Practical device-independent quantum cryptography via entropy accumulation

Abstract

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.

Abstract of "Practical device-independent quantum cryptography via entropy accumulation" by Rotem Arnon-Friedman, Frédéric Dupuis, Omar Fawzi et al., https://doi.org/10.1038/s41467-017-02307-4, used under its Creative Commons Attribution license (CC-BY); markup removed, otherwise unmodified.