The scariest part of this recent news is that TM Signal seem(ed) to be interoperable. People using TM Signal could interact with actual Signal users, and the conversations could be archived.
Is there a way to verify/ enforce users in a group are using the official Signal client?
I mean… you do know someone can just take a screenshot, right?
And even if you use the Android thing that blocks screenshots, they can still take a photo with another phone.
You need to trust the other person for there to be any “privacy”.