A trusted device responsible for evaluating trustworthiness of unknown devices is provided. Trust evaluation rules usable to determine whether to authorize unknown devices to access a resource are received. A request to access the resource and device evaluation attributes are received from an unknown device. The trustworthiness of the unknown device is evaluated based upon the device evaluation attributes using the trust evaluation rules. In response to determining that the unknown device is trustworthy, a credential for accessing the resource is provided to the unknown device, and the device evaluation attributes of the unknown device and an identification of the unknown device are sent to a registrar for the resource.