KR100747451B1 - Apparatus and method for digital rights management - Google Patents

Abstract

The present invention relates to a technology for applying a DRM system designed for a desktop environment to a relatively inexpensive mobile phone environment, and specifically protects copyright when using a large amount of content such as MP3 files, games, and images on a mobile phone. It is suitable to do so. The contents used in the conventional mobile phones were small enough to have no difficulty in downloading wirelessly, but in recent years, the mobile phone technology has been developed and it has been difficult to process the DRM technology applied to a small mobile phone program. Therefore, the present invention provides a method for allowing a user to access a web server through PC to search for or purchase content, and request a mobile phone registration to a service provider server by a DRM server for using the content on the mobile phone; By requesting license from the operator's server to use the contents in the mobile phone, the license is encrypted with the symmetric key so that the mobile phone can be licensed without using the PKI algorithm.

Description

 Digital rights management device and method {APPARATUS AND METHOD FOR DIGITAL RIGHTS MANAGEMENT}

1 is a block diagram of a DRM system according to the prior art.

2 is a block diagram of a DRM system in accordance with the present invention.

3 is a control flowchart of a digital rights management method according to the present invention;

4 is an explanatory diagram showing a license download process of a DRM system according to the present invention;

Figure 5 (a)-(c) is a functional block diagram of a DRM server, operator server, mobile phone applied to the present invention.

*** Description of the symbols for the main parts of the drawings ***

21: PC 22: Web Server

23: DRM Server 24: Operator Server

25: Cell Phone

The present invention relates to a technology for performing a digital rights management (DRM) function for a mobile communication terminal such as a mobile phone. In particular, a DRM system designed to be suitable for an existing desktop environment is applied to a relatively poor mobile phone environment. A digital rights management device and method for enabling the same.

Recently, with the rapid development of information and communication technology, the production and use of digital contents are becoming more and more common. Accordingly, the problem of illegal copying of works has been seriously raised, and the related damages are gradually increasing. Therefore, interest in the DRM system for protecting the intellectual property rights of the content producers is increasing.

In general, the DRM system protects various digital forms of multimedia content such as music, video, electronic documents and images delivered online or offline, so that digital information creators, distributors, publishers, service providers, governments and end users This is to continuously guarantee and manage rights (copyright, license, etc.). Since the DRM system has a main purpose of preventing illegal copying of contents by applying a license policy, a PKI algorithm, and watermarking, it can be called a content protection system using an information protection algorithm in a narrow sense.

According to the purpose of copyright protection, there are various DRM systems implemented for each company. Until now, DRM service mainly considers desktop environment. However, in recent years, the performance of the mobile phone has been greatly improved, and it is possible to access various contents of a large capacity through the mobile phone. For example, most recent mobile phones are equipped with MP3 and digital camera functions as well as basic calling functions. Recently, mobile phones equipped with game functions have emerged. Such game phones are expected to provide 3D content to provide users with enhanced fun.

As contents supported by mobile phones are gradually strengthened and increased in capacity, there is an increasing demand for a system capable of protecting contents and managing copyrights supported by mobile phones. DRM system, which is used in desktop environment, uses PKI algorithm to authenticate users and to protect contents. While the performance of mobile phones is evolving rapidly, it is not yet possible to have enough resources to use the PKI algorithm.

The DRM system according to the prior art is implemented in various ways according to the manufacturing company, which is associated with mutual stakeholders such as content providers, distributors, users. The content provider refers to a person who actually produces the original content, and the content distributor refers to a system for distributing and charging content created such as a shopping mall on a web to a user. In addition, the content user refers to a consumer who actually uses the content purchased from the Internet. Stakeholders from these three areas are linked to operate the DRM system.

A typical configuration example of the DRM system according to the prior art is shown in FIG. 1, which describes the operation thereof.

The following three tasks are required for DRM service. First, the packager server 15 packages the creators to use the pure content created for the DRM service. Second, the web server 16 using the Internet provides a method for a user to search for and purchase desired content. Finally, the DRM server 13, called the clearing house, issues a license to the user including various rules such as usage rules for the contents required to use the distributed contents, the expiration date of the license, and information about the contents.

Meanwhile, the DRM service processing process in the DRM system as shown in FIG. 1 will be described below.

First, the content provider 14 produces the content and registers the content in the content distribution system, and the package server 15 packages the pure content to enable the DRM service. In this process, the packaging information is registered in the DRM server (clearing house) 13.

In this state, the consumer uses the DRM client 18 to search the shopping mall 16 and selects content to purchase, and correspondingly, the web server 16 downloads the packaged content to the consumer.

Then, when the consumer executes the content, the DRM client 18 requests the DRM server 13 to issue a license. On the other hand, the DRM server 13 checks whether the content usage fee exists and if it is found to exist, settles the fee through the payment system 12.

The DRM server 13 creates a license and provides it to the consumer. Accordingly, the consumer can decrypt and execute the packaged content using the issued license.

As a result, by executing the license issuing process as described above, various copyright management services suitable for the characteristics of the contents, such as protection of contents and tracking usage of the contents, which were not possible with existing encryption algorithms, are possible.

However, the DRM system as shown in FIG. 1 is executed in a desktop environment and issues a license using a PKI-based cryptographic algorithm. Although the performance of wireless environments and portable terminals is rapidly improving, it is difficult to apply public key algorithms due to the limitation of system resources in current mobile environments.

In particular, the key of the public key algorithm is much larger than the size of the key used in the symmetric key algorithm, and the amount of resources required for the encryption and decryption algorithm is considerable. In addition, although the stability of the public key is relatively high, generating a public key and a secret key for a public key algorithm using a function that generates a random number is a difficult problem in a desktop computer environment.

As such, the key of the public key algorithm is much larger than the size of the key used in the symmetric key algorithm, the amount of resources required for the encryption and decryption algorithm is quite large, and the function of generating a random number is used for the public key algorithm. Generating public and private keys has been difficult in desktop computing environments.

In addition, the DRM environment in the conventional mobile phone only considers the download using the wireless environment. However, it is very inefficient to directly download a large amount of content such as a game or MP3 in a wireless environment.

For this reason, there is a difficulty in issuing a license for using content using a public key algorithm in a conventional DRM system and effectively distributing and managing content in a mobile phone.

Accordingly, an object of the present invention is to securely and effectively distribute a large amount of content even in a wireless environment by using a public key method having excellent cryptographic capabilities in a desktop environment with a lot of system resources, and using a fast symmetric key algorithm in a wireless environment. To provide a DRM system that can be managed.

The present invention for achieving the above object, the PC to access the web server to search or purchase the content, and to transmit the downloaded content for the mobile phone to the mobile phone; A DRM server that registers a mobile phone of a user of content and generates and issues a license for the content using the user's information; The DRM server may be configured to include a service provider server for authenticating a user and sharing a symmetric key, and for authenticating the user and registering the use of the DRM system in a mobile phone registration process.

In addition, the present invention for achieving the above object, the process of the user to access the web server via the PC to search or purchase the content, the process of requesting the mobile phone registration to the operator server DRM server to use the content in the mobile phone and; By using the process of requesting a license from the operator's server to use the contents in the mobile phone, and receiving a license encrypted with a symmetric key, it is possible to protect the copyright of the content by receiving the license without using the PKI algorithm in the mobile phone. .

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

2 is a block diagram showing an embodiment of a digital rights management device according to the present invention. As shown in FIG. PC 21 for transmitting the content for the mobile phone 25; A web server 22 which enables a user to search or purchase contents through the PC 21 and provides a content distribution function; A DRM server 23 that registers the user's mobile phone 25 of the content and generates and issues a license for the content by using the user's information; A service provider server 24 which enables the DRM server 23 to authenticate the user and share a symmetric key, and also authenticates the user and registers the use of the DRM system at the request of the DRM server in the mobile phone registration process; The mobile phone 25 receives contents from the PC 21 and receives a license through the operator server 24 using a symmetric key algorithm.

3 is a control flowchart of a digital rights management method according to the present invention. As shown in FIG. 3, a user can access a web server through a PC and a wired network to search for or purchase contents, and input payment information from the user. Receiving a first step of registering user information; A second step of transmitting a general packaged PC content when the user information is not used while the user information registration process is performed; A third step of requesting a license from a service provider server to use a content in a mobile phone while the user information registration process is in progress, and issuing a license encrypted with a symmetric key; The PC receives the PC content and the mobile phone content from the web server, and a fourth process of transmitting the received mobile phone content to the mobile phone side, see FIG. 4 attached to the operation of the present invention. When described in detail as follows.

First, referring to FIG. 2, the mobile phone registration processing in the DRM system according to the present invention will be described.

The PC 21 performs a function of searching for or purchasing the content by accessing the web server 22, which is a server of a site that provides the content, using a web browser according to a user's request, and then downloads the contents for the downloaded mobile phone. Uses an application such as (PC Sinc) to transmit to its mobile phone 25.

In this way, the web server 22 as a content provider allows a user to search or purchase packaged content and provides a function of distributing the content. To this end, the web server 22 receives the content from the content provider in advance and packages and manages it to be suitable for applying the DRM system.

In addition, the DRM server 23, which is a clearing house that performs the core functions of the DRM, performs a function of registering the mobile phone 25 to be used by the user of the content during the user registration process. In addition, the DRM server 23 performs a role of generating and issuing a license for the corresponding content by using the information of the user provided while the user requests a license. To this end, the DRM server 23 generates a shared symmetric key for authenticating a user and encrypting a license in association with the operator server 24. At this time, the generated symmetric key is a session key that is used after issuing a license and discarded.

The operator server 24 serves as a trust authority for the DRM server 23 to authenticate users and share symmetric keys. In the mobile phone registration process, the DRM server 23 authenticates a user at the request of a content distributor and registers the use of the DRM system.

Meanwhile, the mobile phone registration procedure will be described with reference to FIG. 3.

The user accesses the PC 21 and the web server 22 that provides the content through a wired network to search for content or purchase desired content from the searched content.

Thereafter, the web server 22 receives payment information from the user and registers the user information with respect to the product which the user decides to purchase.

During the user information registration process, if it is determined that the mobile phone 25 does not use the content, it transmits the general PC content packaged in advance as in the case of the general DRM system. S3, S4)

However, if it is determined that the user is using the content in the mobile phone 25, request the user registration to the communication provider. At this time, if the user's permission is not allowed and the user's permission is not allowed, the user registration cancellation operation is performed, and if the user's permission is granted, the use of the DRM service is registered with the user information provided in the second step (S2) to authenticate the user later. S5-S7)

At this time, the operator server 24 generates a master key for generating a session key later with a confirmation message for the use of the DRM service, and performs a process of exchanging the master key with the mobile phone 25. S8)

When the process of exchanging the master key with the mobile phone 25 in the operator server 24 ends, the DRM server 23 exchanges the mutual key with the operator server 24 in order to ensure secure communication in the license download process. Acquire. That is, the DRM server 23 obtains the certificate of the operator server 24, and the operator server 24 obtains the certificate of the DRM server 23 (S9).

Thereafter, the web server 22 transmits the PC content and the mobile phone content to the PC 21, and the PC 21 transmits the received mobile phone content to the mobile phone 25 using the PC sink. The mobile phone registration process is terminated. (S10, S11)

Meanwhile, a process for authenticating a user and a mobile phone and issuing a license using the stored master key and user information through the series of mobile phone registration processes as described above will be described with reference to FIG. 4.

)를 전송한다.①First, when the user tries to use the contents of the mobile phone 41, the mobile phone 41 connects to the DRM server 42 using an application, and the identifier of the terminal and the license request message (

)) ①

)를 전송받은 후 사업자 서버(43)에 현재의 세션에서 사용할 수 있는 대칭키 요청 메시지(

)를 전송한다.② At this time, the DRM server 42 sends the message (

) After receiving the symmetric key request message available in the current session to the operator server (43).

②)

On the other hand, the operator server 43 uses the session key to be used by the DRM server 42 and the application of the mobile phone 41 by using the public key of the DRM server 42 obtained from the DRM server 42 in the registration process. Encrypt the session key and send the following message ③

Thereafter, the DRM server 42 decrypts the message received from the operator server 43 using its private key to obtain a session key to be used, and then the remaining messages encrypted with the master key of the mobile phone are stored in the mobile phone ( 41). The contents of this message are as follows.

를 그 DRM 서버(42)에 전송한다.⑤ The mobile phone 41 receiving the message encrypted with its master key through the above process obtains the session key currently used by decrypting the master key of the operator generated in the mobile phone registration process. In addition, the mobile phone 41 is a message for authenticating the DRM server 42

Is sent to the DRM server 42. ⑤

The DRM server 42 transmits the following message to the mobile phone 41 after encrypting the license with the obtained session key.

)과 자신이 계산한 값(

)을 비교하여 그 비교 결과를 근거로 DRM 서버(42)를 인증한 후, 상기의 과정에서 획득한 라이센스를 이용하여 컨텐츠를 실행한다.The mobile phone 41 decrypts the message received from the DRM server 42 with the obtained session key, and the value received in the above process (

) And the value you calculated (

) And authenticate the DRM server 42 on the basis of the comparison result, and executes the content using the license obtained in the above process.

On the other hand, Figure 5 (a) shows a functional block diagram of the DRM server 23, which is a clearing house according to the present invention, which is a content packaging system that can package the content of the producer, and the license of the use of the content It consists of a license issuance and generation system for defining and generating rules, a PKI system for providing encryption algorithms to the desktop, and a key distribution system for managing symmetric keys suitable for mobile phone environments.

5B shows a functional block diagram of the operator server 24 according to the present invention. Here, the settlement system performs a task for obtaining the user's permission according to the payment request of the DRM server 23, and performs payment for the corresponding content, and the DRM server and the user authentication system provide the actual user and the content. (23) Authenticate. In addition, the system managing the master key according to the service request of the DRM server 23 is used to generate a key for encrypting the license later. In addition, the key distribution system is used in conjunction with the DRM server 23 to distribute keys capable of decrypting licenses.

In addition, Figure 5 (c) shows a functional block diagram of the mobile phone 3 to decrypt the content according to the present invention, which is the content used in the mobile phone 25 is downloaded through PC Sync (PC Sync) License request system to securely download the encrypted license and its corresponding key by requesting a license from the DRM server 23, a license decrypter that can decrypt the encrypted licensed key, and then to the actual license. It includes a content decoder that can decrypt the content with the existing symmetric key.

As described in detail above, the present invention is a DRM system for protecting a large amount of content, so that the download of content is made through PC, and later, a message for license can be downloaded and used through a wireless path to use the packaged content. In addition, there is an effect that it is easier to create a DRM system for a large-capacity content of a mobile phone.

In addition, by encrypting and transmitting the license using a symmetric key algorithm, it is possible to decrypt the license information with a relatively small amount of storage device, thereby making it possible to construct a DRM system more efficiently.

Claims (5)

delete To use content on your phone, Downloading the content portion to the PC 21 using a public key based algorithm; The license for the content is downloaded to the mobile phone 25 using a symmetric key algorithm; Digital rights management method comprising the step of transmitting the content downloaded to the PC (21) to the mobile phone (25). delete The method of claim 2, wherein the downloading to the PC 21 is performed. Generating a master key in the operator server 24 and exchanging the master key with the mobile phone 25 to perform user authentication; Acquiring a public key between the service provider server 24 and the DRM server 23; When the user authentication for the content is achieved by obtaining the public key of the DRM server 23, the digital rights management method comprising the step of transmitting the content to the PC 21 from the web server 22 The process of claim 2, wherein the downloading of the license to the mobile phone 25 is performed. Requesting a license from an operator server 24 in the mobile phone 25 for content use; Digital service management method comprising the step of issuing a license encrypted with a symmetric key in the operator server (24)

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