Quantum Meets Statistical-Physical Secrecy: A Novel Hybrid Key Distribution Architecture

TL;DR

This paper introduces a hybrid quantum and classical physical key distribution system that enhances efficiency and throughput for short-distance secure communications.

Contribution

It presents a new architecture combining QKD and KLJN methods, including three novel protocols that improve key generation by eliminating public basis disclosure.

Findings

Hybrid system improves key generation efficiency.

Numerical results show increased throughput in short-haul networks.

Protocols eliminate the need for public basis disclosure.

Abstract

This letter proposes a novel hybrid key distribution architecture that jointly exploits quantum key distribution (QKD) and Kirchhoff-law-Johnson-noise (KLJN) statistical-physical key exchange. In the proposed system, an optical BB84-type QKD link operates in coordination with a parallel wired KLJN link, which is used for secure basis handling and, in selected protocols, additional raw key generation. Three novel KLJN-assisted QKD protocols are introduced to eliminate public basis disclosure messages and bit sifting, extract basis-derived key bits, or generate raw key bits under ideal KLJN assumptions. Analytical expressions for the normalized key rate and absolute throughput are derived by accounting for optical channel penalties, KLJN bandwidth constraints, and synchronization bottlenecks. Numerical results show that the proposed hybrid architecture can improve key generation efficiency and throughput in short-haul infrastructures, including metropolitan area networks (MANs) and data center interconnects.