Current Injection Attack against the KLJN Secure Key Exchange

TL;DR

This paper investigates a specific active attack on the KLJN secure key exchange system using circuit simulation, demonstrating that certain security enhancements can effectively prevent information leaks and maintain unconditional security.

Contribution

It introduces a simulation-based analysis of the current injection attack on KLJN and validates security enhancement techniques that preserve unconditional security.

Findings

Security enhancement techniques eliminate information leaks.

The system maintains unconditional security with the proposed methods.

Simulation confirms effectiveness of attack mitigation strategies.

Abstract

The Kirchhoff-law-Johnson-noise (KLJN) scheme is a statistical/physical secure key exchange system based on the laws of classical statistical physics to provide unconditional security. We used the LTSPICE industrial cable and circuit simulator to emulate one of the major active (invasive) attacks, the current injection attack, against the ideal and a practical KLJN system, respectively. We show that two security enhancement techniques, namely, the instantaneous voltage/current comparison method, and a simple privacy amplification scheme, independently and effectively eliminate the information leak and successfully preserve the system's unconditional security.