[giovannibajo1]

Other cases that trigger a key change:

Buying a new phone and switching to it Reinstalling your phone OS because "it's slow" Reinstalling WhatsApp because "it crashes" or "it's slow" Swapping a phone because the screen is broke or I dropped into the toilet

I think it's romantic to think that 1 billion of WhatsApp users can be taught about the risks of MITM attacks and how to do a key check.

This is what I do: I have the warnings turn on. When the key change warning appears, and if I care enough about the person and the discussions we have, I try to match the warning with a real world event, so either I already know that something happened, or I try to remember to ask somehow if the person repaired or changed the phone. If I can match the warning with such an event, I feel satisfied. Otherwise, i ask for a key check when I meet that person in real life.

It would help if WhatsApp provided a UI to show whether I have verified the current key of each user (something like a green check-mark next to the name) because it's hard to remember.