
"[..] Therefore, the authorities were most likely targeting email contents which might have provided further incriminating evidence. The fact that Proton Mail was not able to hand over any messages even under legal order proves that our encryption works, and very likely will be of great assistance to the activist in this case. [..]" The best they can do is hand over "metadata" like your IP address and when you connected to their service, but probably not even that, because I doubt the keep logs. The can't hand over e-mail contents, because it's encrypted and you hold the key. They even give tips to mask your IP using tor and suggest not using gmail or any other public e-mail service to recover your account. I think your quite safe using their products.