Hidden probe attacks on ultralong fiber laser key distribution systems

TL;DR

This paper introduces a hidden probe attack on ultralong fiber laser key distribution systems, demonstrating how an eavesdropper can covertly extract key information by exploiting the laser's noise floor, challenging the assumed security of such systems.

Contribution

It presents a novel hidden probe attack method that can compromise ultralong fiber laser key distribution, along with potential countermeasures to enhance security.

Findings

The attack can extract key information without detection.

Standard noise in the system can be exploited for covert probing.

Countermeasures can mitigate the attack's effectiveness.

Abstract

In ultralong fiber laser key distribution, two sides use standard optical equipment to create kilometer long fiber lasers in a communication link to establish a secret key. Its security rests on the assumption that any attacker would need much more sophisticated equipment and techniques than those of the legitimate user in order to discover the generated key. We present a challenge to that assumption with a hidden probe attack in which the eavesdropper hides a weak signal in the unavoidable noise floor that appears in the laser during amplification and probes with it the configuration of one or both communication parties. We comment how this attack can compromise different proposals for ultralong laser key distribution and propose possible countermeasures.