Is this the end of dual boot systems? I've always had dual boot systems on my home machines (mostly Windows for gaming, Linux for everything else) but this explanation makes it sound that one and only one signing key can be used by UEFI to authenticate the OS. Given that obviously Linux cannot carry Microsoft's key, this leaves no room for multi-OS options.
Did I misunderstand, or what we really need is an independent, third-party "UEFI Signing Authority" that distributes valid, OS-independent keys to trusted and approved OSes? Sorry but leaving this in Microsoft's hands is giving them way too much power!