Email Security Certificates ensure that emails that you send cannot be tampered with before they are received at the destination email address. Any tampering is notified to the recipient thus providing peace of mind. If the email says that it's genuine then it's genuine and came from whoever sent it and it has not been tampered with in any way after it was sent. Certificates are totally unique to one email address.
Certificates can be low cost or even totally free. Search for them on the internet.
They are supplied by Authorised distributors only, like Sertigo (Comodo), Digicert, Thawte, Symantec, Actalis etc. They are easily applied for and installed.
If everyone used Email Certificates then it would cut down on spamming and scamming.
Look for the little padlock in emails you receive. All emails you get from us will have one.
Norman