Experimental Side-Channel-Free Quantum Key Distribution

TL;DR

This paper presents an experimental realization of a quantum key distribution protocol that is immune to all source side-channel attacks and measurement-device-independent, enhancing practical security over fiber links.

Contribution

The authors demonstrate a side-channel-free quantum key distribution protocol that is both measurement-device-independent and source-side-channel immune, with experimental validation over 50 km fiber.

Findings

Achieved a secure key rate of 4.80e-7 per pulse over 50 km fiber

Successfully implemented a protocol immune to all source side-channel attacks

Validated the practicality of secure quantum communication with enhanced security features

Abstract

Quantum key distribution can provide unconditionally secure key exchange for remote users in theory. In practice, however, in most quantum key distribution systems, quantum hackers might steal the secure keys by listening to the side channels in the source, such as the photon frequency spectrum, emission time, propagation direction, spatial angular momentum, and so on. It is hard to prevent such kinds of attacks because side channels may exist in any of the encoding space whether the designers take care of or not. Here we report an experimental realization of a side-channel-free quantum key distribution protocol which is not only measurement-device-independent, but also immune to all side-channel attacks in the source. We achieve a secure key rate of 4.80e-7 per pulse through 50 km fiber spools.