A SIMPLER SECURITY PROOF FOR 6-STATE QUANTUM KEY DISTRIBUTION

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AKYÜZ K., Škorić B.

Quantum Information and Computation, vol.23, no.11-12, pp.949-960, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 11-12
  • Publication Date: 2023
  • Doi Number: 10.26421/qic23.11-12-4
  • Journal Name: Quantum Information and Computation
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, zbMATH
  • Page Numbers: pp.949-960
  • Keywords: quantum cryptography, Quantum Key Distribution
  • Middle East Technical University Affiliated: Yes

Abstract

Six-state Quantum Key Distribution (QKD) achieves the highest key rate in the class of qubit-based QKD schemes. The standard security proof, which has been developed since 2005, invokes complicated theorems involving smooth Rényi entropies. In this paper we present a simpler security proof for 6-state QKD that entirely avoids Rényi entropies. This is achieved by applying state smoothing directly in the Bell basis. We obtain the well known asymptotic rate, but with slightly more favorable finite-size terms. We furthermore show that the same proof technique can be used for 6-state quantum key recycling.