Abstract: In one aspect of specific embodiments, methods are provided for monitoring a supply chain, including detection of the gray market, stolen, or counterfeit goods. In another aspect of specific embodiments, methods are provided for determining an authenticity of goods during a payment process, and reporting authenticity results to an actor in the payment process to allow that actor to determine whether to complete or cancel the process. In some embodiments, at least one of an open key, hidden key, authentication request counter, and optionally, authentication request timer are associated in an authentication database with an item in an authentication server.