Protected Media Path
The Protected Media Path is a set of technologies creating a "Protected Environment," first included in Microsoft's Windows Vista operating system, that is used to enforce digital rights management (or DRM) protections on content. Its subsets are Protected Video Path (PVP) and Protected User Mode Audio (PUMA). Any application that uses Protected Media Path in Windows uses Media Foundation.
Overview
The protected environment in which DRM content is played contains the media components that play DRM content, so the application only needs to provide remote control (play, rewind, pause, and so on), rather than having to handle unprotected content data. The protected environment also provides all the necessary support for Microsoft-approved (signed) third-party software modules to be added. It provides a "wall" against outside copying, where within the walls, content can be processed without making the content available to unapproved software.
In order to prevent users from copying DRM content, Windows Vista provides process isolation and continually monitors what kernel-mode software is loaded. If an unverified component is detected, then Vista will stop playing DRM content, rather than risk having the content copied. The protected environment is implemented completely in software, so software-based attacks such as patching the Windows kernel are possible.[1]
These restrictions concern the various outputs from the PC. For DRM content, digital outputs such as
In Vista, the control of PC video outputs is provided by PVP-OPM, which is essentially the next generation of
Additionally, PVP-UAB (Protected Video Path - User-Accessible Bus) is used to
Possible bypass
In January 2007 the developer Alex Ionescu announced that he had found a method that allows end users to bypass Vista's Protected Media Path. This would allow digital content to be played on equipment that does not implement DRM restriction measures (like rescaling of video resolutions and disabling analog audio outputs). However, he did not release any source code in fear of a Microsoft lawsuit regarding possible violation of the DMCA.[4] On 6 March 2007, Microsoft responded after internal testing that the described method would not work.[5]
Criticism
In addition to common criticisms against
Microsoft has frequently been accused of adding the Protected Media Path feature to Vista to block customers from copying rightfully owned media content[8] (a practice believed to be protected by Fair Use provisions of the Copyright Act), and the feature is widely quoted as an example of Microsoft's uncompromising adherence to DRM.
These accusations have never gained much traction[citation needed] largely because Vista treats non-DRM media exactly the same as previous versions of Windows, and that following Vista's release there has been no change in the availability of free/open source drivers from graphics hardware manufacturers.[citation needed]
See also
- Bus encryption
- Features new to Windows Vista
- Windows Vista I/O technologies
- Trusted Computing
- Image Constraint Token
References
- ^ Ionescu, Alex. "Introducing D-Pin Purr v1.0 - 32bit Edition." Retrieved on April 11, 2007.
- ^ CyberLink Customer Support - FAQ - What operating system should I have installed on my computer when playing Blu-ray Disc or HD DVD titles?
- ^ CyberLink Customer Support - FAQ - PowerDVD displays an error message "The playback of this content is not allowed with a digital output device. Please use an analog output device."
- ^ "Alex Ionescu's Blog » Update on Driver Signing Bypass". Archived from the original on 2007-09-28. Retrieved 2007-10-28.
- ^ "Alex Ionescu's Blog » Vista DRM Issue Aftermath". Archived from the original on 2007-09-28. Retrieved 2007-10-28.
- ^ Peter Gutmann (2006-12-26). "A Cost Analysis of Windows Vista Content Protection". Retrieved 2007-01-28.
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(help) - ^ How to Play Protected Media Files (Windows)
- ^ Why Microsoft must abandon Vista to save itself | The Digital Home – Don Reisinger's take on the tech closest to home – CNET Blogs[permanent dead link]