Abstract:
An apparatus for regenerating a copy-protected signal comprises a decoding module including a decoding section configured to decode a copy-protected signal, and a first control section configured to control the decoding section, and a unit including a signal processing section configured to process a signal decoded by the decoding section, and a second control section configured to control the signal processing section, the first control section permitting a decoding operation by the decoding section when the self-holding identification information corresponds with identification information preset in the second control section.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-012011, filed Jan. 21, 2002, 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 an apparatus for regenerating a copy-protected signal, which receives a copy-protected signal, and decodes (removes) copy protection so that the copy-protected signal can be regenerated. In particular, the present invention relates to improvement of an apparatus including a built-in decoding module for decoding copy protection as a set.  
           [0004]    2. Description of the Related Art  
           [0005]    As publicly known, in systems transmitting information signals to many users, a transmission signal is copy-protected in order to prevent illegal copy of the information signal, and a receiver decodes copy protection so that the signal can be regenerated.  
           [0006]    For example, Jpn. Pat. Appln. KOKAI Publication No. 2000-358227 discloses a copy-protect system for analog video signals other than standard NTSC (National Television System Committee) video signals.  
           [0007]    The above copy-protect system scrambles a non-NTSC video signal, and prepares key information for decoding the scramble or information for verifying a connected side.  
           [0008]    Exchange of key information and authentication information is made between a sender (source device) and a receiver (sync (synchronous) device), and thereby, it is determined whether or not scramble decoding of analog video signals is permitted in the sync device.  
           [0009]    The copy-protect system comprises a decoding module for removing the copy protect. The module is an external adaptor to the existing AV (Audio Visual) apparatuses. It is connected to an AV apparatus by RCA pins or the like.  
           [0010]    In order to prevent the decoding module from being used for illegal copy, if the decoding module is once attached to AV devices, and thereafter, detached, a copy-protect removal function is lost.  
           [0011]    Nowadays, sync devices having a copy-protect removal module built in a module set are appearing. However, present measures to prevent the removal module built in the sync device from being used for illegal copy are inadequate.  
           [0012]    Jpn. Pat. Appln. KOKAI Publication No. 2000-4433 discloses the technique of confirming authentication for each functional module in a personal computer, and limiting digital contents usable for each functional module.  
           [0013]    However, the above Publication has no description relevant to measures for preventing the copy-protect removal module built in the above sync device from being used for illegal copy.  
         BRIEF SUMMARY OF THE INVENTION  
         [0014]    The present invention has been proposed in view of the above circumstances. Therefore, it is an object of the present invention to provide an apparatus for regenerating a copy-protected signal, which can prevent a copy-protect removal module built in the apparatus from being used for illegal copy.  
           [0015]    According to one aspect of the present invention, there is provided an apparatus for regenerating a copy-protected signal, comprising:  
           [0016]    a decoding module including a decoding section configured to decode a copy-protected signal, and a first control section configured to control the decoding section; and  
           [0017]    a unit including a signal processing section configured to process a signal decoded by the decoding section, and a second control section configured to control the signal processing section,  
           [0018]    the first control section permitting a decoding operation by the decoding section when the self-holding identification information corresponds with identification information preset in the second control section. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0019]    [0019]FIG. 1 is a block diagram to explain the configuration of an apparatus for regenerating a copy-protected signal according to a first embodiment of the present invention;  
         [0020]    [0020]FIG. 2 is a flowchart to explain the features of the operation of the apparatus in the first embodiment;  
         [0021]    [0021]FIG. 3A and FIG. 3B are flowcharts to explain an apparatus for regenerating a copy-protected signal according to a second embodiment of the present invention;  
         [0022]    [0022]FIG. 4 is a flowchart to explain an apparatus for regenerating a copy-protected signal according to a third embodiment of the present invention; and  
         [0023]    [0023]FIG. 5 is a block diagram to explain the configuration of an apparatus for regenerating a copy-protected signal according to a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]    [First Embodiment] 
         [0025]    The first embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows the entire configuration of a sync (synchronous) device  11 , which will be described in the first embodiment.  
         [0026]    The sync device  11  includes a color television receiver (CTV) support for high vision (HD), a projection TV (PJTV), a liquid crystal projector TV (LCD-PJTV), etc. By way of the above sync device, the CTV will be described hereinafter.  
         [0027]    The sync device  11  mainly comprises a copy-protect decoding module  12 , a main unit  13 , and a display section  14 . The main unit  13  is arranged after the copy-protect decoding module  12 , and carries out signal processing and the power control of the whole sync device  11 . The display unit  14  displays a signal processed by the main unit  13 .  
         [0028]    The display section  14  is a CRT (Cathode Ray Tube), a liquid crystal display panel, etc. As the case may be, the main unit  13  is divided into two or three, depending on the sync device  11 . Here, one main unit  13  is represented for simplification.  
         [0029]    The signal flows in the following manner. First, a copy-protected signal  15  from a source device (not shown) is supplied to a signal input terminal  16  of the sync device  11 . The copy-protected signal  15  is, for example, a digital visual interface (DVI) signal, etc. The signal input terminal  16  is a DVI input terminal if the copy-protected signal is a DVI signal.  
         [0030]    The copy-protected signal  15  thus supplied to a signal input terminal  16  is inputted to a copy-protect decoder  17  constituting the copy-protect decoding module  12 . The copy-protect decoder  17  carries out copy-protect decoding and digital/analog conversion if the input signal is digital. Here, for simplification, it is called a copy-protect decoder  17 .  
         [0031]    The copy-protect decoding module  12  mainly comprises the above copy-protect decoder  17 , a microcomputer  18  and an EEPROM (Electrically Erasable and Programmable Read Only Memory  19 ). The copy-protect decoding module  12  is built into the rear side corresponding to the signal input terminal  16  in the sync device  11 , and covered with a shield.  
         [0032]    In particular, if the copy-protected signal  15  thus supplied to a signal input terminal  16  is a digital-transmitted DVI signal, high-speed and wideband transmission is made. For this reason, preferably, the copy-protect decoding module  12  has the circuit configuration integrated with the signal input terminal  16  as much as possible. In this case, it is desirable that the copy-protect decoding module  12  shields noise radiation to the outside. In the first embodiment, there is no illustration with respect to the shield for the copy-protect decoding module  12 .  
         [0033]    In the first embodiment, a cable  22  connects the copy-protect decoding module  12  and the main unit  13  via an output connector  20  and an input connector  21 .  
         [0034]    The cable  22  connecting the copy-protect decoding module  12  and the main unit  13  includes a signal line  22   a,  a control line  22   b  and a power supply line  22   c.  The signal line  22   a  is used for supplying a signal in which copy protection is removed by the copy-protect decoder  17  to a signal processing circuit  23  of the main unit  13 . The control line  22   b  connects a microcomputer  18  included in the copy-protect decoding module  12  and a microcomputer  24  included in the main unit  13 . The power supply line  22   c  is used for supplying the power from a power circuit  25  included in the main unit  13  to the copy-protect decoding module  12 .  
         [0035]    The above signal in which copy protection is removed by the copy-protect decoder  17  is, for example, Y/Cb/Cr signals, etc. These signals are outputted from the copy-protect decoding module  12 , and sent to the main unit  13 .  
         [0036]    In this case, users can guess that the copy-protect decoding module  12  has a copy-protect decoding function, based on the form of the module  12  and the display of the signal input terminal  16 . Based on this, it is possible for a malicious user to open the cabinet of the sync device  11  so that the copy-protect decoding module  12  can be detached, and then connected to external recording equipment, and thereby, to make illegal copies.  
         [0037]    The following is a description of a way to prevent the above-described illegal alterations and conversions. FIG. 2 is a flowchart showing the mutual operation of the microcomputer  18  included in the copy-protect decoding module  12  and the microcomputer  24  included in the main unit  13 .  
         [0038]    When power is supplied to the sync device  11  to start it up (step S 2   a ), the microcomputer  18  detects this in step S 2   b.  In step S 2   c,  the microcomputer  18  outputs an ID transmission request to the microcomputer  24 . In this case, the ID is an identification number of a unique code allocated to the sync device  11 , and previously stored in the microcomputer  24 .  
         [0039]    When receiving the above ID transmission request from the microcomputer  18 , the microcomputer  24  sends the ID stored therein to the microcomputer  18  in step S 2   d.  In step S 2   e,  the microcomputer  18  determines whether or not the ID has been received. If it is determined that the microcomputer  18  has not received the ID, in step S 2   f,  the microcomputer  18  makes no copy-protect decoding operation; therefore, the routine operation ends (step S 21 ).  
         [0040]    If the ID is received, the microcomputer  18  determines in step S 2   g  whether or not a write-protect (inhibit) flag stands in the EEPROM  19  included in the copy-protect decoding module  12 . The write-protect flag designates a specific address of the EEPROM  19 . Whether write-protect is made is determined according to whether or not the write-protect flag is set or not.  
         [0041]    Assume that the write-protect flag is not set initially. Therefore, the microcomputer  18  writes the received ID to the designated address of the EEPROM  19  in step S 2   h.  By doing so, the ID unique to the sync device  11  given to the microcomputer  24  of the main unit  13  is transferred to the copy-protect decoding module  12  and stored therein. At the time the microcomputer  18  stores the received ID in the EEPROM  19 , a flag for inhibiting the write into the EEPROM  19  is set.  
         [0042]    The microcomputer  18  determines in step S 2   i  whether or not the received ID corresponds to the ID stored in the EEPROM  19 . If it is determined that correspondence is not made, the routine operation proceeds to step S 2   f.    
         [0043]    If it is determined that correspondence is made, the microcomputer  18  gives an instruction to start a decoding operation to the copy-protect decoder  17  in step S 2   j.  By doing so, in step S 2   k,  the copy-protect decoder  17  carries out the decoding operation, and outputs the result to the main unit  13 , thereafter, the routine operation ends (step S 21 ).  
         [0044]    When the power is turned on next, the operation is the same as the above first power-on operation in the flowchart of FIG. 2 until the microcomputer  18  receives the ID from the microcomputer  24 . However, in this case, when the microcomputer  18  receives the ID and checks the write-protect flag of the EEPROM  19  in step S 2   g,  the flag already stands. For this reason, the microcomputer  18  determines in step S 2   i  whether or not the received ID corresponds with the ID stored in the EEPROM  19  without carrying out the write operation for a new write-protect flag in step S 2   h.  The operation after that is the same as above.  
         [0045]    Here, the following case will be corresponded. In order to make illegal copies, a malicious user opens the cabinet of the sync device  11  so that the copy-protect decoding module  12  can be detached, and installed into another recording device. In this case, even if the power supply to the module succeeds, when the user tries to operate the decoding module, the microcomputer  18  detects the power-on, thereafter, outputs an ID transmission request to the microcomputer  24 .  
         [0046]    However, the ID is not sent, or a non-correspondence ID (noise, etc.) is sent; for this reason, no instruction to start the decoding operation is given to the copy-protect decoder  17 . Therefore, the copy-protect decoding operation is not carried out. The operation routine shown in FIG. 2 is referred to as routine A.  
         [0047]    In the first embodiment, the EEPROM  19  has been used as the typical component for storing the ID. The memory built in the microcomputer  18  may be used in place of the EEPROM  19 .  
         [0048]    [Second Embodiment] 
         [0049]    The following is a description on a second embodiment of the present invention. The second embodiment has the same configuration as the first embodiment. The operation will be described below with reference to flowcharts shown in FIG. 3A and FIG. 3B.  
         [0050]    According to the second embodiment, the routine A of the first embodiment is intactly carried out, that is, the microcomputer  18  collates with the ID from the microcomputer  24 , and thereby, permits the decoding operation by the copy-protect decoder  17 . In addition to the above routine A, the microcomputer  24  detects the presence of the ID transmission request from the microcomputer  18 , and thereby, confirms the existence of the copy-protect decoding module  12 . Unless the existence is confirmed, the microcomputer  24  determines that the copy-protect decoding module  12  is detached, and turns off the power of the sync device  11 .  
         [0051]    The operation will be described below in detail with reference to FIG. 3A and FIG. 3B. Namely, the microcomputer  24  included in the main unit  13  is a microcomputer for controlling the sync device  11 ; therefore, the power of the sync device  11  is turned on according to the instruction from the microcomputer  24 .  
         [0052]    When the operation is started (step S 3   a ), the microcomputer  24  gives the instruction to turn on the power of the entire sync device  11  in step S 3   b  so that the power circuit  25  can turn on a set power supply. The microcomputer  18  detects the above power-on (step S 3   c ), and outputs the ID transmission request to the microcomputer  24 , as in the flow of FIG. 2 (step S 3   d ).  
         [0053]    In step S 3   e,  the microcomputer  24  gives the instruction to turn on the set power supply, thereafter, waits for receiving the ID transmission request for a predetermined time (e.g., 1 or 2 seconds). If the ID transmission request is given within the predetermined time (step S 3   f ), the same procedures as described in FIG. 2 are taken. Namely, steps S 3   g  to S 3   n  are the same as steps S 2   d  to S 2   k  shown in FIG. 2.  
         [0054]    If it is determined in step S 3   f  that the ID transmission request is not given within the predetermined time, the microcomputer  24  determines in step S 3   o  that the copy-protect decoding module  12  is possibly detached. In step S 3   p,  the microcomputer  24  gives the instruction to turn off the power to the power circuit  25 , thereafter, in step S 3   q,  forcedly turns off the set power supply, and thus, the operation ends (step S 3   r ). The operation routine shown in FIG. 3A and FIG. 3B is referred to as routine B.  
         [0055]    As seen from the above description, even if the copy-protect decoding module  12  is detached, the copy-protect decoding module  12  cannot be used in other devices, and in addition, the power of the sync device  11  is turned off. As a result, the sync device  11  is unusable. Therefore, this serves to deter illegal remodeling, and is expected to prevent illegal remodeling.  
         [0056]    [Third Embodiment] 
         [0057]    The third embodiment of the present invention will be described below with reference to FIG. 4. The third embodiment shows the case where the copy-protect decoding module  12  is attached as an after-sales option. FIG. 4 is a flowchart showing the procedures taken by a serviceman.  
         [0058]    When the attachment is started (step S 4   a ), the serviceman additionally attaches the copy-protect decoding module  12  to the sync device  11  from the back side in step S 4   b.  In step S 4   c,  the serviceman operates the sync device  11  so that the sync device carries out the routine A described in FIG. 2, and thereafter, confirms whether or not the sync device  11  is normally operated in step S 4   d.    
         [0059]    In step S 4   e,  the serviceman pulls up a predetermined pin of the microcomputer  24  included in the main unit  13  so as to effect setup relating to additional attachment of the sync device  11  to the copy-protect decoding module  12 . Thereafter, in step S 4   f,  the serviceman operates the sync device  11  so that the sync device carries out the routine B described in FIG. 3A and FIG. 3B. If it is confirmed in step S 4   g  that the sync device  11  is normally operated, the serviceman fixes the pulled-up pin of the microcomputer  24  by a resin seal (step S 4   h ), and thus, the procedure ends (step S 4   i ). The pulled-up pin may be fixed using a bonding agent in place of the above resin seal.  
         [0060]    [Fourth Embodiment] 
         [0061]    The fourth embodiment of the present invention will be described below. According to the fourth embodiment, one feature is added to the above first to third embodiments, and thereby, illegal copy is more securely prevented.  
         [0062]    More specifically, as seen from FIG. 5, the portion connecting the copy-protect decoding module  12  and the main unit  13  are directly connected by the connectors  20  and  21  in place of the cable  22 . The connecting portion between the connectors  20  and  21  is sealed by a resin  26 , or covered with a bonding agent.  
         [0063]    Likewise, in order to cover each substrate back surface of the module  12 , and the main unit  13  on which the pin of the connectors  20  and  21  are soldered and exposed, the resin is sealed thereto, or a bonding agent is applied thereto. By doing so, the module  12  and main unit  13  are physically and firmly fixed; therefore, if these components are forcedly detached, mechanical breakdown occurs in any of the substrate, connector and main unit. As a result, it is possible to obtain the effect of preventing illegal copying.  
         [0064]    In the above embodiments, the microcomputer  18  of the copy-protect decoding module  12  requests for and receives the ID data from the microcomputer  24  of the main unit  13 . Instead, the microcomputer  24  of the main unit  13  may requests and receive the ID data from the microcomputer  18  of the copy-protect decoding module  12 .  
         [0065]    The present invention is not limited to the above embodiments, and various modifications may be made without departing from the spirit or scope of the invention.