Abstract:
A management system for digital broadcast rights and a method thereof, which applies to a digital video broadcasting system and utilizes the function of a multimedia home platform; when the multimedia data is intended to record or replay, the user&#39;s data will be analyzed to determine whether the user is allowed to use the multimedia data; further, encryption and decryption processes are used to monitor and control the record and replay processes of the multimedia data and protect the digital broadcast rights of the multimedia data lest it be unrestrictedly used or duplicated as one pleases.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a digital rights management system, which applies to a digital video broadcasting system, particularly to a management system for digital broadcast rights and a method thereof.  
         [0003]     2. Description of the Related Art  
         [0004]     The so-called DRM (Digital Rights Management) system is a mechanism, which utilizes various technologies, such as Cryptography, Conditional Access, Digital Watermarking, and Biometric Identification, to protect digital data from being unrestrictedly used or spread as one pleases. Via the DRM system, the rights of users, creators, and service providers can be clearly defined and securely protected.  
         [0005]     The television is a main source of multimedia audio/video data in a family. At present, the DVB system (Digital Video Broadcasting System) still lacks a dedicated DRM system but just follows the conventional CA (Conditional Access) technology used in the satellite television. However, after multimedia audio/video data has passed the gate of CA, there is no more protection at all, and the user can unrestrictedly duplicate and spread the multimedia data as he pleases. The high-quality audio/video data transmitted by the DVB system is digital; therefore, with the digital recording technology, it is easily that one duplicates the original digital audio/video data to obtain a duplicate files exactly the same as the original one.  
         [0006]     For the time being, many research organizations and government organizations are conscious of the importance of the aforementioned problem. The TIRAMISU technology (the Innovative Rights and Access Management Inter-platform Solution) being developed by European Union is the very example of that, wherein DRM function is intended to add to the DVB system. The xCP home network proposed by IBM and the Smartright system proposed by Thomson Inc. intend to utilize the Smart Card—a high-security storage and execution device—to monitor and control the usage and spread of home-used digital multimedia. Japanese government also has instructed her domestic industries that the video recorder should meet the requirements of protecting the rights of creators, broadcast companies, and users.  
         [0007]     Therefore, it can be concluded from the above mentioned discussion that developing a mature and expandable management system for digital broadcast rights is necessary and urgent.  
       SUMMARY OF THE INVENTION  
       [0008]     The primary objective of the present invention is to provide a management system for digital broadcast rights and a method thereof, which applies to a digital video broadcasting system and can provide more protection for multimedia data without any extra hardware lest the multimedia data be unrestrictedly used or duplicated as one pleases.  
         [0009]     Another objective of the present invention is to provide a management system for digital broadcast rights and a method thereof, which utilizes MHP (Multimedia Home Platform) function to make the digital video receiving unit of DVB system be a platform able to execute programs to monitor the record and replay of multimedia data, wherein not only the multimedia data itself and the user&#39;s rights are authenticated but also the encryption and digital watermarking mechanisms are also used in order to promote the system safety.  
         [0010]     To achieve the above mentioned objectives, the management system for digital broadcast rights of the present invention comprises: a digital video receiving unit, a user authentication unit, a digital monitoring unit, and a storage unit. The digital video receiving unit is used to receive at least one multimedia data, which comprises a rights expression data. The user authentication unit is used to store a user authentication data. The digital monitoring unit is used to determine whether the user authentication data conforms to the rights expression data of the multimedia data; if it is confirmed, the digital monitoring unit encrypts the multimedia data and creates an encryption key corresponding to the multimedia data and then provides the encryption key and the rights expression data for the user authentication unit. The storage unit is used to store the encrypted multimedia data.  
         [0011]     When the encrypted multimedia data stored in the storage unit is intended to replay, the digital monitoring unit firstly reads the user authentication data, the rights expression data of the multimedia data and the encryption key, which are stored in the user authentication unit, and then determines whether the multimedia data is allowed to replay, and if it is confirmed, the digital monitoring unit utilizes the encryption key to decrypt the encrypted multimedia data, and then, the multimedia data is replayed.  
         [0012]     The present invention also proposes a management method for digital broadcast rights, which comprises the following steps: firstly, receiving at least one multimedia data, which comprises a rights expression data, and reading a user authentication data from a user authentication unit; next, determine whether the user authentication data of the user authentication unit conforms to the rights expression data of the multimedia data; if it is confirmed, encrypting the multimedia data, creating an encryption key corresponding to the multimedia data; next, storing the encryption key and the rights expression data into the user authentication unit; and then, storing the encrypted multimedia data into a storage unit.  
         [0013]     When the encrypted multimedia data stored in the storage unit is intended to replay, the user authentication data, the rights expression data of the multimedia data, and the encryption key, which are stored in the user authentication unit, are read out to determine whether the multimedia data is allowed to replay, and if it is confirmed, the encryption key is used to decrypt the encrypted multimedia data, and then, the multimedia data is replayed.  
         [0014]     To enable the objectives, characteristics and efficacies of the present invention to be more easily understood, the present invention is to be described below in detail in cooperation with the drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a diagram schematically showing the management system for digital broadcast rights of the present invention.  
         [0016]      FIG. 2  is a diagram schematically showing one embodiment of the management system for digital broadcast rights of the present invention.  
         [0017]      FIG. 3  is a diagram schematically showing the process of monitoring and controlling video-recording operation in one embodiment of the management system.  
         [0018]      FIG. 4  is a diagram schematically showing the process of monitoring and controlling display operation in one embodiment of the management system. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]     Refer to  FIG. 1 a  diagram schematically showing the management system for digital broadcast rights of the present invention. The management system for digital broadcast rights of the present invention comprises: a digital video receiving unit  10 , a user authentication unit  20 , a digital monitoring unit  30 , and a storage unit  40 . The digital video receiving unit  10  may be a Set Top Box (STB) of a digital television and can receive multimedia data  50  via a network. The user authentication unit  20  may be a Smart Card and stores authentication and identification data, such as user authentication data. The storage unit  40  may be a hard disc or a Digital Video Disc (DVD) and stores encrypted multimedia data  50 . The digital monitoring unit  30  can operate in the digital video receiving unit  10 .  
         [0020]     Refer to  FIG. 2  for one embodiment of the management system for digital broadcast rights of the present invention. In this embodiment, the digital monitoring unit  81  can utilize a record manager program  73  and a display manager program  74  to execute its task.  
         [0021]     In this embodiment, the management system for digital broadcast rights is based on a DVB system (Digital Video Broadcasting System), and no matter whether the broadcast is via a terrestrial data line or a satellite terrestrial link, the system of the present invention can work well. According to the definition of DVB system, in addition to multimedia data  71  of audio/video data and basic data, this embodiment further add RED  72  (Rights Expression Data), a record manager program  73  and a display manager program  74  into the transport stream  70 . The record manager program  73  and the display manager program  74  are executed according to the definition of DVB-MHP (Multimedia Home Platform), and the rights expression data  72  is a data related to the rights of the multimedia data  71 . All of them are described below in detail.  
         [0022]     To protect the multimedia data  71  for creators or broadcast service providers, the rights expression data  72  is broadcast together with the multimedia data  71  to each user. A variety of multimedia data-related rights are defined in the rights expression data  72 , including: conditions of the record-allowable user, record/spread conditions, valid replay periods, allowed replay times, publisher data, and protection mechanisms. The format of the multimedia data  71  can be defined by the creator or the broadcast service provider, or adopts international standards in order to promote the system compatibility. In the future, the unified international standard may be REL (Rights Expression Language) in MPEG part-5, which utilizes XML format to define the rights of multimedia data and is compatible with other portions of MPEG 21.  
         [0023]     The record manager program  73  is also broadcast together with the multimedia data  71 ; however, unlike the rights expression data  72 , the record manager program  73  is not dedicated to a specific multimedia data  71 , and the broadcast service provider can utilize an identical record manager program  73  to protect all multimedia data  71 . The record manager program  73  is designed according to the DVD-MHP definition and can be executed in a set top box  80  having MHP. The record manager program  73  utilizes an MHP interface to control the operation of the set top box  80 , including: recording the broadcast multimedia data  71 , reading the rights expression data  72 , reading/writing a Smart Card  83 , and protecting/encrypting recorded multimedia data  71 .  
         [0024]     The display manager program  74  is also broadcast together with the multimedia data  71 ; however, unlike the rights expression data  72 , the display manager program  74  is not dedicated to a specific multimedia data  71 , and the broadcast service provider can utilize an identical display manager program  74  to protect all multimedia data  71 . The display manager program  74  is designed according to the DVD-MHP definition and can be executed in the set top box  80  having MHP. The display manager program  74  utilizes an MHP interface to control the operation of the set top box  80 , including: replaying the multimedia data  71  recorded beforehand, reading the rights expression data  72  saved beforehand, reading/writing the Smart Card  83 , and decrypting recorded multimedia data  71 .  
         [0025]     The entire system utilizes the above mentioned data and programs to operate. When the user intends to record, the system utilizes the record manager program  73  to protect broadcast multimedia data  71 . When the user intends to replay the multimedia data  71  recorded beforehand, the system utilizes the display manager program  74  to protect broadcast multimedia data  71 .  
         [0026]     Refer to  FIG. 2  and  FIG. 3 .  FIG. 3  is a diagram schematically showing the process of monitoring and controlling video-recording operation in this embodiment. When the multimedia data protected by the system is displayed, the record manager program  73  begins to operate. The process comprises the following steps:  
         [0027]     Step S 100   
         [0028]     The user utilizes a remote controller  90  to instruct the set top box  80  to record multimedia data from the transport stream  70 .  
         [0029]     Step S 110   
         [0030]     The record manager program  73  detects this instruction and then refers to the Smart Card  83  to determine whether the user authentication data stored in the Smart Card  83  conforms to the rights expression data  72  of the multimedia data  71 .  
         [0031]     Step S 120   
         [0032]     If the record manager program  73  confirms the qualification of the user, the record manager program  73  begins to encrypt the broadcasting multimedia data  71 .  
         [0033]     Step S 130   
         [0034]     The record manager program  73  stores the encryption key and the rights expression data into the Smart Card  83  as a certificate for accessing the multimedia data  71 . Lastly, the record manager program  73  stores the encrypted multimedia data  71  into the storage media  82 .  
         [0035]     Refer to  FIG. 4 a  diagram schematically showing the process of monitoring display operation in this embodiment. The process comprises the following steps:  
         [0036]     Step S 200   
         [0037]     The user utilizes a remote controller  90  to instruct the set top box  80  to replay the multimedia data  71  recorded beforehand. The display manager program  74  detects this instruction and begins to read the user authentication data, the rights expression data  72  of the multimedia data  71 , and the encryption key, which are saved in the Smart Card  83 , in order to determine whether to replay the multimedia data  71  according to whether the user authentication data conforms to the rights expression data  72 .  
         [0038]     Step S 210   
         [0039]     If the display manager program  74  confirms that replaying the multimedia data  71  is allowable, the display manager program  74  begins to read the encrypted multimedia data  71  saved in the storage media  82  and then utilizes the encryption key saved in the Smart Card  83  to decrypt the encrypted multimedia data  71  and then replays the multimedia data  71 .  
         [0040]     When recording multimedia data, the creator or the broadcast service provider may add a digital watermark to the multimedia data in order to trace the distributor. The digital watermark should comprise user data. Any related algorithm may be applied to this method.  
         [0041]     If the display manager program  74  denies the request of replaying the multimedia data  71 , it will also intend to encode and read the contents of the digital watermark. If the multimedia data  71  is restricted on replay times, the display manager program  74  will update the accumulated replay times recorded in the Smart Card.  
         [0042]     Many encryption algorithms can be applied to the management system for digital broadcast rights and the method thereof to protect multimedia data. Some algorithms need a very high calculation quantity and may also need extra auxiliary hardware; therefore, they are not suitable for the system of the present invention. All fast encryption algorithms or effective multimedia-related algorithms can be used in the system of the present invention.  
         [0043]     Further, if the storage media can be transferred to another hardware, such as a personal computer or a mobile phone, the hardware should be able to read the user authentication unit and should have the display manager program that can be executed in this platform. It is unnecessary for the display manager program used in another platform to meet MHP (Multimedia Home Platform) regulations.  
         [0044]     Besides, the Conditional Access system originally existing in DVB (Digital Video Broadcasting) system does not conflict with the system of the present invention but can provide more protection for broadcast multimedia data.  
         [0045]     In summary, the present invention proposes a management system for digital broadcast rights and a method thereof, which utilizes MHP (Multimedia Home Platform) function to make the digital video receiving unit of a DVB system be a platform able to execute programs, wherein DRM executive programs and the rights definition can be downloaded via broadcast channels of the DVB system, and the safety mechanism of MHP-STB can also provide security and reliability for programs. Further, when multimedia data pass the DRM system and enter into a storage device, the downloaded programs can be used to encrypt the multimedia data or put a watermark on the multimedia data. Those critical data, such as the authentication data of the user or the multimedia data can be accessed in a Smart Card, so that the user can easily carry about and conveniently utilize those critical data. Besides, in the embodiment of the present invention, the digital rights management mechanism is implemented with software; therefore, if some portion of the system function is damaged, the related portion of the programs can be easily modified and updated via the broadcast system, and no hardware modification is needed.  
         [0046]     The present invention has been disclosed above with those embodiments; however, they are not intended to limit the scope of the present invention. Any equivalent modification and variation according to the spirit of the present invention is to be included within the scope of the claims of the present invention, which are to be stated below.