Proton’s mails are encrypted… between proton accounts. Send an email to a hotmail account and bye-bye encryption. Proton does rely on PGP so you can use that if the recipient supports it.
A Password-protected Email is an email that requires a password to open it. It’s a way you can send a secure, end-to-end encrypted email to anyone who isn’t on Proton Mail.
Proton’s mails are encrypted… between proton accounts. Send an email to a hotmail account and bye-bye encryption. Proton does rely on PGP so you can use that if the recipient supports it.
They mean encrypted at rest. As in, Proton cannot hand over a copy of all your emails to a law enforcement agency, they don’t have access.
This means law enforcement would have to capture an unencrypted email in transit, or obtains your emails from either recipient individually.
Mail stored in proton is encrypted
https://proton.me/support/password-protected-emails