For the rotating key it would be automatically signed by the previous key or master key so no user-visible change would be shown.
So you don't think that if I cross-sign devices A and B, and then I would cross-sign devices B and C, if I would revoke B then C would automatically become invalid as well?
Kind of similar question about "key backups" (to which keys would device C have access to?).
(I honestly did not ever look into all these details - I was hoping that this would be covered by more clever people)
Maybe the best solution would be revocation after a date. So you can say "don't trust anything after {time-i-lost-the-device}" or "don't trust anything after {now}" and it does the right thing. However that could be complex to implement correctly in software. Lots of bookkeeping.
Aha, didn't notice that, thx!
> I'm also confused why each device is handled separately.
Well, I can understand it more or less (I guess kind of similar to confirming in Whatsapp your multiple open sessions on different devices, to ensure that nobody is using something that you forgot/left behind?), but doing it this way is quite hardcore - on the other hand it could be that the whole thing is deeply embedded in the software's encryption principles/guidelines => it would probably still be ok, but it needs to be explained better, be more clearly accessible.
I guess that having a rotating key (with the software asking from time to time "do you want to accept key jf8k4d9k?") would probably be confusing for non-technical users and would probably generate uncertainty/anxiety/etc... ?