Back in January Microsoft encrypted all my hard drives without saying anything. I was playing around with a dual boot yesterday and somehow aggravated Secureboot. So my C: panicked and required a 40 character key to unlock.
Your key is backed up to the Microsoft account associated with your install. Which is considerate to the hackers. (and saved me from a re-install) But if you’ve got an unactivated copy, local account, or don’t know your M$ account credentials, your boned.
Control Panel > System Security > Bitlocker Encryption.
BTW, I was aware that M$ was doing this and even made fun of the effected users. Karma.
SecureBoot pretty much does this. There is nothing preventing motherboard manufacturers from blocking adding non-MS keys if they wanted to.
Except AFAIK loose mainboards aimed at the DIY market, as well as barebones kits, don’t ship with SecureBoot turned on by default and an off switch for that is mandatory to the PC spec.