ProtonMail has a publicly available threat model: https://protonmail.com/blog/protonmail-threat-model/ https://protonmail.com/blog/protonmail-threat-model/ Wit

ProtonMail has a publicly available threat model: https://protonmail.com/blog/protonmail-threat-model/ https://protonmail.com/blog/protonmail-threat-model/ Without a threat model (that is, the set of threats that one is trying to secure a system against), you have no idea what someone means by "secure". It could mean unpickable doorlocks, it could mean unbreakable windows, it could mean angry-Hippopotamus-proofing. It could mean that you smelly farts can't escape your pants. Any claim of security without a threat-model is in the most literal sense meaningless. And don't get me started on "Military Grade Encryption", which is a term that at this point should give you a sense of concern, rather than safety.