"With little fanfare, Microsoft just announced that the x64 version of Windows Vista will require all kernel-mode code to be digitally signed. This is very different than the current WHQL program, where the user ultimately decides how they want to handle unsigned drivers. Vista driver developers must obtain a Publisher Identity Certificate (PIC) from Microsoft. Microsoft says they won't charge for it, but they require that you have a Class 3 Commercial Software Publisher Certificate from Verisign. This costs $500 [EUR 412] per year, and as the name implies, is only available to commercial entities."