Why not develop tox instead, which is open source, end to end encrypted, on more platforms, and seemingly further along in general?
Money quote from a tox dev: "Tox provides some strong security guarantees. We haven't got to the point where we can enumerate them properly, given the general lack of understanding of the code and specification."
I've looked through a lot of the documentation and can't find anything other than references to bluetooth and wi-fi, which is opaque to me.
I'm kind of wondering about something like briar, but that can connect over a cjdns network if available... is that what it's doing?
I'm not a crypto expert, but I also personally wouldn't put much stock in the security of their protocol or implementation.