Patent Application
20070118766
Not applicable.
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.
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.
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.
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.
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'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.
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.
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.
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).
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's personal enjoyment.
The process that occurs in the device of
Referring now to
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.
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.
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.
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.
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.
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.
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.
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.
