Ma et al. [Int. J. Theor. Phys. (2021): 1328–1338] proposed a multi-party quantum key distribution (MQKD) protocol using Bell states, in which multiple participants can distribute a group key efficiently. However, this study indicates that Ma et al.’s protocol has two security loopholes. First, an attacker can obtain the pre-shared key K_s using an eavesdropping attack. Second, the attacker uses an intercept-and-resend attack to steal the group key shared among the participants without being detected. An improved MQKD protocol is proposed to overcome these loopholes.

中文翻译：

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新型贝尔态编码方式的多方量子密钥分发协议的密码分析与改进

马等人。[国际。J. 理论。物理。(2021): 1328–1338] 提出了一种使用贝尔状态的多方量子密钥分发 (MQKD) 协议，其中多个参与者可以有效地分发组密钥。然而，这项研究表明，马等人的协议存在两个安全漏洞。首先，攻击者可以在预共享密钥获得ķ_小号使用窃听攻击。其次，攻击者使用拦截和重发攻击来窃取参与者之间共享的组密钥而不被发现。提出了一种改进的 MQKD 协议来克服这些漏洞。