A directional coupler attack against the Kish key distribution system

Abstract

The Kish key distribution system has been proposed as a class ical alternative to quantum key distribution. The idealized Kish scheme elegantly promise s secure key distribution by exploiting thermal noise in a transmission line. However, we demonstrate that it is vulnerable to nonidealities in its components, such as the finite resistance of the transmission line connecting its endpoints. We introduce a novel attack against this nonideality using directional wave measurements, and experimentally demonstrate its efficacy. Our attack is based on causality: in a spatially distributed system, propagation is needed for thermodynamic equilibration, and that leaks information.

References in corpus (1)

• Noise in the wire: the real impact of wire resistance for the Johnson (-like) noise based secure communicator

Cited by in corpus (3)

• 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
• Generalized DC loop current attack against the KLJN secure key exchange scheme