Patent ID: 8872619

Claim:
A transponder device, comprising: encryption circuitry configured to: encrypt, with a transponder device authentication key, a transponder device authentication signal received from a reader to create an encrypted transponder device authentication signal, encrypt an account code with an account code key to create an encrypted account code, and decrypt, with a reader authentication key, an encrypted reader authentication signal received from the reader to create a decrypted reader authentication signal; a protocol/sequence controller configured to: transmit the encrypted transponder device authentication signal to the reader, and transmit the encrypted account code to the reader to facilitate a payment transaction responsive to the decrypted reader authentication signal matching a reader authentication signal; and authentication circuitry configured for mutual two-way authentication with the reader via the transponder device authentication signal and the reader authentication signal, including authenticating the reader responsive to the decrypted reader authentication signal matching the reader authentication signal transmitted from the transponder device to the reader.