Information Reconciliation for Quantum Key Distribution

Abstract

Secret-key agreement, a well-known problem in cryptography, allows two parties holding correlated sequences to agree on a secret key communicating over a public channel. Secret-key agreement is usually divided into three different procedures: advantage distillation, information reconciliation and privacy amplification. The efficiency of each one of these procedures is needed if a positive key rate is to be attained from the legitimate parties’ correlated sequences. Quantum key distribution (QKD) allows the two parties to obtain correlated sequences, provided that they have access to an authentic channel. The new generation of QKD devices is able to work at higher speeds and in noisier or more absorbing environments. This exposes the weaknesses of a current information reconciliation protocols, a key component to their performance. Here we present a new protocol based in Low Density Parity-Check codes that presents the advantages of low interactivity, rate adaptability and high efficiency, characteristics that make it highly suitable for next generation QKD devices.