Evolution allows you to add certificates for yourself as well as for contacts. This allows you to communicate with others securely over an encrypted connection, or sign a message confirming your identity to the contact. These settings only apply to S/MIME encryption.
Your Certificates: Click the Your Certificates tab to display a list of certificates that you own. You can import, view, back up and delete your certificates from this page.
Contact Certificates: Click the Contact Certificates tab to display a list of certificates that you have for contacts. These certificates allow you to decrypt messages as well verify signed messages. You can import, view, edit, and delete your contact certificates from this page.
Authorities: Click the Authorities tab to display a list of trusted certificate authorities who verify that the certificate you have is valid. You can import, view, edit, and delete certificate authorities from this page.