Abstract:
A broadcast receiving apparatus having demodulator for demodulating signal received from the tuner and releasing video and audio signals, first encryption decoder for encrypting or decoding the video and audio signals with the use of first encryption key, recorder for recording the encrypted video and audio signals, second encryption decoder for encrypting or decoding the video and audio signals with the use of second encryption key, communication devices for transmitting the video and audio signals encrypted in the second encryption decoder to another recorder over network, and controllers for, when the video and audio signals are recorded in the recorder, directing the video and audio signals to be encrypted with the first encryption decoder and recorded, and when the video and audio signals are transmitted via the communicator, directing the video and audio signals to be encrypted with the second encryption decoder and transferred.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-280472, filed Sep. 27, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a broadcast receiving apparatus such as a television receiver equipped with a network function and particularly to a broadcast receiving apparatus and a broadcast receiving method where video and audio signals to be exchanged over a network can be improved in the security.  
         [0004]     2. Description of the Related Art  
         [0005]     As is well known, the television broadcasting systems have been digitized in recent years. In Japan, for example, digital terrestrial broadcasting services are now in their early stages, following digital broadcast satellite (BS) broadcasting services and 110-degree communication satellite (CS) digital broadcasting services.  
         [0006]     Such a digital broadcast receiver for receiving the digital television broadcast is arranged to handle a digital form video and audio information and can thus conduct with much ease processes of recording, reproducing, retrieving, and managing contents information as well as utilizing its relevant information of electronic program information. One of the conventional technologies for picking up the information of electronic program information from the digital television broadcast is disclosed in patent document 1 (Jpn. Pat. Appln. KOKAI Publication No. 2002-142163).  
         [0007]     However, the technology disclosed in patent document 1 fails to clarify the use of digital contents over a network and takes no measure for protecting the information from being illegally accessed by a third or unauthorized person over the network.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     A broadcast receiving apparatus according to the present invention comprises: a tuner which receives broadcast signals and selectively outputs the received signal; a demodulator which demodulates the received signal outputted from the tuner and outputs video and audio signals; a first encryption decoder which encrypts or decodes the video and audio signals with the use of a first encryption key; a recorder which records the video and audio signals encrypted in the first encryption decoder; a second encryption decoder which encrypts or decodes the video and audio signals with the use of a second encryption key which is different from the first encryption key; a communicator which performs communication to transmit the video and audio signals encrypted in the second encryption decoder to another recorder over a network; and a controller which, when the video and audio signals received from the demodulator or the outside are recorded in the recorder, directs the video and audio signals to be encrypted with the first encryption decoder and recorded, when taken out, decodes the signals in the first encryption decoder to be outputted, and when the video and audio signals are transmitted via the communicator, directs the video and audio signals to be encrypted with the second encryption decoder and transferred to another recorder over the network. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0009]      FIG. 1  is a schematic view of a digital television broadcast receiver and a network system constructed with the digital television broadcast receiver at the center, according to one embodiment of the present invention;  
         [0010]      FIG. 2  is a block diagram showing a configuration of the digital television broadcast receiver according to one embodiment of the present invention;  
         [0011]      FIG. 3  is a block diagram showing a remote controller for the digital television broadcast receiver according to one embodiment of the present invention;  
         [0012]      FIG. 4  is a network diagram showing one feature of the digital television broadcast receiver according to one embodiment of the present invention; and  
         [0013]      FIG. 5  is a flowchart illustrating a procedure of decoding an encrypted signal in the digital television broadcast receiver according to one embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]     Embodiments of the present invention will be described in more detail, referring to the relevant drawings.  
         [0000]     &lt;Television Receiver Equipped with a Network Function According to the Present Invention&gt; 
         [0015]     A television receiver equipped with a network function as a communication apparatus according to the present invention will be described referring to the drawings.  FIG. 2  is a block diagram of a digital television broadcast receiver according to one embodiment of the present invention.  FIG. 3  is a block diagram of a remote controller for the digital television broadcast receiver according to one embodiment of the present invention.  
         [0016]     A digital television broadcast receiver  11  consists mainly of a thin type cabinet  12  and a support base  13  which supports the cabinet  12  upright. The cabinet  12  includes a flat-panel display  14  such as a liquid crystal display panel, a speaker  15 , an operation unit  16 , and a remote control detector  18  which receives operation information from a remote controller  17 .  
         [0017]     The digital television broadcast receiver  11  is arranged to have a memory card  19  detachably loaded thereon, such as a secure digital (SD) memory card, a multimedia card (MMC), or a memory stick. The memory card  19  may be an IC card in which a contract information is saved. This allows the receiver to record and reproduce a variety of information including TV programs and photographs on the memory card  19 .  
         [0018]     The digital television broadcast receiver  11  includes a first local area network (LAN) port  21 , a second LAN port  22 , a universal serial bus (USB) port  23 , and an i.Link port  24 .  
         [0019]     The first LAN port  21  is provided as an LAN specific HDD dedicated port used for recording and reproducing information on a LAN specific HDD  25  as a network attached storage (NAS) over the Ethernet (registered trademark).  
         [0020]     Since the first LAN port  21  serves as the LAN specific HDD dedicated port, it allows the HDD  25  to be operated for recording of the program information at high-definition TV quality regardless of the conditions of the network environment and the busyness of the network.  
         [0021]     Also, the second LAN port  22  is provided as a common LAN specific port over the Ethernet. For example, the second LAN port  22  may be connected via a hub  26  with a LAN specific HDD  27 , a personal computer (PC)  28 , and an HDD built-in digital versatile disk (DVD) recorder  29  for exchanging information with each other.  
         [0022]     Since the DVD recorder  29  receives substantially a digital information of control information from the second LAN port  22 , a dedicated analog signal transmission path  30  is needed between the DVD recover  29  and the digital television broadcast receiver  11  for transmission of analog video and audio information.  
         [0023]     The second LAN port  22  may be connected via a combination of the hub  26  and a broadband router  31  with a network  32 , such as the Internet, for exchanging information with a PC  33  or a mobile phone  34  over the network  32 .  
         [0024]     The USB port  23  is provided as a common USB specific port. For example, the USB port  23  may be connected via a hub  35  with USB devices such as a mobile phone  36 , a digital camera  37 , a card reader/writer  38  for the memory card, an HDD  39 , a keyboard  40  for exchanging information with these devices.  
         [0025]     The i.Link port  42  is provided for serial connection with, e.g., an AV-HDD  41 , a D-VHS (digital video home system)  42  for exchanging information with these devices.  
         [0026]      FIG. 2  illustrates a main signal processing system in the above-described digital television broadcast receiver  11 . Specifically, a digital satellite television broadcast signal received by a digital BS/CS broadcast signal antenna  43  is transferred via an input port  44  to a digital satellite broadcast tuner  45  where it is tuned to selectively pick up a broadcast signal of a desired channel.  
         [0027]     The broadcast signal selectively picked up by the tuner  45  is then transferred to a phase key shifting (PSK) demodulator  46  where it is demodulated to a digital video signal and a digital audio signal which are then outputted a signal processor  47 .  
         [0028]     A digital terrestrial television broadcast signal received by a terrestrial broadcast receiving antenna  48  is transferred via an input port  49  to a digital terrestrial broadcast tuner  50  where it is tuned to selectively pick up a broadcast signal of a desired channel.  
         [0029]     The broadcast signal selectively picked up by the tuner  50  is then transferred to an orthogonal frequency division multiplexing (OFDM) demodulator  51  where it is demodulated to a digital video signal and a digital audio signal which are then outputted to the signal processor  47 .  
         [0030]     An analog terrestrial television broadcast signal received by the terrestrial broadcast receiving antenna  48  is transferred via the input port  49  to an analog terrestrial broadcast tuner  52  where it is tuned to selectively pick up a broadcast signal of a desired channel. The broadcast signal selectively picked up by the tuner  52  is transferred to an analog demodulator  53  where it is demodulated to an analog video signal and an analog audio signal which are outputted to the signal processor  47 .  
         [0031]     The signal processor  47  is provided for selectively subjecting the video signal and the audio signal received from the PSK demodulator  46  and the OFDM demodulator  51  respectively to predetermined digital signal processing, such as MPEG2 decoding, and then transferring them to a graphic processor  54  and an audio processor  55 .  
         [0032]     The graphic processor  54  is has a function of superimposing an OSD (on-screen display) signal received from an OSD signal generator  57  over the digital video signal received from the signal processor  47 . The graphic processor  54  is also arranged to selectively output the video output signal of the signal processor  47  and the OSD output signal of the OSD signal generator  57  or output both the output signals for simultaneously displaying two separate images on the screen.  
         [0033]     The digital video signal outputted from the graphic processor  54  is supplied to a video processor  58 . The video processor  58  is provided for converting the input digital video signal into an analog video signal of the format displayable on the image display  14 . The analog video signal is further outputted to the image display  14  for displaying its image and via an output port  59  to the outside.  
         [0034]     The audio processor  55  is provided for converting the input digital audio signal into an analog audio signal of the format reproducible with the speaker  15 . The analog audio signal is then outputted to the speaker  15  for reproducing its sound and via an output port  60  to the outside.  
         [0035]     All the operations of the digital television broadcast receiver  11  including the above-described receiving operations are entirely controlled by a controller  61 . The controller  61  is equipped with a built-in central processing unit (CPU) for controlling the operation of each component in response to operation information received from the operation unit  16  or from the remote controller  17  via the remote control detector  18 .  
         [0036]     The controller  61  mainly includes a read only memory (ROM)  62  where control programs to be conducted by the CPU are stored, a random access memory (RAM)  63  for providing a working area for the CPU, and a non-volatile memory  64  where various setting and control information are stored.  
         [0037]     The controller  61  is connected via a card I/F (port)  65  to a card holder  66  on which the memory card  19  can detachably be loaded. This allows the controller  61  to exchange information via the card I/F  65  with the memory card  19  loaded on the card holder  66 . The controller  61  is also connected via another card I/F and another card holder, both not shown, to a second memory card (not shown) which can detachably be loaded. This allows the controller  61  to exchange information with the second memory card.  
         [0038]     The controller  61  is further connected via a communication I/F  69  to the first LAN port  21 . This allows the controller  61  to exchange information via the communication I/F  69  with the LAN specific HDD  25  connected to the first LAN port  21 . In this case, the controller  61  includes a dynamic host configuration protocol (DHCP) server function for assigning and controlling the LAN specific HDD  25  connected to the first LAN port  21  with an Internet protocol (IP) address.  
         [0039]     The controller  61  is further connected via another communication I/F  70  to the second LAN port  22 . This allows the controller  61  to exchange information via the communication I/F  70  with each device (see  FIG. 1 ) connected to the second LAN port  22 .  
         [0040]     The controller  61  is further connected via a USB I/F  71  to the USB port  23 . This allows the controller  61  to exchange information via the USB I/F  71  with each device (see  FIG. 1 ) connected to the USB port  23 .  
         [0041]     The controller  61  is further connected via an i.Link port  72  to the i.Link port  24 . This allows the controller  61  to exchange information via the i.Link I/F  72  with each device (see  FIG. 1 ) connected to the i.Link port  24 .  
         [0042]     The receiver  11  further includes a transfer controller  73  which controls the transfer of video and audio signals, a discrete encryption decoder  81  which encrypts the video and audio signals received from the signal processor  47  with the use of a discrete key, and a disk drive  82 , such as a hard disk drive, which receives an output of the discrete encryption decoder  81 . Alternatively, the disk drive  82  may preferably be a large-scale memory or any other information storage region. The controller  61  also includes a register  80  which registers a recording/reproducing apparatus over the network to which the contents information transmitted from the digital television broadcast receiver  11  is stored.  
         [0043]      FIG. 3  illustrates an external view of the remote controller  17 . The remote controller  17  comprises mainly a power key  17   a , an input switch key  17   b , an array of digital satellite broadcast channel direct access keys  17   c , an array of terrestrial broadcast channel direct access keys  17   d , a quick key  17   e , a cursor key  17   f , a decision key  17   g , a program list key  17   h , page switch keys  17   i , a face net (navigation) key  17   j , a return key  17   k , an end key  17   l , color keys  17   m  of blue, red, green, and yellow, a channel up/down key  17   n , a volume adjusting key  17   o , and a menu key  17   p.    
         [0000]     &lt;Encryption Decoding Process Depending on Type of Storage&gt; 
         [0044]     The process of encryption decoding in the digital television broadcast receiver depending on the type of a storage will now be described referring to a flowchart shown in  FIG. 4 .  FIG. 4  illustrates a network diagram showing one feature of the digital television broadcast receiver according to one embodiment of the present invention.  FIG. 5  is a flowchart showing an example of the encryption decoding process of the digital television broadcast receiver according to one embodiment of the present invention.  
         [0045]     A processor  2  in the digital television broadcast receiver of the present invention shown in  FIG. 4  as denoted by A 1  is arranged for allowing the contents information received from a tuner  1  to be encrypted by a discrete encoder  3  using a discrete key before stored in a built-in storage  4 . When the contents are demanded by another apparatus A 2  over the network to be stored and recorded, the encrypted contents are decoded with a first discrete key and encrypted again by a common encryption encoder  5  using a common key to the network. The encrypted contents are then supplied via an I/F port  6  to the network N and received by the apparatus A 2 . In turn, the apparatus A 2  conducts the same process for decoding the encrypted contents information using the common key before reproduction.  
         [0046]     As may not be reproduced by other apparatus connected to the network, the contents information saved in the network HDD is decoded and then encrypted with the use of a key which is compatible with the demanding apparatus before transferred to the communication path.  
         [0047]     Since the process of information encryption with the use of a discrete key assigned to a particular apparatus and the process of information encryption with the use of a common key open to the network are carried out separately, the system allows the contents information shared by discrete apparatuses to be accessed over the network at higher convenience while being maintained for high security.  
         [0048]     The operation of the television receiver equipped with the network function for reproducing a contents information received over the network by the above described security system will be described referring to the flowchart of  FIG. 5 . The operation starts with the digital television broadcast receiver  11 , which demands for receiving the contents information over the network, recognizing the DVD recorder  29  shown in  FIG. 1  as a contents information managing apparatus and conducting an access operation trying to reproduce the contents (S 1 ). This is followed by the DVD recorder  29  examining the authentication of the demanding receiver  11 . When it is judged that the demand is received from an authorized apparatus, the contents information is retrieved from the storage  4  and decoded by the discrete encryption decoder  3  using the discrete key (S 2 ). (When it is judged that the demand is received from an unauthorized apparatus, the operation will be canceled and not continue.) Then, the contents information is encrypted again by the common encryption encoder  5  using the common key (S 3 ). The encrypted contents information is transferred via the I/F port  6  to the demanding apparatus (S 4 ).  
         [0049]     When received in the demanding apparatus or digital television broadcast receiver  11 , the encrypted contents information is decoded by a common encryption decoder  83  using the common key (S 5 ). The contents information is thus reproduced by a combination operation of the signal processor  47 , the audio processor  55 , and the video processor  58  (S 6 ). This is followed by the contents information being either encrypted by a discrete encryption encoder  81  using the discrete key and saved into a disk drive  82  (a hard disk drive or a memory) which is a built-in storage or encrypted by the common encryption encoder  83  and returned back to the DVD recorder  29  (S 7 ). In the DVD recorder  29 , the encrypted contents information is decoded by the common encryption decoder  5  and encrypted again by the discrete encryption encoder  3  using the discrete key before saved in the storage  2  (S 8 ).  
         [0050]     As set forth above, the broadcast receiving apparatus of the embodiment when provided in the form of a television receiver equipped with the network function allows a desired contents information, e.g., a television program, to be encrypted using a first discrete key and then saved in a hard disk drive or any other storage installed therein. When the contents information is demanded for transfer to another hard disk recorder or the like connected to the network, it is decoded using the first discrete key and then encrypted again by a second common key open to the network before transferred over the network interface to the hard disk recorder or the like as a storage on the network. This allows the contents information to be encrypted and decoded at a higher level of the security.  
         [0051]     It would be understood that the present invention is embodied in various forms by those skilled in the art and also changes and modifications are made without departing from the scope of the present invention. The present invention may be applicable to any other system which has no inventive features. The present invention can thus cover a wider range of the application compatible with the disclosed principles and novel features thereof as is not limited to the foregoing embodiments.