Apple already does this[0]. However, this relies on users creating and managing certificates and keys, which is not an easy thing for most users. I was playin

Apple already does this[0]. However, this relies on users creating and managing certificates and keys, which is not an easy thing for most users. I was playing around with using my own CA to issue certificates for internal stuff. I created a personal certificate for myself and imported it to my keychain - without doing anything, Apple Mail was digitally signing my messages. On the other side, however, people saw digital signatures that couldn't be verified and got confused by that. [0] https://support.apple.com/en-ca/guide/mail/sign-encrypt-messages-increased-security-mlhlp1180/mac https://support.apple.com/en-ca/guide/mail/sign-encrypt-mess...