论文标题
用单个光子翻转量子弱硬币
Quantum weak coin flipping with a single photon
论文作者
论文摘要
薄弱的硬币翻转是确保现代通信网络安全的基本密码基础。当两个不信任的政党偏爱相反的结果时，它们可以随机同意。与其他两党的计算不同，只能使用量子力学实现信息理论安全性：防止双方以高于$ 1/2+ε$的概率偏向翻转，其中$ε$任意低。从经典上讲，不诚实的聚会总是可以用概率$ 1 $作弊，除非使用计算假设。尽管它很重要，但尚未提出实施量子弱的硬币翻转。在这里，我们提出了一个仅需单个光子和线性光学器件的实用协议。我们表明，即使使用阈值单光子探测器，也是公平和平衡的，并且偏见低至$ε= 1/\ sqrt {2} -1/2} -1/2 \ of 0.207 $。我们进一步表明，该协议可以通过最先进的技术显示几百米的量子优势。
Weak coin flipping is among the fundamental cryptographic primitives which ensure the security of modern communication networks. It allows two mistrustful parties to remotely agree on a random bit when they favor opposite outcomes. Unlike other two-party computations, one can achieve information-theoretic security using quantum mechanics only: both parties are prevented from biasing the flip with probability higher than $1/2+ε$, where $ε$ is arbitrarily low. Classically, the dishonest party can always cheat with probability $1$ unless computational assumptions are used. Despite its importance, no physical implementation has been proposed for quantum weak coin flipping. Here, we present a practical protocol that requires a single photon and linear optics only. We show that it is fair and balanced even when threshold single-photon detectors are used, and reaches a bias as low as $ε=1/\sqrt{2}-1/2\approx 0.207$. We further show that the protocol may display quantum advantage over a few hundred meters with state-of-the-art technology.
