I've occasionally tinkered with building software (but never released said software) that uses encrypted peer-to-peer connections as the _sole_ way of communicating, because it seemed like the most natural way to build said software _and_ the most interesting technically. (And I have zero interest in hosting servers for FOSS side projects.) If I were to actually release one of these projects and it were to become popular, should I expect to be shut down by law enforcement on the grounds that it's already unambiguously illegal? Or would I likely receive a "Technical Assistance Notice" at some point, effectively requiring me to sneak a back door into the software? Or is it actually fine?
I seem to recall all sorts of stories about law enforcement and "TLA agencies" pressuring vendors of secure messaging software to make the software unavailable or to add back doors, including at least one who chose to shut down their business rather than lying to their users about the security of the product. But somehow in all this I failed to glean whether or not it's actually meant to be legal, even on paper.