Validate an instance of your software by sending metadata about the user. For example, sending the hwid of the device the user logged in from can help you ensure an instance of your software is only being used on one device. A valid key is one whose key_status is either approved or listed, and whose subscription_status is either completed, active, or trialing. It is up to your auth system to determine if hwid is already set. A key that returns value: true does not necessarily mean that they should be let into the program.