Learning with Errors and Extrapolated Dihedral Cosets

Zvika Brakerski, Elena Kirshanova, Damien Stehlé, Weiqiang Wen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The hardness of the learning with errors (LWE) problem is one of the most fruitful resources of modern cryptography. In particular, it is one of the most prominent candidates for secure post-quantum cryptography. Understanding its quantum complexity is therefore an important goal. We show that under quantum polynomial time reductions, LWE is equivalent to a relaxed version of the dihedral coset problem (DCP), which we call extrapolated DCP (eDCP). The extent of extrapolation varies with the LWE noise rate. By considering different extents of extrapolation, our result generalizes Regev’s famous proof that if DCP is in BQP (quantum poly-time) then so is LWE (FOCS 02). We also discuss a connection between eDCP and Childs and Van Dam’s algorithm for generalized hidden shift problems (SODA 07). Our result implies that a BQP solution for LWE might not require the full power of solving DCP, but rather only a solution for its relaxed version, eDCP, which could be easier.

Original languageEnglish
Title of host publicationPublic-Key Cryptography - PKC 2018
EditorsMichel Abdalla, Ricardo Dahab
PublisherSpringer-Verlag Italia
Pages702-727
Number of pages26
ISBN (Print)9783319765778
DOIs
StatePublished Online - 1 Mar 2018
Event21st IACR International Conference on Practice and Theory of Public-Key Cryptography, PKC 2018 - Rio de Janeiro, Brazil
Duration: 25 Mar 201829 Mar 2018

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume10770 10769 LNCS
ISSN (Print)0302-9743

Conference

Conference21st IACR International Conference on Practice and Theory of Public-Key Cryptography, PKC 2018
Country/TerritoryBrazil
CityRio de Janeiro
Period25/03/1829/03/18

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science

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