KR20110073149A - Method of packaging a digital content - Google Patents

Abstract

PURPOSE: A method for packaging digital contents is provided to reduce the size of packaged digital contents by implementing a lossless compression process with respect to original data before an encoding process. CONSTITUTION: A packaging interface part(50) receives original data. A key generating part(52) generates a contents encoding key with respect the original data. A digital rights management(DRM) header forming part(54) forms a DRM header based on DRM information with respect to the original data. An compressing part(56) compresses the original data using the contents encoding key without loss. An encoding part(58) implements an encoding process using the contents encoding key with respect to compressed original data.

Description

Method of packaging a digital content

The present invention relates to a method for packaging digital content, and more particularly, to a method for packaging digital content using lossless compression in a digital rights management (DRM) system.

Unlike analog content, digital content has features such as nondestructiveness that maintains the same quality as the original after several copies, convenience for archiving, and the ability to easily combine various types of digital content.

When digital content having such characteristics meets Internet communication media, the same copy as the original can be propagated infinitely rapidly. As a result, content owners who have invested so much capital and effort are reluctant to digitize their content and commercialize it on the Internet. This climate eventually results in a disadvantage that the content consumer (user) loses the opportunity to receive high quality content.

Accordingly, digital rights management (DRM) systems have emerged to protect copyrights of copyright holders.

Digital rights management (DRM) systems are commonly used to protect online information assets such as digital music and video files such as music files. Nowadays, due to the rapid development of digital contents, contents that are the subject of a digital rights management (DRM) system are not limited to digital sound sources or images, but are spread to various contents such as geographic information or documents.

The contents distribution process using the digital rights management (DRM) system is outlined as follows. After encrypting and transmitting the sound source or the video content to the user, the server issues a license to the user, so that the user can use the sound source content or the video content. License refers to data containing contents specifying the decryption key used to decrypt the encrypted content and the right to use the content (eg, number of times, duration, etc.).

Such a conventional digital rights management (DRM) system has no room for improvement when distributing video content as a sound source, but it is necessary to improve performance when distributing large content such as geographic information or large document content. .

That is, a problem arises with the repository of the service provider. Content such as geographic information is quite large in size, requiring additional storage to manage the packaged (encrypted) content, which leads to an increase in the service construction cost of the service provider.

Then, there is a problem about network traffic generated while delivering the packaged (encrypted) content to the user. Content such as geographic information uses a large amount of network resources from the service provider to the user because of the large data size. As a result, service users need to secure additional network resources, which leads to an increase in the service construction cost of the service provider. In addition, dissatisfaction with the service because a large amount of capacity must be delivered from the user's point of view.

In addition, problems arise with the user's repository. Packaged geographic information or document data received from the service provider is ultimately stored on the user's PC. As a result, the user must have more data than the size of the original, and thus requires an increase in the storage of the user's PC.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned conventional problems, and an object thereof is to provide a method of packaging digital content that can reduce the use of storage and network resources of a service provider and reduce the storage space of a user. have.

An object of the present invention is to circumvent a method of distributing digital content simply by encrypting and distributing it to a user, and then distributing it through packaging that compresses and encrypts the original content in a server. In this way, the user can reduce the time to receive the digital content to solve the user's inconvenience, reduce the cost for the server storage and network to provide high-quality content at a lower cost.

In order to achieve the above object, a packaging method of digital content according to a preferred embodiment of the present invention, the compression unit, the compression step of compressing the original file accompanying a packaging request; And an encryption step of encrypting, by the encryption unit, the compressed original file.

Preferably, the compression step performs lossless compression.

The compression step compresses the entire area of the original file. In this case, the encryption step encrypts the entire compressed original file.

The compression step performs partial compression on the original file. Partial compression of the compression step compresses the area containing the actual data of the original file. In this case, the encryption step encrypts the region in which partial compression is performed on the original file in which partial compression has been performed. Alternatively, the encryption step encrypts the entirety of the original file, which has been partially compressed.

According to the present invention of such a configuration, the size of the packaged content is reduced by lossless compression of the original before encryption at the time of packaging. As a result, the efficiency of the server can be improved and the contents can be efficiently distributed.

In other words, since the original file is compressed and encrypted at the time of packaging, the size of the distributed content is smaller than that of the conventional method. As a result, the cost of storage media and network resources required for service maintenance is reduced.

In addition, the user can easily hold the content to provide the user with convenience in terms of storage.

1 is an exemplary diagram illustrating a configuration of a DRM service system to which a digital content packaging method according to an embodiment of the present invention is applied.
FIG. 2 is a diagram illustrating an internal configuration of the content packager of FIG. 1.
3 is a diagram illustrating an internal configuration of the DRM agent of FIG. 1.
4 is a flowchart illustrating a digital content packaging method according to an embodiment of the present invention.
5 is an exemplary view for explaining the compression employed in the present invention.
6 to 8 are exemplary diagrams for explaining the compression and encryption employed in the present invention.

Hereinafter, a method of packaging digital content according to an embodiment of the present invention will be described with reference to the accompanying drawings. Prior to the detailed description of the present invention, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is an exemplary diagram illustrating a configuration of a DRM service system to which a digital content packaging method according to an embodiment of the present invention is applied. Some of the components shown in FIG. 1 are generally similar to the serviced DRM service system.

The DRM agent 12 is a terminal operated by a user.

The presentation server 14 processes the part related to the purchase in connection with the charging system 16 when there is a willingness to purchase the content from the user through the DRM agent 12. When the processing of the part related to the purchase is completed, the presentation server 14 requests the DRM content to the business server 18.

The business server 18 requests the DRM server 100 to package the original file of the corresponding DRM content and transfers the user's permission to the DRM server 100.

The interface server 30 of the DRM server 100 stores the input user's usage rights and information on the corresponding DRM content that requested packaging in the database 34 for management.

The contents packager 36 of the DRM server 100 packages the original file of the DRM content after lossless compression. Prior to lossless compression, the content packager 36 generates a content encryption key by means of a packaging request and constructs a header using the DRM information (ie, information about the DRM content). The content packager 36 encrypts the lossless compressed original file with the content encryption key. The content packager 36 configures the configured header information and the encrypted data into a file of the DRM content and delivers the file to the download server 38.

The download server 38 of the DRM server 100 downloads the file of the received DRM content to the DRM agent 12 so that the user can check it.

In FIG. 1, reference numeral 20 denotes a conventional content management server (CMS), and reference numeral 22 denotes a database of the content management server 20. Reference numeral 32 is a rights object issuing server that provides a rights object corresponding to the downloaded DRM content.

The present invention is to reduce the size of the packaged content by lossless compression to the original file prior to the encryption at the time of packaging, as a result, to increase the efficiency of the server and to enable efficient distribution of the content. Accordingly, it can be said that the role of the content packager 36 among the components of FIG. 1 is very important.

FIG. 2 is a diagram illustrating an internal configuration of the content packager 36 of FIG. 1.

The content packager 36 includes a packaging interface unit 50, a key generating unit 52, a DRM header constructing unit 54, a compressing unit 56, an encryption unit 58, and a file constructing unit 60. .

The packaging interface unit 50 receives an original file accompanied by a packaging request.

The key generation unit 52 generates a content encryption key (CEK) for the original file input through the packaging interface unit 50.

The DRM header configuration unit 54 constructs a DRM header with DRM information (ie, content metadata) for the original file. Here, the content metadata refers to data containing additional description of the content. For example, the content metadata may include an ID for identifying digital content, a mime-type of the original digital content, a right issuer URL for obtaining the right object, and an encryption method. Included.

The compression unit 56 losslessly compresses the original file with the content encryption key generated by the key generation unit 52.

The encryption unit 58 encrypts the original file compressed by the compression unit 56 with the content encryption key generated by the key generation unit 52.

The file construction unit 60 configures and outputs the DRM header information by the DRM header construction unit 54 and the original file encrypted by the encryption unit 58 as a DRM content file.

In an embodiment of the present invention, it is assumed that the DRM content file format extends the OMA DRM v2.0 DCF (DRM Content Format) to protect a large amount of U-GIS content under lossless compression. As a result, the DRM content file constructed by the file structuring unit 60 is inserted into the existing content object insertion area by compressing a large amount of geographic information data in the 7z file format. In the DRM header, the DRM content packaged file is set to "application / x-7z-compressed" in the Mime-Type field to indicate that the file is a 7z file format. 7-Zip supports the AES-256 encryption algorithm supported by OMA DRM and uses compression based on 256-bit AES calculation, so the padding scheme (null-padding) follows that used by 7-Zip.

3 is a diagram illustrating an internal configuration of the DRM agent 12 of FIG. 1.

DRM agent 12 includes a compression library 70, a DRM format library 72, and a DRM interface 74.

The compression library 70 decompresses the decoded data.

The DRM format library 72 decrypts the encrypted DRM content file input via the DRM interface 74.

When the packaged DRM file is delivered to the user by applying compression, the user should be able to use it in the same way as a normal DRM file. The DRM agent 12 to which the compression library 70 is applied is designed to be used as a general file I / O. Accordingly, the compressed DRM agent 12 supports decryption for encryption and uses the compression library 70 to decompress the decrypted data. The data delivered to the user by the DRM agent 12 is the data of the actual original content.

Next, a method of packaging digital content according to an embodiment of the present invention will be described with reference to the flowchart of FIG. 4. 5 is an exemplary view for explaining the compression employed in the present invention. The method of packaging digital content to be described below may be understood as an operation mainly performed in the content packager 36.

First, the packaging interface unit 50 receives an original file accompanying a packaging request (S10).

The original file accompanying the packaging request is delivered to the key generation unit 52 through the packaging interface unit 50. Accordingly, the key generation unit 52 generates a content encryption key (CEK) for the received original file (S12). The generated content encryption key is set in the user password setting part (CryptoSetPassword) used in the existing 7-Zip.

In addition, the DRM header configuration unit 54 configures the DRM header using the DRM information (ie, content metadata) of the original file (S14).

Thereafter, the compression unit 56 losslessly compresses the original file using a content encryption key (CEK) (S16). Here, lossless compression means decoding original content as it is. For example, when the original data is "888883333333" as shown in (a) of FIG. 5, the expression of lossless compression is that "8" is five times consecutive and "3" is seven times as shown in (b) of FIG. 5. Express that it is continuous. However, the expression of lossy compression represents only "8" and "3" as in FIG. 5C. In other words, lossy compression has the advantage of greatly reducing the size of data, but causes loss of original data. However, in the case of lossless compression, decoding is performed without loss of original data.

Subsequently, the encryption unit 58 encrypts the original file compressed by the compression unit 56 with the content encryption key (S18).

Finally, the file configuration unit 60 configures and outputs the DRM header information and the encrypted original file into a DRM content file (S20).

As a result, the DRM content file output from the file configuration unit 60 is delivered to the user via the DRM agent 12 through the download server 38.

In the above-described embodiment of the present invention, the original file used to package the DRM may be compressed in whole or in part according to use. Full compression proceeds to compress the entire original file. Partial compression is performed on a payload basis or on a specific basis, depending on the characteristics of the original file. In the case of partial compression, the overall compression and the overall service scenario are the same, but it is assumed that the compression library 70 can control the partially compressed file.

6 to 8 are exemplary views for explaining in more detail the compression and encryption employed in the present invention.

6 shows that the entire area of the original file is compressed and the entire area is encrypted in the entire compressed original file. The total encryption for the full compression is the length (size) of the encrypted file for the length (size) n of the compressed file according to the encryption algorithm and the padding method, cn≥n.

Fig. 7 shows that only a partial region (that is, a region containing actual data) is compressed without encrypting a specific region, such as a header of the original file, and encrypted only for the compressed partial region. In the case of Fig. 7, the lengths (sizes) cn1 and cn2 of the encrypted constant area files cn1 and cn2 for the lengths (sizes) n1 and n2 of the compressed constant areas also constitute cn1≥n1 and cn2≥n2.

FIG. 8 shows that a certain area, such as a header of the original file, is compressed without compressing only a part of the area (that is, an area containing actual data) and encrypting the entire file including the rest of the uncompressed area. In the case of Fig. 8, the length (size) l1 of the encrypted file as a whole is equal to l1?

As such, the correlation between the original file, the compressed file, and the encrypted file is shown in Table 1 below.

 compression  Correlation (Source rn, Compression an, Encryption cn)  Full compression  rn> cn ≥ an  Partial compression  rn> cn ≥ an

On the other hand, the present invention is not limited only to the above-described embodiments and can be carried out by modifications and variations within the scope not departing from the gist of the present invention, the technical idea that such modifications and variations are also within the scope of the claims Must see

36: content packager 50: packaging interface unit
52: key generation unit 54: DRM header configuration unit
56 compression unit 58 encryption unit
60: file organization

Claims (1)

A compression step of compressing, by the compression unit, the original file accompanying the packaging request; And
And an encryption unit encrypting the compressed original file.

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