"There is no centralised signing authority for these UEFI keys," Garrett explained. "If a vendor key is installed on a machine, the only way to get code signed with that key is to get the vendor to perform the signing. A machine may have several keys installed, but if you are unable to get any of them to sign your binary then it won't be installable."

Microsoft has said it will require that Windows 8 logo machines ship with secure boot enabled. Most likely, Windows on such systems will be signed with a Microsoft key, Garrett predicted.

Other operating systems, such as , won't include any such signatures in their current state, of course. So, unless deliberate measures are taken to make them available, "a system that ships with only OEM and Microsoft keys will not boot a generic copy of Linux," Garrett explained.

'Kernels Will Also Have to Be Signed'

Options for Linux include providing signed versions of the operating system, but there are several problems associated with that approach, Garrett pointed out.