I needed to boot a Debian Live USB stick on a new Lenovo Thinkpad X230, preinstalled with Windows 8 Professional, and with Secure Boot enabled.
This laptop did not have USB boot preset in the Boot Menu so I had to enter BIOS to add USB as a boot option.
While I was there, I disabled Secure Boot and changed UEFI/Legacy Boot method to “Both”.
The options were easily at hand, and it was not difficult to change them. Nobody asked me for a key, password or any other thing. I would have needed to go into BIOS anyways because USB HDD was not a boot option in the first place.
F10 to save, the laptop rebooted, F12 for the boot menu, selected USB HDD and voila.