Current injection and voltage insertion attacks against the VMG-KLJN secure key exchanger

TL;DR

This paper demonstrates vulnerabilities in the VMG-KLJN secure key exchanger to active injection and voltage insertion attacks, showing that existing defenses are insufficient against both attack types simultaneously, supported by theoretical analysis and simulations.

Contribution

It reveals security flaws in the VMG-KLJN scheme due to impedance differences and evaluates defense schemes, highlighting the need for improved security measures.

Findings

Effective driving impedances differ between HL and LH cases in VMG-KLJN.

Existing defenses protect against only one attack type.

Theoretical results are confirmed by computer simulations.

Abstract

In this paper, the vulnerability of the Vadai, Mingesz and Gingl (VMG)- Kirchhoff-Law-Johnson-Noise (KLJN) Key Exchanger (Nature, Science Report 5 (2015) 13653) against two active attacks is demonstrated. The security vulnerability arises from the fact that the effective driving impedances are different between the HL and LH cases for the VMG-KLJN scheme; whereas for the ideal KLJN scheme they are same. Two defense schemes are shown against these attacks but each of them can protect against only one of the attack types; but not against the two attacks simultaneously. The theoretical results are confirmed by computer simulations.