Elimination of a Second-Law-attack, and all cable-resistance-based attacks, in the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system

Abstract

We introduce the so far most efficient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. This attack utilizes the lack of exact thermal equilibrium in practical applications and is based on cable resistance losses and the fact that the Second Law of Thermodynamics cannot provide full security when such losses are present. The new attack does not challenge the unconditional security of the KLJN scheme, but it puts more stringent demands on the security/privacy enhancing protocol than for any earlier attack. In this paper we present a simple defense protocol to fully eliminate this new attack by increasing the noise-temperature at the side of the smaller resistance value over the noise-temperature at the at the side with the greater resistance. It is shown that this simple protocol totally removes Eve's information not only for the new attack but also for the old Bergou-Scheuer-Yariv attack. The presently most efficient attacks against the KLJN scheme are thereby completely nullified.

accepted for publication in Entropy (open access)

References in corpus (6)

• Noise in the wire: the real impact of wire resistance for the Johnson (-like) noise based secure communicator
• Noise properties in the ideal Kirchhoff-Law-Johnson-Noise secure communication system
• A classical key distribution system based on Johnson (like) noise - How secure?
• Do electromagnetic waves exist in a short cable at low frequencies? What does physics say?
• On the "cracking" scheme in the paper "A directional coupler attack against the Kish key distribution system" by Gunn, Allison and Abbott
• What kind of noise guarantees security for the Kirchhoff-Loop-Johnson-Noise key exchange?

Cited by in corpus (3)

• Analysis of an attenuator artifact in an experimental attack by Gunn-Allison-Abbott against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system
• Resource requirements and speed versus geometry of unconditionally secure physical key exchanges
• Perspective -- On the thermodynamics of perfect unconditional security