基于部分纠缠态的高效量子安全直接通信

基于两粒子部分纠缠态提出一种高效量子安全直接通信方案。该方案利用诱骗态来检测窃听，协议安全性等价于BB84协议的安全性。通信双方分别通过受控非操作和局域幺正变换编码秘密消息，利用von Neumann测量，结合经典通信实现秘密消息的高效直接传递。与现有协议不同，通信双方通过不同的操作编码和传输秘密消息，共享两个不对称的量子信道，同时在恢复秘密消息时通信双方各自持有攻击者不能掌握的关键量子比特，使得协议在理想和噪声信道中均安全。所有纠缠比特都用于传输秘密消息，协议的量子比特效率较高。

Efficient Quantum Secure Direct Communication Based on Partially Entangled State

An efficient quantum secure direct communication scheme is proposed based on two partially entangled states. The scheme uses the decoy state to detect eavesdropping, and the protocol security equals the security of BB84 protocol. By Encoding the secret messages by CNOT and nonlocal unitary operations, communicating parties use the yon Neumann measurement to transmit secret messages efficiently in combination with classic communication. Compared with existing protocols, communicating parties take different operations to encode and transmit secret messages and share two asymmetric quantum channels. Meanwhile, in recovering the secret messages, communicating parties hold the key qubit that attackers cannot obtain, thus making the protocol secure in both ideal or noisy channels. All entangled qubits are used to transmit secret messages, so that it achieves much higher qubit efficiency.