Which was the one used in the Hong Kong demonstrations? And if there's an app that misses a feature I would guess adding the feature should be less work than w

Which was the one used in the Hong Kong demonstrations? And if there's an app that misses a feature I would guess adding the feature should be less work than writing a completely new app that has all the features plus the new one. Especially 1-on-1 chat is a subproblem of n-on-n chat. Make a max 2 people "chat room" and you're done. "No crypto" is a feature, btw. It's very very very unlikely that a small open source project can get the right talent to make a secure chat app. Also I'm no expert but it might be impossible technically, with how the App infrastructure is designed and the flash storage that can't delete data at all and can't predictably overwrite it. So if everybody who tries it fails you do your users a favour by not trying and openly telling them that it's not secure. Tell them to use a Laptop and PGP emails for these usecases.