Robust and Efficient Sifting-Less Quantum Key Distribution Protocols

TL;DR

This paper introduces a family of quantum key distribution protocols that replace the sifting step with reverse reconciliation, significantly enhancing robustness against photon-number-splitting attacks while maintaining key rates.

Contribution

It proposes a new protocol family using multiple polarization states, increasing PNS attack robustness exponentially with the number of states m.

Findings

Robustness against PNS attacks increases exponentially with m.

Effective key rate decreases with transmission T as T^{1+1/(m-2)}.

Protocol maintains raw key rate similar to BB84.

Abstract

We show that replacing the usual sifting step of the standard quantum-key-distribution protocol BB84 by a one-way reverse reconciliation procedure increases its robustness against photon-number-splitting (PNS) attacks to the level of the SARG04 protocol while keeping the raw key-rate of BB84. This protocol, which uses the same state and detection than BB84, is the m=4 member of a protocol-family using m polarization states which we introduce here. We show that the robustness of these protocols against PNS attacks increases exponentially with m, and that the effective keyrate of optimized weak coherent pulses decreases with the transmission T like T^{1+1/(m-2)}.