Semiquantum key distribution (SQKD) allows two parties (Alice and Bob) to create a shared secret key, even if one of these parties (say, Alice) is classical. However, most SQKD protocols suffer from severe practical security problems when implemented using photons. The recently developed "Mirror protocol" [Boyer, Katz, Liss, and Mor, Phys. Rev. A 96, 062335 (2017)] is an experimentally feasible SQKD protocol overcoming those drawbacks. The Mirror protocol was proven robust (namely, it was proven secure against a limited class of attacks including all noiseless attacks), but its security in case some noise is allowed (natural or due to eavesdropping) has not been proved yet. Here we prove security of the Mirror protocol against a wide class of quantum attacks (the "collective attacks"), and we evaluate the allowed noise threshold and the resulting key rate.

翻译：emiquantum 密钥分布( SQKD) 允许两方( Alice 和 Bob) 创建一个共享的秘密密钥, 即使其中一方( Alice 和 Bob ) 是古典的。 然而, 多数 SQKD 协议在使用光子实施时存在严重的实际安全问题。 最近开发的“ Mirror 协议 ” ( Boyer, Katz, Liss 和 Mor, Phys. Rev. A 96, 062335 (2017 ) ) 是一个实验性可行的 SQKD 协议, 克服了这些缺陷。 镜像协议被证明是强有力的( 也就是说, 它被证明是针对有限种类的攻击, 包括所有无声攻击的安全 ), 但是, 在允许某些噪音( 自然的或由于窃听) 的情况下, 它的安全还没有被证明。 我们在这里证明镜子协议对于广泛的量攻击( “ 集体攻击 ” ) 的安全性, 我们评估允许的噪音阈值和由此产生的关键率。