Content protection features in Windows Vista are preventing customers from playing high-quality video and audio and harming system performance, even as Microsoft neglects security programs that could protect users, computer researcher Peter Gutmann argued at the USENIX Security Symposium in Boston Wednesday.

“If there was any threat modeling at all, it was really badly done,” Gutmann, from the University of Auckland, New Zealand, said while giving a talk on Vista content protection. “Once the enemy is the user and not the attacker, standard security thinking falls apart.”

Vista requires premium content like high-definition movies to be degraded in quality when sent to high-quality outputs, so users are seeing status codes that say “graphics OPM resolution too high.” Gutmann calls this “probably the most bizarre status code ever.”

While Microsoft’s intent is to protect commercial content, home movies are increasingly being shot in high definition, Gutmann said. Many users are finding they can’t play any content if it’s considered “premium.”

“This is not commercial HD content being blocked, this is the users’ own content,” Gutmann said. “The more premium content you have, the more output is disabled.”

Gutmann, who wore a white T-shirt marked with a Windows Vista logo during his presentation, first issued his criticisms several months ago with a paper titled A Cost Analysis of Windows Vista Content Protection.

Gutmann’s paper called Vista’s content protection rules “the longest suicide note in history.”

Microsoft acknowledged that quality of premium content would be lowered if requested by copyright holders, the BBC reported. Microsoft defended its copyright protections after Gutmann’s paper came out, saying they are common features of many playback devices, the BBC article says.

The protections allow copyright holders to prevent video from being played in high definition unless users have equipment that supports the High-bandwidth Digital Content Protection (HDCP) digital rights management system developed by Intel. If PC users have graphics cards with video connections that don’t support HDCP, they are out of luck.

High-definition audio is also blocked in many cases, Gutmann said Wednesday.

“It’s taking this open architecture that IBM created 25 years ago and making it closed again,” he said.