Experimental demonstration of confidential communication with quantum security monitoring

Yupeng Gong,Ian H White,Richard V Penty,Jeffrey H Hunt,Adrian Wonfor

doi:10.1038/s41598-021-01013-y

Abstract

Security issues and attack management of optical communication have come increasingly important. Quantum techniques are explored to secure or protect classical communication. In this paper, we present a method for in-service optical physical layer security monitoring that has vacuum-noise level sensitivity without classical security loopholes. This quantum-based method of eavesdropping detection, similar to that used in conventional pilot tone systems, is achieved by sending quantum signals, here comprised of continuous variable quantum states, i.e. weak coherent states modulated at the quantum level. An experimental demonstration of attack detection using the technique was presented for an ideal fibre tapping attack that taps 1% of the ongoing light in a 10 dB channel, and also an ideal correlated jamming attack in the same channel that maintains the light power with excess noise increased by 0.5 shot noise unit. The quantum monitoring system monitors suspicious changes in the quantum signal with the help of advanced data processing algorithms. In addition, unlike the CV-QKD system which is very sensitive to channel excess noise and receiver system noise, the quantum monitoring is potentially more compatible with current optical infrastructure, as it lowers the system requirements and potentially allows much higher classical data rate communication with links length up to 100 s km.

Highlights

Security issues and attack management of optical communication have come increasingly important
Possible candidates to respond to this threat are post quantum cryptography (PQC)[17] which is a refinement of current cryptography not susceptible to Shor’s algorithm[18], and quantum key distribution (QKD)[19] which transmits secure keys using quantum states for classical symmetry encryption
QKD was proposed in response to the vulnerabilities of conventional cryptography in the face of future technology, i.e. the quantum c omputer[56]

Summary

Introduction

Security issues and attack management of optical communication have come increasingly important. Unlike the CV-QKD system which is very sensitive to channel excess noise and receiver system noise, the quantum monitoring is potentially more compatible with current optical infrastructure, as it lowers the system requirements and potentially allows much higher classical data rate communication with links length up to 100 s km. In addition to optical encryption methods[4,5], classical physical layer security protection relies on active fiber monitoring techniques. These are generally based on statistical analysis of the received signal, e.g. by measuring the mean optical power[6], or incorporating active diagnostics via sending a separate signal into the network[7,8], e.g. using optical time domain reflectometry (OTDR)[9,10]. QKD is an emerging technology with a few commercial implementations, but still far from widespread deployment

Methods

Results

Conclusion