KR20060082808A - Apparatus and method for digital rights management - Google Patents

Abstract

The present invention relates to a digital rights management apparatus and method.

The digital rights management apparatus according to an embodiment of the present invention provides a storage module for storing a rights object including predetermined meta information, and a control for providing meta information of the rights object stored in the storage module when a request for searching for a rights object is input. Module, and an integrity check module for maintaining the integrity of the meta information.

DRM, rights object, meta information, search

Description

Apparatus and method for digital rights management

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

2 is a block diagram illustrating a digital rights management apparatus according to an embodiment of the present invention.

3 is a flowchart illustrating a digital rights management method according to an embodiment of the present invention.

4 is a flowchart illustrating a meta information integrity maintenance process according to an embodiment of the present invention.

5 is a block diagram illustrating a host device according to an exemplary embodiment of the present invention.

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

7 is a block diagram illustrating a portable storage device according to an embodiment of the present invention.

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

9 is a flowchart illustrating a process of searching for a rights object stored in a portable storage device according to an embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>

110: storage module 120: search module

130: integrity check module 140: status information update module

150: encryption / decryption module 160: control module

The present invention relates to digital rights management, and more particularly, to a digital rights management apparatus and method capable of efficiently managing information of a rights object.

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 have been made to protect digital content 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 license of a right object (RO) 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.

As mentioned above, rights objects play an important role in DRM. Therefore, the device storing the rights object needs to secure the rights object from the access of the external device. To this end, in the related art, a device stores a rights object in a predetermined secure storage area not only to protect the rights object in hardware but also to store the rights object in a encrypted state by using various encryption algorithms. It is also protected.

However, encryption-based software protection techniques are the cause of slowing down the read and write operations of the device memory. For example, according to the related art, when a user tries to retrieve information about a rights object stored by a device, the device decrypts the encrypted rights object, extracts predetermined information from the decrypted rights object, and then extracts the information. There is a problem that the response speed to the user's request is reduced because it is displayed. In particular, the above-mentioned problem is inevitably aggravated when a right object stored in a portable storage device having low computational power is searched compared to a general device capable of playing a content object.

An object of the present invention is to enable a more effective search for information on a rights object.

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, the digital rights management apparatus according to an embodiment of the present invention includes a storage module for storing a rights object including predetermined meta information, and a rights object stored in the storage module when a right object search request is input. And a control module for providing meta information of the metadata, and an integrity check module for maintaining the integrity of the meta information.

In order to achieve the above object, in the digital rights management method according to an embodiment of the present invention, when the right object search request is input, providing the meta information of the rights object stored in a predetermined storage medium, and the provided meta information Maintaining integrity to the.

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.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

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.

Host device

The host device may be connected to a portable storage device and may be a device capable of consuming a rights object to play back a content object. The host 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.

Portable storage

The portable storage device includes a nonvolatile memory having a property of reading, writing, and erasing data, such as a flash memory, and has a predetermined computing power for data, and is a storage device that can be easily connected to or disconnected from a host device. do. Examples of portable storage devices include smart media, memory sticks, CF cards, XD cards, and multimedia cards.

-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 a content encryption key, permission information, restriction information, state information, and a content object identifier for identifying a content object that can be played back with the content encryption key.

Content encryption key

The content encryption key is a key capable of playing the content object and may have a form of a predetermined binary value. For example, the content encryption key can be used to decrypt the content object to obtain the original content.

Permission information

The permission information is information indicating a play back method of the content object and a copy method of the rights 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 content object relates to a video or music, play may be set as permission information of the right 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, when the content object relates to a still image, at least one of display and printing may be set as permission information of the right 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 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 rights object stored in one device to another device. In case of moving, if the right object is saved in another device, the right object stored in the existing device is inactivated. However, in the case of copying, even if the right object is saved in another device, the right object saved in the existing device remains in an active state. Will be. In this case, deactivation may mean deletion of a rights 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 is set to 10 in the rights object, the host device can play the content object 10 times by consuming the rights 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 host device consumes the right object for which the temporary limit is set, the host device may play the content object after the date and time indicated by the start element of the temporary limit, and play the content object until the date and time indicated by the end element. For example, if the temporary restriction is set to 0: 0: 0 seconds on December 1, 2005 as a starting element, the host device will consume the rights object after 0: 0: 0 seconds on December 1, 2005. You can play the content object.

The time limit limits the period of time in which the content object can be reproduced by consuming the rights object from the time when the content object is first reproduced by consuming the rights object. For example, if the time limit is set to one week as restriction information in the rights object, and the host device consumes the rights object for the first time at 0: 0: 0 second on December 1, 2005, the host device will display the 2005 content object. It is possible to play the content object by consuming the rights object until 0: 0: 0 seconds on December 8.

The cumulative time limit defines the total amount of time that the content object can be consumed to play the content object. For example, if the cumulative time limit is set to 10 hours in the rights object, the host device may consume the rights object and play the content object for a total of 10 hours. At this time, the host device is not limited to the number or date of playing the content object by consuming the rights object.

Status information

The rights object can be consumed within the limits allowed by the restriction information. The status information is information indicating whether the rights object is available based on the restriction information. The status information of each rights object includes one of a valid state indicating that the rights object is available, an invalid state indicating that the rights object is unavailable, and an unidentifiable state in which the rights object cannot be checked. do. Here, the uncheckable state is a state that can be set when the availability of the rights object can change over time. For example, if a temporary restriction or a period restriction is set as the restriction information of the rights object, it is not possible to determine whether the rights object can be used only by the restriction information, and additional time information at the time of checking the status information is needed. Therefore, the status information of the rights object for which the temporary limit or the period limit are set may be set to an unconfirmable state.

Meta Information

The meta information is metadata about a rights object and includes at least one of permission information, restriction information, and state information.

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 Criptography

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.

- module

A module refers to software or a hardware component such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), which plays a role. 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.

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

2 is a block diagram illustrating a digital rights management apparatus 100 according to an embodiment of the present invention. The illustrated digital rights management apparatus 100 includes a storage module 110, a retrieval module 120, an integrity check module 130, a status information update module 140, an encryption / decryption module 150, and a control module 160. ).

The storage module 110 may include a storage medium such as a flash memory, and may be divided into a secure storage area and a general storage area. The secure storage area contains security data that needs to be protected from access of an external device (not shown) or an external module (not shown), such as a rights object, a hash value of the rights object's meta information, and a predetermined encryption key. Is stored. On the other hand, non-secure data that can be leaked to the outside is stored in the general storage area, such as a content object. Data stored in secure storage areas are physically or logically protected from access by external devices or external modules.

Each rights object stored in the storage module 110 may include meta information. The meta information is preferably included in a fixed field in the rights object (for example, the ath to nth bits of the rights object may be previously agreed upon as a field in which meta information is recorded). In this case, regardless of the type of the rights object, accessing a fixed field of each rights object enables to obtain meta information of each rights object.

When the right object search request is input, the search module 120 searches meta information of the rights object stored in the storage module 110. The rights object search request may be input from an external device or an external module.

The integrity check module 130 maintains the integrity of the meta information. That is, the integrity check module 130 may prevent the meta information from being changed by checking the integrity of meta information (for example, meta information accessed by an external device or an external module). For example, the integrity check module 130 calculates a hash value for meta information accessed by an external device or an external module using a predetermined hash function, and compares the calculated hash value with the hash value stored in the storage module 110. Can be compared. If the two hash values are the same, the integrity check module 130 may determine that the integrity of the meta information is maintained. Here, the hash value stored in the storage module 110 may be calculated by the integrity check module 130 about meta information of the rights object when the rights object is stored in the storage module 110. Accordingly, the meta information may be disclosed to the external device or the external module, but is not changed by the external device or the external module.

In addition, when the state information included in any meta information is changed by the state information update module 140, the integrity check module 130 calculates a hash value for the meta information whose state information is changed, and stores the calculated hash value. It is stored in the module 110. Accordingly, the hash value previously stored in the storage module 110 is updated with the newly calculated hash value for the meta information whose state information is updated.

When the status information included in the meta information searched by the search module 120 is set to the unresolved state, the status information update module 140 compares time information at the time of the meta information search with restriction information included in the meta information. You can then determine whether the rights object is available. For example, as the limit information included in the meta information, the end element of the time limit is set to 0: 0: 0 second on November 1, 2005, and the time information at the time of searching for meta information is 0: 0 on November 2, 2005. If it is 0 minutes, the rights object is determined to be unavailable. The time information at the time of the meta information search may be obtained from an external device or an external module.

As a result of the determination, if the rights object is available, the state information update module 140 maintains the state information included in the meta information in an indeterminate state. However, if it is determined that the rights object is not available, the state information update module 140 changes the state information included in the meta information into an invalid state.

In addition, the state information update module 140 changes the state information included in the meta information of the rights object to an invalid state when the rights object is no longer available as all the rights objects in the valid state are consumed.

The encryption / decryption module 150 is a module for encrypting and decrypting predetermined data, and encrypts data to be transmitted to an external device or an external module or receives encrypted data from an external device or an external module at the request of the control module 160. The decoded data can be decrypted. The encryption / decryption module 150 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 150 may generate a predetermined random number necessary for a mutual authentication process with an external device or an external module. Meanwhile, each right object stored in the storage module 110 may be encrypted with a unique encryption key owned by the digital rights management apparatus 100 by the encryption / decryption module 150 except for meta information. An example of the portion of the rights object encrypted is a content encryption key. Therefore, if the rights object is to be provided to an external device or an external module, the encryption / decryption module 150 decrypts the encrypted portion of the rights object, and then the external device or external module to which the rights object is provided can decrypt. You can encrypt the rights object again.

The control module 160 controls the operations of the modules 110 to 150 constituting the digital rights management apparatus. Therefore, the control module 160 may function as a DRM agent that manages the DRM tasks of the digital rights management device. In addition, the control module 160 may control a mutual authentication process with an external device or an external module.

The control module 160 may provide the meta information searched by the search module 120 to an external device or an external module. Providing the meta information in the present invention means that the meta information is actively transmitted to the external device or the external module that requests the rights object search, and that the external device or the external module that requests the rights object search accesses the meta information of the rights object. It may mean to allow things.

Hereinafter, an operation process of the above-described digital rights management apparatus 100 will be described with reference to FIG. 3.

3 is a flowchart illustrating a digital rights management method according to an embodiment of the present invention.

First, when a right object search request is input from an external device or an external module (S410), the search module 120 searches meta information of the rights objects stored in the storage module 110 (S415).

If the meta information includes the state information, the state information update module 140 checks whether the state information is set to the non-confirmable state (S420).

As a result of the check, if the state information is not in the uncheckable state (for example, when the state information is valid or invalid state), the control module 160 provides the retrieved meta information to the external device or the external module (S450).

On the other hand, when the status information is indeterminate state as a result of the check in step S420, the status information updating module 140 compares the time information at the time of meta information search with the restriction information included in the meta information, and includes the rights object including meta information. It is determined whether is available (S425).

As a result of the determination, if the right object is available, the state information updating module 140 maintains the state information included in the meta information in an indeterminate state (S445), and the control module 160 provides the meta information (S450).

However, as a result of the determination in step S425, if the rights object is not available, the state information update module 140 changes the state information included in the meta information into an invalid state (S430). At this time, the integrity check module 130 calculates a hash value for meta information whose state information is changed using a predetermined hash function (S435). Thereafter, the integrity check module 130 stores the calculated hash value in the storage module 110 (S440). That is, the integrity check module 130 replaces the existing hash value for the meta information whose state information is changed among the hash values stored in the storage module 110 with the hash value calculated in step S435. Thereafter, the control module 160 provides meta information including the changed state information (S450).

If there is a residual right object in the storage module 110 (S455), the search module 120 searches for meta information of the residual right object (S415).

Therefore, the above-described process may be repeated until meta information of all rights objects stored in the storage module 110 is retrieved.

Meanwhile, while the process of FIG. 3 is performed, the integrity check module 130 prevents meta information from being changed by an external device or an external module, and a process thereof is illustrated in FIG. 4.

If the control module 160 provides the meta information (S510), and the external device or the external module accesses the meta information (S520), the integrity check module 130 is the integrity of the meta information accessed by the external device or the external module It is maintained (S530). For example, the integrity check module 130 calculates a hash value of meta information accessed by an external device or an external module by using a predetermined hash function, and the calculated hash value is compared with the hash value stored in the storage module 110. It is possible to prevent unauthorized change of meta information by forcing it to have the same value.

The digital rights management apparatus 100 described with reference to FIGS. 2 to 4 may be implemented in various types of devices. For example, the digital rights management apparatus 100 may be implemented as a host device, which is illustrated in FIG. 5.

5 is a block diagram illustrating a host device according to an exemplary embodiment of the present invention.

The illustrated host device 200 includes the digital rights management apparatus 100 described above. That is, the storage module 210, the retrieval module 220, the integrity check module 230, the status information update module 240, the encryption / decryption module 250, and the control module 260 of the host device 200 may be configured. The storage module 110, the retrieval module 120, the integrity check module 130, the status information update module 140, the encryption / decryption module 150, and the control module 160 of the digital rights management device 100, respectively. Can perform the same function as Therefore, for the storage module 210, the retrieval module 220, the integrity check module 230, the status information update module 240, the encryption / decryption module 250, and the control module 260 of the host device 200. The description is omitted.

In addition, the host device further includes a user input module 215, a device interface module 225, a playback module 235, a display module 245, and a time management module 255.

The user input module 215 receives a predetermined command or request from a user. To this end, the user input module 215 may include input means such as a keypad, a touch pad, and a touch screen. Accordingly, the user may request a search for the rights object stored in the storage module 210 through the user input module 215. When the request for the search for the rights object is input, the operation as described with reference to FIGS. 3 and 4 may be performed. Can be.

The device interface module 225 transmits data to or receives data from an external device (eg, portable storage device). Therefore, the host device 200 may be connected to an external device through the device interface module 225.

The playback module 235 plays the content object using the rights object. For example, the playback module 235 may include a video decoding module, and may play back a content object composed of video data compressed in a Moving Picture Experts Group (MPEG) format.

The display module 245 displays the content object played by the playback module 235 or displays meta information provided by the control module 260. Accordingly, the user may check the meta information of the rights object stored in the storage module 210 through the display module 245. The display module 245 may be implemented as a display panel such as a PDP, an LCD, an organic EL, or the like.

The time management module 255 manages current time information.

An operation process of searching for the rights object stored in the host device 200 by the host device 200 having such a structure may be understood through the description with reference to FIGS. 3 and 4.

At this time, the time information required in the operation of confirming whether or not the right object whose state information is not confirmed, described in process S425 of FIG. 3, may be provided from the time management module 255. In addition, the meta information provided in process S450 of FIG. 3 may be displayed through the display module 245.

According to another embodiment of the present invention, the user may store the rights object in the portable storage device in addition to the host device 200, and consume the rights object stored in the portable storage device using the host device 200, or use the portable storage device. You can search for rights objects stored in. In this case, the digital rights management apparatus 100 described with reference to FIG. 2 may be implemented as a portable storage device. First, a DRM system using a portable storage device will be described with reference to FIG. 6, and then a configuration of the portable storage device will be described with reference to FIG. 7.

6 is a diagram illustrating a DRM system according to an embodiment of the present invention. The illustrated DRM system includes a host device 200 and a portable storage device 300.

The user may acquire a content object from the content provider 20 through the host device 200 or may purchase a rights object from the rights object issuer 30 at a predetermined cost. The purchased rights object may be stored in the host device 200, but the rights object stored in the host device 200 may be moved or copied to the portable storage device 300. In addition, the portable storage device 300 may store one or more rights objects from the time of its production.

When the portable storage device 300 stores the rights object, the host device 200 may be connected to the portable storage device 300 and consume the rights object stored in the portable storage device 300 to play the content object. . The host device 300 may perform the structure and function as described with reference to FIG. 5.

7 is a block diagram illustrating a portable storage device 300 according to an embodiment of the present invention.

The illustrated portable storage device 300 includes the digital rights management device 100 described above. That is, the storage module 310, the search module 320, the integrity check module 330, the status information update module 340, the encryption / decryption module 350, and the control module 360 of the portable storage device 300. The storage module 110, the retrieval module 120, the integrity check module 130, the status information update module 150, the encryption / decryption module 150, and the control module 160 of the digital rights management device 100, respectively. Can perform the same function as). Therefore, the storage module 310, the search module 320, the integrity check module 330, the status information update module 340, the encryption / decryption module 350, and the control module 360 of the portable storage device 300 may be used. The description is omitted. In addition, the portable storage device 300 further includes a device interface module 370.

The device interface module 370 transmits data to or receives data from an external device (eg, the host device 200). Accordingly, the portable storage device 300 may be connected to an external device through the device interface module 370.

When connecting the host device 200 and the portable storage device 300 to retrieve the rights object stored in the portable storage device 300, the host device 200 and the portable storage device 300 is mutual authentication (Authentication) It is preferable to go through. Mutual authentication is a basic process for the host device 200 and the portable storage device 300 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. 8.

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

In the present embodiment, the subscript “H” means data owned by or generated by the host device 200, and the subscript “S” is owned by the portable storage device 300 or the portable storage device 300. Means the data generated by.

First, when the host device 200 and the portable storage device 300 are connected, the host device 200 requests mutual authentication from the portable storage device 300 (S610). In this case, the host device 200 may transmit a certificate _H issued by the Certification Authority to the host device 200 together. _H certificate is included in the ID and the public key _H of the host device _H 200, and the electronic signature by a certificate authority. In addition, the connection of the host device 200 to the portable storage device 300 means that the host device 200 and the portable storage device 300 are in electrical contact through a wired medium. However, this means that the connection is an example. It should also be interpreted that the host device 200 and the portable storage device 300 are in a state where they can communicate with each other through a wireless medium in a non-contact state.

The portable storage device 200 having received the certificate _H of the host device 200 checks whether the certificate _H is valid by using a certificate revocation list (hereinafter referred to as "CRL") (S612). If the certificate _H of the host device 200 is a certificate registered in the CRL, the portable storage device 300 may reject mutual authentication with the host device 200. However, if the certificate _H of the host device 200 is a certificate not registered in the CRL, the portable storage device 300 may obtain the public key _H of the host device 200 through the certificate _H.

If it is determined that the host device 200 through the certificate _H determine legitimate device portable storage 300 generates a random number _S and (S614), encrypts the generated random number _S to the public key _H of the host device 200 (S616).

Thereafter, the portable storage device 300 performs a mutual authentication response (S620). In response to the mutual authentication, the portable storage device 300 transmits the certificate _S and the encrypted random number _S issued by the certification authority to the portable storage device 300 together. Certificate _S is contained in the ID and the public key _{S S} of the portable storage device 300, an electronic signature by the certificate authority.

The host device 200 receiving the certificate _S and the encrypted random number _S from the portable storage device 300 confirms that the portable storage device 300 is a legitimate device through the certificate _S , and receives the encrypted random number _S of the host device 200. Decrypt with the private key _H (S622). In this case, the host device 200 may obtain the public key _S of the portable storage device 300 through the certificate _S of the portable storage device 300. In addition, the certificate _S verification operation may be performed through the CRL like the portable storage device 300.

If it is determined that the through the certificate _S OK portable storage device 300 is a legitimate device, the host device 200 encrypts the generated random number _H and (S624), the generated random number _H with public key _S of the portable storage device 300 (S626).

Thereafter, the host device 200 requests the portable storage device 300 to terminate mutual authentication (S630). In the mutual authentication termination request, the host device 200 transmits the encrypted random number _H together.

Host device portable storage device 300 receives the encrypted random number _H from 200 decrypts the encrypted random number _H with his private key _S (S632).

Accordingly, the host device 200 and the portable storage device 300 share two random numbers (random number _H and random number _S ).

Mutual authentication result of two random numbers (the random number _H and the random number _S), the host device 200 and the portable storage device 300 share the use of two random number (random number _H and the random number _S) generates a session key (S640, S642). At this time, the key generation algorithm used by the host device 200 and the portable storage device 300 to generate the session key is the same. Therefore, the host device 200 and the portable storage device 300 share the same session key.

The host device 200 and the portable storage device 300 encrypt the data to be transmitted to the other party with the session key after mutual authentication, and decrypt the encrypted data received from the other party with the session key. Accordingly, security may be maintained for data transmission between the host device 200 and the portable storage device 300. Although not specifically mentioned in the following embodiments, the host device 200 and the portable storage device 300 encrypt the data to be transmitted to the counterpart with the session key generated as a result of mutual authentication, and encrypt the encrypted data received from the counterpart with the session key. It can be understood as decoding.

After the mutual authentication is completed, the host device 200 may move or copy the rights object to the portable storage device 300 or consume the rights object stored in the portable storage device 300 to play the content object.

In addition, according to an embodiment of the present invention, the host device 200 may request a search for the rights object stored in the portable storage device 300, which will be described with reference to FIG. 9.

9 is a flowchart illustrating a process of searching for a rights object stored in the portable storage device 300 according to an embodiment of the present invention.

First, when the user input module 215 of the host device 200 receives a search request for the rights object stored in the portable storage device 300 from the user (S710), the control module 260 may use the device interface module 245. The mobile terminal 300 requests the search for the rights object through the mobile storage device 300 (S720). In this case, the control module 260 may generate a rights object search request message, and the device interface module 245 may transmit the rights object search request message to the portable storage device 300.

When the device interface module 370 of the portable storage device 300 receives a rights object search request from the host device 200, the search module 320 searches meta information of the rights object stored in the storage module 310 ( S730).

Thereafter, the control module 360 provides the retrieved meta information to the host device 200 through the device interface module 370 (S740). Here, before providing meta information to the host device 200, the portable storage device 200 may perform processes S420 to S445 of FIG. 3. In this case, time information required in step S425 may be obtained from the host device 200.

On the other hand, providing the meta information to the host device 200 is not only a case where the portable storage device 300 actively transmits the meta information to the host device 200 through the device interface module 370, the host device 200 ) Includes allowing access to meta information.

When the device interface module 225 of the host device 200 obtains meta information from the portable storage device 300, the display module 245 displays the meta information (S750).

At this time, if the user wants to change the meta information of the rights object stored in the portable storage device 300 through the user input module 240, by the integrity check operation of the integrity check module 330 of the portable storage device 300; Changes in meta information may be rejected.

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 digital rights management apparatus and method of the present invention as described above, the information on the rights object can be searched more effectively.

Claims (14)

A storage module for storing a rights object including predetermined meta information; A control module for providing meta information of the rights object stored in the storage module when a right object search request is input; And And an integrity check module for maintaining the integrity of the meta information. The method of claim 1, The storage module stores a predetermined hash value for the meta information, The integrity check module calculates a hash value for meta information provided by the control module using a predetermined hash function, and maintains the meta information such that the calculated hash value is equal to a hash value stored in the storage module. Digital rights management device to manage the. The method of claim 1, The meta information includes restriction information indicating a limit to which the rights object can be consumed to reproduce a predetermined content object, permission information indicating a reproduction method of the content object available through the rights object, and use of the rights object. Digital rights management device including at least one of the status information indicating the availability. The method of claim 3, wherein The state information may include any one of a valid state indicating that the rights object is available, an invalid state indicating that the rights object is unavailable, and a non-confirmable state in which the rights object may not be confirmed. Copyright management device. The method of claim 4, wherein And a status information update module for setting and changing the status information according to the restriction information and the degree of consumption of the rights object. The method of claim 5, The integrity check module calculates a hash value for meta information whose state information is changed and digital rights management to update the hash value for meta information of the rights object previously stored in the storage module to the calculated hash value. Device. The method of claim 4, wherein When the status information is in the unconfirmable state, it is determined whether the right object is usable by comparing predetermined time information with the restriction information, and when the result of the determination is not available, the status information of the right object is determined. Further comprising a status information update module for changing to an invalid state, The integrity check module calculates a hash value for meta information whose state information is changed and digital rights management to update the hash value for meta information of the rights object previously stored in the storage module to the calculated hash value. Device. When the rights object search request is input, providing meta information of the rights object stored in a predetermined storage medium; And Maintaining integrity to the provided meta information. The method of claim 8, The storage medium stores a predetermined hash value for the meta information, The maintaining of the integrity may include calculating a hash value for the meta information using a predetermined hash function, and managing the meta information such that the calculated hash value maintains a numerical value equal to a hash value stored in the storage medium. Digital rights management method comprising the steps of. The method of claim 8, The meta information includes restriction information indicating a limit to which the rights object can be consumed to reproduce a predetermined content object, permission information indicating a reproduction method of the content object available through the rights object, and use of the rights object. Digital rights management method comprising at least one of the status information indicating the availability. The method of claim 10, The state information may include any one of a valid state indicating that the rights object is available, an invalid state indicating that the rights object is unavailable, and a non-confirmable state in which the rights object may not be confirmed. How to manage copyright. The method of claim 11, And changing the status information according to the restriction information and the degree of consumption of the rights object. The method of claim 12, The updating step, Calculating a hash value for meta information whose state information has been changed; And And updating a hash value of meta information of the rights object previously stored in the storage medium with the calculated hash value. The method of claim 11, If the status information is the unconfirmable state, Determining whether the rights object is usable by comparing predetermined time information with the restriction information; Changing the state information of the rights object to an invalid state if the rights object is unavailable as a result of the determination; Calculating a hash value for meta information whose state information has been changed; And And updating a hash value of meta information of the rights object previously stored in the storage medium with the calculated hash value.

Images