KR20200118752A - A security system for broadcasting system - Google Patents

Abstract

The present invention relates to a broadcasting content security system comprising: a CAS system including a security information transmitting module for transmitting security information including an entitlement control message (ECM) generated by scrambling broadcasting content for broadcasting content security, and an entitlement management module for generating an entitlement management message (EMM) for each broadcasting content to transmit broadcasting content receiving entitlement information; and a DRM system for performing authority control on the CAS system by interworking with the CAS system wherein the DRM system includes a DRM encryption module for encrypting the broadcasting content, and a forgery prevention module for generating and managing a license including user authority information and a decryption key so that the encrypted broadcasting content can be decrypted. The receiving entitlement information is converted into a channel key required for broadcasting content encryption by the DRM encryption module. According to the present invention, reliability on IPTV security can be improved.

Description

UHD broadcasting contents security system {A SECURITY SYSTEM FOR BROADCASTING SYSTEM}

The present invention relates to a broadcast content security system, and more particularly, to a broadcast content security system in which the security reliability of IPTV is improved by operating by combining CAS technology and DRM technology in one integrated platform.

IPTV (Internet Protocol Television) is a service that combines communication and broadcasting that provides information or broadcasting through a high-speed Internet network, and provides digital information services, video contents, and various personalized services.

All contents provided by IPTV must be digitized in order to be transmitted, but digitized contents can be easily and quickly copied by anyone using a computer, and the copied contents are provided with the same quality as the original and have a fast spreading speed. Accordingly, security and copyright protection for digital contents are emerging as important issues.

Currently, research is being actively conducted on technologies to prevent illegal copying and distribution of contents, and representative security technologies include CAS (Conditional Access System) and DRM (Digital Rights Management).

CAS, which has been used for the purpose of controlling viewers' access in the existing broadcasting system, can be used as an alternative, but there are various problems with various additional services that IPTV intends to provide. For example, a content protection problem for a service that requires hard disk storage, such as PVR (Private Video Recording), is a difficult problem to cope with only CAS. Accordingly, there is a DRM technology that has been developed in IP and PC environments as a system that can replace the insufficient functions of CAS.

DRM technology is a technology for countering illegal use and illegal copying of all types of digitally distributed content, and can solve content security problems in a wider range than CAS. However, although DRM technology is a technology that can be easily applied to services such as PVR, it is insufficient to be applied to the current broadcasting system as it is.

Meanwhile, with the recent development of communication technology and smartphone technology, individuals possess various portable devices. For example, individuals can simultaneously possess various portable devices such as smart watches, tablet PCs, and mobile phones. In this case, individuals have a need to view contents distributed through IPTV on multiple screens. However, in the case of authenticating all of the contents so that the individual can view the contents on multiple screens, security problems may arise because the keys required for the authentication may be exposed when the individual's device is lost.

Accordingly, the present invention intends to develop a broadcast content security system capable of protecting content from malicious users by combining DRM with CAS so that DRM/CAS technology operates on one platform. In addition, an object of the present invention is to provide a security system that allows individuals who own various portable devices to be able to perform on various screens while providing a broadcasting service with greatly improved security of broadcasting content.

The problem to be solved by the present invention is to provide a broadcast content security system capable of effectively protecting content from malicious users while reducing costs by combining a hardware method and a software method.

Another problem to be solved by the present invention is to provide a broadcast content security system in which the security reliability of IPTV is improved by operating CAS technology and DRM technology in one platform.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above-described problems, the broadcast content security system according to an embodiment of the present invention includes an entitlement control message (ECM) generated by scrambling broadcast content for broadcast content security. A security information transmission module for delivering security information; And a CAS system including an entitlement management module for generating entitlement management messages (EMMs) for each of the broadcasting contents and transmitting entitlement information for receiving broadcasting contents. And a DRM encryption module for encrypting the broadcast content. A forgery prevention module for generating and managing a license including user right information and a decryption key to enable decryption of the encrypted broadcast content; A user authentication module that generates an authentication key based on user information in order to authenticate a broadcast content user; And a decryption module that compares the generated authentication key with the channel key and generates the decryption key according to whether or not they match, and performs decryption on the encrypted broadcast content, and interlocks with the CAS system to provide the CAS system. A DRM system that performs authority control for; And a display device including an STB system interlocked with the CAS system. Mobile devices; And a content management server, wherein the reception qualification information is converted into a channel key required for encryption of the broadcast content by the DRM encryption module, and the forgery prevention module duplicates use of the channel key decrypted by the decryption module. When it is determined that the license is authenticated, the license authentication is blocked, the channel key includes reception qualification information for the broadcast content, the authentication key includes a user ID and password for the broadcast content user, and the authentication key is A one-time authentication generated based on a random number, offset, and repetition number generated and shared by the portable device, the content management server, and the display device on a one-to-one basis. When the display device is authenticated by the content management server according to the value, it may be transmitted from the content management server to the display device.

In this case, when the transmission of the decryption key is repeated by the number of repetitions, the content management server may request the portable device to share a random number, an offset, and the number of repetitions.

In addition, the display device may generate the one-time authentication value by overlapping the hash function to the random number by the sum of the offset and the number of times the decryption key is transmitted.

According to the present invention, by combining a hardware method and a software method, it is possible to reduce cost and effectively protect content from malicious users.

In addition, the present invention can improve the security reliability of IPTV by operating CAS technology and DRM technology on one platform.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a block diagram of a broadcast content security system according to an embodiment of the present invention.
2 is a block diagram showing a CAS system and a DRM system.
3 is an exemplary diagram illustrating a process of generating reception qualification information according to an embodiment of the present invention.
4 is an exemplary diagram for explaining a CAS system according to an embodiment of the present invention.
5 is an exemplary diagram illustrating a hardware method of a CAS system according to an embodiment of the present invention.
6 is an exemplary diagram illustrating a software method of a CAS system according to an embodiment of the present invention.
7 is a diagram illustrating a content management server, a portable device, and a display device according to another embodiment of the present invention.
8 is a diagram illustrating a process of generating and confirming a group key (decryption key) of a content management server, a mobile device, and a display device according to another embodiment of the present invention.

The following content merely illustrates the principle of the invention. Therefore, although those skilled in the art may implement the principles of the invention and invent various devices included in the concept and scope of the invention, although not clearly described or illustrated herein. In addition, it should be understood that all conditional terms and examples listed in this specification are, in principle, expressly intended only for the purpose of making the concept of the invention understood, and are not limited to the embodiments and states specifically listed as such. do.

In addition, in the following description, ordinal expressions such as first, second, etc. are intended to describe objects that are equivalent and independent of each other, and in the order of main/sub or master/slave It should be understood as meaningless.

The above-described objects, features, and advantages will become more apparent through the following detailed description in connection with the accompanying drawings, and accordingly, a person of ordinary skill in the technical field to which the invention pertains will be able to easily implement the technical idea of the invention. .

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and as a person skilled in the art can fully understand, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other. It may be possible to do it together in a related relationship.

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

1 is a block diagram of a broadcast content security system. 2 is a block diagram showing a CAS system and a DRM system. 3 is an exemplary diagram illustrating a process of generating reception qualification information according to an embodiment of the present invention. 4 is an exemplary diagram for explaining a CAS system according to an embodiment of the present invention. 5 is an exemplary diagram illustrating a hardware method of a CAS system according to an embodiment of the present invention. 6 is an exemplary diagram illustrating a software method of a CAS system according to an embodiment of the present invention.

Referring to FIG. 1, the broadcast content security system includes a CAS system 100, a DRM system 200, and an STB system 300. Referring to FIG. 2, the CAS system 100 includes a security information transmission module and a qualification management module, and the DRM system 200 includes a DRM encryption module and a forgery prevention module.

The CAS system 100 is a system that allows only users who have subscribed to the broadcast content security system to receive a specific program, and can protect business profits of pay broadcasters. For example, the CAS system 100 may perform scrambling/descrambling, entitlement control, and entitlement management functions. In the present invention, it is preferable that the CAS system 100 scrambles the broadcast content according to a preset encryption level with the same algorithm and operates based on hardware and/or software.

Further, in the present invention, the broadcast content includes an image header including information on an image to be downloaded; And image data, which is the content of the image. In addition, the downloaded content image file may further include Signature data necessary for verification request. Specifically, the downloaded content image basically includes one SM Client image (CAS or DRM or ASD), but in the case of the first SM Client download, two or more of CAS, DRM, and ASD images are downloaded as one download image. Can be created and transmitted. Therefore, information about the image can be included in the download image header. For example, packed_image_num is the number of SM Client images included in the downloaded image, total_image_length indicates the total size of the SM Client image, and Reserved may indicate additional information. Accordingly, the above-described information may be included in the image header.

At this time, when the CAS system 100 operates based on hardware, the set-top box (STB) system 300 interlocked with the CAS system 100 to perform security processing for security information, qualification control messages, and qualification management messages. It can be performed on the Smart Card of. Specifically, as shown in Figure 5, the hardware-type CAS system 100 is a smart system that provides physical security for storing service subscription information (entitlement, PIN code, etc.) and keys, ECM/EMM security processing, etc. Take charge from the card. At this time, it is set so that the CAS code and data cannot be accessed from outside.

In addition, when the CAS system 100 operates based on software, security processing for security information, qualification control messages, and qualification management messages may be performed in the main memory of the broadcast content security device. Specifically, as shown in FIG. 6, storage of service subscription information (Entitlement, PIN Code, etc.) and keys, ECM/EMM security processing, etc. may be processed by the main CPU in the terminal.

Specifically, the scrambling function is a function of transforming the original TV signal so that a recipient who is not authorized by the scrambler 110 cannot view the broadcast content, and the TV program type (eg, audio, video, data) and signal The method may be different depending on the form (eg, analog or digital). The descrambling function is a function of descrambles the received broadcast content by using a control word (CW), which is a descrambling key of the descrambler 320. In this case, the scrambling method may be configured with a highly advanced encryption mechanism. Here, the CW is periodically generated, encrypted, and transmitted.

1 and 2, the entitlement control function includes an entitlement control message (ECM) generated by scrambling the broadcast content for the security information transmission module. It means to deliver security information. Here, the entitlement control message (ECM) may include a control variable, and all receivers compare the transmitted control variable with the authentication variable of the receiver, and if the user is a correct user, CW with the secret key in the smart card as shown in FIG. It is possible to decode (CW1, CW2, CW3) and descramble the received broadcast content.

Referring to FIGS. 1 and 2, the entitlement management function means that the entitlement management module generates an entitlement management message (EMM) for each broadcast content to manage the broadcast content reception entitlement. The qualification management module generates a qualification management message by encrypting the authentication key using the distribution key and transmits it to the receiving side. In this case, the transmitted entitlement management message may perform a function of granting entitlements to a smart card at the receiving side. However, in order to increase security, it can be used as a substitute for a smart card through direct communication with a user's personal terminal. Increasing security by using a personal terminal will be described later with reference to FIGS. 7 and 8.

Referring to FIG. 1, the broadcast content security system includes a DRM system 200 that interworks with the CAS system 100 to perform authority control for the CAS system 100. At this time, as shown in FIG. 2, the DRM system 200 generates and manages a DRM encryption module for encrypting broadcast content and a license including user right information and a decryption key to enable decryption of the encrypted broadcast content. Includes anti-counterfeiting module.

Specifically, the DRM (Digital Right Management) system 200 encrypts and distributes broadcast content data, and can prevent illegal copying of broadcast content by issuing user authentication and a license to a terminal. Although not shown in the drawing, the DRM system may further include a DRM packager for encrypting broadcast content and a DRM client using a license. At this time, the license includes the right to use the content and the decryption key, and performs the decryption function only when the condition is met by comparing it with the restriction condition on the use right.

Accordingly, the anti-counterfeiting module of the DRM system 200 may be protected by tamper resistance technology to prevent illegal leakage of broadcast contents by malicious users. The forgery prevention module may block license authentication when it is determined that the use of the channel key decrypted by the decryption module is duplicated. Meanwhile, the DRM system can be divided into DRM for VOD content and DRM for multicast content.

In addition, the DRM system 200 includes a user authentication module that generates an authentication key based on user information in order to authenticate a broadcast content user; And a decryption module that compares the generated authentication key with the channel key and generates a decryption key according to whether they match or not, and decrypts the encrypted broadcast content. Here, the channel key includes reception qualification information for broadcast content, and the authentication key includes user ID and password for the broadcast content user. Meanwhile, the authentication key may be delivered to the broadcast content user in the form of an authentication partial key.

Referring to FIG. 1, the broadcast content security system includes a CAS system 100 and an STB system 300 operating in conjunction with the DRM system 200. The STB system 300 can safely watch the broadcast by receiving a channel device from the DRM system 200 and decrypting the encrypted broadcast content.

를 키 복호화 모듈로 보낸다. 키 복호화 모듈에서는 가지고 있던 그룹키나 키 관리 서버(KMS)에서 보내온 그룹키(복호화 키)를 이용하여 암호화된 채널키를 복호화하여 채널키를 다시 미디어 복호화 모듈로 보낸다. 채널키를 받은 미디어 복호화 모듈에서 암호화된 콘텐츠를 채널키로 복호화 하면서 인증모듈에 채널키 사용함을 알리면 인증모듈은 수신 자격 정보를 생성한다.3, when the media decryption module receives the encrypted and multicasted content sent from the DRM multicaster, the media decryption module

Is sent to the key decryption module. In the key decryption module, the encrypted channel key is decrypted using the group key that has been held or the group key (decryption key) sent from the key management server (KMS), and sends the channel key back to the media decryption module. When the media decryption module that received the channel key decrypts the encrypted content with the channel key and informs the authentication module that the channel key is used, the authentication module generates reception qualification information.

As shown in FIG. 3, the reception qualification information for authentication consists of a user ID (User_ID), information for limiting the set-top box of a specific user (Div_info), and a channel number (Channel_num) using a channel key. Has been. User_ID is a user ID issued when initially subscribing to an IPTV service, and must not be duplicated because it must be information that can identify each broadcast content user. Div_info refers to a value created to bind a user and a set-top box with a user's specific device ID. In the present specification, a set-top box refers to all devices equipped with a function for viewing content to which scrambling and DRM are applied at the same time, and may be various devices such as a smartphone and a smart TV according to the development of technology in addition to the traditional set-top box.

Div_info consists of User_ID and hash value of MAC address of set-top box. Channel_num is the number of the channel being decoded using the current channel key, and the user can determine whether the channel can be used.

When sending the reception qualification information to the reception qualification information server (REIS), User_ID is sent in plain text, and Div_info and Channel_num are encrypted with the user's private key.

Hereinafter, with reference to FIGS. 7 and 8, a system that includes both a CAS system and a DRM system, and uses a portable device carried by a specific user as an authentication device, and allows users to view security content on various screens. It will be described in detail.

Referring to FIG. 7, the content management server 500 refers to a server or server group that performs functions of key management, authentication, and content provision. In this case, the content management server 500 may be interlocked with the portable device 400, the router 600, and the display device 310 including a set-top box function.

The portable device 400 may be connected to the display device 310 directly or through a local network generated by the router 600, and may also be connected to the content management server 500.

Referring to FIG. 8, when the mobile device 400 is initially connected to the content management server 500, the mobile device 400 requests authentication to receive authentication. In this case, when there is a display device 310 that can be connected to the mobile device 400 directly or through a local network generated by the router 600, the mobile device 400 may perform functions of the display device 310, Sends a query for the type or product number (product identification number, UUID). At this time, the display device transmits a response to the function, product number, or product type in response to the query.

In this case, when the function or product type is a device capable of playing content such as a display device or an audio device, the portable device 400 stores the response of the device.

On the other hand, in the case of wanting to play the content of the content management server 500, a group key is requested from the portable device 400 through the display device 310. In that case, the portable device 400, the content management server 500, and the display device 310 share a random number, an offset, and the number of repetitions with each other. In this case, a procedure for sharing random numbers, offsets, and repetitions is initiated by the portable device 310 to which all connections are established.

In this case, in order to prevent any one of the connections from being hacked and the number of random numbers, offsets, and repetitions all leaked, the mobile device 400, the content management server 500 and It is preferable to generate a one-to-one correspondence in the display device 310. For example, the random number may be set in the content management server 500, the offset may be set in the portable device 400, and the number of repetitions may be set in the display device 310, respectively.

Thereafter, the display device 310 may generate a one-time authentication value based on a random number and an offset, and transmit it to the content management server 500. For example, the display device 310 may generate a one-time authentication value by overlapping a hash function with a random number by the number of offsets.

The content management server 500 calculates the one-time authentication value with the same algorithm as the display device 310, compares the values, and, if the same, transmits the group key to the display device 310.

Meanwhile, the display device 310 releases the DRM of the content management server 310 by using the received group key and plays the content. The method of using the group key is as described above.

Next, the content management server 500 requests the display device 310 to update the authentication. In this way, the request of the authentication update to the display device 310 is to reduce the number of communication times of the mobile device, thereby saving resources such as a battery of the mobile device.

After initial authentication, when an authentication update is requested from the content management server 500, the display device 310 regenerates the one-time authentication value based on the offset, the number of previous group key transmissions, and the same random number. Then, the one-time authentication value is updated.

After repeating the update as many times as the number of iterations, the content management server 500 requests the mobile device 400 for a procedure for sharing a random number, an offset, and the number of iterations, and repeats the one-time authentication value verification process until the content is finished. . Here, the one-time authentication value verification process includes random number/offset/repeated number and. It refers to a procedure for generating and checking a one-time authentication value based on the number of previous group key transmissions. Therefore, the security can be maintained until the play of the content ends. At this time, the coverage that the mobile device 400 can be connected to the display device 310, for example, when directly connected via Bluetooth, out of the Bluetooth connection range, or when connected to a local network through the router 600, local network coverage If it is out of range, the display device 310 notifies that the authentication portable device is out of the authentication range, and playback of the content may be stopped until the mobile device 400 enters the coverage again.

Accordingly, through such a secure connection, a content user can play content to which CAS and DRM security are applied at the same time without a set-top box through any display devices 310 in the vicinity capable of such secure communication.

In addition, by combining a broadcast content security hardware method and a software method according to an embodiment of the present invention, it is possible to reduce costs and effectively protect content from malicious users. In addition, the present invention can improve the security reliability of IPTV by operating CAS technology and DRM technology on one platform.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: CAS system 200: DRM system
300: STB system

Claims (3)

A security information transmission module for delivering security information including an entitlement control message (ECM) generated by scrambling broadcast content for security of broadcast content; And a CAS system including an entitlement management module for generating entitlement management messages (EMMs) for each of the broadcasting contents and transmitting entitlement information for receiving broadcasting contents. And a DRM encryption module for encrypting the broadcast content. A forgery prevention module for generating and managing a license including user right information and a decryption key to enable decryption of the encrypted broadcast content; A user authentication module that generates an authentication key based on user information in order to authenticate a broadcast content user; And a decryption module that compares the generated authentication key with the channel key and generates the decryption key according to whether or not they match, and performs decryption on the encrypted broadcast content, and interlocks with the CAS system to provide the CAS system. A DRM system that performs authority control for; And a display device including an STB system interlocked with the CAS system.
Mobile devices;
And a content management server,
The reception qualification information is converted into a channel key required for encryption of the broadcast content by the DRM encryption module, and the forgery prevention module determines that the use of the channel key decrypted by the decryption module is duplicated, the license authentication And the channel key includes receiving qualification information for the broadcast content, the authentication key includes a user ID and password for the broadcast content user, and the authentication key is an authentication partial key for the broadcast content user. Is delivered in the form of
The decryption key is a one-time authentication value generated based on a random number, an offset, and a number of repetitions generated and shared by the portable device, the content management server, and the display device on a one-to-one basis. In the case of being transmitted from the content management server to the display device,
Broadcast content security system. The method of claim 1,
When the delivery of the decryption key is repeated by the number of repetitions, the content management server requests the portable device to share a random number, an offset, and the number of repetitions,
Broadcast content security system. The method of claim 1,
The display device generates the one-time authentication value by overlapping and applying a hash function to the random number by the sum of the offset and the number of times the decryption key is transmitted,
Broadcast content security system.

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