Arnon-Friedman Rotem, Dupuis Frédéric, Fawzi Omar, Renner Renato, Vidick Thomas
Institute for Theoretical Physics, ETH-Zürich, Wolfgang-Pauli-Str. 27, 8093, Zürich, Switzerland.
Faculty of Informatics, Masaryk University, Brno, Czech Republic.
Nat Commun. 2018 Jan 31;9(1):459. doi: 10.1038/s41467-017-02307-4.
Device-independent cryptography goes beyond conventional quantum cryptography by providing security that holds independently of the quality of the underlying physical devices. Device-independent protocols are based on the quantum phenomena of non-locality and the violation of Bell inequalities. This high level of security could so far only be established under conditions which are not achievable experimentally. Here we present a property of entropy, termed "entropy accumulation", which asserts that the total amount of entropy of a large system is the sum of its parts. We use this property to prove the security of cryptographic protocols, including device-independent quantum key distribution, while achieving essentially optimal parameters. Recent experimental progress, which enabled loophole-free Bell tests, suggests that the achieved parameters are technologically accessible. Our work hence provides the theoretical groundwork for experimental demonstrations of device-independent cryptography.
与设备无关的密码学超越了传统量子密码学，它提供的安全性与底层物理设备的质量无关。与设备无关的协议基于非局域性的量子现象和贝尔不等式的违背。到目前为止，这种高度的安全性只能在实验上无法实现的条件下建立。在此，我们提出一种熵的性质，称为“熵积累”，它断言大系统的总熵量是其各部分熵之和。我们利用这一性质来证明包括与设备无关的量子密钥分发在内的密码协议的安全性，同时实现基本最优的参数。最近实现无漏洞贝尔测试的实验进展表明，所实现的参数在技术上是可达到的。因此，我们的工作为与设备无关的密码学的实验演示提供了理论基础。
