[bigiain]

Lavabit used to not be able to do that, and Protonmail can't either still... (To be fair, Lavabit _could have_ made changes so they could do that, but the owner refused when law enforcement asked him to do that fpr Snowden's email, and risked very real threats of jail instead. I don't think Protonmail have been tested lie that yet, but they have at least incorporated outside of US jurisdiction,which changes their risk in some important ways...)

https://en.wikipedia.org/wiki/Lavabit