Abstract:
Copy-protected content material is screened for an indication of the availability of an enhanced version of a screening system and forcing an upgrade to the advanced screening system by refusing to process the copy-protected content material until the upgrade is preformed. When security standards change, and corresponding security techniques are available for downloading to existing consumer devices, newly published content material will contain an indication to that effect. When the newly published content material is processed by an existing consumer device, the consumer device will detect this indication of an available update, and will prevent the processing of this newly published content material until the update is received. In this manner, a phased approach to enhanced security can be effected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/133,377, filed May 10, 1999. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to the field of consumer electronics, and, in particular, to screening techniques for copy-protected material. 
   2. Description of the Related Art 
   Digital recordings have the unique property that copies of the content material have the same quality as the original. As such, the need for an effective copy-protection scheme is particularly crucial for the protection of content material that is digitally recorded. A number of protection schemes have been developed (or proposed) that record the content material in an encrypted form. Other protection schemes have been developed (or proposed) that record an encrypted key that controls the playback, or rendering, of the content material. In a number of these approaches, an attempt is made to minimize the value, or worth, of an illicit copy of copy-protected material by incorporating screens, or filters, in playback or recording devices that prevent the rendering or recording of these illicit copies. Because many alternative techniques are currently available, and because many other alternative techniques are being developed, the adoption of a single protection scheme by the providers of copy-protected material and the vendors of consumer electronic devices has been, and continues to be, a daunting task. 
   The Secure Digital Music Initiative (SDMI) has proposed a phased approach to enhanced methods of screening for illicit copies of copy-protected material. That is, because most security systems are embodied in programming code, it is relatively easy to upgrade a security system to effect alternative security measures as these measures are developed and standardized. Such an upgrade can be accomplished by sending a replacement memory device to a user, by having the user download the new programming code from an Internet site, and so on. Initially, for example, copy-protected material will contain an indication, or mark, that it is copy-protected material, or, in some cases, a mark that indicates that the material has been tampered with. For example, a mark may indicate that the content material has been converted to a compressed format when it should not have been compressed. A compliant player will not play content material that contains such a mark but does not contain the appropriate SDMI authorization. For ease of reference, content material that does not contain the appropriate SDMI authorization for the content material is termed Non-SDMI, or NSDMI. Also, for ease of understanding, the SDMI approach is used herein as a paradigm for security systems that utilize a phased approach to protection schemes. 
   A conventional SDMI screening process  100  is illustrated in FIG.  1 . User material  101  is received by the process  100 , and tested to determine whether it is material that has an appropriate SDMI authorization. If so, the SDMI material is provided to the processing components of the player or recorder, labeled “SDMI Functions”  120 , in FIG.  1 . These SDMI functions  120  process the material and provide the intended output  121  associated with the device; that is, a player renders the material via acoustic devices, a recorder records the material, typically in a secure form, on another medium, such as a recordable CD, and the like. 
   If, at  110 , the material  101  does not contain the appropriate SDMI authorization, it is screened for a mark, at  130 . If the material  101  does not contain the aforementioned mark, it is deemed not to be copy-protected material, and, therefore, freely playable or recordable. For example, copy-protected material may be marked using a “watermark” that cannot be removed from the material without destroying, or significantly degrading, the quality of the material. If a watermark is not detected at  130 , it is likely that the user material  101  is not copy-protected. Such material may be commercial material that has been provided before the use of a watermark is adopted, or material, such as, private recordings or other recordings, that are intentionally not copy-protected. If, at  130 , a mark is not found, the material  101  is processed, at  170 , to be SDMI-compatible, for subsequent rendering or other processing, via the SDMI functions  120 . Other security tests, such as commonly used existing copy-protection tests, may also be applied in block  130  to determine the validity of the user material  101 . Similarly, the SDMI functions  120  may also include further protection-providing functions that are used to determine whether the output  121  is provided. 
   If, at  140 , the material  101  is determined to be illicit, or potentially illicit, the state of the process  100  is assessed to determine whether it contains phase II security screens. That is, the aforementioned security mark will contain an indication that phase II security screens are available. When illicit copies of the content material containing this mark are made, they will also contain the mark. Thus, when the user of the illicit copy attempts to play or record from this illicit copy, the test at  140  will detect this indication, and will advise the user, at  150 , that there&#39;s a problem rendering the user material  101 , and will further advise the user that an upgrade is available for the user&#39;s system. When the user upgrades the user&#39;s system in response to this advice, advanced screening techniques are provided, as illustrated by block  160 . That is, when the user upgrades to the Phase II system, the block  160  is provided or upgraded, via a memory device upgrade, a download from an Internet site, and so on. Other blocks, such as the SDMI functions block  120 , the mark detection block  130 , and the pre-processing block  170  may also be enhanced or modified by the upgrade. Thereafter, subsequent attempts to render or otherwise process illicit material will be subject to these enhanced security techniques. It is expected, for example, that one of the enhanced techniques will be a trace of the source of illicit material. That is, for example, future recording or providing systems may add a unique identifier to each provided material, identifying itself; for example, material downloaded from a web-site may contain that web-site name. When such material is determined to be illicit, the block  160  may provide a message such as: “This material has been illicitly obtained from site xxx.com, and the performers are being deprived of their royalty rights. Please refrain from purchasing material from xxx.com.” In this manner, the unintentional purchaser of illicit material is advised of the nature of the product he or she is receiving from the identified site, and will seek another source for the desired material. Eventually, the identified providers of illicit material will lose their customer base to the authorized providers, and the economic infeasibility of providing such illicit material to a dwindling customer base will force the illicit operation to shut down. Also, advanced systems may be configured to communicate this information to a central authority, so that preventive measures may be taken to prevent future losses. 
   SUMMARY OF THE INVENTION 
   It is an object of this invention to improve the effectiveness of a phased approach to screening for illicit copies of copy-protected material. 
   This invention is based on the observation that, after some experience with the conventional phased approach of  FIG. 1 , the intentional users of illicitly obtained copies of copy-protected material will “spread the word”, via, for example, the Internet, advising both the intentional users and unintentional users of illicit material of the perils associated with upgrading. Thereafter, a dwindling number of people will be expected to voluntarily upgrade their systems, and the phased approach to advanced security will likely fail. 
   The object of this invention is achieved by testing for the availability of an enhanced version of a screening system and forcing an upgrade to the advanced screening system when material that complies with the existing standards is being processed. When security standards change, and corresponding security techniques are available for downloading to existing consumer devices, newly published content material will contain an indication to that effect. When the newly published content material is processed by an existing consumer device, the consumer device will detect this indication of an available update, and will prevent the processing of this newly published content material until the update is received. In this manner, a phased approach to enhanced security can be effected. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in further detail, and by way of example, with reference to the accompanying drawings wherein: 
       FIG. 1  illustrates an example conventional screening process for illicit copies of copy-protected content material; 
       FIG. 2  illustrates an example screening process for illicit copies of copy-protected content material in accordance with this invention; and 
       FIG. 3  illustrates an example block diagram of a system for screening for illicit copies of copy-protected content material in accordance with this invention. 
   

   Throughout the drawings, the same reference numerals indicate similar or corresponding features or functions. 
   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   As noted above in the Summary Of The Invention, the conventional approach to a phased upgrade of security measures, enforces the phased upgrade on users who attempt to play or otherwise process illicit copies of copy-protected material. That is, consistent with a non-intrusive approach to the enforcement of copy protection, the conventional approach does not impose a burden on the user until the user commits a wrong. Although this approach is minimally intrusive, it has the potential of being minimally effective. When wrong-doers determine that upgrading their system provide no benefit to them, they will cease such upgrades. Because messages can now be effectively communicated virtually worldwide to large portions of the population, the wrong-doers can also influence others, particularly unknowing wrong-doers, to also cease such upgrades. Thus, the conventional upgrade strategy of  FIG. 1  that provides no tangible benefits for upgrading is likely to fail. 
     FIG. 2  illustrates an example alternative screening process  200  for illicit copies of copy-protected content material in accordance with this invention. This alternative screening process  200  does impose a burden on the users of legitimate copies of copy-protected material, but the burden is not considered to be overbearing. As in  FIG. 1 , the user material  101  is tested for the presence of an SDMI-authorization, at  110 . If the material  101  is an SDMI-authorized copy of copy-protected material, the update status of the system is tested, at  220 . The SDMI-authorized material includes an indication of the phase of the upgrade strategy that was in effect when the material  101  was generated. If the current state of the system is not up-to-date with this phase, the user is advised to upgrade the system, at  150 . Alternatively, if the current state of the system is at the indicated phase, or at a higher phase, the system is up-to-date, and the SDMI-authorized material is provided to the SDMI functions  120  for rendering  121  or other processing. 
   By preventing access to the SDMI functions  120  when the system is determined to be out-of-date, the user&#39;s “incentive” for upgrading the system is the rendering of this new content material having the higher upgrade indication. In this manner, users are likely to continue to upgrade the system at each phase of a phased security-upgrade process. To ease the “surprise” factor associated with having to unexpectedly or inconveniently upgrade the system, the packaging of the content material could include an indication of the applicable upgrade level, and the user could effect the upgrade before attempting to render or otherwise process newly acquired content material. Alternative techniques, common in the art, may also be utilized, such as an automatic notification of new upgrades to users via e-mail messages, and the like. 
   As in the process of  FIG. 1 , legitimate copies of non-SDMI material (SDMI(L)), typically copies that do not have a copy-protection marking, such as a watermark, are identified at  130 , and pre-processed for SDMI processing, at  170 . Non-legitimate copies of non-SDMI material (SDMI(NL)), typically copies of content material having copy-protection marking but not an appropriate SDMI-authorization, are rejected for rendering or other processing, at  260 . The processing will be dependent upon the current upgrade state the system. That is, for example, if the system has been upgraded to identify the source of the illicit material, the processing at  260  will include the “do not purchase material from xxx.com” messaging discussed above with regard to FIG.  1 . 
     FIG. 3  illustrates an example block diagram of a system  300  for identifying illicit copies of copy-protected content material in accordance with this invention. A format checker  310  checks the content material  101  to determine whether the material is authorized content material, using for example, standards established by the SDMI. A status determinator  320  extracts an upgrade status indicator from the authorized content material  311 , and compares it to a system upgrade state  302 , to produce an upgrade status  321 . As noted above, the upgrade status indicator is associated with the content material  101 , preferably cryptographically bound to the material  101 , and indicates a version of upgrade that is available for the system. This version indicator is typically the latest version of the upgrade that was available when the content material  101  was created. In the context of this invention, the upgrade version indicator facilitates an identification of a new phase of copy-protection in a copy-protection system, although the principles presented herein can be applied for other upgrade strategies and applications as well. Note that, in a conventional upgrade process, such as illustrated in  FIG. 1 , the upgrade status indicator is encoded as an “in-band” signal relative to the content material. That is, the status indicator is conventionally encoded within the content material, so that it cannot be easily removed from the material. In accordance with this invention, on the other hand, the status indicator is determined after the content material is verified as being authorized, and there is little or no incentive to remove it. Alternatively, the format checker  310  can be configured to assure that a status indicator is present before declaring that the material is authorized. Thus, the status indicator in this invention can be encoded as an out-of-band signal, which, as is commonly known in the art, is often easier to extract and determine than a conventional in-band signal. As a further measure of security, the status indicator in a preferred embodiment is bound to the content material, using a digital signing technique or similar security measure. 
   A processor  330  processes the content material  101  in dependence upon the upgrade status  321 . If the system upgrade state  302  is at the level determined from the upgrade status indicator associated with the content material  101 , or higher, the processor  330  processes the content material  101  to provide a rendered output  121 . Note that an acceptable upgrade status  321  is only produced from authorized content material  311 . The upgrade status  321  is also provided to a notification device  340  that notifies a user when the system  300  is out-of-date relative to the status indicator included with the content material  101 . 
   If the content material  101  is not-authorized  312 , that does not necessarily imply that the material is illegitimate. A copy-protection detector  350  is configured to detect the presence of a copy-protection scheme, such as a watermark, on the not-authorized content material  312 . If the not-authorized material  312  contains a copy-protection mark, then it must be an illicit copy of copy-protected material, and the processor  330  is configured to prevent the rendering or other processing of the content material  101  if the copy-protection flag  351  is asserted, and, optionally, to utilize the notification device  340  to recommend an upgrade. Conversely, if the not-authorized material  312  does not contain a copy-protection mark, the copy-protection detector  350  does not assert the copy-protection flag, and the processor  330  renders or otherwise processes the content material  101  without constraint. 
   The foregoing merely illustrates the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are thus within its spirit and scope. For example, the test block  220  or the processor  330  may be structured to allow the user material  101  to be rendered or otherwise processed for a limited number of times before preventing such rendering or other processing based on an out-of-date upgrade. That is, the system will display a message indicating that the system needs to be updated, and will cease to render the higher-upgrade-status content material after the next  5  plays. Contrarily, the test block  220  or the processor  330  may be structured to prevent any subsequent processing of content material  101  upon the first determination of an outdated upgrade status. That is, the test block  220  could prohibit subsequent access to the functions  120  regardless of the upgrade indicator on subsequent user material  101 . Combinations of these approaches, and others, will be evident to one of ordinary skill in the art. These and other system configuration and optimization features will be evident to one of ordinary skill in the art in view of this disclosure, and are included within the scope of the following claims.