To secure your database, you can use any of these three authentication factors:
- A master password
- A key file
- A YubiKey
And you can use a combination of one, two, or all three of the above. For instance you could use:
- Only a master password
- A master password and a key file
- A master password, a key file and a YubiKey
- Or any combination of these three
Whichever combination of factors you choose, you must provide all of them every time you unlock your database. So if you've chosen to use a master password and a YubiKey, you cannot provide either your master password or your YubiKey to unlock your database, you must have both.