基于逻辑单粒子的多方量子密钥协商协议

集体噪声对量子密码协议的影响不可忽视，然而可抵抗集体噪声的多方量子密钥协商（MQKA）协议还很少。为了抵抗集体噪声的影响，分别针对可抗集体退相位噪声的逻辑单粒子和可抗集体旋转噪声的逻辑单粒子提出了两组逻辑酉算符，使得将其作用在逻辑单粒子上后，其中两个酉算符不改变测量基，而另外两个会改变测量基。基于此性质提出一个MQKA协议。首先，每个参与者传输逻辑单粒子给下一位；然后，该逻辑单粒子经过其他所有参与者的加密重新回到这个参与者，形成一个“环形”；最后，通过测量来获取共享密钥。安全性分析证明，该协议能够抵抗截取重发攻击、纠缠测量攻击以及参与者攻击；效率分析表明，该协议具有较高的量子比特效率。

Multiparty quantum key agreement protocol based on logical single particle

The influence of collective noise on quantum cryptographic protocols can not be ignored， however there are few Multiparty Quantum Key Agreement （MQKA） protocols that can resist collective noise. In order to resist the influence of collective noise， two sets of logical unitary operators were proposed for the logical single particle which can resist collective-dephasing noise and the logical single particle which can resist collective rotation noise respectively， so that after acting them on the logical single particles， two unitary operators did not change the measurement base， while the other two would change the measurement base. Based on this property， an MQKA protocol was proposed. Firstly， a logical single particle was transmited to the next participant by each participant.Then， the logical single particle was encrypted by all other participants and returned to the participant to form a “ring”. Finally， the shared key was obtained by measurement. Security analysis shows that the proposed protocol can resist intercept-resend attack， entanglement-measurement attack and participant attack. Efficiency analysis shows that this protocol achieves higher qubit efficiency.