A lattice attack on homomorphic NTRU with non-invertible public keys

Soyoung Ahn, Hyang Sook Lee, Seongan Lim, Ikkwon Yie

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In 2011, Stehlé and Steinfeld modified the original NTRU to get a provably IND-CPA secure NTRU under the hardness assumption of standard worst-case problems over ideal lattices. In 2012, López-Alt et al. proposed the first multikey fully homomorphic encryption scheme based on the IND-CPA secure NTRU. Interestingly, this homomorphic NTRU and subsequent homomorphic variants of NTRU removed the condition ‘invertible public key’ of the underlying IND-CPA secure NTRU. In this paper, we investigate the security influence of using non-invertible public key in the homomorphic NTRU. As a result, we present how to mount a lattice attack to message recovery for the homomorphic NTRU when the public key is non-invertible. Our result suggests that using invertible public keys in the homomorphic NTRU is necessary for its security.

Original languageEnglish
Title of host publicationInformation and Communications Security - 19th International Conference, ICICS 2017, Proceedings
EditorsSihan Qing, Dongmei Liu, Chris Mitchell, Liqun Chen
PublisherSpringer Verlag
Pages248-254
Number of pages7
ISBN (Print)9783319894997
DOIs
StatePublished - 2018
Event19th International Conference on Information and Communications Security, ICICS 2017 - Beijing, China
Duration: 6 Dec 20178 Dec 2017

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume10631 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference19th International Conference on Information and Communications Security, ICICS 2017
Country/TerritoryChina
CityBeijing
Period6/12/178/12/17

Bibliographical note

Publisher Copyright:
© Springer International Publishing AG, part of Springer Nature 2018.

Keywords

  • Homomorphic NTRU
  • IND-CPA security
  • LLL algorithm
  • Lattices
  • NTRU

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