If you have a person's certificate in Outlook, you can send that person an encrypted message.
Do any of the following:
Import a certificate
Note To set the default certificate for a contact, select the certificate, click , and then click Set as Default.
Export a certificate
Certificates can be exported in three formats: DER encoded X.509, PEM (Base-64 encoded X.509), and PKCS #7. The DER encoded X.509 format is the most common, but you might want to ask what format your recipient requires.
To set the format of the certificate, make a selection on the Format menu.
Delete a certificate
Add a sender's certificate to the Address Book
Send a digitally signed or encrypted message
About digital signing, encryption, and smart cards