Nowadays, even Gmail — both free and G-suite — supports S/MIME digital signatures in received emails (Gmail doesn't support S/MIME fully-encrypted emails instead, but this is not the point). When the sender uses a valid S/MIME signature, Gmail will say that the sender is verified by a public CA and the email message has not been compromised.
I don't understand why Protonmail refuses to do the same. It doesn't have to support full S/MIME encryption: recognizing valid S/MIME signatures would be great!
Giuseppe
Nowadays, even Gmail — both free and G-suite — supports S/MIME digital signatures in received emails (Gmail doesn't support S/MIME fully-encrypted emails instead, but this is not the point). When the sender uses a valid S/MIME signature, Gmail will say that the sender is verified by a public CA and the email message has not been compromised.
I don't understand why Protonmail refuses to do the same. It doesn't have to support full S/MIME encryption: recognizing valid S/MIME signatures would be great!