I've been bouncing around the idea of a fully decentralized end-to-end encrypted chat protocol for exactly this reason, but I've been afraid to work on it for precisely the reason this thread is being discussed. I know that if my name were attached to the project, I'd be facing all kinds of unwelcome scrutiny from the government and news agencies. I'd lose the very privacy I want to maintain by designing privacy-protecting software.
There's a lot I'm not explaining, in part because I don't (yet) understand crypto well enough to know if my idea even makes sense, let alone is feasible.
Matrix is close, but not what I'm describing. It's far more centralized than I'd like to see.
I would take a look at Matrix[1], which is basically what you're describing (it's a federated replacement from group chats that has Signal-like E2EE and has an open protocol) and it's already implemented.
Not exactly. I rather dislike XMPP's design, and what I'd like to see is something not only decentralized (relying at most on a DHT seed), but supporting group chats with trivially-expirable keys. My limited exposure to OTR suggests it only reliably supports one-on-one exchanges.
