Weakly verifying device through an image hidden by pin

[Frozentime345]

Along the lines of what I read in the anti-evil maid blog it would be
nice if you could have an image with the google 3M privacy filter behind
a pin available on the lock screen to verify this is your device. I
understand the anti evil maid test checks for all sorts of hardware
manipulation and so it's the superior check but a)not every device
supports intel txt so a weaker universal check would be nice and b) I
don't want to restart my device every-time there's a chance my device
was switched out or something, weak somewhat passive protection would be
nice. Maybe add that pin as another password requirement just for a
random security boost.

Ideally the image could be stored in an appvm ofc so as not to have to
bring anything into dom0, and you could have multiple images for
different situations.

Also, wondering if its possible to have a lock-screen background stored
in an appvm?