Give Mail Users Permission to Use S/MIME

To create a signed or encrypted message, a valid Communications Express Mail user must have permission to do so. This involves using the mailAllowedServiceAccess or mailDomainAllowedServiceAccess LDAP attributes for a user’s LDAP entry. These attributes can be used to include or exclude mail users from S/MIME on an individual or domain basis.

See Granting Permission to Use S/MIME Features for more information.