One-way quantum key distribution: Simple upper bound on the secret key rate

Journal Article · Wed Nov 15 04:00:00 EST 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.052301· OSTI ID:20974692

Moroder, Tobias; Luetkenhaus, Norbert ^[1]; Curty, Marcos ^[1]

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1. Institute of Theoretical Physics I and Max-Planck Research Group, Institute of Optics, Information and Photonics, University Erlangen-Nuremberg, Staudtstrasse 7, 91058 Erlangen (Germany)

We present a simple method to obtain an upper bound on the achievable secret key rate in quantum key distribution (QKD) protocols that use only unidirectional classical communication during the public-discussion phase. This method is based on a necessary precondition for one-way secret key distillation; the legitimate users need to prove that there exists no quantum state having a symmetric extension that is compatible with the available measurements results. The main advantage of the obtained upper bound is that it can be formulated as a semidefinite program, which can be efficiently solved. We illustrate our results by analyzing two well-known qubit-based QKD protocols: the four-state protocol and the six-state protocol.

• OSTI ID: 20974692
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 5 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMMUNICATIONS
QUANTUM COMPUTERS
QUANTUM CRYPTOGRAPHY
QUANTUM MECHANICS
QUBITS
SECURITY