I previously stored my recovery key for macOS FileVault with iCloud, but ran into issues one day and couldn't get back into my computer. (Thank god for Backblaze!) Now I store it in 1Password, but I had a panic this morning when setting up encryption for some other disks - did I have the correct recovery key saved? Was it an old recovery key from a previous install? I started poking around to figure out how to validate without trying to put my machine into some sort of recovery mode, and found this awesome article. It's an easy Terminal command:
sudo fdesetup validaterecovery
Enter this command in there Terminal, enter your login password, then your recovery key. If you get true, then all is good! If you get false, then disable and re-enable FileVault.