I obtained an encryption certificate and sent an email to someone who then sent me an email which was signed and encrypted. When I click on his checkmark adjacent to "signed," I can see his certificate in a drop down box, but I can't access the certificate. When I attempt to send him an encrypted message, my "lock" remains open. How do I get my Mac to recognize his certificate?
iMac Pro
There are two different systems for sending encrypted emails.
S/MIME support is built-in to Apple Mail, Mail on iOS and Outlook however PGP is not built-in and requires additional software.
S/MIME requires each party have their own S/MIME certificate, it seems from your post that you have one successfully installed and it also sounds like the other party has as well. The S/MIME process would be roughly as follows.
It is in theory possible to use self generated aka self-signed S/MIME certificates however this often causes more problems than its worth. I personally prefer using an officially generated S/MIME certificate which can still be obtained free of charge e.g. from Comodo. By being issued by a 'trusted' organisation it will automatically be trusted by the other party whereas a self-signed one would require manually trusting.
Until you and the other party have successfully exchanged signed emails and if needed manually trusted their certificate you will not be able to send them an encrypted email. (Or vice versa.)
There are two different systems for sending encrypted emails.
S/MIME support is built-in to Apple Mail, Mail on iOS and Outlook however PGP is not built-in and requires additional software.
S/MIME requires each party have their own S/MIME certificate, it seems from your post that you have one successfully installed and it also sounds like the other party has as well. The S/MIME process would be roughly as follows.
It is in theory possible to use self generated aka self-signed S/MIME certificates however this often causes more problems than its worth. I personally prefer using an officially generated S/MIME certificate which can still be obtained free of charge e.g. from Comodo. By being issued by a 'trusted' organisation it will automatically be trusted by the other party whereas a self-signed one would require manually trusting.
Until you and the other party have successfully exchanged signed emails and if needed manually trusted their certificate you will not be able to send them an encrypted email. (Or vice versa.)
Exchanging encryption certificates
