If you were hoping you would be able to run your favorite Linux distribution on Microsoft's new Surface Tablet, it doesn't look like it will be an easy task to accomplish. After going through the state of Linux distributions handling SecureBoot, UEFI-guru Matthew Garrett confirmed via his blog that Linux on the Microsoft Surface is likely a lemon.
The challenge with loading Linux (or any non-Microsoft operating system) on the new ARM-based tablet is that while it implements UEFI SecureBoot, it doesn't have the "Microsoft Windows UEFI Driver Publisher" key. This is the key used to sign Windows drivers and other non-Microsoft software (e.g. the signed Linux UEFI boot-loaders). Microsoft meanwhile has its own private key and this is the only UEFI SecureBoot key present on the Surface. Without the Surface having the "Microsoft Windows UEFI Driver Publisher" standard key, it's simply not a matter of having OS boot-loader be signed already to have support for this tablet. Microsoft only wants its OS on their tablet.