Garrett: UEFI secure booting
Microsoft requires that machines conforming to the Windows 8 logo
program and running a client version of Windows 8 ship with secure boot
enabled. The two alternatives here are for Windows to be signed with a
Microsoft key and for the public part of that key to be included with all
systems, or alternatively for each OEM to include their own key and sign
the pre-installed versions of Windows. The second approach would make it
impossible to run boxed copies of Windows on Windows logo hardware, and
also impossible to install new versions of Windows unless your OEM provided
a new signed copy. The former seems more likely.
A system that ships with only OEM and Microsoft keys will not boot a generic copy of Linux.
As he notes, it is not time to panic yet, but it is worth being concerned
about. Those who are interested in learning more about Microsoft's plans
may want to watch this
video which describes them in detail.
