The Protected Media Path is a set of technologies creating a "Protected Environment," first included in
Microsoft
Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...
's
Windows Vista
Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
, that is used to enforce
digital rights management
Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted works. ...
(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
Media Foundation (MF) is a COM-based multimedia framework pipeline and infrastructure platform for digital media in Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, and Windows 11. It is the intended replacement for Microsoft Direc ...
.
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.
[Ionescu, Alex.]
Introducing D-Pin Purr v1.0 - 32bit Edition
" Retrieved on April 11, 2007.
These restrictions concern the various outputs from the PC. For DRM content, digital outputs such as
Digital Visual Interface
Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a co ...
(DVI) and High Definition Multimedia Interface (
HDMI
High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, ...
) will have
High-bandwidth Digital Content Protection
High-bandwidth Digital Content Protection (HDCP) is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio and video content as it travels across connections. Types of connections include DisplayPort ...
(HDCP) enabled, to prevent someone from recording the digital stream. Even analog TV-style outputs typically require some restrictions, provided by mechanisms such as
Macrovision
TiVo Corporation, formerly known as the Rovi Corporation and Macrovision Solutions Corporation, was an American technology company. Headquartered in San Jose, California, the company is primarily involved in licensing its intellectual property ...
and
CGMS-A
Copy Generation Management System – Analog (CGMS-A) is a copy protection mechanism for analog television signals. It consists of a waveform inserted into the non-picture Vertical Blanking Interval (VBI) of an analogue video signal. If a compatib ...
. These restrictions only apply to DRM-restricted content, such as
HD DVD
HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to th ...
or
Blu-ray
The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of sto ...
that are encrypted with
AACS, and also apply in Windows XP using supported playback applications. Users' standard unprotected content will not have these restrictions. Some output types such as
S/PDIF
S/PDIF (Sony/Philips Digital Interface) is a type of digital audio interface used in consumer audio equipment to output audio over relatively short distances. The signal is transmitted over either a coaxial cable (using RCA or BNC connectors) ...
(Sony/Philips Digital Interchange Format) typically don't have a suitable DRM scheme available, so these need to be turned off reliably if the content so specifies.
In Vista, the control of PC video outputs is provided by PVP-OPM, which is essentially the next generation of
Certified Output Protection Protocol (COPP) introduced in
Windows XP
Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Windows 2000 for high-end and ...
. However, rather than being a software
application programming interface
An application programming interface (API) is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software. A document or standard that describes how t ...
, PVP-OPM operates with the Windows media components in the protected environment.
Additionally, ''PVP-UAB'' (Protected Video Path - User-Accessible Bus) is used to
encrypt
In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...
video and audio data as it passes over the
PCI-Express
PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common mot ...
bus
A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...
, to prevent it from being intercepted and copied on the way to the
graphics card
A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer moni ...
. It is complementary to PVP Output Protection Management.
Possible bypass
In January 2007 the developer
Alex Ionescu
Alex is a given name. It can refer to a shortened version of Alexander, Alexandra, Alexis.
People
Multiple
*Alex Brown (disambiguation), multiple people
*Alex Gordon (disambiguation), multiple people
*Alex Harris (disambiguation), multiple peop ...
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
The Digital Millennium Copyright Act (DMCA) is a 1998 United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization (WIPO). It criminalizes production and dissemination of technology, devices, or s ...
. On 6 March 2007, Microsoft responded after internal testing that the described method would not work.
Criticism
In addition to common criticisms against
Digital Rights Management
Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted works. ...
schemes, there has been speculation that this scheme has been motivated by the fact that it would affect official
free/open source graphics driver support by manufacturers. The scheme relies on the internals of
graphics card
A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer moni ...
s to tell whether the hardware is trustworthy (permitted to play copy-protected content). This could be subverted if an attacker knows certain details about the hardware's operation, which could be disclosed by hardware
documentation
Documentation is any communicable material that is used to describe, explain or instruct regarding some attributes of an object, system or procedure, such as its parts, assembly, installation, maintenance and use. As a form of knowledge manageme ...
or open source
device driver
In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and ot ...
s.
However, this will not affect platform independency, as the scheme is provided with no charge.
Microsoft has frequently been accused of adding the Protected Media Path feature to Vista to block customers from copying rightfully owned media content
Why Microsoft must abandon Vista to save itself , The Digital Home – Don Reisinger's take on the tech closest to home – CNET Blogs
/ref> (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 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.
See also
* Features new to Windows Vista
Compared with previous versions of Microsoft Windows, features new to Windows Vista are very numerous, covering most aspects of the operating system, including additional management features, new aspects of security and safety, new I/O techno ...
* Windows Vista I/O technologies
Windows Vista introduced a number of new I/O functions to the Microsoft Windows line of operating systems. They are intended to shorten the time taken to boot the system, improve the responsiveness of the system, and improve the reliability of da ...
* Trusted Computing
Trusted Computing (TC) is a technology developed and promoted by the Trusted Computing Group. The term is taken from the field of trusted systems and has a specialized meaning that is distinct from the field of Confidential Computing. The core ide ...
References
External links
Protected Media Path
windows7sins.org
{{Windows Components
Windows Vista
Microsoft Windows multimedia technology
Digital rights management