Quantum information authentication using entangled states

This paper provides a quantum information authentication protocol using entangled states. The two parties share EPR (Einstein-Podolsky-Rosen) pairs as authentication key. Information is coded in two-qubits systems. The two parties confirm the validity of the information by making the coding systems to interact with the authentication key. We prove that information from anyone who has no authentication key can´t pass the authentication. So our protocol is secure. If there are no errors and eavesdroppers existing in transmission, the authentication key can be reused