关键词: 量子密码, 量子通信, 确定型安全直接通信, 对称W态, 身份认证

Abstract: Due to the better robustness of entangled W state, it is considered to be better qualified as information carrier for quantum information processing and quantum secure communication. Recently, many kinds of quantum direct communication protocols based on four-particle W state or three-particle asymmetric W state have been proposed. However, these protocols either have low communication efficiency or are difficult to be implemented in physics experiment. By utilizing three-particle W state and the mechanism of quantum identity authentication, a new deterministic secure quantum communication protocol was proposed. This protocol consisted of five parts: authentication code generating, quantum states preparation, quantum states distribution, eavesdropping check and identity authentication, and information communication. The two participants only needed to perform the two-particle Bell measurement, the single-particle 〖WTBX〗Z〖WTBZ〗-basis or 〖WTBX〗X〖WTBZ〗-basis measurement, and the communication efficiency was also improved: One W state can transmit one classical bit of information. The security analysis shows that the present protocol is secure against various eavesdropper Eve's attacks and impersonation attacks, so it has better security.

Key words: quantum cryptography, quantum communication, deterministic secure direct communication, symmetric W state, identity authentication