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Structured Codes Improve the Bennett-Brassard-84 Quantum Key Rate

Smith, Graeme and Renes, Joseph M. and Smolin, John A. (2008) Structured Codes Improve the Bennett-Brassard-84 Quantum Key Rate. Physical Review Letters, 100 (17). Art. No. 170502. ISSN 0031-9007.

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A central goal in information theory and cryptography is finding simple characterizations of optimal communication rates under various restrictions and security requirements. Ideally, the optimal key rate for a quantum key distribution (QKD) protocol would be given by a single-letter formula involving optimization over a single use of an effective channel. We explore the possibility of such a formula for the simplest and most widely used QKD protocol, Bennnett-Brassard-84 with one-way classical postprocessing. We show that a conjectured single-letter formula is false, uncovering a deep ignorance about good private codes and exposing unfortunate complications in the theory of QKD. These complications are not without benefit—with added complexity comes better key rates than previously thought possible. The threshold for secure key generation improves from a bit error rate of 0.124 to 0.129.

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Additional Information:©2008 The American Physical Society. (Received 11 December 2006; published 28 April 2008) We thank Debbie Leung, John Preskill, and Renato Renner for several valuable discussions. This work grew out of discussions between G.S. and J.M.R. at the University of Queensland, whose hospitality we appreciate. J.M.R. acknowledges the Alexander von Humboldt Foundation, G.S. NSF Grant No. PHY-0456720 and Canada’s NSERC, and J.A.S. ARO Contract No. DAAD19-01-C-0056.
Subject Keywords:cryptographic protocols; information theory; quantum cryptography
Issue or Number:17
Record Number:CaltechAUTHORS:SMIprl08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10341
Deposited By: Archive Administrator
Deposited On:30 Apr 2008
Last Modified:03 Oct 2019 00:08

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