National Institute of Standards and Technology, Boulder, CO, USA.
Department of Physics, University of Colorado, Boulder, CO, USA.
Nature. 2018 Apr;556(7700):223-226. doi: 10.1038/s41586-018-0019-0. Epub 2018 Apr 11.
From dice to modern electronic circuits, there have been many attempts to build better devices to generate random numbers. Randomness is fundamental to security and cryptographic systems and to safeguarding privacy. A key challenge with random-number generators is that it is hard to ensure that their outputs are unpredictable. For a random-number generator based on a physical process, such as a noisy classical system or an elementary quantum measurement, a detailed model that describes the underlying physics is necessary to assert unpredictability. Imperfections in the model compromise the integrity of the device. However, it is possible to exploit the phenomenon of quantum non-locality with a loophole-free Bell test to build a random-number generator that can produce output that is unpredictable to any adversary that is limited only by general physical principles, such as special relativity. With recent technological developments, it is now possible to carry out such a loophole-free Bell test. Here we present certified randomness obtained from a photonic Bell experiment and extract 1,024 random bits that are uniformly distributed to within 10. These random bits could not have been predicted according to any physical theory that prohibits faster-than-light (superluminal) signalling and that allows independent measurement choices. To certify and quantify the randomness, we describe a protocol that is optimized for devices that are characterized by a low per-trial violation of Bell inequalities. Future random-number generators based on loophole-free Bell tests may have a role in increasing the security and trust of our cryptographic systems and infrastructure.
从骰子到现代电子电路，人们已经尝试了许多方法来制造更好的设备来生成随机数。随机性是安全和密码系统以及保护隐私的基础。随机数生成器的一个关键挑战是很难确保其输出是不可预测的。对于基于物理过程的随机数生成器，例如嘈杂的经典系统或基本的量子测量，需要一个描述基础物理的详细模型来断言不可预测性。模型中的不完美会损害设备的完整性。然而，利用量子非局域性现象并通过无漏洞的贝尔测试来构建随机数生成器是可能的，这种生成器可以产生对任何仅受一般物理原理（如狭义相对论）限制的对手来说是不可预测的输出。随着最近技术的发展，现在可以进行这样的无漏洞贝尔测试。在这里，我们展示了从光子贝尔实验中获得的经认证的随机性，并提取了 1024 位均匀分布的随机位，其分布精度在 10 以内。根据任何禁止超光速（超光速）信号并允许独立测量选择的物理理论，这些随机位是不可能被预测的。为了认证和量化随机性，我们描述了一种针对具有低每试违规的贝尔不等式的设备进行了优化的协议。基于无漏洞贝尔测试的未来随机数生成器可能在提高我们的密码系统和基础设施的安全性和信任方面发挥作用。
