Abstract: A Radio Frequency Identification (RFID) reader containing a reader key authenticates an RFID tag containing a tag key by receiving a tag identifier from the tag; challenging the tag with a tag challenge; receiving a tag response based at least on the tag challenge and the tag key but not including the tag key; sending a second message including at least the tag identifier and the tag response to a verification authority; and receiving a reply from the verification authority. The reader and the verification authority may mutually authenticate each other before, during, or after the tag authentication process. The verification authority may notify a designated party if a response is incorrect.