Abstract:
The present invention relates to a method of encoding and decoding an optical disc, which could contain both confidential data and public viewing data. The method manipulates on the file system of the optical disc and protects the confidential data with ID field, password entry mechanism and burner/player/reader using the method of the present invention. Further, the present invention provides control over types of audience and time of viewing since ordinary optical disc player can only play public viewing data and the present invention complying player will be able to play the confidential data providing with correct password and ID field.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the invention  
         [0002]     The present invention relates to method of encoding and reading confidential optical disc. More particularly the present invention relates to method of encoding optical disc by manipulating the file system and reading the produced optical disc with confidential protection of ID field, password and entries limitation mechanism.  
         [0003]     2. Description of Prior-Art  
         [0004]     In the field of disc encoding and decoding technology many methods has been developed. Most of encoded optical disc contains data that uses different standard file system can be viewed by general player/reader. There are also many encrypting methods that cooperate with encoding methods to protect the confidential data contained. In the current market, most data containing discs either holds public viewing data or confidential data. The two types of data could not be held by the same optical disc. Further, the outcome products of confidential data containing optical disc are mostly protected by encryption only and all player/reader could read the disc if correct password given. Furthermore, if the password is lost or deciphered there are no further mechanisms to protect the data within the disc. Nevertheless, many various encrypting processes are not easily understood or used by public. There is no easy and safe system yet on the market for general user to make their private disc. The safety measure should be higher and robust to password decipher.  
       SUMMARY OF THE INVENTION  
       [0005]     The presentation was produced after reviewing the above-mentioned prior-art. It is designed to cater for people who want to make some private or confidential videos/movies/files that are not for public viewing. Further, one might also want certain people to be able to view those videos/movies/data at certain time. Hence, the method of the present invention is invented to accomplish these goals.  
         [0006]     The present invention provides a method for encoding and decoding a confidential optical disc. According to the present invention, a produced optical disc can contain both public and confidential viewing data. Both data are organized and stored under a file system, but in different manner. Wherein a specified ID field and password that are only functional on burner/player/reader using the method according to the present invention to further protect the confidential data from exposing to unauthorized party.  
         [0007]     It is an objective of the present invention to provide a method for encoding a confidential optical disc. The method requires a password and data source before starting to create public viewing (dummy) and confidential viewing (real) data according to file system. Wherein the directory tree containing addresses to real data in the file system is hidden away in a secret location that only burner/player using the method according to present invention with correct password and ID field can locate.  
         [0008]     It is another objective of the present invention to provide a method for reading a confidential optical disc created by the production method described in this invention. The method involves a player/reader with function of verifying ID field and identifying whether if the disc contains any confidential data. The confidential data is further protected from any unauthorized party by a password verification and entries restriction mechanism.  
         [0009]     The method of the present invention gives the facility of having both public and confidential viewing data on an optical disc, which is easily made with a burner using the method according to the present invention. A person must possess both password and optical disc made with the present invention in order to access the hidden confidential data using the player/reader functioning according to the method of present invention. Hence, without any one of the three above factors will not put the confidential data to the risk of being exposed. Consequently, one has the control on assigning different audiences for viewing different type of data. Further, time of viewing is also possible to determine and control since it is the time one grants another party the possession of both password and optical disc made by the present invention, providing that another party is using the player which is practicing the method according to the present invention.  
         [0010]     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0011]      FIG. 1  is the schematic diagram of an optical disc volume layout;  
         [0012]      FIG. 2  is the schematic diagram of ISO 9660 file system extraction that relates to the preferred embodiment of the present invention;  
         [0013]      FIG. 3  is the schematic diagram containing extraction of UDF Bridge file system that relates to the preferred embodiment of the present invention;  
         [0014]      FIG. 4  is a flow-chart of a confidential optical disc encoding process in the present invention;  
         [0015]      FIG. 5  is a first sub-flow-chart of the confidential disc encoding process in the preferred embodiment of the present invention;  
         [0016]      FIG. 6  is a second sub-flow-chart of the confidential disc encoding process in the preferred embodiment of the present invention;  
         [0017]      FIG. 7  the third sub-flow-chart of the disc encoding process for the preferred embodiment of the present invention;  
         [0018]      FIG. 8  the schematic diagram of UDF file system implement and conversion to optical disc data in the preferred embodiment of the present invention;  
         [0019]      FIG. 9  the flow-chart of the disc reading process in the preferred embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     Reference will now be made in detail to the present preferred embodiment of the invention, examples of which are illustrated in the accompany drawings  
         [0021]     There are two main preferred embodiments for the present invention. The first embodiment relates to an encoding process for an optical disc of the present invention and the second embodiment relates to a reading process for an optical disc of the present invention. However, before we reveal both embodiments, some pre-knowledge pertains to optical disc volume layout and file systems in the present invention must be given.  
         [0022]     Please refer to  FIG. 1  the schematic diagram of an optical disc volume layout. The diagram shows a linear frame with segments representing the physical data on the tracks of an optical disc. The linear frame contains many segments of different properties and usages. Some segments may further contain other sub-segments of information. The first segment on the linear from is a lead-in zone  10  containing some basic information about an optical disc player for identifying the general properties of an optical disc (e.g. sync sectors and control data including disc key and other information). Relatively, there is also a lead-out zone  22  at the end of the linear frame. Between the lead-in zone  10  and lead-out zone  22  is the file system and data area, which holds the data content of the disc. The data content in this diagram for example are file  14 , file  16 , file  18  and file  20 . Further, in front of all the data files is a file system  12 , which defines way of storing files with directions and information about them on an optical disc. A file system is public known and applied to all optical disc. It is a standard way of managing the whole file structure and sorting data. Two possible file systems namely ISO 9660 and UDF Bridge can be applied to the optical disc in the preferred embodiment of the present invention.  
         [0023]     The mentioned file system contains descriptors that describe the properties of a whole directory of folders and files. Refer to  FIG. 2  the schematic diagram of ISO 9660 file system extraction that relates to the preferred embodiment of the present invention. The diagram shows an ISO 9660 file system  200  with the content that relates to the present invention. A primary volume descriptor  204  contains the addresses that point to a path table  206  and directory records  208 . The path table  206  further contains addresses that point to other directory records  208 . The directory records  208  also have other addresses that point to other directory records  208  and data addresses that point to file contents  210 , which is the actual data on the disc. The path tables  206 , directory records  208  and file content  210  described above is the standard directory and files that can be read by any optical disc player, because they are located at the standard addresses of the ISO 9660 file system  200 . There are also spaces in the ISO 9660 file system that is unused and denoted as Undefined Area  202 . However, in the preferred embodiment of the present invention, user can specify their secret primary volume descriptor  212 , secret path table  214 , secret directory records  216  and secret file content  218  to be stored in these undefined area  202  or in the other places file system where only known by a player/reader using the method of the present invention.  
         [0024]     The UDF (Universal Disk Format) is a file system standard format that was developed to overcome the limitations of ISO 9660 file system and ensuring consistency of data written to various optical discs. Hence, UDF is installed to all players/readers in order to read all optical discs. Now, refer to  FIG. 3  the schematic diagram containing extraction of UDF bridge file system that relates to the preferred embodiment of the present invention. The UDF Bridge file system in the diagram shown contains a main volume descriptor sequence and reserve volume recognition sequence  302 , which contains addresses that point to other descriptors such as file set descriptor  304 . Wherein the file set descriptor  304  is the descriptor known by all optical disc burner/reader/player because it is located at the position specified by the UDF Bridge file system. In the file set descriptor  304 , there is at least an address which points to a root directory record of a directory tree in UDF. Wherein, the directory tree is stored in the UDF specified location, namely UDF directory structure  306 . The directory tree consists of root directory record, directory records and file records. Further, data addresses are stored in the file records and they point to the locations of files  308 , which containing actual data content stored in optical disc under the UDF system. The files  308  in UDF stores the actual data that will be read by optical disc reader/player. Further, the precedent mentioned file set descriptor  304 , UDF directory structure  306  and files  308  are described as the standard directory and files that can be read by any optical disc reader/player. Because the locations of all these are specified in UDF, hence they are known by all optical disc burner/player/reader as a universal format.  
         [0025]     In the preferred embodiment of the present invention, however, includes a secret file set descriptor  310 , which is pointed by the address stored in the sequence  302  and can only be found by a optical disc player/reader using the method according to the present invention (e.g. Power DVD). The secret file set descriptor  310  stores a preset address that points to a root directory record of a real directory tree in UDF system. This real directory tree is stored in a secret UDF directory structure  312  and containing root directory record, directory records and file records. Wherein the file records hold some data addresses that point to the actual data content of the optical disc inside a secret files  314 . The precedent mentioned secret file set descriptor  310 , secret UDF directory structure  312  and secret files  314  are named non-standard directory and files and can only be found by a present invention complying reader/player. Hence, a reserve data can be stored in UDF file system separately from standard data.  
         [0026]     In addition, there are other descriptors in the UDF bridge file system  300  such as implementation user volume descriptor  316 , primary volume descriptor  318 , partition descriptor  320 , logical volume descriptor  322  and unallocated space descriptor  324 . These descriptors can also store information (e.g. directory tree) if there is any unused space in them.  
         [0027]     The two above-mentioned ISO 9660 and UDF bridge file systems can both apply to the present invention. However, the following preferred embodiments would mainly describe on base of the UDF system. The subtle differences between implementations of the two systems will be pointed out only where necessary. However, a person skills in art should readily understand the concept behind.  
       First Preferred Embodiment  
       [0028]     The present invention relates to a method for encoding and decoding a confidential optical disc. In order to achieve the confidentiality of the disc, the present invention defines two different data on an optical disc; they are dummy data and real data. Wherein a general optical disc reader/player can only read dummy data and in contrast, the real data could only be found and read by specified optical disc reader/player (e.g. Cyberlink&#39;s Power DVD player).  
         [0029]     Please refer to  FIG. 4 : flow-chart of a confidential optical disc encoding process in the present invention. After a signal of creating confidential optical disc S 42  has been received by a present invention complying optical disc burner, which is normally associated with a computer, the burner would switch to a confidential disc burning mode and promptly requesting for a data-accessing password S 44 . This data-accessing password S 44  will be used for accessing data in the reading process later. After the burner has received a data-accessing password, a pre-selected data and an actual specified data source would be given to the optical disc burner from a sample menu and actual specified data source respectively S 46 . The pre-selected data is named as dummy data and the actual specified data is the real data in the present invention. Next, the optical disc burner would receive a start burning signal S 48  and start the disc burner process up on completion of the above steps. The next step is for the associated computer to create a temporary file system (Buffer) in its hard disc S 50 . Once the temporary file system has been completely set up, the disc burner performs the physical burning process on an optical disc S 70 . In this way, a confidential optical disc is created up on completion of the burning process.  
         [0030]     The step of creating temporary file system S 50  and burn buffer to disc S 70  in the above mentioned encoding process each consists of further steps that would be described in details bellow.  
         [0031]     There are two major stages in the step of creating temporary file system S 50 . They are: creating standard file set  50 A and crating parallel file set with real data  50 B. These two stages are created in a hard disc of an associated computer for temporary storing the file system before they are burned to onto optical disc.  
         [0032]     Next, refer to  FIG. 5 : a first sub-flow-chart of the confidential disc encoding process in the preferred embodiment of the present invention and  FIG. 8 : the schematic diagram of UDF file system implement and conversion to optical disc data in the preferred embodiment of the present invention. The diagram in  FIG. 5  shows the first stage of creating temporary file system S 50 , which is creating standard file set  50 A. The first step in creating standard file set  50 A is to import directory tree of dummy data from a source. It could come from a preset sample menu or another specified folder S 502 . The directory tree of dummy data is stored in the UDF directory structure in UDF file system  822 . Wherein, the directory tree consists of root directory record  802 , directory records  803  and file records  804 . Although we already knew that file records contains data addresses that point to some dummy data content  805 ; however, the dummy data  805  does not need to be a meaningless data. It could be any data, which is allowed for public viewing and playing by using an optical disc player/reader. Afterwards, the descriptors that describe the whole file system are created in UDF file system S 504 . Then, UDF assigns a disc address for the root directory record  821  of the dummy directory tree S 506 . The root directory is saved in a file set descriptor  801  once the root directory of dummy directory tree has been defined, the UDF file system would start reading the imported dummy directory tree S 508 . The rest of the directory tree (directory records  803  and file records  804 ) is then converted into UDF filing format and each of them are assigned with a disc address S 510 . The stage of creating standard file set  50 A is now completed and it contains file system and data that any optical disc reader/player can read.  
         [0033]     Because some application layer specifies fixed address for some data on an optical disc, thereby the file system this invention modifies will be affected. Hence, it is recommended that dummy directory and its related data should always comply with both application layer and file system. In other words, dummy data should be placed at the fixed address or addresses specified by an application layer.  
         [0034]     Now, the next step is to enter the stage of creating parallel file set with real data  50 B. Please refer to  FIG. 6 : a second sub-flow-chart of the confidential disc encoding process in the preferred embodiment of the present invention and  FIG. 8 : the schematic diagram of UDF file system implementation and conversion to an optical disc data in the preferred embodiment of the present invention. The first step of this stage is to import directory tree of real data from a source S 512 . The source could be an actual specified folder from hard disc, CD or DVD etc. The UDF file system will now read the dummy directory tree and find out where the tree ends in order to define the next available address as the start of secret file set descriptor  810  in the preferred embodiment of the present invention S 514 . The secret file set descriptor  810  belongs to the non-standard directory files and records in the UDF system. Because only a specified optical disc burner using the encoding method according to present invention can define the address of secret file set descriptor  810  and reserve it for storing information that relate to a confidential disc. Therefore, only a specified reader/player knows how and where to find this reserved descriptor. Now, the UDF system assigns a disc address  811  to the root directory record  812  of the above-mentioned real directory tree S 516 . Next, the UDF reads the imported real directory tree S 518  and then the rest of the directory tree (directory records  813  and file records  814 ) would be converted into the UDF filing format. Each of the directory records  813  and file records  814  is then assigned with a disc address S 520 . Finally as described in the precedent article, the data addresses that should contain inside of dummy or real file records are finally assigned S 522 . As shown on the FIG.  8 , the data addresses in real file records point to the real data files/contents on an optical disc (e.g. file  806 , file  807 , file  808 , file  809 ).  
         [0035]     Further, the above mentioned real directory tree is actually stored in an implementation user volume descriptor  815  and the address for finding the real root directory  811  is stored in the secret file descriptor  810 . The implementation user volume descriptor  815  is another descriptor inside the UDF file system  300 . It is designed for use by another implementation (e.g. for your eyes only) to identify another “volume” that only another specified burner/player/reader can read. Therefore, the implementation user volume descriptor  815  is the most appropriate and safest place to store the real directory tree. Hence, the preferred embodiment of the present invention stores the real directory tree in this descriptor rather than the secret UDF directory structure  312 .  
         [0036]     Furthermore, for the same reason, the implementation user volume descriptor  815  is therefore also used to store a specified ID field  816 , which is an identification mark for a present invention complying specified reader/player, and the actual data-accessing password  817 . The data-accessing password  817  can be found by a password address  818  containing inside the secret file set descriptor  810 .  
         [0037]     In contrast to dummy data, if the application layer disregarding the file system and fixes the addresses, some reader/player will play the content of the confidential disc without referring to the file system at all. In order to avoid a non-specified reader/player from playing real data, the real data should not be placed at an address or addresses specified by an application layer. The specified reader/player should hence always depend on the real directory tree and not any absolute addresses fixed by an application layer for finding any real data.  
         [0038]     Although the real root directory  812 , specified ID field  816  and data-accessing password  817  mentioned in the precedent article are stored in the implementation user volume descriptor  815 . However, it is not the only place that these fields can be placed. They can be allocated any where on an optical disc, as long as the storing space does not have a piece of data or descriptor&#39;s address fixed by a file system or an application layer.  
         [0039]     Please refer to the  FIG. 7 : the third sub-flow-chart of the disc encoding process for the preferred embodiment of the present invention and  FIG. 8 : the schematic diagram of UDF file system implement and conversion to optical disc data in the preferred embodiment of the present invention. Fig. 7  is the sub flow-charts that representing the step of Burn Buffer to Disc S 70  in the  FIG. 4 : flow-chart of a confidential optical disc encoding process in the present invention. The optical disc burner firstly burns the descriptors of the file system  800  onto the optical disc S 702 . Then, it burns the dummy directory and file records into the UDF directory structure  822  of the file system onto the optical disc S 704 . Similarly, it then burns real directory and file records into the implementation user volume descriptor  815  of the file system onto disc S 706 . The above-mentioned descriptors, dummy directory and records and real directory and records are all burned into the file system zone  800  in front of all the data content. Behind the file system zone  800  is where the burner will burn on all the files/data content at the different addresses assigned by dummy file records S 708  and real data records S 710 .  
       Second Preferred Embodiment  
       [0040]     This preferred embodiment of the present invention relates to a method for reading confidential optical disc. This method is applied by a specified player/reader to play an optical disc, which is encoded by the previously said method in first preferred embodiment. Refer to  FIG. 9 : the flow chart of the disc reading process in the preferred embodiment of the present invention. The first step is for a player/reader to read the inserted optical disc data S 900 . At this stage, any player, including specified player (e.g. power DVD player), does not know if the inserted optical disc is an ordinary disc or a confidentially encoded disc. Therefore the player/reader will only show and play the dummy data, which is designed to be read by any reader/player. However, only if a specified player/reader were used and a view confidential disc command was received, then could the real data be possibly identified S 902  by a specified player. However, before viewing the real data (if there is any) the specified player will request for a password and also count whether if there has been more than five password entries in this session S 906 . If there is, then the player will disregard the correctness of the password and ignore it and other further entries completely S 912 . Otherwise, if the password entered has not yet exceeded five time limits, then the player will proceed to check if the correct ID field exists in the file system S 908 . If the specified player/reader does find a correct ID field in the system, it will proceed further and check the accuracy of the password entered S 910 . However, if there is no correct ID field in the file system then the player will again proceed to ignore the password entered step S 912 . Now, the player/reader will play the real data if the entered password is correct S 914 , if not the player will ignore the password entered S 912 . Furthermore, the player will go back to read dummy data if a refresh signal is received while viewing or playing the real data. In this situation, a correct password will need to be entered again through procedure step S 900  to S 910  as a new session. Another situation is that the player/reader receives signal of ejecting disc, turning off player/reader or turning off view confidentially encoded disc while viewing the real data S 918 , then the reading process session will end S 920 .  
         [0041]     Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. For example, the optical disc can be one of CDRW, DVDRW, and DVD RAM. The data source is one of hard disc, CD, DVD and DVD RAM. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.