Duality on the Thermodynamics of the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange Scheme

TL;DR

This paper explores a duality approach to detect information leaks in the KLJN secure key exchange scheme, demonstrating that non-equilibrium conditions compromise security and emphasizing the importance of thermal equilibrium.

Contribution

It introduces a dual sampling method using currents at zero-voltage crossings to identify vulnerabilities in non-equilibrium KLJN systems, extending previous voltage-based analyses.

Findings

Duality method detects information leaks effectively.

Non-equilibrium conditions reveal vulnerabilities.

Thermal equilibrium is essential for security.

Abstract

This study investigates a duality approach to information leak detection in the generalized Kirchhoff-Law-Johnson-Noise secure key exchange scheme proposed by Vadai, Mingesz, and Gingl (VMG-KLJN). While previous work by Chamon and Kish sampled voltages at zero-current instances, this research explores sampling currents at zero-voltage crossings. The objective is to determine if this dual approach can reveal information leaks in non-equilibrium KLJN systems. Results indicate that the duality method successfully detects information leaks, further supporting the necessity of thermal equilibrium for unconditional security in KLJN systems. Our findings confirm that the duality method successfully detects information leaks, with results closely mirroring those of Chamon and Kish, showing comparable vulnerabilities in non-equilibrium conditions. These results further support the necessity of thermal equilibrium for unconditional security in the KLJN scheme.