KR100831726B1 - Method and Device for Security on Digital Rights Management System - Google Patents

Abstract

The present invention relates to a security method and system in a Digital Rights Management (DRM) system, and more particularly, to a rights issuer for a content issuer in a DRM system including a content issuer and a right issuer. The present invention relates to a security method and system in a DRM system that can improve security.

 According to the security system and method in the DRM system according to the present invention, the authority issuer may have improved security for the access of the content issuer, and through this, a reliable cooperation with the external content issuer of the authority issuer may be achieved. do. In addition, even a service provider that provides a plurality of services can provide a reliable service only by operating a single integrated authority issuer to enable consistent policy establishment of the DRM business.

CI, RI, DRM system, encryption, integrity, security

Description

Security method and system in the DRM system {Method and Device for Security on Digital Rights Management System}

1 is a block diagram of a security system in a DRM system according to the present invention;

2 is a flowchart illustrating a security method in the security system shown in FIG. 1;

3 is an exemplary view showing a system configuration to which a security method according to the present invention is applied when interworking with an external content issuer.

<Explanation of symbols for the main parts of the drawings>

10: security system 11: content issuer

13: authority issuer 20: user terminal device

The present invention relates to a security method and system in a Digital Rights Management (DRM) system, and more particularly, to a rights issuer for a content issuer in a DRM system including a content issuer and a right issuer. The present invention relates to a security method and system in a DRM system that can improve security.

As computer technology develops and becomes popular, most commercial works, such as books, comics, records, movies, broadcasts, and newspapers, which were produced, stored, and managed in analog form, are becoming digital.

Infinite repetition, the quality of the original is not damaged at all, and it is easy to modify and copy, and the digital characteristics and advantages that can transmit and distribute even a large amount of work in a short time by using a high-speed communication network, the speed of analog works It is digitizing it.

However, these digital advantages are infringing on the original author's rights and interests in the work. Even if you have a copy, it is the same as the original, which weakens your willingness to purchase the original, and it is easy to steal the copyrighted work because it is simple to modify and copy without the author's consent. It can spread quickly and make even legal control impossible.

These negative factors can reduce the morale of the authors and reduce their willingness to produce them, which in turn can cause hesitation. Therefore, for digital works, there is a need for a technical protection device that can effectively manage copyright while fully utilizing the advantages of digital.

Efforts have been made to protect digital content in the past, but in the past, access to digital content (ACCESS) was granted only to some people who paid for it, with a focus on preventing unauthorized access to digital content. However, if the payer deliberately distributes the digital content to a third party, the third party can use the digital content without paying a fair price. To solve this problem, the concept of DRM was introduced.

DRM (Digital Rights Management) is a method to secure and systematically manage the rights of digital assets. It prevents unauthorized copying of content, and also processes the content from being created, published, distributed and used. Provide a set of protection and management mechanisms for DRM technology ensures that digital content is always encrypted so that only authorized users can decrypt and use it instantaneously, and prevents unauthorized copying even if the content is copied. .

A general DRM system is composed of a content issuer (CI) for supplying digital content as a target of protection by a DRM and a right issuer (RI) for issuing a right to use the content.

Rights issuers are responsible for securing Rights Objects (ROs) and providing them only to trusted, legitimate devices. This means that the authority issuer is not exposed to illegal access from an external system, and a technology that can prepare for a hacking attack on the authority issuer server is required.

In particular, the content issuer requests the authority issuer to register a large amount of content information and issue a Rights Object Acquisition Protocol Trigger (ROAP) every time the content and privilege object is issued. Therefore, if the content issuer accepts the request of an unauthorized content issuer, it is illegal. There is a risk of exposure to attacks and attacks.

Therefore, there is a need for security in the DRM system, particularly for the content issuer of the authority issuer.

Accordingly, the present invention has been made to solve the above-described problems, the object of the present invention is to perform the content of each request through the encrypted message transmission and message verification step in the message exchange between the content issuer and the authority issuer An object of the present invention is to provide a security method and system in a DRM system that improves the security of the authority issuer for the issuer and further suggests a reliable alliance model between the authority issuer and the external content issuer.

The security system in the DRM system for achieving the above object, to perform the packaging of the content requested from the user, to generate an encrypted message for requesting information registration and ROAP trigger for the content to the authority issuer A content issuer for performing the transmission of the; And an authority issuer that receives a message requesting information registration and a ROAP trigger for the content from the content issuer, decrypts the message, and performs security verification on the message.

In addition, in a security system consisting of a content issuer and an authority issuer sharing a master key, the security method in the case where the content issuer transmits a request message to the authority issuer includes a method in which the content issuer generates a session key for the request message. Stage 1; A second step of the content issuer generating a MAC value for the request message by using the session key generated as a result of performing the first step; A third step of a content issuer encrypting the session key generated in the first step using the master key; A fourth step in which the content issuer inserts the MAC value and the encrypted session key generated as a result of performing the second and third steps into the request message and sends the same to the authority issuer; A fifth step in which the authority issuer receiving the request message from the content issuer decrypts the session key in the request message through the master key to generate a MAC key value; A sixth step of the authority issuer generating a MAC value for the request message by using the MAC key value generated as a result of the fifth step; A seventh step of the authority issuer performing comparison verification on the MAC value generated as a result of the sixth step and the MAC value in the request message received from the content issuer; And an eighth step of transmitting a response message corresponding to the comparison verification result of the seventh step to the content issuer.

Hereinafter, a security method and system in a DRM system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates a security system configuration in a DRM system. As illustrated, the DRM system includes a content issuer 11, an authority issuer 13, and a user terminal device 20. The security system 10 according to the present invention is constituted.

When describing each component in detail, the user terminal device 20 is a terminal device using the DRM content, and receives the desired content through connection with the content issuer 11 and the authority issuer 13 through a wired / wireless communication network to execute this. Let's do it. More specifically, the content provider connected to the wired / wireless communication network requests the desired content, receives the desired content, and executes the DRM content by receiving an authorization object for the corresponding content from the authority issuer for use and execution of the provided DRM content.

Such a user terminal device must have a security function, a function for storing content or a rights object, a data exchange function between devices, a data transmission / reception function for communicating with a content provider or an authority issuer, and a DRM management function.

The content issuer 11 serves to supply content to a user terminal device that wants to access content protected by DRM, and provides digital content to be provided to a plurality of user terminal devices connected through a wired / wireless communication network. And encrypts the digital contents, and downloads them to the corresponding user terminal device when a use request for the digital contents is requested.

Whenever a content issuer receives a content request and a selected authority object from a user terminal device, the content issuer performs a content information registration request and a request for issuing a Rights Object Acquisition Protocol Trigger (ROAP), respectively. When generating, the content issuer performs encryption on the request message for security of the authority issuer.

The right issuer 13 issues a rights object for the corresponding content so that the user terminal device can access the content provided from the content issuer. At this time, the rights object has the right contents for digital content, and the reproduction, display, execution, printing, and transmission of digital content such as the right to use the content object, the usage restriction information on the content, and the copy restriction information of the rights object are performed. Or, it is the part that sets the authority such as reading. In order to perform the DRM content provided from the content issuer, the user terminal device needs to use a rights object having information on whether to grant the right to the content.

When the authority issuer receives the content registration request and ROAP trigger issue request message from the content issuer, it verifies the message and prevents access to the unauthorized content issuer and ensures integrity when sending and receiving messages with the content issuer. It plays a role and, for the request message of the appropriate content issuer, registers the corresponding content information and generates a ROAP trigger.

As described above, the security system in the DRM system is composed of a content issuer and an authority issuer, and a security method for the content issuer of the authority issuer in the DRM system is illustrated in FIG. 2.

2 is a flowchart illustrating a security method in a security system, and as shown, the security method according to the present invention is applied when exchanging messages between a content issuer and an authority issuer.

The content issuer receives content request from the user terminal device or receives selected Rights Object information of the user terminal device, and in response to the request of the user terminal device, the content issuer registers information on the corresponding content after packaging the content. Or it requests the authority issuer to issue a ROAP trigger. In this case, the content packaging may be performed before the request of the user terminal device. The authority issuer receiving the request performs an operation corresponding to the request and performs a response to the content issuer.

As such, the content issuer and the authority issuer perform a request and response through message exchange. The security method according to the present invention applied in the message exchange process will be described below.

First, the content issuer generates a request message for requesting content information registration or issuance of a ROAP trigger, and transmits the generated request message to the authority issuer (S10).

In more detail, the content issuer generates a session key for requesting a message for content registration or ROAP trigger issuance (S11). In this case, the session key is generated each time the content issuer sends a request message to the authority issuer. The session key has a characteristic that there is no redundancy because the value is changed for each generation, which has the advantage of enhancing security for message transmission. The generated session key is then used as a MAC key for the MAC value.

When the session key is generated, a MAC (Message Authentication Code) value for the request message is generated using the generated session key (S13). MAC is a code calculated in the encryption process and added to the request message. If the code calculated in the decryption process of the authority issuing the request message is equal to this MAC value, it guarantees that the message has not been changed in the process of transmission. . In other words, the MAC value is a code value that guarantees the integrity of the message transmission.

Thereafter, the content issuer encrypts the generated session key with a master key and inserts it into the request message (S15). Encryption using a master key shared between a content issuer and an authority issuer is a symmetric encryption algorithm. For example, an encryption method such as AES (Advanced Encryption Standard) may be used.

As a result of performing steps S11 to S15, the request message has a form including a message, a MAC value of the request message and an encrypted session key, and the generated request message is transmitted to the authority issuer (S17).

Upon receiving the request message for requesting registration of content information and issuing a ROAP trigger from the content issuer, the authority issuer performs decryption and verification on the request message and transmits a response message according to the verification result to the content issuer (S20).

More specifically, when the authority issuer receives the request message from the content issuer, first, the session key of the request message is decrypted (S21). The decryption of the session key is performed through a master key shared between the authority issuer and the content issuer. The MAC key is obtained by decrypting the session key, and the MAC for the request message is obtained through the MAC key. Generate a value (S23).

The generated MAC value is compared with the MAC value of the request message received from the content issuer to verify the integrity of the message through the match of the MAC value (S25). Integrity refers to a property that protects information and resources from illegal changes. The authority issuer can check whether a change has been made in the process of transmitting a request message received from the content issuer by comparing MAC values.

According to the result of the comparison of the MAC value, the response message corresponding to the result is transmitted to the content issuer (S27). If the result of the comparison of the MAC value, the MAC value generated by the authority issuer matches the MAC value of the request message. If not, the request is sent to the content issuer as a failure to verify integrity. If the MAC value generated by the authority issuer and the MAC value of the request message match, it is determined that the integrity verification is successful, and after performing a procedure corresponding to the request message, the response message is transmitted to the content issuer. That is, in the case of the content information registration request, the response message is transmitted after the content information registration is performed, and in the case of the ROAP trigger issuance request, the ROAP trigger is generated, and the generated ROAP trigger is transmitted to the content issuer.

In addition to verifying message integrity according to the MAC value comparison procedure, the content issuer may insert a request time into the request message. When the authorization issuer receives the request message with the request time inserted, the content issuer checks the request time in the message. If the message reception exceeds a specified time, it is determined as an error state and an error message is transmitted to the content issuer. Through this request time checking procedure, the authority issuer can prevent the same message having the same request from the content issuer from being received multiple times.

The security system to which the above-described security method is applied may operate in conjunction with an external content issuer, which is illustrated in FIG. 3.

3 is an exemplary view showing a system configuration to which a security method according to the present invention is applied when interworking with an external content issuer.

As shown in the drawing, when the internal system 30 constituting the authority issuer 31 and the content issuer 33 interworks with an external content issuer 50, that is, the internal authority issuer 31 and the outside When exchanging messages between the content issuers 50, the security method according to the present invention is applied, even if the content issuer 50 exists outside, so that it can be trusted, thereby enabling a business model through cooperation with an external content issuer. .

As described above, according to the security system and method in the DRM system according to the present invention, the authority issuer may have an improved security for the access of the content issuer, thereby making it more reliable to the external content issuer of the authority issuer. Allow for partnerships

In addition, even a service provider that provides a plurality of services can provide a reliable service only by operating a single integrated authority issuer to enable consistent policy establishment of the DRM business.

Claims (9)

delete delete As a security method in a case where a content issuer sends a request message to an authority issuer in a security system consisting of a content issuer and an authority issuer sharing a master key, A first step of the content issuer generating a session key for the request message; A second step of the content issuer generating a message authentication code (MAC) value for the request message by using the session key generated as a result of performing the first step; A third step of a content issuer encrypting the session key generated in the first step using the master key; A fourth step in which the content issuer inserts the MAC value and the encrypted session key generated as a result of performing the second and third steps into the request message and sends the same to the authority issuer; A fifth step in which the authority issuer receiving the request message from the content issuer decrypts the session key in the request message through the master key to generate a MAC key value; A sixth step of the authority issuer generating a MAC value for the request message by using the MAC key value generated as a result of the fifth step; A seventh step of the authority issuer performing comparison verification on the MAC value generated as a result of the sixth step and the MAC value in the request message received from the content issuer; An eighth step of transmitting a response message corresponding to the comparison verification result of the seventh step to a content issuer; Security method in the DRM system comprising a. The method of claim 3, In the fourth step, the request message comprises a message, a MAC value of the message and an encrypted session key. The method of claim 3, In the fourth step, the request message further comprises a request time, characterized in that the security method in the DRM system. The method of claim 3, In the eighth step, if the generated MAC value and the MAC value of the request message received from the content issuer match, the response message to the content issuer is transmitted to the content issuer. The method of claim 3, In the eighth step, if the generated MAC value and the MAC value of the request message received from the content issuer do not match, a re-request message is transmitted to the content issuer. The method of claim 3, The seventh step further comprises the step of confirming the request time in the request message. The method of claim 8, And transmitting an error message to a content issuer when a request message reception time exceeds a specific time as a result of checking the request time of the request message.

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