Much scientific work has focused on the generation of random numbers, as well as the distribution of said random numbers for use as a cryptographic key, in recent times. However, focus is often directed to one of the two, to the exclusion of the other, but both are often simultaneously important. Here we present a simple hybrid free-space link scheme for both the generation and secure distribution of (pseudo-)random numbers between two remote parties, drawing the randomness from the stochastic nature of atmospheric turbulence. The atmosphere is simulated using digital micro-mirror devices for efficient, all-digital control. After outlining one potential algorithm for extracting random numbers based on finding the centre-of-mass (COM) from simple turbulent beam intensity profiles, the statistics of our experimental COM measurements is studied and found to agree well with the literature. After implementing the scheme in the laboratory, Alice and Bob are able to establish a string of correlated random bits with an 84% fidelity. Finally, we make a simple modification to the original setup in an attempt to thwart the hacking attempts of an eavesdropper, Eve, who has access to the free-space portion of the link. We find that the fidelity between Eve's key and that of Alice/Bob is 54%, only slightly above the theoretical minimum.

中文翻译：

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从稀薄（或浓稠）空气中生成和分配随机数

最近，许多科学工作都集中在随机数的生成以及用作加密密钥的所述随机数的分布上。然而，焦点往往指向两者之一，而排除另一个，但两者通常同时重要。在这里，我们提出了一个简单的混合自由空间链接方案，用于在两个远程方之间生成和安全分配（伪）随机数，从大气湍流的随机性中提取随机性。使用数字微镜设备模拟大气，以实现高效的全数字控制。在概述了一种基于从简单湍流光束强度分布中寻找质心 (COM) 来提取随机数的潜在算法之后，研究了我们的实验 COM 测量的统计数据，发现与文献非常吻合。在实验室中实施该方案后，Alice 和 Bob 能够建立具有 84% 保真度的相关随机位串。最后，我们对原始设置进行了简单的修改，试图阻止窃听者 Eve 的黑客攻击，他可以访问链接的自由空间部分。我们发现 Eve 的密钥与 Alice/Bob 的密钥之间的保真度为 54%，仅略高于理论最小值。我们对原始设置进行了简单的修改，试图阻止窃听者 Eve 的黑客攻击，他可以访问链接的自由空间部分。我们发现 Eve 的密钥与 Alice/Bob 的密钥之间的保真度为 54%，仅略高于理论最小值。我们对原始设置进行了简单的修改，试图阻止窃听者 Eve 的黑客攻击，他可以访问链接的自由空间部分。我们发现 Eve 的密钥与 Alice/Bob 的密钥之间的保真度为 54%，仅略高于理论最小值。