Quantum cryptography with coherent states

TLDR

Quantum key distribution security relies on eavesdropping inducing errors, and the amount of leaked information depends on the specific system and attack strategy. The authors aim to develop quantum cryptographic protocols with weak coherent states and introduce a system that significantly reduces eavesdropper information. The system combines two existing protocols and proposes a feasible experimental implementation. This system is therefore safer than the two previous ones.

Abstract

The safety of a quantum key distribution system relies on the fact that any eavesdropping attempt on the quantum channel creates errors in the transmission. For a given error rate, the amount of information that may have leaked to the eavesdropper depends on both the particular system and the eavesdropping strategy. In this work, we discuss quantum cryptographic protocols based on the transmission of weak coherent states and present a system, based on a symbiosis of two existing systems, for which the information available to the eavesdropper is significantly reduced. This system is therefore safer than the two previous ones. We also suggest a possible experimental implementation.