Performance limits of quantum key distribution with asymmetric integrated detection

Lutong Chen, Kaiping Xue, Jian Li +2 more

WireGuard is a pioneering and lightweight Virtual Private Network (VPN) protocol that has been merged into the Linux kernel. It leverages the Noise secure framework to provide advanced security functionalities, such as identity hiding and perfect forward security. Although WireGuard has an optional pre-shared key mode to ensure key security, the advanced security features are guaranteed by asymmetric cryptography algorithms, which cannot be held in the face of superior quantum computers. To achieve quantum-resistant security, WireGuard should avoid using vulnerable asymmetric cryptography algorithms that are currently deeply integrated into the WireGuard protocol. In this paper, we present a solution to enhance the security of WireGuard by integrating Quantum Key Distribution (QKD). We first change the security mode to tunnel-orient Pre-Shared Keys (PSK) as the authentication anchor. We also design QKD-assisted ephemeral keys and corresponding Key Encapsulation Mechanism (KEM) to achieve WireGuard's advanced security properties without using asymmetric cryptography. We also integrate QKD keys during the key derivation to provide further security. Finally, we implement the entire protocol named WireGuard-QKD in Golang and evaluate its performance and security.

Osamu Hirota

Víctor Zapatero

LU Zeyang, Gang Wang, Chan Li +1 more

Mode-pairing quantum key distribution (MP-QKD) can surpass the repeaterless rate-transmittance bound (Pirandola-Laurenza-Ottaviani-Banchi bound) without requiring global phase locking, exhibiting remarkable flexibility. However, MP-QKD necessitates equal communication distances in two channels, which is a challenging requirement in practical applications. To address this limitation, we extend the original MP-QKD to asymmetric cases. Our decoy-state estimation confirms that asymmetric channel transmittances and asymmetric intensities do not compromise the security of the protocol. We focus on the pulse-intensity relationship, a key factor for optimizing the performance of asymmetric MP-QKD. Unlike previous asymmetric protocols, the intensities of different bases in asymmetric MP-QKD cannot be decoupled. We introduce an optimal-pulse-intensity method, adaptable to various scenarios, to enhance key rates by calculating ideal pulse intensities. Simulation results in various representative scenarios indicate that our method effectively reduces the impact of asymmetric channel distances on MP-QKD performance, enhancing its practical applicability.

Wei-Xin Xie, Guan‐Jie Fan‐Yuan, Ze-Hao Wang +8 more

Integrating measurement-device-independent quantum key distribution (MDI QKD) with classical networks guarantees security and economy. Unfortunately, the performance of MDI QKD, suppressed though it is by network asymmetry, is further degraded by the addition of integration noise. As a consequence, symmetric systems are always believed to be better for a higher key rate. However, we reveal a counterintuitive fact that asymmetric MDI QKD has better performance in integrated systems. Modeling the mechanism of the asymmetric effect in integrated MDI systems and analyzing the noise-suppression effect of asymmetric structures, we observe an unanticipated increase of the key rate up to 260%, giving a conclusion diametrically opposite that for the original system. The phenomenon found and the proposed analytical model provide a method for noise suppression and performance improvement, permitting high adaptability for realistic asymmetric networks.

Federico Grasselli