Abstract:
A method has been developed for enhanced content protection for use in a DVD player or other apparatus where it is desired to store content in a secure manner for personal use and enjoyment. By this technique, a user could input content into an apparatus, and store a single copy of the content in a storage library within the apparatus in encrypted form. When the user is ready to enjoy the content, the user triggers a decryption algorithm to be run on the stored content for viewing, audio or both. The encryption/decryption algorithms are designed to avoid the likelihood of hacking into and retrieving the content from storage. Whereupon, numerous volumes of content may be retrieved for viewing or audio listening with assurance that the content is locked into its storage library.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0002]     There has been much concern by content-owners, in both the music industry and the movie industry in particular, about the potential revenue loss due to unauthorized (unlicensed, and therefore non-revenue bearing) copying of copyrighted material. The target of this concern has been not only the actual copiers, but those such as hardware, software and service providers, who have been perceived as enabling such copying.  
         [0003]     The Copyright Act in the United States recognizes that certain acts are “fair use” which are not acts of infringement. More recently, however, legislation such as the Digital Millennium Copyright Act (DMCA), has been enacted to more closely control activities surrounding copyrighted material.  
         [0004]     Designers and users of consumer electronics devices and systems that handle copyrighted content are well advised to consider the implications of the various legislation relating to handling copyrighted content.  
         [0005]     A concern that copyright legislation is aimed at protecting against is the ability to hack into an electronic device and reproduce the contents of stored material without authorization. Typically, if there is any copy protection at all, the protection is limited to a single, uniformly used protection key. Once the uniformly used protection key is identified, then a hacker can easily decrypt the content and enjoy it without paying for the content.  
         [0006]     By providing a fairly minimal protection for the copyrighted content, then for content security, the suppliers of content seem to place greater reliance upon the user&#39;s own sense for the right and wrong usages of the material. But when copying becomes facilitated through the digitization of the content, then copying becomes a matter of transferring bits of data, through electronic media, and the likelihood of unfair use of the material grows. At the same time, with the advent of larger and larger electronic storage capabilities, consumers have a greater desire to store the material in a single, easy to retrieve location, to enjoy the material easily without any intention of violating the copyright law.  
         [0007]     If users are allowed the freedom to store material electronically in a single location and retrieve the desired material on demand with the single push of a button, users may be inclined to purchase more content in the first place. But of course, with the interest in storing material electronically, there is a greater demand for electronic content and, there comes a greater likelihood people desiring to cheat the copyright system. It therefore is important to create new ways to protect the material to secure it in its electronic library location.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     There is described herein an apparatus and process for enabling the enhanced protection of content that is transmitted within an electronic device. The enhanced protection scheme includes a content importer as well as a content protection scheme interconnected with the content importer, wherein the content protection scheme includes an encryptor, a key generator, and a data processor for implementing a pre-defined algorithm for conducting the encryption and key generation. The content is stored on a storage device that allows for a plurality of unique content to be stored. The content is stored in encrypted form and may be played only by first decrypting the storage format for the content.  
         [0009]     An embodiment of the invention in the context of a DVD (“Digital Video Disc”) is described. A DVD content playback system includes a rewritable storage medium (such as a hard drive) that stores DVD content. The system also includes processing to emulate “playback” of the DVD content from the rewritable storage medium as if the DVD content were actually being played directly (i.e., discounting the inevitable existence of some buffer circuitry) from a DVD storage medium. Processing is also included to minimize the probability that the DVD content can be exported outside the system from the rewritable storage medium. In one example, the DVD content is stored on the rewritable storage medium and encrypted in a manner that depends on unique characteristics of the DVD content playback system and, in some cases, unique characteristics of the DVD (at least, unique to that “title” of content). 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  illustrates, in block form, an example of an electronic device having content protection included therein.  
         [0011]      FIG. 2  illustrates an exemplary content protection process implementing an embodiment of the invention.  
         [0012]      FIG. 3  is a block diagram of an embodiment of the content protection method of the invention.  
         [0013]      FIG. 4  is a block diagram of the use of the invention in the context of a DVD. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]      FIG. 1  is a block diagram of an electronic device utilizing an embodiment of the invention. The electronic device of  FIG. 1  is generally a box that includes a computing device. The electronic device contains an input port for content, such as a reader for an optical disk, and a processor for enabling the transport of data from the content to storage while implementing security algorithms designed to allow for a single copy to be made of a piece of content for storage preferably within the same box. The box of  FIG. 1  may further include storage media for creating electronic libraries of content input to the box, and a player for sensory enjoyment of the content. If desired, the box of  FIG. 1  may include Ethernet or other contacts to the worldwide internet and an integrated viewing screen. There is an input for content  100 . Content  100  may be any content, preferably in digital form, for which copy protection is desired such as a video, audio, or still picture. The content  100  is placed within a media content security scheme  105 . Therein is included a content importer  110 , which enables the copying of the content onto a storage device. Content importer  110  is preferably a software algorithm that when implemented, causes data from content  100  to be read, a file created, and transported to a storage medium so as to create a file library  135 . Prior to content  100  data being transported into electronic storage, a content protection algorithm  115  is implemented to cause the content  100  data tobe encoded. When the algorithm  115  is run, files from content  100  are transported into a data processor  120  (via a bus, which is not shown) where the content protection algorithm  115  triggers an encryptor  125  to run and cause the content  100  files to become scrambled. The data processor  120  may be any microprocessor capable of processing mathematical functions on data, preferably in at least  32  bit blocks. The encryptor  125  calls a key generator  130  to create a unique key for content  100  encrypted files. Whereupon, the content  100  files are transmitted out of the data processor (via a bus, which is not shown) in encrypted form, and sent to content storage library  135 . Content storage library  135  stores content  100  files in encrypted form for security purposes. Content storage library  135  may be ahard disk, flash memory or other storage medium that enables the permanent storage of content for use and enjoyment by an end user.  
         [0015]     When the user is ready to enjoy the content, the user enables the content player  140 . Content player  140  is a component that, among other things, retrieves digital data from the content storage library  135  and converts the digital data into a format that is viewable or audible or both. To achieve sensory enjoyment for the user, the content player  140  first virtually re-implements content protection algorithm  115  to regenerate a key from key generator  130  to decrypt the content  100  files via the encryptor  125 . Throughout this protected content retrieval process, data processor  120  applies the necessary algorithms to cause the content protection algorithm  115  to run through a signal processor  145 , for instance, a graphics processor. Whereupon, a secure reproduction of content  100  then is output to either a video out  150  or audio out  155  for the user&#39;s personal enjoyment.  
         [0016]     The process that occurs in the device of  FIG. 1  is illustrated in block form in  FIG. 2 . First, content is provided that has been placed on a medium  205  such as an optical disk. Then, upon command by the user, the content  205  is processed through a data file retrieval  210  step. There, data files are retrieved from the content medium  205  and an encryption algorithm  215  is applied to the data files. The encryption algorithm  215  uses a combination of pre-selected numbers and calls upon a key generator to scramble the data files into unreadable form  220 . Next, the encoded data files are stored in a single copy onto a storage medium  225 . The storage medium may be a writeable disk drive or semiconductor-based memory such as flash memory. The key created at step  220  is used for encoding purposes but the key itself is not stored in storage medium  225 . When a user desires to play the content  205 , the user issues a command that triggers the step of assimilating the data files into a playable form  230 . The assimilation step  230  is similar to step  215 . A key is regenerated  235  by applying the algorithm that generated the key for the encryption in the first place, at step  215 ,  220 . The key regeneration step  235  enables the data files to be decrypted or decoded  240 . When the decoding step  240  is complete, the data files are ready to be played. The regenerated key from step  235  is not stored in storage medium  225 . The data files are transmitted to a player  245 . This step includes, among other things, applying video and audio processing sequences to the data to format the data into a viewable or audible form. Finally, the data files are transmitted to a sensory device  250  such as a television display, an audio receiver or other device that allows sensory enjoyment of the content  205 . It should be noted that step  245  can not be implemented unless assimilation step  230  is first done.  
         [0017]      FIG. 3  illustrates the key generation step in block diagram form. Preferably, there are three components used for creating a unique key. Each of the components is derived in a manner suitable to the programmer of the security device, but each component is identified and derived in a pre-defined manner selected by the programmer of the security device. There is first a number based upon the particular content  300 . Content number  300  may be derived from the volume label for the content or another source for the content number  300  based upon the content itself could be used. Second, there is a number that is based upon the device identifier  305 , for instance, the serial number of the device such as that shown in  FIG. 1 . The device identifier number  305  may be alternatively an Ethernet MAC address for the device or another convenient, fixed number preferably related to the device itself. Third, another number, for instance, a public key  310  is provided. A public key  310  may be issued by any commercial source. The three numbers  300 ,  305  and  310  may be the actual numbers themselves, but preferably are composed of a derivation of the original numbers, where the derivation is performed in a manner defined by or known only to the person programming the security aspect of the device. To these three numbers, an algorithm for creating a secret key is applied  315 . Preferably, the algorithm is an AES algorithm that results in a 128-bit unique key  320 . The actual manner that the algorithm is used on the three numbers  300 ,  305  and  310  to create the unique key  320  is selected and implemented by the programmer of the security mogul and is written preferably in the language C, using programming skills typical of a person ordinarily skilled in the art. The programmer creates a program that causes the same secret 128-bit key  320  to be output for the three numbers  300 ,  305  and  310 . Key  320  is created during the encryption process and is not stored in the storage medium  135  referred to in  FIG. 1 . Instead, when a user wishes to play encrypted content, a key  320  is recreated, preferably using the same three input numbers, and used to decrypt and prepare the content for enjoyment in a player.  
         [0018]     Referring now to  FIG. 4 , an example DVD content playback system  400  is illustrated in block form. Generally speaking, the system  400  includes elements to copy content from a DVD-formatted optical disc  405  onto a preferably rewritable storage medium  425  such as a hard drive or semiconductor-based memory such as a flash memory. Rewritable storage medium  425  may also be implemented in software. The DVD  405  content is replayed via suitable playback equipment such as through a television  445 . The processing of the system  400 , in general, may be executed by a general purpose computer programmed in a manner so as to carry out the needed processing of digital data.  
         [0019]     The importer process  410  is configured to retrieve the contents of the disc  405  in its entirety and saving a corresponding disc image to the storage medium  425 . During the process of saving the contents of the disc  405  to the storage medium  425 , an encryption process  415  encrypts the disc contents using a key provided by a key generator process  420 . The key generator process  420  uses, in part, an indicator that is unique to a particular DVD title to generate the key. The key generator process may operate according to an AES algorithm and may be a 128-bit key. The system  400  operates in such a way as to preserve the copy protection benefits of CSS.  
         [0020]     That is, the DVD standard format includes a copy protection requirement known as Content Scrambling System, or CSS. Basically, as envisioned by the CSS license, each CSS licensee is given a key from a master set of keys stored on every CSS-encrypted disc. At playback, the CSS decryption algorithm operating within a standard DVD player or computer exchanges keys with the drive unit to generate an encryption key that is then used by the drive unit to encrypt the CSS disc keys and title keys before passing them to the player playback process.  
         [0021]     Turning back to the import process  410 , at no time during the import process  410  are the CSS keys in cleartext format. Rather, like the standard CSS decrypting algorithm operating within a standard DVD player or computer, the importer process  410  negotiates a session key with the DVD drive, and the CSS keys are retrieved from the DVD drive directly in an encrypted format. The encrypted CSS keys are stored on the storage device  425 .  
         [0022]     Furthermore, as part of the importer process  410 , the volume label from the DVD content is stored (e.g., in the first 32K bytes) in a header section of the DVD file on the storage device  425 . In one case, a unique brand identifier (for instance, “MOLINO”) is stored into the header also. Then the CSS-encrypted CSS keys, further AES encrypted, are stored in the header section. In addition, to bind the DVD image to a particular system, a system-unique identification is placed in the header section and the title-unique identifier is also placed in the header section. Finally, the entire header section is secured with a secured hash value (signed using a public key) to further guard against tampering.  
         [0023]     To “play back” the DVD using the system  400 , the process is roughly symmetrical to that just described to store the DVD image on the storage device  400 . First, a virtual DVD drive  435  causes a decryption process  430  to decrypt the DVD image using a key generated by the key generator process  420 . It is noted that, even if the key is compromised, this only compromises a particular DVD title.  
         [0024]     The play back process also includes processing to ensure that the DVD image has been bound to the system  400 . That is, the secured hash value is validated; if the secured hash value is invalid, then the header has been tampered. Furthermore, the data that is nominally the system-unique identification, that was placed in the header section during the import process, is compared to a system-unique identification of the playback system  400 . If there is a mismatch, then the DVD image was potentially surreptitiously placed on the system  400 , and playback is prohibited.  
         [0025]     Once the DVD image is decrypted and the secured hash value is validated, the virtual DVD drive process and the DVD player process  440  operate in a conventional manner.  
         [0026]     The preferred embodiments of the invention have been described in general terms as well as in the context of a DVD. The invention may be applied to other contexts as well for which enhanced protection schemes may be desired, for instance, still pictures, audio, or text. Although the present invention has been described in reference to particular embodiments, persons of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention, as claimed below.