Improved multiparty quantum key agreement in travelling mode

The need to simultaneously balance security and fairness in quantum key agreement(QKA) makes it challenging to design a flawless QKA protocol, especially a multiparty quantum key agreement(MQKA) protocol. When designing an MQKA protocol,two modes can be used to transmit the quantum information carriers: travelling mode and distributed mode. MQKA protocols usually have a higher qubit efficiency in travelling mode than in distributed mode. Thus, several travelling mode MQKA protocols have been proposed. However, almost all of these are vulnerable to collusion attacks from internal betrayers. This paper proposes an improved MQKA protocol that operates in travelling mode with Einstein-Podolsky-Rosen pairs. More importantly, we present a new travelling mode MQKA protocol that uses single photons, which is more feasible than previous methods under current technologies.

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。