we presented is weaknesses in the protection mechanism. It still requires the system under attack to have a vulnerability. Without the presence of a vulnerability these techniques don't really [accomplish] anything." The vulnerability Sotirov and Dowd used in their paper as an example was the 2007 animated cursor bug, . One security researcher (Dino Dai Zovi) claimed that this means that it is "completely game over" for Vista security though Sotirov refuted this, saying that "The articles that describe Vista security as 'broken' or 'done for,' with 'unfixable vulnerabilities' are completely inaccurate. One of the suggestions I saw in many of the discussions was that people should just use Windows XP. In fact, in XP a lot of those protections we're bypassing [such as ASLR] don't even exist." Digital rights management Another common criticism concerns the integration of a new form of digital rights management (DRM) into the operating system, specifically the Protected Video Path (PVP), which involves technologies such as High-bandwidth Digital Content Protection (HDCP) and the Image Constraint Token (ICT). These features were added to Vista due to licensing restrictions from the HD-DVD consortium and Blu-ray association. This would have concerned only the playback resolution of protected content on HD DVD and Blu-ray discs, but it had not been enabled as of 2017. A lack of a protected channel did not stop playback. Audio plays back as normal but high-definition video downsampled on Blu-ray and HD DVD to slightly-better-than-DVD quality video. The Protected Video Path mandates that encryption must be used whenever content marked as "protected" will travel over a link where it might be intercepted. This is called a User-Accessible Bus (UAB). Additionally, all devices that come into contact with premium content (such as graphics cards) have to be certified by Microsoft. Before playback starts, all the devices involved are checked using a hardware functionality scan (HFS) to verify if they are genuine and have not been tampered with. Devices are required to lower the resolution (from 1920×1080 to 960×540) of video signals outputs that are not protected by HDCP. Additionally, Microsoft maintains a global revocation list for devices that have been compromised. This list is distributed to PCs over the Internet using normal update mechanisms. The only effect on a revoked driver's functionality is that high-level protected content will not play; all other functionality, including low-definition playback, is retained. Notable critics Peter Gutmann, a computer security