Bit errors in the Kirchhoff-Law–Johnson-Noise secure key exchange

Abstract

We classify and analyze bit errors in the voltage and current measurement modes of the Kirchhoff-law–Johnson-noise (KLJN) secure key distribution system. In both measurement modes, the error probability decays exponentially with increasing duration of the bit sharing period (BSP) at fixed bandwidth. We also present an error mitigation strategy based on the combination of voltage-based and current-based schemes. The combination method has superior fidelity, with drastically reduced error probability compared to the former schemes, and it also shows an exponential dependence on the duration of the BSP.