As you may know, Windows 8 ships with the requirement that drivers be signed digitally. You can turn it off with a series of safe-boot menu selections, but the downside is that Bitlocker-encrypted machines require the full recovery key. That's a pain, and thanks to RadiatorTwo from the Dangerous Prototypes forums have a simpler workaround:
Open a command prompt as Administrator run these commands.
bcdedit -set loadoptions DISABLE_INTEGRITY_CHECKS
bcdedit -set TESTSIGNING ON
This should avoid the need to enter your recovery key, but we all know you should have those numbers handy anyway. This feature is handy for Arduinos or any other homebrew drivers that don't go through Microsoft's driver qualification process. The original post is here.