Patent ID: 9565022
Date: 2017-02-07
CPC Classifications: G06K,G06Q,H04L,H04W

Claim:
1. A method to authenticate a Radio Frequency Identification (RFID) tag, the method comprising: sending a message to the RFID tag; receiving an identifier from the RFID tag; receiving a cryptographically-secured response from the RFID tag; determining, based on the identifier, a plurality of potential keys including a used key and at least one unused key; generating a plurality of processed tag responses, each processed tag response based on the received tag response and a respective potential key in the plurality of potential keys; extracting a verification value from a first one of the plurality of processed tag responses; determining whether the verification value corresponds to the message; in response to determining that the verification value corresponds to the message, authenticating the RFID tag; in response to determining that the verification value does not correspond to a challenge included in the message: and in response to determining that the other verification values do not correspond to the challenge, considering the RFID tag suspect.