License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/OASIcs.SOSA.2018.12
URN: urn:nbn:de:0030-drops-83062
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2018/8306/
Aggarwal, Divesh ;
Stephens-Davidowitz, Noah
Just Take the Average! An Embarrassingly Simple 2^n-Time Algorithm for SVP (and CVP)
Abstract
We show a 2^{n+o(n)}-time (and space) algorithm for the Shortest Vector Problem on lattices (SVP) that works by repeatedly running an embarrassingly simple "pair and average" sieving-like procedure on a list of lattice vectors. This matches the running time (and space) of the current fastest known algorithm, due to Aggarwal, Dadush, Regev, and Stephens-Davidowitz (ADRS, in STOC, 2015), with a far simpler algorithm. Our algorithm is in fact a modification of the ADRS algorithm, with a certain careful rejection sampling step removed.
The correctness of our algorithm follows from a more general "meta-theorem," showing that such rejection sampling steps are unnecessary for a certain class of algorithms and use cases. In particular, this also applies to the related 2^{n + o(n)}-time algorithm for the Closest Vector Problem (CVP), due to Aggarwal, Dadush, and Stephens-Davidowitz (ADS, in FOCS, 2015), yielding a similar embarrassingly simple algorithm for gamma-approximate CVP for any gamma = 1+2^{-o(n/log n)}. (We can also remove the rejection sampling procedure from the 2^{n+o(n)}-time ADS algorithm for exact CVP, but the resulting algorithm is still quite complicated.)
BibTeX - Entry
@InProceedings{aggarwal_et_al:OASIcs:2018:8306,
author = {Divesh Aggarwal and Noah Stephens-Davidowitz},
title = {{Just Take the Average! An Embarrassingly Simple 2^n-Time Algorithm for SVP (and CVP)}},
booktitle = {1st Symposium on Simplicity in Algorithms (SOSA 2018)},
pages = {12:1--12:19},
series = {OpenAccess Series in Informatics (OASIcs)},
ISBN = {978-3-95977-064-4},
ISSN = {2190-6807},
year = {2018},
volume = {61},
editor = {Raimund Seidel},
publisher = {Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
address = {Dagstuhl, Germany},
URL = {http://drops.dagstuhl.de/opus/volltexte/2018/8306},
URN = {urn:nbn:de:0030-drops-83062},
doi = {10.4230/OASIcs.SOSA.2018.12},
annote = {Keywords: Lattices, SVP, CVP}
}
Keywords: |
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Lattices, SVP, CVP |
Collection: |
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1st Symposium on Simplicity in Algorithms (SOSA 2018) |
Issue Date: |
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2018 |
Date of publication: |
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05.01.2018 |