Microsoft Details on Vista Protections

For those who would like to see some corroboration of Peter Gutmann’s A Cost Analysis of Windows Vista Content Protection which I posted about previously you can access a document from Microsofts own website called Output Content Protection and Windows Vista which goes into some detail about what you can expect.

In the future, some types of premium content— through its content policy—will specify that a full-resolution analog VGA output is not allowed and that the resolution must be reduced. It is not practical to change the actual scanning rate of the display, particularly because some displays are fixed resolution. But what is important is that the information content of the signal is reduced to the resolution specified by the content owner. Basically, a high-resolution picture needs to be degraded to make it soft and fuzzy.

You may find that if you connect your LCD flat screen via a digital DVI cable it might just stop working.

In contrast, DVI without HDCP is definitely not liked by content owners, because it provides a pristine digital interface that can be captured cleanly. When playing premium content such as HD-DVD and Blu-Ray DVD, PVP-OPM will be required to turn off or constrict the quality of unprotected DVI. As a result, a regular DVI monitor will either get slightly fuzzy or go black, with a polite message explaining that it doesn’t meet security requirements.

Even your analog VGA monitor may get turned off in future.

There have been some successes in getting content owners to make some allowances for this ubiquitous interface. Consumers would certainly be unhappy if it were immediately outlawed; so instead, many content owners are requiring that its resolution be constricted when certain types of premium content are being played. Eventually they may require that analog VGA outputs be turned off completely; but for the moment, it is possible to provide the necessary level of protection by constricting the information content.

It’s not just users who are going to be worse off under this scheme – would you like to be a graphics card manufacturer when Microsoft tell you things like this ?

Content Industry Agreement hardware robustness rules must be interpreted by the graphics hardware manufacturer. Vendors should work to ensure that their implementations will not be revoked for playback of high-level premium content, as the result of a valid complaint from the content owners.


It is the responsibility of the graphics chip manufacturer to ensure that their chips are not used to manufacture “hacker friendly” graphics cards or motherboards. If someone does try to manufacture such a card, then the graphics manufacturer should refuse to sell chips to that board manufacturer.

So those are some random restrictions, if you read the whole document you’ll find plenty more to get your blood boiling quite nicely..

Found via a useful comment by Sergio on Bruce Schneier’s blog post about PG’s analysis.