Patent ID: 8171289

Claim:
A method of utilizing a radio-frequency identification (RFID) tag comprising: receiving a challenge at the RFID tag from a reader; calculating S=f(s, O E ), U=f(u, O O ), B=E(n, k E ), G=f(A, k O ), where A is a function of the challenge and a private key of the RFID tag; s and u are random numbers generated by the RFID tag, n is a tag ID, k E and k O are functions of a first public key and a second public key of the reader respectively, and O E and O O are originators, provided by the reader; and returning S, U, B, and G from the RFID tag to the reader, the returned data including a challenge response and the tag ID, and being unique for each response even when responding to an identical challenge.