Quantum Authentication Protocol for Classical Messages Based on Bell states and Hash Function

Quantum authentication protocols can be used to authenticate both quantum messages and classical messages. In this paper, a new quantum authentication protocol of classical messages is proposed. In our protocol, a sequence of Bell states is shared by the message sender and the corresponding receiver. This sequence is used as the authentication key. Four different unitary operations U 0 , U 1 , U 2 and U 3 are used to encode a classical message m and its hash value h(m) into a sequence of Bell states. To authenticate the classical message, the message receiver extracts m and h(m) from the qubits owned by himself/herself, and verifies whether h(m) matches m. The adversary's disturbance to the quantum channel can be detected by checking whether h(m) matches m. The transmitted message has the properties of both secrecy and authentication. Our quantum authentication protocol is secure against message attack and no-message attack.