“Bitlocker Drive Encryption Service”: Thankfully, this is a Microsoft thing, thanks for not letting us know

Recently, my computer started slowing down.  I heard nightmares about hackers encrypting data on drives and only unlocking the drives if you pay a ransom.  How nice. Then, after Ctrl+Alt+Del and checking on programs running, I've started to see "Bitlocker Drive Encryption Service".  Sounds scary.  Apparently, it's part of Microsoft Windows.  How many times have…