Patent Publication Number: US-2004044900-A1

Title: Copy protection of DVD related web content

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention relates to a method, system, and computer code for running a DVD disc having a link to web content of a web site, wherein the web content is directly related the content on the DVD disc, and wherein the system generates a decryption key to decrypt the web content received from the web site.  
       [0002] 2. Related Art  
       [0003] WebDVD is a technology in which a Digital Versatile Disc or Digital Video Disc (DVD) disc is linked to web content of a web site, wherein the web content is directly related the content on the DVD disc. The content on the DVD disc may include video and audio content. WebDVD combines Digital Versatile Disc or Digital Video Disc (DVD) with Internet technology, thus providing fast access to high-quality video and audio data offered by DVD along with advantages offered by Internet technology (e.g., interactivity, dynamic updates, etc.). For example, WebDVD enables local DVD to be enhanced with HTML web pages.  
       [0004] It is desired that web content from a web site, where such web content relates to a DVD disc, be accessible to a user of a WebDVD system linked to the web site only when the DVD disc is running on a DVD device of the WebDVD system. Accordingly, there is a need for said access to be available only to said user.  
       SUMMARY OF THE INVENTION  
       [0005] In first embodiments, the present invention provides a decryption method for decrypting web content associated with a DVD disc, comprising the steps of:  
       [0006] running, by a WebDVD system, the DVD disc on a DVD device comprised by the WebDVD system, wherein the DVD device is linked by a communication link to a web site that is targeted by the DVD disc, and wherein the WebDVD system may have access to the web content only when the DVD disc in running on the DVD device;  
       [0007] requesting, by the WebDVD system, the web content from the web site;  
       [0008] receiving, by the WebDVD system from the web site, a disc address set on the DVD disc, wherein the disc address set points to a data block on the DVD disc;  
       [0009] acquiring knowledge, by the WebDVD system, of the extent of the data block, wherein the data block is determined by the disc address set and the extent;  
       [0010] attempting by the WebDVD system to read the data block, and if a new disc address set requesting feature is operative on the WebDVD system and if said attempting is not successful then: directing the web site to send a new disc address set to replace the previously received disc address set for pointing to a new data block on the DVD disc, followed by a maximum of N repetitions of said receiving, acquiring, and attempting steps until said attempting is successful, wherein N is at least 1; and  
       [0011] mapping the data block to a decryption key by a defined function if said attempting is successful.  
       [0012] In second embodiments, the present invention provides a method for transmitting, by a web site to a WebDVD system, information that may be used by the WebDVD system to generate a decryption key, comprising the steps of:  
       [0013] receiving, by the web site, a present request from the WebDVD system for web content associated with a DVD disc that is running on a DVD device comprised by the WebDVD system, wherein the DVD device is linked by a communication link to the web site, wherein the web site is targeted by the DVD disc, and wherein the WebDVD system may have access to the web content only when the DVD disc is running on the DVD device;  
       [0014] determining, by the web site, a disc address set on the DVD disc, wherein the disc address set points to a data block on the DVD disc, wherein the data block is adapted to be mapped to the decryption key by a defined function, and wherein the decryption key is adapted to be used by the WebDVD system to decrypt the web content; and  
       [0015] sending, by the web site, the disc address set to the WebDVD system.  
       [0016] In third embodiments, the present invention provides a network, comprising a WebDVD system, wherein the WebDVD system is adapted to:  
       [0017] request, from a web site targeted by a DVD disc, web content associated with the DVD disc, wherein the DVD disc is running on a DVD device comprised by the WebDVD system, wherein the DVD device is linked by a communication link to the web site, and wherein the WebDVD system may have access to the web content only when the DVD disc is running on the DVD device;  
       [0018] receive from the web site a disc address set that points to a data block of the DVD disc;  
       [0019] acquire knowledge of the extent of the data block, wherein the data block is determined by the disc address set and the extent;  
       [0020] attempt to read the data block, and if a new disc address set requesting feature is operative on the WebDVD system and if said attempt to read the data block is not successful then: direct the web site to send a new disc address set to replace the previously received disc address set to point to a new data block on the DVD disc, and repeat a maximum of N times said receive, acquire, and attempt until said attempt is successful, wherein N is at least 1; and  
       [0021] map the data block to a decryption key by a defined function if said attempt is successful, wherein the decryption key may be used by the WebDVD system to decrypt the web content.  
       [0022] In fourth embodiments, the present invention provides a network, comprising a web site, wherein the web site is adapted to:  
       [0023] receive a present request from a WebDVD system for web content associated with a DVD disc that is running on a DVD device comprised by the WebDVD system, wherein the DVD device is linked by a communication link to the web site, wherein the web site is targeted by the DVD disc, and wherein the WebDVD system may have access to the web content only when the DVD disc is running on the DVD device;  
       [0024] determine a disc address set on the DVD disc, wherein the disc address set points to a data block on the DVD disc, wherein the data block is adapted to be mapped to a decryption key by a defined function, and wherein the decryption key is adapted to be used by the WebDVD system to decrypt the web content; and  
       [0025] send the disc address set to the WebDVD system.  
       [0026] In fifth embodiments, the present invention provides a computer program product, comprising a computer usable medium having a computer readable program code embodied therein for decrypting web content associated with a DVD disc, said computer code embedded within a readable storage device of a WebDVD system, said computer code comprising an algorithm adapted to:  
       [0027] request, from a web site targeted by the DVD disc, web content associated with the DVD disc, wherein the DVD disc is running on a DVD device comprised by the WebDVD system, wherein the DVD device is linked by a communication link to the web site, and wherein the WebDVD system may have access to the web content only when the DVD disc is running on the DVD device;  
       [0028] receive from the web site a disc address set that points to a data block of the DVD disc;  
       [0029] acquire knowledge of the extent of the data block, wherein the data block is determined by the disc address set and the extent;  
       [0030] attempt to read the data block, and if a new disc address set requesting feature is operative on the WebDVD system and if said attempt to read the data block is not successful then: direct the web site to send a new disc address set to replace the previously received disc address set to point to a new data block on the DVD disc, and repeat a maximum of N times said receive, acquire, and attempt until said attempt is successful, wherein N is at least 1; and  
       [0031] map the data block to a decryption key by a defined function if said attempt is successful, wherein the decryption key may be used by the algorithm to decrypt the web content.  
       [0032] In sixth embodiments, the present invention provides a computer program product, comprising a computer usable medium having a computer readable program code embodied therein for transmitting, by a web site to a WebDVD system, information that may be used by the WebDVD system to generate a decryption key, said computer code embedded within a readable storage device of the web site, said computer code comprising an algorithm adapted to:  
       [0033] receive a present request from the WebDVD system for web content associated with a DVD disc that is running on a DVD device comprised by the WebDVD system, wherein the DVD device is linked by a communication link to the web site, wherein the web site is targeted by the DVD disc, and wherein the WebDVD system may have access to the web content only when the DVD disc is running on the DVD device;  
       [0034] determine a disc address set on the DVD disc, wherein the disc address set points to a data block on the DVD disc, wherein the data block is adapted to be mapped to a decryption key by a defined function, and wherein the decryption key is adapted to be used by the WebDVD system to decrypt the web content; and  
       [0035] send the disc address set to the WebDVD system.  
       [0036] The present invention enables web content from a web site, where such web content relates to a DVD disc, to be accessible to a user of a WebDVD system linked to the web site only when the DVD disc is running on a DVD device of the WebDVD system. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0037]FIG. 1 depicts a WebDVD system linked to a web site by a communication link such that the WebDVD system includes a DVD device, in accordance with embodiments of the present invention.  
     [0038]FIG. 2 depicts the DVD device of FIG. 1 on which a DVD disc is placed, in accordance with embodiments of the present invention.  
     [0039]FIG. 3 depicts the DVD disc of FIG. 2, in accordance with embodiments of the present invention.  
     [0040]FIG. 4 depicts the DVD disc of FIG. 3 showing sectors, in accordance with embodiments of the present invention.  
     [0041]FIG. 5 depicts the DVD disc of FIG. 4 showing a logical block, in accordance with embodiments of the present invention.  
     [0042]FIG. 6A depicts a direct pointer to a data block of a disc, in accordance with embodiments of the present invention.  
     [0043]FIG. 6B depicts a first-level indirect pointer to a data block of a disc, in accordance with embodiments of the present invention.  
     [0044]FIG. 6C depicts a second-level indirect pointer to a data block of a disc, in accordance with embodiments of the present invention.  
     [0045]FIG. 7 is a flow chart depicting decryption of web content associated with a DVD disc through mapping a data block to a decryption key, in accordance with embodiments of the present invention.  
     [0046] FIGS.  8 A- 8 D depict embodiments of the mapping of FIG. 7, in accordance with embodiments of the present invention.  
     [0047]FIG. 9 is a flow chart that depicts sending a DVD disc address set from a web site to a WebDVD system for subsequent generation of the decryption key of FIG. 7, in accordance with embodiments of the present invention.  
     [0048]FIG. 10 is a table showing various methods for determining the DVD disc address set in FIG. 9, in accordance with embodiments of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0049]FIG. 1 depicts a network  200 , comprising a WebDVD system  90  and a web site  82 , in accordance with embodiments of the present invention. The WebDVD system  90  is linked to the web site  82  by a communication link  80 . “DVD” stands for Digital Versatile Disc or Digital Video Disc. The communication link  80  may comprise the Internet, an Intranet, etc., to which the web site  82  is linked. The web site  82  includes a computer code  83  which may represent, or be comprised by, a web server of the web site  82 . The web site  82  generates web content (e.g., web pages) which is understood herein to include any type of internet-based content, including any content available on a server connected to the Internet. The web site  82  may comprise, inter alia, any information stored on a internet connected server.  
     [0050] The WebDVD system  90  comprises a processor  91 , a DVD device  99 , an electronics device  100 , an input device  92 , a memory device  94 , a display device  95 , and an output device  93 . The processor  91  is coupled to the communication link  80 , the DVD device  99 , the electronics device  100 , the input device  92 , the memory device  94 , the display device  95 , and the output device  93 . In various embodiments, one or more of the preceding devices may be absent.  
     [0051] The DVD device  99  is a device or apparatus that reads and/or writes on a DVD disc. The DVD device  99  is shown in FIG. 2 as holding a DVD disc  11  and is described infra. The DVD disc  11  is shown in FIG. 3 and is described infra.  
     [0052] In FIG. 1, the electronics device  100  is one or more electronic devices that may be used in conjunction with the DVD device  99  and may be a component of an integrated electronics device (e.g., a consumer electronics device). Examples of pertinent consumer electronics devices include, inter alia, a video game player (e.g., Sony Playstation 2®), a DVD-VHS device that includes the DVD device  99  coupled to the electronics device  100  representing a VHS video cassette recorder, a stereo system that includes the DVD device  99  coupled the electronics device  100  representing stereo components. In a given embodiment, the electronics device  100  may be present or absent in the WebDVD system  90 .  
     [0053] The memory device  94  may be, inter alia, a hard disk, a floppy disk, a magnetic tape, an optical storage (e.g., DVD or compact disc (CD): with Read/Write and/or Read Only capabilities), a dynamic random access memory (DRAM), a flash memory, a read-only memory (ROM), etc. The memory device  94  includes software, namely a computer code  97 . The computer code  97  includes an algorithm for generating a decryption key to decrypt web content received from the web site  82 , as described infra. The processor  91  executes the computer code  97 . The memory device  94  may also include input data  96  which includes input used by the computer code  97 . The memory device  94  may additionally include DVD data  98  which may comprise, inter alia, DVD data derived from a web page of a web site, DVD data derived from a DVD disc (e.g., the DVD disc  11  shown in FIGS. 2 and 3 described infra), etc.  
     [0054] The memory device  94  (or one or more additional memory devices not shown in FIG. 1) may be embodied as a readable medium for storing program code and data, and for reading program code and data. The memory device  94  may be, inter alia, a computer usable medium, a computer readable medium, a program storage device, a readable memory device, a data storage device, etc. The memory device  94  may have a readable program code (e.g., a computer readable program code) embodied therein and/or having other data stored therein, wherein the computer readable program code comprises the computer code  97 . Generally, a computer program product (or, alternatively, an article of manufacture) of the computer system  90  may comprise said memory device  94 .  
     [0055] The display device  95  is any device having a display screen (e.g., a television, a monitor, etc.).  
     [0056] The input device  92  may be, inter alia, a keyboard, a mouse, a joystick combinations thereof, etc.  
     [0057] The output device  93  represents one or more output devices such as, inter alia, a printer, a plotter, a computer screen, a magnetic tape, a removable hard disk, a floppy disk, etc. The output device  93  may display output from the computer code  97 . The output device  93  may also express output from a DVD disc that is running in the DVD device  99 . Accordingly, the output device may be an audible device such as a speaker. Of course, the DVD device  99  itself may include a speaker for audibly expressing subject content being played on a DVD disc. In a given embodiment, the output device  93  may be present or absent in the WebDVD system  90 .  
     [0058] While FIG. 1 shows the WebDVD system  90  as a particular configuration of hardware and software, any configuration of hardware and software, as would be known to a person of ordinary skill in the art, may be utilized for the purposes stated in this patent application in conjunction with the particular computer system  90  of FIG. 9. For example, one or more additional multiple memory devices may be used instead of the single memory device  94 . As another example, various components WebDVD system  90  may be directly coupled to each other (e.g., the DVD device  99  and the electronics device  100  may be directly coupled to each other such as in a single device).  
     [0059] The WebDVD system  90  may be configured in accordance with various embodiments including, inter alia, a DVD player embodiment, a computer system embodiment, and an integrated device embodiment.  
     [0060] In the DVD player embodiment, the WebDVD system  90  comprises a DVD player which includes: the DVD device  99 , the processor  91 , the input device  92 , and the memory device  94 . The DVD player may also internally include the display device  95 , or be coupled to the display device  95  wherein the display device  95  is external to the DVD player yet is within the WebDVD system  90 . As an external display device, the display device  95  may be a television or a monitor.  
     [0061] In the computer system embodiment, the WebDVD system  90  comprises a computer system which includes: the processor  91 , the input device  92 , the memory device  94 , the output device  93 , and the display device  95  (e.g., a computer monitor). The computer system may also internally include the DVD device  99 , or be coupled to the DVD device  99  wherein the DVD device  99  is external to the computer system yet is within the WebDVD system  90 .  
     [0062] In the integrated device embodiment, the WebDVD system  90  comprises an integrated device that includes: the DVD device  99 , the electronics device  100  in the form of a consumer electronics device, the processor  91 , the input device  92 , and the memory device  94 . The integrated device may also internally include the display device  95 , or be coupled to the display device  95  wherein the display device  95  is external to the integrated device yet is within the WebDVD system  90 . As an external display device, the display device  95  may be a television or a monitor. As stated supra, the integrated device may comprise a video game player, a DVDVHS device, a stereo system, etc.  
     [0063]FIG. 2 depicts the DVD device  99  of FIG. 1 on which a DVD disc  11  is placed, in accordance with embodiments of the present invention. The web site  82  of FIG. 1 is targeted by the DVD disc  11 , which means that the WebDVD system  90  may have access to web content relating to the DVD disc  11  only when the DVD disc  11  in running on the DVD device  99 . The DVD device  99  may be used for reading the DVD disc  11 , writing to the DVD disc  11  (if the DVD disc  11  is a rewritable disc), or both. Accordingly, a read/write head  22  reads or writes data at the spot  23  on the DVD disc  11 . The driver  21  rotates the DVD disc  11  on a spindle  27 , and a positioner  25  moves the head  22  radially between the center and outer boundary of the DVD disc  11 . When the DVD device  99  is used for reading the DVD disc  11 , the head  22  serves as a read head and the data apparatus  28  retrieves the data read by the head  22 . When the DVD device  99  is used for writing to the DVD disc  11 , the head  22  serves as a write head and the data apparatus  28  distributes data from a data source (not shown) to the head  22  for subsequent writing. The DVD device  99  depicted in FIG. 2 is merely exemplary, and may be varied in any manner known to one of ordinary skill in the art for reading a DVD disc or writing to a DVD disc.  
     [0064]FIG. 3 depicts the DVD disc  11  of FIG. 2, in accordance with embodiments of the present invention. The DVD disc  11  has a central hole  10  that fits on the spindle  27  of FIG. 2. The DVD disc  11  is arranged in accordance with a spiral pattern of turns constituting substantially parallel tracks as illustrated by track  19 . Information may be represented on the DVD disc  11  by optically detectable marks recorded along the track, e.g. pits and lands. The DVD disc  11  may have special regions or areas for recording particular types of information. For example, an auxiliary data area  12  may be used to store data other than the DVD subject content (e.g., movies) intended to be played by the WebDVD user. An example of such auxiliary data includes tables, pointers, format identification for the DVD subject content intended to be played by the WebDVD user, etc. The DVD subject content intended to be played by the WebDVD user may include video information, audio information, or both.  
     [0065]FIG. 4 depicts the DVD disc  11  of FIG. 3 divided into angular sectors  51 - 58 , in accordance with embodiments of the present invention. FIG. 4 also shows representative tracks  30  and  40 . Track  30  is divided into sectors  31 - 38  corresponding to the angular sectors  51 - 58 , respectively. Track  40  is divided into sectors  41 - 48  corresponding to the angular sectors  51 - 58 , respectively. Sector  42  of track  40  is bounded by boundary lines  16  and  17 , which define the end points of sector  42 . Sector  42  of track  40  begins at location  18  and is characterized by a sector address at location  18 . A data block on a track (e.g., track  40  or track  50 ) may comprise a fraction of a sector, a full sector, or more than one sector. As examples, a data block may: fill sector  42  (1 sector); fill sectors  35 - 37  (3 sectors); fill sector  35  and a half of sector  36  that is contiguous with sector  35  (1 ½ sectors); etc.  
     [0066] A data block on the DVD disc  11  may be a physical data block or a logical data block. A physical data block is a data block whose extent is defined by disc addresses. For example, a data block that fits into sector  42  and whose extent is defined by the boundaries  16  and  17  of sector  42  is a physical data block. Since the boundaries  16  and  17  are defined by actual disc addresses, the boundaries  16  and  17  may be viewed as physical boundaries that define the extent of the physical data block that fills sector  42 . Note that the extent of a physical data block may also be viewed as the length of the physical data block expressed as the number of bits (or bytes or similar units) in the physical data block.  
     [0067] In contrast, FIG. 5 depicts a logical data block  39  within the DVD disc  11  of FIG. 4, in accordance with embodiments of the present invention. The sector boundaries shown in FIG. 4 are omitted in FIG. 5 for simplicity. The logical data block  39  encompasses a group of linked data such as in a record, file, array, etc. The logical data block  39  exists between boundaries  14  and  15 , which are not required to be aligned with sector boundaries. Hence, the boundaries  14  and  15  may viewed as logical boundaries that define the extent of the logical data block  39 . Note that the extent of a logical data block may also be viewed as the length of the logical data block expressed as the number of bits (or bytes or similar units) in the logical data block, or expressed in terms of the number of bits (or bytes or similar units) in the record, file, array, etc.  
     [0068] A data block could comprise an Error Correction Code (ECC) block. An ECC block has a known size. As an example, an EEC block on DVD may comprise 16 physical blocks such that each physical block of the ECC block includes 2048 bytes of user data, for a total of 32,768 bytes in the ECC block. An ECC block, or one or more physical block within the ECC block, could be the data block that is used to generate a decryption key. See FIG. 7 and accompanying description infra for a discussion of how a decryption key may be generated in accordance with the present invention.  
     [0069] FIGS.  6 A- 6 C illustrate direct and indirect pointers to data blocks of a disc, in accordance with embodiments of the present invention. FIG. 6A illustrates a direct pointer, and FIGS.  6 B- 6 C illustrate indirect pointers.  
     [0070]FIG. 6A depicts a direct pointer to a data block of a DVD disc, in accordance with embodiments of the present invention. In FIG. 6A, a disc address A 1  points to the beginning of data block D 1  of the DVD disc. Data block D 1  may be a physical data block or a logical data block. In FIG. 6A, the data block D 1  contains data. The disc address A 1  points directly to the data block D 1  or to the data contained in the data block D 1 .  
     [0071]FIG. 6B depicts a first-level indirect pointer to a data block of a DVD disc, in accordance with embodiments of the present invention. The disc address A 1  points to the beginning of data block D 1  of the DVD disc, as in FIG. 6A Data block D 1  may be a physical data block or a logical data block. In FIG. 6B, the data block D 1  includes disc address A 2  which points to the beginning of data block D 2  of the DVD disc. Data block D 2  may be a physical data block or a logical data block. In FIG. 6B, the data block D 2  contains data. The disc address A 1  points indirectly (through the disc address A 2 ) to the data block D 2  or to the data contained in the data block D 2 . In FIG. 6B, the disc address A 1  is a first-level indirect pointer to the data block D 2 , because one auxiliary pointer (i.e., A 2 ) is required for A 1  to point to D 2 .  
     [0072]FIG. 6C depicts a second-level indirect pointer to a data block of a DVD disc, in accordance with embodiments of the present invention. The disc address A 1  points to the beginning of data block D 1  of the DVD disc, as in FIG. 6A or FIG. 6B. Data block D 1  may be a physical data block or a logical data block. In FIG. 6C, the data block D 1  includes disc address A 2  which points to the beginning of data block D 2  of the DVD disc. Data block D 2  may be a physical data block or a logical data block. In FIG. 6C, the data block D 2  includes disc address A 3  which points to the beginning of data block D 3  of the DVD disc. Data block D 3  may be a physical data block or a logical data block. The disc address A 1  points indirectly (through the disc addresses A 2  and A 3 ) to the data block D 3  or to the data contained in the data block D 3 . In FIG. 6C, the disc address A, is a second-level indirect pointer to the data block D 3 , because two auxiliary pointers (i.e., A 2  and A 3 ) are required for A 1  to point to D 3 .  
     [0073] The data within a data block need not be contiguously distributed on a DVD disc. For example, a first contiguous portion of a data block could comprise a pointer (e.g., an address pointer such as A 2  or A 3  as described supra in conjunction with FIGS. 6B and 6C) that points to a second contiguous portion of the data block, wherein said first and second contiguous portions of the data block are not contiguous with respect to each other. In general, a data block comprises M contiguous portions of the DVD disc such that M is a positive integer of at least 1. If M is at least 2, then the M contiguous portions may be linked by pointers (e.g., address pointers). The M contiguous portions may be alternatively linked in any other way known to a person of ordinary skill in the art. For example the M contiguous pointers may each represent a record of a file, or a row of a table, such that each of the M contiguous pointers is independently identified by its own disc address. For the case M&gt;1 such that more than one disc address is required to located a data block on the DVD disc, a disc address set comprising a plurality of disc addresses together with the extent of the data block (which may be expressed in terms of the extent of each of the M contiguous portions) is utilized by the WebDVD system  90  to locate the data block in its entirety.  
     [0074]FIG. 7 is a flow chart with steps  60 - 69  that depict decryption of web content associated with the DVD disc  11  through mapping a data block to a decryption key, in accordance with embodiments of the present invention. The reader is also referred to FIGS. 1 and 2 for reference numerals referred to in the following description of FIG. 7. In step  60 , the WebDVD system  90  runs the DVD disc  11  on the DVD device  99 , wherein the DVD device  99  is comprised by the WebDVD system  90 . As stated supra in conjunction with FIG. 2, the web site  82  is targeted by the DVD disc  11 , which means that the WebDVD system  90  may have access to web content relating to the DVD disc  11  only when the DVD disc  11  in running on the DVD device  99 . Note that the DVD device  99  is linked by the communication link  80  to the web site  82 .  
     [0075] In step  61 , the WebDVD system  90  requests web content from the web site  82 .  
     [0076] In step  62 , the WebDVD system  90  receives, from the web site  82 , a disc address set on the DVD disc  11 , wherein the disc address set directly or indirectly points to a data block on the DVD disc  11 . The data block may be a physical data block or a logical data block. As described supra, the data block may be contiguous or non-contiguous. Thus, the disc address set that points to the data block is one or more disc addresses as necessary to determine the location of the data in the data block. If data block consists of one contiguous portion or if the data block comprises a plurality of non-contiguous portions linked exclusively by address pointers as described supra, then the disc address set received by the WebDVD system  90  from the web site  82  requires no more than one disc address. In some applications, however, the disc address set will need two or more disc addresses to determine the location of the data in the data block, such that different disc addresses in the disc address set point to different contiguous portions of the data block. If the disc address set includes at least two disc addresses, then the disc address set is said to directly point to the data block if each disc address of the disc address set directly points to a portion of the data block. If the disc address set includes at least two disc addresses, then the disc address set is said to indirectly point to the data block if each disc address of the disc address set indirectly points to a portion of the data block.  
     [0077] In step  63 , the WebDVD system  90  acquires knowledge of the extent of the data block, wherein the data block is determined by the disc address set and the extent of the data block. The extent of the data block may have a predetermined value that is stored at a physical or logical location within the WebDVD system, such as in the memory device  94 , such that acquiring knowledge of the extent of the data block comprises accessing the predetermined extent from the physical or logical location. A physical location is a location within a physical data block, while a logical location is a location within a logical data block. Alternatively, the WebDVD system  90  may acquires knowledge of the extent of the data block from the web site  82 .  
     [0078] In step  64 , the WebDVD system  90  attempts to read the data block. The attempt to read the data block may or may not be successful. For example, the attempt to read the data block from a scratched location on the disc may not be successful.  
     [0079] Step  65  is a decision block taking alternative action depending on whether the attempt to read the data block in step  64  was successful. If NO (i.e., the attempt to read the data block in step  64  was not successful), then the WebDVD system  90  request a new disc address set in step  66  to replace the previously received disc address set, wherein the new disc address set will point to a new data block on the DVD disc  11 . The request for the new disc address set is followed by a maximum of N repetitions of steps  62 - 64  until the attempt to read the data block in step  64  is successful, wherein N is at least 0. The embodiment of N=0 represents a case in which a request for a new disc address set is not permitted such that steps  64  and  65  are effectively deleted from the flow chart in FIG. 7. IF N&gt;0 then a “new disc address set requesting feature” is said to operative on the WebDVD system  90 . If N=0, the “new disc address set requesting feature” is not operative on the WebDVD system  90 . If YES (i.e., the attempt to read the data block in step  64  is successful), then step  67  is executed.  
     [0080] In step  67 , the WebDVD system  90  maps the data block to a decryption key by a defined function. The defined function may be an identity function, which effectively maps the data block to itself with no change in the data block. Thus with an identity function, the decryption key is the data block itself. Alternatively, the defined function may be a function that is not an identity function, which effectively maps the data block to the encryption key that differs from the data block. Any defined function may be used. As an example, the defined function may select a subset of bits from the data block. As another example, the defined function may be a hashing function of the bits (or groups of bits) in the data block.  
     [0081] After the decryption key is generated from mapping the data block using the defined function, then through use of the decryption key, the WebDVD system  90  may decrypt the web content (see step  69 ) received from the web site  82  (see step  68 ). The web content may be received from the web site  82  after or before the decryption key is generated.  
     [0082] While particular process steps in a particular order are shown in FIG. 7, the process steps of FIG. 7 may be varied in substance and order as would be known or obvious to a person of ordinary skill in the art to generate a decryption key for decrypting the web content. For example, step  68  (receive web content) may precede step  62  (receive address set pointing to data block).  
     [0083] FIGS.  8 A- 8 D depict embodiments of the mapping of the data block to the decryption key in step  69  of FIG. 7, in accordance with embodiments of the present invention. FIG. 8A shows the mapping of the data block to the decryption key generally. The data block being attempted to be read in step  64  may be encrypted or may not be encrypted. As shown in FIG. 8B, if the data block is encrypted, the mapping in step  67  may directly map the encrypted data block to the decryption key by the defined function. Alternatively as shown in FIG. 8C, if the data block is encrypted, the mapping in step  67  may first decrypt the data block to generate a decrypted data block, followed by mapping the decrypted data block to the decryption key by the defined function. As shown in FIG. 8D, another embodiment is to map the data block to an encrypted key by the defined function, followed by decrypting the encrypted key to generate the decryption key. For example, the encrypted key could be decrypted using a DVD encryption system (e.g., Content Scrambling System (CSS)) in current use to generate the final decryption key.  
     [0084] The preceding steps  60 - 69  shown in FIG. 7, and the mapping embodiments shown in FIGS.  8 A- 8 D, may be executed by the computer code  97 , and algorithms thereof, in the memory device  94 .  
     [0085]FIG. 9 is a flow chart with steps  72 - 75  that depict the web site  82  sending a DVD disc address set to the WebDVD system  90  for subsequent generation of a decryption key, in accordance with embodiments of the present invention. In step  72 , the web site  82  receives a present request from the WebDVD system  90  for web content associated with the DVD disc  11  that is running on the DVD device  99  comprised by the WebDVD system  90 , which corresponds to steps  60  and  61  of FIG. 7. The DVD device  99  is linked by the communication link  80  to the web site  82 . The web site  82  is targeted by the DVD disc  11  and the WebDVD system  90  may have access to the web content from the web site  82  only when the DVD disc  11  is running on the DVD device  99 .  
     [0086] In step  73 , the web site  82  determines a disc address set on the DVD disc  11 , wherein the disc address set points to a data block on the DVD disc  11 , wherein the data block is adapted to be mapped to the decryption key by a defined function, and wherein the decryption key is adapted to be used by the WebDVD system  90  to decrypt the web content.  
     [0087] In step  74 , the web site  82  sends the disc address set to the WebDVD system  90 , which corresponds to step  62  of FIG. 7.  
     [0088] In step  75 , the web site  82  causes the disc address set to be stored in a cookie in the memory device  84  of the WebDVD system  90 . A cookie is a text string within a text file, typically called a “cookie file” and is stored on the web user&#39;s machine (e.g., computer; DVD device, etc.). As an example of using a cookie, the web site  82  may have the disc address set be a parameter of a “Set-Cookie” command transmitted by the web site  82  to the WebDVD system  90 . Step  75  is optional and is available to the web site  82  to enable the web site  82  to know what disc address set the web site  82  sent to the WebDVD system  90  the last time that the WebDVD system  90  accessed the web site  82 , since the cookie is be sent to web site  82  in response to each request from the WebDVD system  90  for web content. Such request for the web content is received by the web site  82  in step  72 . Information on cookies may be obtained from, inter alia, RFC2965 (see http://www.ietf.org/rfc/rfc2965.txt).  
     [0089] While particular process steps in a particular order are shown in FIG. 9, the process steps of FIG. 9 may be varied in substance and order as would be known or obvious to a person of ordinary skill in the art to generate a decryption key for decrypting the web content. For example, step  75  (cause disc address set to be stored in a cookie) may be eliminated as discussed supra.  
     [0090]FIG. 10 is a table showing Methods 1-11 for determining a DVD disc address set in step  73  of FIG. 9, in accordance with embodiments of the present invention.  
     [0091] Method 1 randomly or deterministically selects a disc address set from an collection of disc addresses or a collection of disc address sets (e.g., an array of disc addresses or an array of disc address sets) stored at the web site  82 . An example of random selection of the disc address set is picking each disc address of the disc address set from a uniform probability distribution. Another example of random selection of the disc address set is picking each disc address of the disc address set from a normal probability distribution. An example of deterministic selection of a disc address set is marching sequentially through an array of disc address sets by selecting the next sequential disc address set in the array of disc address sets the next time a disc address set is to be selected. Accordingly, the web site  82  can maintain a number of copies of the same web content with different disc addresses sets and associated decryption keys, so that for the same DVD system  90 , a different decryption key can be supplied to the same DVD system  90  for each request for the web content by the same DVD system  90 . It is up to the web site  82  to decide how many disc addresses sets to currently support and how often to change the disc address sets. Each change of disc address set requires the corresponding web content to be re-encrypted. The use of multiple disc address sets at the web site  82 , or more generally changes of disc address sets for successive disc addresses sets supplied to the same DVD system  90  which occur in other Methods described infra, makes ineffective any caching of disc address sets or associated decryption keys at the DVD system  90 . Thus the web site  82  can deliberately choose a different disc address set to ensure that the disc address set or associated decryption key has not been effectively cached at the DVD system  90 . As described supra, cookies can be used to store disc addresses sets.  
     [0092] Method 2 determines the DVD disc address set to be a same address set that was sent by the web site  82  to the DVD system  90  at a previous time when the DVD system  90  requested the web content.  
     [0093] Method 3 is the same as method 1, except that the previous time is randomly selected from more than one previous time when the DVD system  90  requested the web content. An example of random selection of the previous time is picking from a uniform probability distribution of the previous times when the DVD system  90  requested the web content. Another example of random selection of the previous time is picking from a weighted probability distribution based on selective weighting of the previous times when the DVD system  90  requested the web content.  
     [0094] Method 4 is the same as method 1, except that the previous time is deterministically selected from more than one previous time when the DVD system  90  requested the web content. An example of deterministic selection of the previous time is selection of the next to last previous times when the DVD system  90  requested the web content.  
     [0095] Method 5 determines the DVD disc address set to be a same address set that was sent by the web site  82  to the DVD system  90  at a last time when the DVD system  90  requested the web content.  
     [0096] Method 6 determines the DVD disc address set to be a same address set that was sent by the web site  82  to the DVD system  90  at a last time when the DVD system  90  requested the web content if the last time occurred not less than D days prior to the present request, wherein D is a finite positive real number.  
     [0097] Method 7 determines the DVD disc address set to be a different address set from a previous address set that was sent by the web site  82  to the DVD system  90  at a previous time the DVD system  90  requested the web content.  
     [0098] Method 8 determines the DVD disc address set to be a different address set from a last address set that was sent by the web site  82  to the DVD system  90  at a last time the DVD system  90  requested the web content.  
     [0099] Method 9 determines the DVD disc address set to be a different address set from a last address set that was sent by the web site  82  to the DVD system  90  at a last time the DVD system  90  requested the web content if the last time occurred more than D days prior to the present request, wherein D is a finite positive real number.  
     [0100] Method 10 determines a disc address (or each disc address) of DVD disc address set to be a function of the date and time that the web site  82  received the request for web content.  
     [0101] Method 11 is determines a unique DVD disc address and may be employed for, inter alia, the special case in which the WebDVD system  90  requests a new disc address set following a previously unsuccessful attempt to read a data block (see steps  64 - 66  in FIG. 7). Method 11 determines a unique DVD disc address set that has never been used and is intended not to be used again in the future for the WebDVD system  90 , in recognition of the possibility that the user of the WebDVD system  90  may invoke the request for a new disc address set for an improper purpose such as for, inter alia, effectively caching either the previous disc address set received or the new disc address set to be received. With method 11, the web site  82  may decide that the unique disc address set should be utilized when the web site receives a request for the web content from WebDVD system within a predetermined time interval (e.g., 1 minute, 5 minutes, 30 minutes, etc.) following a prior request received from the same WebDVD system, which could indicate that the same WebDVD system is repeating its request for the same web content in accordance with steps  64 - 66  in FIG. 7.  
     [0102] In practice, the web site  82  may choose to have the addresses of the disc address set be close to the center of the disc (e.g., close to the central hole  10  in FIG. 3), since startup information may be stored close to the center of the disc. Thus, having the addresses of the disc address set be close to the center of the disc may reduce the startup time if the disc driver  21  (see FIG. 2) only needs to make a small jump to read the disc address set or the data block pointed to by the disc address set.  
     [0103] The preceding steps  72 - 75  shown in FIG. 9, and methods for determining the DVD disc address set in FIG. 10, may be executed by the computer code  83 , and algorithms thereof, in the web site  82  (e.g., within the web server of the web site  82 ).  
     [0104] The computer code  83  (and/or web server) of the web site  82  may have access the DVD content on the DVD disc  11 , either through use of an actual DVD drive together with the DVD disc  11  or through use of bit copy of the DVD disc  11 . This enables the computer code  83  (and/or web server) of the web site  82  to automatically generate other disc address sets and associated encryption/decryption keys and to re-encrypt the web content with said associated encryption keys and in correspondence with said other disc address sets. Each of said other disc address sets points to a corresponding data set on the DVD disc  11  for subsequent transmission of the other disc address set to some WebDVD system (e.g., the WebDVD system  90  or another WebDVD system) that subsequent requests the web content. Said automatic generation may be implemented periodically, at fixed dates and times, as triggered by a pre-defined condition or event, etc.  
     [0105] Based on the embodiments described herein, the present invention provides copy protection of DVD-related web content.  
     [0106] While the embodiments described herein are expressed in terms of a DVD disc (e.g., the DVD disc  11  of FIGS. 2 and 3), the present invention, as illustrated herein by the DVD disc  11 , is not limited to DVD discs. The scope of the present invention generally includes any medium having any physical disc format (e.g. CD, DVD, Blu-ray, etc.), including ROM, Write once, and Rewritable discs. The present invention generally applies to discs that include different application formats (e.g. video, audio, games, etc.).  
     [0107] While embodiments of the present invention have been described herein for purposes of illustration, many modifications and changes will become apparent to those skilled in the art. Accordingly, the appended claims are intended to encompass all such modifications and changes as fall within the true spirit and scope of this invention.