I mean, if you want secure/private communication, email should not be your go-to. It’s a horrible platform by today’s standards. It was never designed to have any serious level of security. Once they have an unencrypted email on the target with timestamps and mail headers, all they need to do is see who was communicating with Proton at that point. I don’t know if anything has changed since the PRISM days, but back in the 2000s, they definitely had that level of insight into the web.
I mean, if you want secure/private communication, email should not be your go-to. It’s a horrible platform by today’s standards. It was never designed to have any serious level of security. Once they have an unencrypted email on the target with timestamps and mail headers, all they need to do is see who was communicating with Proton at that point. I don’t know if anything has changed since the PRISM days, but back in the 2000s, they definitely had that level of insight into the web.