Creates and configures a client-side encryption identity that's authorized to send mail from the user account. Google publishes the S/MIME certificate to a shared domain-wide directory so that people within a Google Workspace organization can encrypt and send mail to the identity. For administrators managing identities and keypairs for users in their organization, requests require authorization with a service account that has domain-wide delegation authority to impersonate users with the https://www.googleapis.com/auth/gmail.settings.basic scope. For users managing their own identities and keypairs, requests require hardware key encryption turned on and configured.