Current Injection and Voltage Insertion Attacks Against the VMG-KLJN Secure Key Exchanger

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 the 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.