The present disclosure involves a method of conducting a transaction. In one aspect, the method includes: displaying a media program on a media display device; indicating, while the media program is being displayed, an item associated with the media program is available for purchase; receiving authentication information of a prospective purchaser of the item; and completing a purchase of the item in response to the authentication information. In another aspect, the method includes: receiving, from a media display device, a user authentication request that contains user login credentials; granting the user authentication request in response to the user login credentials; and sending an authentication permission to the media display device; wherein the receiving and the sending are each performed such that the user login credentials and the authentication permission are sent through one or more intermediate hops without being inspected by any of the intermediate hops.