KR20110071407A - Method of sharing digital contents applied drm between apparatuses in theater - Google Patents

Abstract

PURPOSE: A method for sharing digital contents in theater of digital cinema contents of which DRM(Digital Rights Management) is applied, is provided to enable the screening device to share the KDM(Key Delivery Message) by setting the multiple screening device in the theater as the domain. CONSTITUTION: When the KDM transfer request is received from a contents server, the KDM or mastering server authenticates the general KDM(S100). When the general KDM is authenticated, the server cancels the encoding(S200). The server decides the domain right request(S300). The server adds the domain authority to the encoded KDM and inputs the domain certificate. The server issues the domain KDM of which the domain certificate is inputted to the screening server.

Description

Method of sharing digital contents applied DRM between apparatuses in theater}

The present invention relates to a method for sharing digital cinema content between devices in a theater, and more particularly, to a domain without issuing a KDM issued by being included in an Extra Theater Message (ETM) generated by a mastering server for each screening device. It is a method for enabling digital cinema content sharing among multiple screening devices by managing them as a single KDM.

The present invention is derived from a study conducted as part of the cultural contents industry technical support project of the Ministry of Culture, Sports and Tourism and the Korea Creative Content Agency. [Task management number: 2-09-1205-001-10987-09-001, Assignment name: DCI Development of technology for digital cinema distribution management and copyright protection that conforms to the standard].

Films that were shot and screened in the past are now being screened through digitized files. Film was scanned and digitized or digitally shot using a digital camera from the time of production, making it easier to edit and distribute movies. However, unlike film films, digitalized movies have no deterioration in image quality when copying, and there is a need for copyright protection because copying is easy and there is a fear of illegal copying and distribution.

Accordingly, the Digital Cinema Initiative (DCI) encrypts digital cinema contents in the form of DCP (Digital Cinema Package) to prevent illegal distribution of digital cinema contents as a digital cinema standard, and distributes the encrypted digital cinema contents for playback in theaters. A KDM (Key Delivery Message) containing a decryptable key is also distributed so that the movie can be played.

However, since KDM is issued for each device to play digital cinema content, the digital cinema content cannot be decoded except for the corresponding device, so that digital cinema content cannot be played. Therefore, even if you have a DCP file, you will not be able to play and watch movies, preventing illegal distribution of digital cinema.

Many modern theaters, however, are screening not only one movie at a theater, but multiple films at the same time. For this reason, the existing method of screening a movie only through a unique KDM for each screening device causes many problems such as inconvenience in KDM management and duplication of KDM analysis work through a security manager (SM).

Accordingly, in the present invention, when issuing a KDM, a plurality of screening devices in the theater are set as domains, and the screening devices in the theater are joined to a domain to receive an encryption key so that a plurality of screening devices can share the KDM. An object of the present invention is to propose a method for sharing digital cinema content between devices in a theater.

As a means for solving the above problems, the method for sharing the digital cinema content between the devices in the theater according to an embodiment of the present invention, when receiving a KDM (Key Delivery Message) transmission request from the content server, the KDM server or the mastering server; Authenticating the general KDM; if the general KDM is authenticated, decrypting the KDM server or the mastering server; determining whether the KDM server or the mastering server requests the domain authority if the decryption is completed; Requesting a KDM server or mastering server to add domain authority to the unencrypted KDM to input a domain certificate, and the KDM server or mastering server issuing a domain KDM in which the domain certificate is entered to the screening server; And managing the domain KDM by the screening server.

According to the method for sharing digital cinema content between devices in a theater, it is possible to share content and KDM between the screened devices set as domains, so that the management and use of content and permissions in a multi-screened environment are possible. It becomes easy.

In addition, according to the method of sharing the digital cinema content between the devices in the theater, it is possible to issue a KDM to a plurality of screening devices in an integrated manner, which facilitates copyright management of the copyright holders of the digital cinema.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and like parts are denoted by similar reference numerals throughout the specification.

In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

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

1 is a conceptual diagram of a system for sharing in-theater devices of digital cinema content according to an embodiment of the present invention.

Referring to FIG. 1, a system for sharing in-the-house devices of digital cinema content according to the present embodiment includes a mastering server 100, a KDM server 200, a content server 300, and a screening server 400. can do.

The mastering server 100 compresses a digital cinema original file of a digital cinema distribution master (DCDM) format to JPEG2000, generates a MXF (Material eXchange Format), encrypts the DCP, and generates a DCP to decrypt the encrypted DCP. A KDM containing a key is generated using a certificate, a trusted device list (TDL), and a key value used in the encoding. In addition, the mastering server 100 transmits the generated DCP and KDM to the content server and KDM server, respectively.

Although not shown in the figure, the mastering server 100 may directly generate a domain KDM and transmit it to the screening server 400 as needed.

The KDM server 200 manages the KDM received from the mastering server 100, and when the domain KDM transmission is requested from the content server 300, converts the KDM to a domain KDM using a certificate and TDL and transmits the content to the content server. do.

The KDM transmitted from the mastering server 100 to the KDM server 200 or the KDM transmitted from the KDM server 200 to the content server 300 is generally included in the ETM and transmitted.

When the content server 300 requests a transmission of the DCP or KDM (or domain KDM) from the screening server 400, the content server 300 requests the transmission of the DCP and KDM (or domain KDM) to the mastering server and the KDM server. Receives the DCP and KDM and performs the role of issuing to the screening server (400).

The screening server 400 decrypts the received domain KDM, extracts the key used when encrypting the digital cinema content, and delivers a decryption key (CDK) to the screening device registered in the domain. In addition, the received DCP can be provided and managed to the connected screening devices. That is, the screening server 400 allows KDM and DCP to be shared by a number of screening devices. In addition, if DCP and KDM (or domain KDM) are required, the content server can request the transmission of DCP and KDM (or domain KDM).

The screening server 400 registers the screening device in the domain if the number of screening devices that can be registered does not exceed when there is a domain registration request of the connected screening devices. In addition, when the screening server 400 requests a key for decrypting the DCP from the registered screening device, the screening server 400 decrypts the corresponding domain KDM, extracts an encryption key, and transmits the encryption key to the screening device.

2 is a functional block diagram of a mastering server for sharing between digital cinema content in-theater devices according to one embodiment of the invention.

2, the mastering server 200 includes a digital cinema compression module 110, a key generation module 120, an MXF encoding module 130, a DCP management module 140, a KDM management module 150, and a certificate. It may include a management module 160 and a TDL management module 170.

The digital cinema compression module 110 performs a function of compressing a digital cinema original file in a DCDM format using an image compression technique. Since video data (digital cinema) has a large data capacity, it is necessary to reduce the data capacity through video compression in order to transmit it. The standard for mastering servers requires JPEG2000 as the video compression technology.

The key generation module 120 generates a key used to encrypt the compressed image data. The reason for encrypting compressed video is to allow only authorized users to use video data for screening. This is because digital media has a high risk of duplication, and thus serves as a means for protecting copyrights of copyright holders (digital cinema producers, etc.). The generated key value is transmitted to the MXF encryption module 130 and the KDM management module 150.

The MXF encryption module 130 encrypts the compressed image data according to the SMPTE-429-6-2006 scheme by using the generated key value according to a standard. As the encrypted image data can be decrypted only when there is a KDM including a key value, only an authorized user can restore and display the image data.

The DCP management module 140 collects the encrypted data and packages them to be one digital cinema content. It also performs the function of transmitting the generated DCP when requested by the content server.

The certificate management module 160 and the TDL management module 170 store data about a certificate issued by an authorized user and data about a list of screening devices that are permitted to be screened. When the KDM management module 150 generates the KDM, a reference to the above data is required, so when the KDM management module 150 requests, the corresponding certificate and the TDL are transmitted to the KDM management module 150.

The KDM management module 150 generates a KDM using a key value, a certificate, a TDL, and other necessary information received from the key generation module 120, the certificate management module 160, and the TDL management module 170. It also sends the created KDM to the KDM server.

Although not shown in FIG. 2, the screening server 400 may directly request the domain KDM transmission to the mastering server 100, and in this case, the mastering server 100 may directly generate and transmit the domain KDM. . In addition, the mastering server 100 may include a KDM (or domain KDM) in the ETM and transmit the same to the screening server 400.

3 is a functional diagram of a KDM server for sharing between digital cinema content in-theater devices according to an embodiment of the present invention.

Referring to FIG. 3, the KDM server 200 of the present invention includes a KDM management module 210, a certificate management module 230, a TDL management module 240, and a domain KDM generation and issuance module 220. The KDM server 200 receives a KDM transmitted from the mastering server 100 and performs a function of providing a KDM or a domain KDM to a content server according to a request.

The KDM management module 210 receives and stores the KDM transmitted from the mastering server 100, and transmits the KDM to the domain KDM generation and issuance module 220 when there is an issue request.

The certificate management module 230 and the TDL management module 240 respectively store data about a certificate issued by an authorized user and data about a list of screening devices that are permitted to be screened. When the domain KDM generation and issuance module 220 generates a domain KDM, reference to the above data is required, so when a request of the domain KDM generation and issuance module 220 is requested, the corresponding certificate and TDL are generated. 220).

The domain KDM generation and issuance module 220 receives the KDM from the KDM management module by referring to the certificate and the TDL when the domain KDM transmission is requested, and generates a domain KDM to which the domain authority is added. Thereafter, the domain KDM generation and issuance module 220 transmits the generated domain KDM to the content server 300.

However, when the general KDM is requested, the domain KDM generation and issuance module 220 transmits the KDM received from the KDM management module 210 to the KDM server without conversion.

The domain KDM is created by adding domain authority to the KDM so that a plurality of screening devices connected to the screening server 400 can share the KDM. The domain KDM may include not only domain authority but also a limitation on the number of devices that can be screened. This is because there is a need to limit the number of screening devices that can be screened by one domain authority depending on the security level and the business model.

In addition, although not shown in FIG. 3, the KDM server 200 may include a KDM (or domain KDM) in the ETM and transmit the content to the content server 300.

4 is a functional block diagram of a content server for sharing between digital cinema content in-theater devices according to one embodiment of the invention.

Referring to FIG. 4, the content server 300 of the present invention includes a DCP management module 310, a domain KDM management module 320, and an issuing interface 330.

The DCP management module 310 receives and stores a DCP transmitted from the mastering server 100. In addition, the DCP management module 310 requests the transmission of the DCP to the mastering server 100 when the DCP transmission request from the screening server 400. If there is a request from the screening server 400 requiring the DCP, the DCP is transmitted to the issuing interface 330.

The domain KDM management module 320 receives and stores a KDM or a domain KDM transmitted from the KDM server 200. In addition, the domain KDM management module 320 requests the transmission of the KDM or the domain KDM to the KDM server 200 when there is a transmission request of the KDM or the domain KDM from the screening server 400. If there is a request from the screening server 400 requiring KDM or domain KDM, the KDM or domain KDM is transmitted to the issuing interface 330.

The issue interface 330 sends a DCP or KDM (or domain KDM) to the screening server 400. In addition, when the DCP or KDM (or domain KDM) transmission request is received from the screening server 400, the DCP management module 310 or the domain KDM management module 320 requests the DCP or KDM (or domain KDM).

5 is a flow chart for KDM generation in a KDM server for sharing between in-theater devices of digital cinema content in accordance with one embodiment of the present invention.

When the KDM server 200 receives a KDM transmission request, the KDM server 200 searches for a corresponding KDM among the KDMs received from the mastering server 100.

In the KDM authentication step (S100), if the KDM is found, authentication is performed on the corresponding KDM. If the KDM fails to authenticate, the KDM creation operation is terminated.

In the decryption step (S200), if the KDM authentication succeeds, the encrypted KDM is decrypted. This is to convert KDM after decrypting KDM.

In the domain authority request step (S300), it is determined whether a request is made to the domain KDM when a KDM transmission request is made. If a domain KDM is requested, it is necessary to add domain authority to the general KDM and convert the domain KDM.

The domain authority input step (S400) and the domain certificate input step (S500), when there is a request for domain authority, authority to allow the screening devices connected to the screening server 400 through the domain KDM to share the KDM Convert KDM to include a certificate that grants and authenticates it.

The KDM server 200 encrypts the converted domain KDM and transmits the same to the content server 300.

General authority input step (S600) and screening device certificate input step (S700), if there is no request for domain authority, the screening server is authorized to issue a KDM only to a single screening device and screening screening device Convert KDM to include the authenticating certificate.

The KDM server 200 encrypts the general KDM converted as described above and transmits the encrypted KDM to the content server 300.

FIG. 6 is an exemplary diagram of an XML document for generating KDM in a KDM server for sharing in-theater devices of digital cinema content according to an embodiment of the present invention.

Referring to FIG. 6, the generation of the domain KDM may be a general KDM or a domain KDM according to an issuance form. When the domain KDM is required, the underline partial field is required as shown in FIG. 6, and in this case, some fields of the general KDM should be modified.

In addition, in the ETM, the user authority portion is required to be modified in the CipherData field of the AuthenticatedPrivate region, and a portion for defining the number of screening apparatuses to display digital cinema content among screening apparatuses actually connected to the screening server 400 is required. The table below is a partial modification of the CipherData part of the AuthenticatedPrivate area.

Length Field Description 16 Structure ID. A 128-bit identifier for this structure. The value of the Structure ID shall be f1.dc.12.44.60.16.9a.0e.85.bc.30.06.42.f8.66.ab (hexadecimal). 20 Certificate Thumbprint in binary form as specified in "certificate and Public Key Thumbprint" of [D-Cinema Digital Certificate]. 16 CompositionPlaylistId, a UUID in binary form as specified in RFC 4122. 4 KeyType, a byte string of length four bytes (see section 5.2.8.2 table). 16 KeyId, a UUID in binary form as specified in RFC 4122. 8 How many devices can display digital cinema content within your domain 25 Not Valid Before, a UTC date-time encoded as specified in Section 5.2.6, e.g. "2004-05-01T13: 20: 00-00: 00" 25 Not Valid After-a UTC date-time encoded as specified in per Section 5.2.7, e.g. "2004-06-30T13: 20: 00-00: 00" 16 AES Content Decryption Key 146 Total

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

1 is a conceptual diagram of a system for sharing in-theater devices of digital cinema content according to an embodiment of the present invention.

2 is a functional diagram of a mastering server for sharing between digital cinema content in-theater devices according to an embodiment of the present invention.

3 is a functional diagram of a KDM server for sharing between digital cinema content in-theater devices according to an embodiment of the present invention.

Fig. 4 is a functional diagram of a content server for sharing in-theater devices of digital cinema content according to an embodiment of the present invention.

5 is a flow chart for KDM generation in a KDM server for sharing between in-theater devices of digital cinema content in accordance with one embodiment of the present invention.

Claims (1)

Authenticating the general KDM by the KDM server or the mastering server when receiving a key delivery message (KDM) transmission request from the content server; Deciphering encryption by a KDM server or a mastering server when the general KDM is authenticated; Determining, by the KDM server or the mastering server, whether or not to request a domain authority when the decryption is completed; Inputting a domain certificate by adding a domain authority to the unencrypted KDM by a KDM server or a mastering server when a domain authority request is made; Issuing, by the KDM server or the mastering server, the domain KDM in which the domain certificate is input to the screening server; And And managing the domain KDM by the screening server.

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