Facts, myths and fights about the KLJN classical physical key exchanger

TL;DR

This paper reviews the KLJN classical physical key exchange method, addresses criticisms, and demonstrates that its extended system maintains unconditional security despite some valid attacks.

Contribution

It clarifies misconceptions about KLJN and shows that its extended system remains secure against various criticisms, reinforcing its robustness.

Findings

Extended KLJN system remains secure against all examined attacks.

Some criticisms are valid but do not compromise security.

The paper clarifies misconceptions about the KLJN method.

Abstract

This paper deals with the Kirchhoff-law-Johnson-noise (KLJN) classical statistical physical key exchange method and surveys criticism - often stemming from a lack of understanding of its underlying premises or from other errors - and our related responses against these, often unphysical, claims. Some of the attacks are valid, however, an extended KLJN system remains protected against all of them, implying that its unconditional security is not impacted.