Strong pulse illumination hacks self-differencing avalanche photodiode detectors in a high-speed quantum key distribution system

TL;DR

This paper investigates security loopholes in self-differencing avalanche photodiode detectors used in high-speed quantum key distribution systems, demonstrating a strong pulse illumination attack and proposing protective criteria.

Contribution

It identifies a specific attack on SD APD detectors in high-speed QKD and offers criteria to safeguard against this vulnerability.

Findings

SD APD detectors are vulnerable to strong pulse illumination attack

The attack can blind detectors without increasing QBER

Proposed criteria can prevent such attacks

Abstract

Implementation of high-speed quantum key distribution~(QKD) has become one of the major focus in the field, which produces high key-generation rate for applications. To achieve high-speed QKD, tailored techniques are developed and employed to quickly generate and detect quantum states. However, these techniques may introduce unique loopholes to compromise the security of QKD systems. In this paper, we investigate the loopholes of self-differencing~(SD) avalanche photodiode~(APD) detector, typically used for high-speed detection in a QKD system, and demonstrate experimental testing of SD APD detector under strong pulse illumination attack. This attack presents blinding stability and helps an eavesdropper to learn the secret key without introducing extra QBER. Based on this testing, we propose a set of criteria for protecting SD APD detectors from the strong pulse illumination attack.