To assign a premium encryption key to a Template, open the vault and the template to which you want to apply the encryption key and scroll to the bottom of the Template.

Scroll to the bottom of the Template

Under Security, click Add in the Encryption Key tile

Select the Encryption key you want to assign to the Template

The Encryption Key is added to the Template, and the Template is saved

You will notice the Encryption Key icon is now showing on the Template when it appears in your Vault directory.