Unclear why this requires a TPM. Boot the system from a static unencrypted partition containing no sensitive data, display the login screen, when the user authenticates the system uses their credentials to get the FDE decryption key from the directory server. Bonus: Now the FDE keys are stored in the directory server and if the system board fails in the laptop you can remove the drive and recover the data.
An attacker with physical access could modify the unencrypted partition to compromise the user's password the next time the user logs in, but they could do the same thing with a hardware keylogger.
> And for casual home Windows users, it lets them log in with a 4-digit PIN or with biometrics, so it's got usability benefits for them too.
This could be implemented the same way using Microsoft's servers, given that they seem to insist you create a Microsoft account these days anyway.
It's not clear that unsophisticated users actually benefit from default-FDE though. They're more likely to lose their data to it than have it protect them from theft, and losing your family photos is generally more of a harm than some third party getting access to your family photos.
