Cable Capacitance Attack against the KLJN Secure Key Exchange
This addresses a security vulnerability in practical implementations of KLJN key exchange, though it is incremental as it focuses on mitigating a known non-ideality.
The paper tackled the information leak in the KLJN secure key exchange system caused by parasitic cable capacitance, using LTSPICE simulations to show that privacy amplification and capacitance compensation can effectively eliminate this leak.
The security of the Kirchhoff-law-Johnson-(like)-noise (KLJN) key exchange system is based on the Fluctuation-Dissipation-Theorem of classical statistical physics. Similarly to quantum key distribution, in practical situations, due to the non-idealities of the building elements, there is a small information leak, which can be mitigated by privacy amplification or other techniques so that the unconditional (information theoretic) security is preserved. In this paper, the industrial cable and circuit simulator LTSPICE is used to validate the information leak due to one of the non-idealities in KLJN, the parasitic (cable) capacitance. Simulation results show that privacy amplification and/or capacitor killer (capacitance compensation) arrangements can effectively eliminate the leak.