriction information and permission information, and the sub-rights object includes a content object identifier and a content encryption key. Hereinafter, in order to help understanding of the invention, it will be described that the limited information is included in the sub-rights object, but the present invention is not limited thereto. Therefore, all or part of the restriction information may be included in the child rights object, and the role of the restriction information included in the child rights object may be understood through the role of the restriction information included in the sub rights object. Meanwhile, the sub-right object and the sub-right object include an inheritance relationship identifier for identifying the inheritance relationship between them. One sub-rights object may have an inheritance relationship with multiple sub-rights objects, and one sub-rights object may also have inheritance relationships with multiple sub-rights objects.

Content encryption key

The content encryption key is a key capable of decrypting the content object and may have a form of a predetermined binary value. The content encryption key is included in the child rights object, and the child rights object includes a content object identifier for identifying a content object that can be decrypted with the content encryption key.

Permission information

The permission information is information indicating a play back method of a content object and a duplication method of a sub-right object.

Examples of the reproduction method may include play, display, execute, print, and the like. Here, play means the right to represent a content object in audio or video form. For example, if the DRM content relates to a video or music, play may be set as permission information of a sub-rights object to be consumed for playing the content object. In addition, the display means the right to represent the content object to the visual device, and the printing means the right to create a hard copy of the content object. For example, if the content object relates to a still image, at least one of display and printing may be set as permission information of the sub-rights object to be consumed to reproduce the content object. And execution means the right to use content objects in the form of games or other applications. For example, when the content object is a Java game, execution may be set as permission information of a sub-rights object to be consumed for playing the content object.

On the other hand, examples of the copying method include copy and move. Copy and move is the right to save the sub-rights object stored in one device to another device. In case of moving, if the sub-rights object is stored in another device, the sub-rights object stored in the existing device is deactivated.However, in case of copying, even if the sub-rights object is stored in other device, the sub-rights object stored in the existing device It remains active. In this case, deactivation may mean deleting a sub-right object.

Constraint information

The restriction information is information representing a limit for playing the content object, and one or more restriction information may be set for the permission information. Examples of the restriction information include a count limit, a datetime limit, an interval limit, and an accumulated time limit.

The number limit here limits the number of times the content object can be played. For example, if the number of times limit is set to 10 in the sub-right object, the master device can play the content object 10 times by consuming the sub-right object.

The temporary limit defines a date and time at which the content object can be played, and may include at least one of a start element and an end element. When the master device consumes the sub-right object for which the temporary limit is set, the master device can play the content object after the date indicated by the start element of the temporary limit, and can play the content object until the date and time indicated by the end element. . For example, if the temporal restriction is set to 0: 0: 0 seconds on December 1, 2005 as the starting element, the master device will start the sub rights object after 0: 0: 0 seconds on December 1, 2005. It can consume the content object to play.

The time limit restricts the period of time in which the content object can be played by consuming the secondary right object from the time when the content object is first played and consumed by the secondary right object. For example, if the time limit is set to one week as the restriction information on the sub-rights object, if the master device consumes the sub-rights object for the first time at 0: 0: 0 second on December 1, 2005, the master device On December 8, 2005, the secondary rights object is consumed until 0: 0: 0 seconds to play the content object.

The cumulative time limit limits the total amount of time that the Content Object can be played by consuming the Sub-rights object regardless of the date. For example, if the cumulative time limit is set to 10 hours in the sub-right object, the master device may consume the sub-right object and play the content object for a total of 10 hours. At this time, the master device is not limited to the number or date of playing the content object by consuming the sub-rights object.

Public-key Cryptography

Also known as asymmetric encryption, a key used to encrypt data and a key used to decrypt data are composed of different keys. In public key cryptography, a key consists of a pair of public and private keys. The public key does not need to be kept secret and can be easily known to the public, and the private key must be known only to the specific device itself. Examples of public key encryption algorithms include a Diffie-Hellman method, an RSA method, an ElGamal method, and an elliptic curve method.

Symmetric-key Cryptography

Also known as secret key encryption, a key used to encrypt data and a key used to decrypt data are composed of the same key. As an example of such a symmetric key encryption, the DES scheme is most commonly used, and recently, an application using the AES scheme is increasing.

Random number

It means a string of numbers, a string, or a combination of them.

- connect

In the present invention, the master device is connected to the slave device means that the master device and the slave device is in electrical contact through the wired medium, but this is an example, the connection means that the master device and the slave device is connected to the wireless medium in a non-contact state It should also be interpreted as including meaning that they are in a state where they can communicate with each other.

Terms not described above will be described separately in necessary parts below.

2 is a diagram illustrating a DRM system according to an embodiment of the present invention. The illustrated DRM system includes a master device 100 and a slave device 200.

The user may acquire the content object from the content provider 20 through the master device 100 as in the related art. In addition, it is possible to purchase a rights object that can play a content object from the rights object issuer 30 at a predetermined cost. The purchased rights object may be stored in the master device 100, but the rights object stored in the master device 100 may be moved or copied to the slave device 200. In addition, the slave device 200 may store one or more rights objects since its production.

When the slave device 200 stores the rights object, the master device 100 may play the content object by consuming the rights object stored in the slave device 200 after being connected to the slave device 200. In order to play the content object, the master device 100 may use a plurality of rights objects having an inheritance structure. A plurality of rights objects with inheritance structure include at least one sub-rights object and one child rights object. Hereinafter, for convenience of description, one sub-right object and one sub-right object in mutual inheritance relationship are used to reproduce a content object, but the present invention is not limited thereto.

On the other hand, it is preferable that the master device 100 is connected to the slave device 200 and undergoes mutual authentication before exchanging predetermined data. Mutual authentication is a basic process for each of the master device 100 and the slave device 200 to confirm that the other party is a legitimate device, and to maintain the security of data exchanged with each other, which will be described with reference to FIG. 3.

3 is a flowchart illustrating a mutual authentication process according to an embodiment of the present invention.

In the present embodiment, the subscript “M” means data owned by the master device 100 or generated by the master device 100, and the subscript “S” is owned by the slave device 200 or generated by the slave device 200. Means one piece of data.

First, when the master device 100 and the slave device 200 is connected, the master device 100 requests the mutual authentication to the slave device 200 (S10). At this time, the master device 100 may transmit a certificate _M issued by the Certification Authority to the master device 100 together. _M certificate may contain the ID and Public Key _{M M} of the master device 100, and the electronic signature by a certificate authority.

Upon receiving the certificate _M of the master device 100, the slave device 200 checks whether the certificate _M is valid using a certificate revocation list (hereinafter referred to as "CRL") (S12). If the certificate _M of the master device 100 is a certificate registered in the CRL, the slave device 200 may reject mutual authentication with the master device 100. However, if the certificate _M of the master device 100 is a certificate not registered in the CRL, the slave device 200 may obtain the public key _M of the master device 100 through the certificate _M.

Once through the certificate _M check determines that a legitimate device, the master device 100, slave device 200 encrypts the generated random number _S, and (S14), generates a random number _S to the public key _M of the master device 100 ( S16).

Thereafter, the slave device 200 performs a mutual authentication response (S20). In response to the mutual authentication, the slave device 200 transmits the certificate _S and the encrypted random number _S issued by the certification authority to the slave device 200 together. _S certificate may include the ID and the public key _{S S} of the slave device 200, the electronic signature by a certificate authority.

Upon receiving the certificate _S and the encrypted random number _S from the slave device 200, the master device 100 confirms that the slave device 200 is a legitimate device through the certificate _S and uses the encrypted random number _S as the private key of the master device 100. _Decode by _M (S22). In this case, the master device 100 may obtain the public key _S of the slave device 200 through the certificate _S of the slave device 200. In addition, the certificate _S check operation may be performed through the CRL like the slave device 200.

Through the certificate _S OK if it is determined that the slave device 200 is a legitimate device, the master device 100 encrypts the generated random number _M and (S24), generates a random number _M to the public key _S of the slave device 200 ( S26).

Thereafter, the master device 100 requests the slave device 200 to terminate mutual authentication (S30). When the mutual authentication termination request, the master device 100 transmits the encrypted random number _M together.

Upon receiving the encrypted random number _M from the master device 100, the slave device 200 decrypts the random number _M encrypted with its private key _S (S32).

Accordingly, the master device 100 and the slave device 200 share two random numbers (random number _M and random number _S ).

Mutual authentication result of two random numbers by the master device 100 and slave device 200 share (random number _M and the random numbers _S) using the two random numbers (the random number _M and the random numbers _S) generates a session key (S40, S42 ). At this time, the key generation algorithm used by the master device 100 and the slave device 200 to generate the session key is the same. Accordingly, the master device 100 and the slave device 200 share the same session key.

After mutual authentication, the master device 100 and the slave device 200 encrypt the data to be transmitted to the counterpart with the session key, and decrypt the encrypted data received from the counterpart with the session key. Accordingly, security may be maintained for data transmission between the master device 100 and the slave device 200. Although not specifically mentioned in the following embodiments, the master device 100 and the slave device 200 encrypt the data to be transmitted to the other party with the session key generated as a result of mutual authentication, and decrypt the encrypted data received from the other party with the session key. I can understand that.

After the mutual authentication is completed, the master device 100 may obtain a rights object having an inheritance structure from the slave device 200. Rights objects that have an inheritance structure can be divided into sub-rights and child rights objects. Any one of the sub-rights object and the sub-rights object cannot play the content object. Only the sub-rights object and the sub-rights object can play the content object. That is, the master device 100 uses the content encryption key included in the child rights object within the range allowed by the permission information and the restriction information included in the sub rights object, and the content identified by the content object identifier included in the child rights object. You can play the object. Accordingly, the rights object acquired by the master device 100 from the slave device 200 may be either one of the sub-rights object and the sub-rights object, or both the sub-rights object and the sub-rights object. Which rights object is obtained from the slave device 200 may vary depending on which rights object the master device 100 stores. 4 and 5 illustrate a process in which the master device 100 obtains the self rights object and the sub rights object from the slave device 200.

4 is a flowchart illustrating a process of acquiring a rights object according to an embodiment of the present invention. The master device 100 to play the content object requests the self rights object to the slave device 200 (S410), and the slave device 200 transmits the requested self rights object to the master device 100 (S420). . Here, the slave device 200 may allow the master device 100 to access the child rights object without directly transmitting the child rights object to the master device 100. In addition, when the child rights object is requested, the master device 100 may transmit an identifier of a content object to be played back to the slave device 200. In this case, the slave device 200 may search for the requested self rights object among the rights objects stored by the slave device 200 using the identifier of the content object.

5 is a flowchart illustrating a process of acquiring an auxiliary right object according to an embodiment of the present invention. The master device 100 to play the content object requests the sub-rights object from the slave device 200 (S510), and the slave device 200 transmits the requested sub-rights object to the master device 100 (S520). . Here, the slave device 200 may allow the master device 100 to access the secondary right object without directly transmitting the secondary right object to the master device 100. In addition, when the sub-rights object is requested, the master device 100 may transmit the inheritance relation identifier included in the sub-rights object to the slave device 200. The slave device 200 may retrieve the requested sub-rights object from among the rights objects stored by the slave device 200 using the inheritance relationship identifier.

As can be seen in Figures 4 and 5, the query for obtaining the child rights object and the sub-right object is preferably started from the master device (100).

As described above, since the own rights object and the sub-rights object may be stored in the master device 100, the master device 100 includes the process of acquiring the own rights object described with reference to FIG. 4 to play a specific content object. Only one of the sub-rights object acquisition processes described with reference to FIG. 5 may be performed or both processes may be performed.

The sub-rights object and the sub-rights object according to the embodiment of the present invention are shown in Figs.

6 is a diagram illustrating a sub-rights object according to an embodiment of the present invention in a markup language. The illustrated sub-rights object includes permission information 620 and restriction information 630, where play 622 is set as permission information 620, and temporary restriction 632 as restriction information 630 for play. Is set.

On the other hand, Figure 7 is a view showing a child rights object in a markup language according to an embodiment of the present invention. In the illustrated child rights object, the child rights object includes a content object identifier 730 and a content encryption key 720.

Referring to the sub-rights object shown in FIG. 6 and the sub-rights object shown in FIG. 7, it can be seen that they include inheritance relationship identifiers 610 and 710, respectively. In FIG. 6 and FIG. 7, the inheritance relationship identifiers 610 and 710 are indicated by subscriptionGUID. If the subordinate object and the subordinate object have the same inheritance identifier, the subordinate object and the subordinate object are in mutual inheritance. When the master device 100 obtains both the sub-rights object and the sub-rights object, the master device receives the content object identified by the content object identifier 730 included in the sub-rights object. The content encryption key 720 included in the child rights object may be played within the range allowed by the 620 and the restriction information 630.

Hereinafter, the master device 100 and the slave device 200 described above will be described in more detail with reference to FIGS. 8 to 11.

8 is a block diagram illustrating a master device 100 according to an embodiment of the present invention. The master device 100 may include a device interface module 110, an encryption / decryption module 120, a storage module 130, a search module 140, a message generating module 150, a playback module 160, and a user input module ( 170, and control module 180.

The device interface module 110 transmits data to or receives data from the slave device 200. The master device 100 may be connected to the slave device 200 through the device interface module 110.

The encryption / decryption module 120 is a module that performs encryption and decryption on predetermined data. The encryption / decryption module 120 encrypts data transmitted to the slave device 200 at the request of the control module 180 or is encrypted from the slave device 200. The received data can be decrypted. The encryption / decryption module 120 may perform not only a public key encryption method but also a secret key encryption method, and there may be one or more encryption / decryption modules for performing each of the two methods.

In addition, the encryption / decryption module 120 may generate a predetermined random number required for the mutual authentication process.

The storage module 130 stores a content object, a sub-right object, a sub-right object, a CRL, a certificate of the master device 100, and the like. To this end, the storage module 130 includes a storage medium such as a hard disk or a flash memory.

The search module 140 searches the storage module 130 for the own rights object and the sub-rights object required for playing the content object.

The message generating module 150 generates a child rights object request message and a sub rights object request message. The sub-rights object request message may include a content object identifier, and the sub-rights object request message may include an inheritance relationship identifier. The child rights object request message and the sub rights object request message may be generated when the search module 140 does not search the child rights object and the sub rights object required to play a specific content object in the storage module 130, respectively.

The reproduction module 160 reproduces the content object using the sub-right object and the sub-right object. For example, the playback module 160 may include a video decoding module, and may play back a content object composed of video data compressed in a moving picture expert group (MPEG) format.

The user input module 170 receives a predetermined command or request from a user. To this end, the user input module 170 may include an input means such as a keypad, a touch pad, and a touch screen.

The control module 180 controls the operation of each module 110 to 170 constituting the master device 100. Therefore, the control module 180 may function as a DRM agent that manages the DRM tasks of the master device 100. In addition, the control module 180 may control the mutual authentication process described with reference to FIG. 3 when the master device 100 is connected to the slave device 200.

9 is a block diagram illustrating a slave device 200 according to an embodiment of the present invention. The illustrated slave device 200 includes a device interface module 210, an encryption / decryption module 220, a storage module 230, a search module 240, and a control module 250.

The device interface module 210 transmits data to or receives data from the master device 100. The slave device 200 may be connected to the master device 200 through the device interface module 210.

The encryption / decryption module 220 is a module that performs encryption and decryption on predetermined data. The encryption / decryption module 220 encrypts data transmitted to the master device 100 at the request of the control module 250 or is encrypted from the master device 100. The received data can be decrypted. The encryption / decryption module 220 may perform not only the public key encryption method but also the secret key encryption method, and there may be one or more encryption / decryption modules for performing each of the two methods.

In addition, the encryption / decryption module 220 may generate a predetermined random number required for the mutual authentication process.

The storage module 230 stores a content object, a sub-right object, a sub-right object, a CRL, a certificate of the slave device 200, and the like. To this end, the storage module 230 may include a flash memory. The sub-right object and the sub-right object stored in the storage module 230 may be moved or copied from the master device 100 or may be stored in the production of the slave device 200.

When the child rights object request message or the sub rights object request message is received from the master device 100, the search module 240 searches the child rights object or the sub rights object in the storage module 230.

The control module 250 controls the operation of each module 210 to 240 constituting the slave device 200. Accordingly, the control module 250 may function as a DRM agent that manages the DRM tasks of the slave device 200. In addition, the control module 250 may control the mutual authentication process described with reference to FIG. 3 when the slave device 200 is connected to the master device 100.

In the descriptions of FIGS. 8 and 9, 'module' refers to a hardware component such as software or a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the module plays certain roles. However, modules are not meant to be limited to software or hardware. The module may be configured to be in an addressable storage medium and may be configured to execute one or more processors. Thus, as an example, a module may include components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, subroutines. , Segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality provided by the components and modules may be combined into a smaller number of components and modules or further separated into additional components and modules.

Hereinafter, an operation process of the above-described master device 100 and slave device 200 will be described with reference to FIGS. 10 and 11.

10 is a flowchart illustrating a method for consuming a rights object according to an embodiment of the present invention. The illustrated right object consumption method is performed by the master device 100.

First, when a content object play request is input from a user through the user input module 170 (S810), the search module 140 stores a child rights object including a content encryption key capable of playing the requested content object. The search is made at 130 (S815). In this case, the search module 140 may obtain the content object identifier from the content object requested to be played back, and search for the rights object using the content object identifier. For example, as shown in FIG. 7, since the child rights object includes an identifier 730 of a content object that can be played back, the search module 140 may identify content object identifiers of the child rights objects stored in the storage module 130. By checking the fields, you can retrieve the required content objects.

If the child rights object is not found (S820), the child rights object request operation for the slave device 200 is performed. To this end, the message generating module 150 generates a self rights object request message (S825), and the device interface module 110 transmits the rights object request message to the slave device 200 (S830). The rights object request message may include a content object identifier.

Thereafter, when the device interface module 110 receives the child rights object from the slave device 200 (S835), a task for acquiring the sub rights object is performed. However, if the child rights object is not received from the slave device 200 (the child rights object may not be received for a predetermined time or a response indicating that the child rights object has not been received) may be played. Therefore, the content object playback operation is terminated.

On the other hand, when the child rights object is retrieved from the storage module 130 or the child rights object is received from the slave device 200, the search module 140 stores the sub-rights object having an inheritance relationship with the child rights object in the storage module 130. Search for (S840). To this end, the search module 130 may obtain the inheritance relation identifier from the child rights object and search for the sub-rights object including the same inheritance relation identifier.

If the sub-right object is not found (S845), the sub-right object request operation for the slave device 200 is performed. To this end, the message generating module 150 generates a secondary right object request message (S850), and the device interface module 110 transmits the secondary right object request message to the slave device 200 (S855). The sub-rights object request message may include an inheritance identifier.

Thereafter, if the sub-rights object is not received from the slave device 200 (S860) (the sub-rights object may not be received for a predetermined time or a response indicating that the sub-rights object is not retrieved may be received). Since the object cannot be played back, the content object play operation is terminated.

However, when the child rights object is retrieved from the storage module 130 or the child rights object is received from the slave device 200, the playback module 160 plays the content object using the child rights object and the sub rights object (S865). ).

As can be seen from the description of FIG. 10, according to the present invention, a query for obtaining a sub-right object and a query for obtaining a sub-right object may be independently performed.

11 is a flowchart illustrating a process of providing a rights object of a slave device 200 according to an embodiment of the present invention.

First, when the device interface module 210 receives a child rights object request message from the master device 100 (S910), the search module 240 searches for the requested child rights object in the storage module 230 (S920). . In this case, the search module 240 may acquire the content object identifier included in the child rights object request message, and search the child rights object including the same content object identifier as the obtained content object identifier.

When the child rights object is found (S930), the device interface module 210 transmits the child rights object to the master device 100 (S940).

Meanwhile, when the device interface module 210 receives the sub-rights object request message from the master device 100 (S950), the search module 240 searches for the requested sub-rights object in the storage module 230 (S960). . In this case, the search module 240 may acquire the inheritance relation identifier included in the sub-rights object request message and search for the sub-rights object including the inheritance relation identifier identical to the obtained inheritance relation identifier.

If the sub-right object is found (S970), the device interface module 210 transmits the sub-right object to the master device 100 (S980).

Although the slave device 200 actively transmits the self rights object and the sub rights object to the master device 100 in steps S940 and S980, the present invention is not limited thereto. For example, the control module 250 of the slave device 200 may allow the master device 210 to access the retrieved child rights object and the sub rights object.

As can be seen through the process described above, the operation of acquiring the content object identifier from the content object to search the child rights object or the inheritance relation identifier from the child rights object to search the subright object and the child rights object The query for acquiring the second right object from the slave device 200 is performed by the master device 100. Therefore, when the master device 100 performs a task of playing a content object using a rights object having an inheritance structure stored in the slave device 200, the slave device 200 may perform at least a task for searching for a necessary rights object. Since only needs to be performed, it is possible to reduce the computational load of the slave device (200).

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. You will understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

According to the method and the device for consuming a rights object having an inheritance structure in the distributed device environment of the present invention as described above has one or more of the following effects.

First, there is an advantage in that the content object, the sub-right object, and the sub-right object can be reproduced according to the inheritance structure of the rights object even in an environment where they are stored in different devices.

Second, when a rights object having an inheritance structure is stored in a slave device having a lack of computing power as compared to the master device, there is an advantage of facilitating the consumption of the rights object having an inheritance structure by using the computing power of the master device.

Claims (18)

A storage module for storing a rights object having an inheritance structure; A retrieval module for retrieving a rights object required to play a predetermined content object in the storage module; A message generation module for generating a rights object request message for requesting an unsearched rights object if the search module fails to search for the rights object required to play the content object; A device interface module for transmitting the rights object request message to a slave device and receiving a rights object according to the rights object request message from the slave device; And And a playback module for playing the content object using at least one of a rights object searched by the search module and a rights object received by the device interface module. The method of claim 1, The rights object includes at least one of a child rights object and a sub-rights object having a mutual inheritance relationship, The child rights object includes restriction information indicating a content object identifier for identifying the content object, a content encryption key for playing the content object, and a limit for using the child rights object for playing the content object. At least one of The sub-rights object includes at least one of the restriction information and permission information indicating a reproduction method of the content object available through the sub-rights object. The method of claim 2, The message generating module generates a child rights object request message requesting the child rights object, The device interface module receives the child rights object according to the child rights object request message from the slave device, The playback module is a master device for playing the content object using the sub-right object and the received child rights object searched by the search module. The method of claim 3, wherein The child rights object request message includes the content object identifier, The child rights object received from the slave device is a rights object that the slave device retrieves from the slave device using the content object identifier, And the search module searches for the sub-rights object using the inheritance relationship identifier included in the sub-rights object received from the slave device. The method of claim 2, The message generating module generates a sub-rights object request message requesting the sub-rights object and a sub-rights object request message requesting the sub-rights object. The device interface module receives a sub-rights object according to the sub-rights object request message and a sub-rights object according to the sub-rights object request message from the slave device, The playback module is a master device for playing the content object using the received child rights object and sub-rights object. The method of claim 5, The child rights object request message includes the content object identifier, The sub-rights object request message includes the inheritance relationship identifier included in the sub-rights object received from the slave device, The sub-rights object received from the slave device is a rights object retrieved from the slave device by the slave device using the content object identifier, and the sub-rights object received from the slave device is inherited by the slave device. A master device which is a rights object retrieved from the slave device using an identifier. The method of claim 2, The message generating module generates a sub-rights object request message requesting the sub-rights object. The device interface module receives the sub-rights object according to the rights object request message from the slave device, The playback module is a master device for playing the content object using the child rights object and the received sub-rights object searched by the search module. The method of claim 7, wherein The sub-rights object request message includes the inheritance relation identifier included in the sub-rights object searched by the search module. The sub-rights object received from the slave device is a rights object that the slave device retrieves from the slave device using the inheritance relationship identifier. The method of claim 1, The slave device is a portable storage device. Obtaining a rights object having a predetermined inheritance structure from the slave device; And And playing back a predetermined content object using the obtained rights object. The method of claim 10, The rights object includes at least one of a child rights object and a sub-rights object having a mutual inheritance relationship, The child rights object includes restriction information indicating a content object identifier for identifying the content object, a content encryption key for playing the content object, and a limit for using the child rights object for playing the content object. At least one of The sub-rights object includes at least one of the restriction information and permission information indicating a reproduction method of the content object available through the sub-rights object. The method of claim 11, The obtaining step, Requesting the slave rights object from the slave device; And Receiving the child rights object from the slave device, The regenerating step, And playing the content object using the sub-rights object and the received child rights object. The method of claim 12, The requesting the child rights object may include transmitting the content object identifier to the slave device. And the child rights object received from the slave device is a rights object that the slave device retrieves from the slave device using the content object identifier. The method of claim 12, Requesting the slave rights object from the slave device; And And receiving the sub-right object from the slave device. The method of claim 14, The requesting the sub-rights object may include: Obtaining an inheritance relationship identifier for identifying the sub-right object from the sub-right object; And Transmitting the inheritance relationship identifier to the slave device; And the sub-rights object received from the slave device is a rights object retrieved from the slave device by the slave device using the inheritance relationship identifier. The method of claim 11, Requesting the slave rights object from the slave device; And Receiving the secondary rights object from the slave device, The regenerating step, Playing the content object using the child rights object and the received sub-rights object. The method of claim 16, The requesting the sub-rights object may include: Obtaining an inheritance relationship identifier for identifying the sub-right object from the sub-right object; And Transmitting the inheritance relationship identifier to the slave device, And the sub-rights object received from the slave device is a rights object retrieved from the slave device by the slave device using the inheritance relationship identifier. The method of claim 10, And the slave device is a portable storage device.

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