Breaking Quantum Key Distributions under Quantum Switch-Based Attack

TL;DR

This paper reveals a novel vulnerability in quantum key distribution protocols by demonstrating how a quantum switch with indefinite causal order can be exploited by an eavesdropper to compromise security, highlighting the need for new countermeasures.

Contribution

The paper introduces a new attack scenario using quantum switches with indefinite causal order, showing how they can undermine the security of existing QKD protocols.

Findings

Quantum switch-based attack significantly reduces QKD security

Metrics like information gain and Bell violation are affected

Highlights a previously overlooked vulnerability in QKD

Abstract

Quantum key distribution (QKD) enables secure key sharing between distant parties, with several protocols proven resilient against conventional eavesdropping strategies. Here, we introduce a new attack scenario where an eavesdropper, Eve, exploits a quantum switch using the indefinite causal order to intercept and manipulate quantum communication channel. Using multiple metrics such as the information gain, mutual information, and Bell violation, we demonstrate that the presence of a quantum switch significantly compromises QKD security. Our results highlight a previously overlooked vulnerability, emphasizing the need for countermeasures against quantum-controlled adversarial strategies.