I’m not sure about the Proton thing, but yeah, Mailbox sets up PGP for you at server-level, which means they are still unencrypted on the server but will always be sent encrypted.
The initial mode is that they will try to negotiate whether PGP is supported by the other side, with you having the option to always use it for the price of the opposite side having to encrypt them.
You can even enforce it on a case by case basis by adding “secure.” To the mailbox.org domain, however I don’t know if that is also possible when using your own domain.
I’m not sure about the Proton thing, but yeah, Mailbox sets up PGP for you at server-level, which means they are still unencrypted on the server but will always be sent encrypted.
The initial mode is that they will try to negotiate whether PGP is supported by the other side, with you having the option to always use it for the price of the opposite side having to encrypt them.
You can even enforce it on a case by case basis by adding “secure.” To the mailbox.org domain, however I don’t know if that is also possible when using your own domain.