Side-channel-free quantum key distribution

TL;DR

This paper introduces a new QKD protocol that eliminates side-channel vulnerabilities by replacing real channels with virtual ones and uses quantum memory to securely bound the secret-key rate.

Contribution

It proposes a side-channel-free QKD method that enhances security by isolating detectors and settings and employs quantum memory for secure key rate estimation.

Findings

Eliminates side-channel attacks in QKD implementations.

Provides a method to bound secret-key rate using entanglement distillation.

Enhances practical security of quantum communication systems.

Abstract

Quantum key distribution (QKD) offers the promise of absolutely secure communications. However, proofs of absolute security often assume perfect implementation from theory to experiment. Thus, existing systems may be prone to insidious side-channel attacks that rely on flaws in experimental implementation. Here we replace all real channels with virtual channels in a QKD protocol, making the relevant detectors and settings inside private spaces inaccessible while simultaneously acting as a Hilbert space filter to eliminate side-channel attacks. By using a quantum memory we find that we are able to bound the secret-key rate below by the entanglement-distillation rate computed over the distributed states.