Quantum randomness protected against detection loophole attacks

TL;DR

This paper introduces a method to secure semi-device independent quantum randomness generators against detection loophole attacks by using a blocking device, with experimental validation demonstrating effective private randomness generation.

Contribution

The authors propose a novel blocking strategy to protect SDI-QRNGs from detection inefficiency attacks, applicable at any detection efficiency level.

Findings

Protection against detection loophole attacks achieved with a blocking device.

Experimental demonstration of private randomness generation using standard components.

Protection method effective regardless of detection efficiency.

Abstract

Device and semi-device independent quantum randomness generators (DI- and SDI-QRNGs) are crucial for applications requiring private randomness. However, they are vulnerable to detection inefficiency attacks and this limits severely their usage for practical purposes. Here, we present a method for protecting SDI-QRNGs in prepare-and-measure scenarios against detection inefficiency attacks. The key idea is the introduction of a blocking device that adds failures in the communication between the preparation and measurement devices. We prove that, for any detection efficiency, there is a blocking rate that provides protection against these attacks. We experimentally demonstrate the generation of private randomness using weak coherent states and standard avalanche photo-detectors.