After you activated the Email Encryption module in the Control Panel, you can set up the usage of S/MIME encryption in a few further steps.

1. Navigate to the S/MIME user tab and add the mailboxes you want to use for S/MIME encryption. You trigger an order for an S/MIME certificate. The mailbox needs to exist in the Control Panel. Possibly you already own S/MIME certificates for yourself you can provide them to the Hornetsecurity Support to import them and make them ready to use. Be aware that both importing and new orders for S/MIME certificates are chargeable.
2. Take care of activating the S/MIME encryption method in the Email Encryption module. Otherwise, S/MIME will not be applied although Hornetsecurity obtain the certificates.
3. Exchanging public S/MIME keys is an automated process via signing. If an outgoing unencrypted but signed email is sent, the recipient get the public S/MIME key to encrypt the future email traffic between both communication partners. Other way around is the same method: When an inbound unencrypted but signed email arrives the Hornetsecurity Gateways we will import the public S/MIME key automatically to our key store. Alternatively you can import public keys from communication partners via Hornetsecurity Support.