Numerical finite-key analysis of quantum key distribution
Name
s41534-020-00322-w.pdf
Description
Published version
Size
1.46 MB
Format
Adobe PDF
Checksum (MD5)
9a5f2df1c148db49c5a0b3fe1aeb8f3f
Author(s)
Bunandar, Darius
Govia, Luke CG
Krovi, Hari
Englund, Dirk
Date Issued
2020
Journal
npj Quantum Information
Publisher
Springer Science and Business Media LLC
Citation
Bunandar, Darius, Govia, Luke CG, Krovi, Hari and Englund, Dirk. 2020. "Numerical finite-key analysis of quantum key distribution." npj Quantum Information, 6 (1).
Version
Final published version
Abstract
© 2020, The Author(s). Quantum key distribution (QKD) allows for secure communications safe against attacks by quantum computers. QKD protocols are performed by sending a sizeable, but finite, number of quantum signals between the distant parties involved. Many QKD experiments, however, predict their achievable key rates using asymptotic formulas, which assume the transmission of an infinite number of signals, partly because QKD proofs with finite transmissions (and finite-key lengths) can be difficult. Here we develop a robust numerical approach for calculating the key rates for QKD protocols in the finite-key regime in terms of two semi-definite programs (SDPs). The first uses the relation between conditional smooth min-entropy and quantum relative entropy through the quantum asymptotic equipartition property, and the second uses the relation between the smooth min-entropy and quantum fidelity. The numerical programs are formulated under the assumption of collective attacks from the eavesdropper and can be promoted to withstand coherent attacks using the postselection technique. We then solve these SDPs using convex optimization solvers and obtain numerical calculations of finite-key rates for several protocols difficult to analyze analytically, such as BB84 with unequal detector efficiencies, B92, and twin-field QKD. Our numerical approach democratizes the composable security proofs for QKD protocols where the derived keys can be used as an input to another cryptosystem.
MIT Department
Massachusetts Institute of Technology. Research Laboratory of Electronics
Terms of Use
Creative Commons Attribution 4.0 International license
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DOI of Published Version
https://doi.org/10.1038/S41534-020-00322-W
