On NTRU-ν-um Modulo $X^N − 1$

Marc Joye

Paper 2022/1092

On NTRU-ν-um Modulo $X^N − 1$

Marc Joye

, Zama

Abstract

NTRU-ν-um is a fully homomorphic encryption schemes making use of NTRU as a building block. NTRU-ν-um comes originally in two versions: a first instantiation working with polynomials modulo $X^N - 1$ with $N$ a prime [cyclic version] and a second instantiation working with polynomials modulo $X^N + 1$ with $N$ a power of two [negacyclic version]. The cyclic version is now deprecated. This work shows that the cyclic version of NTRU-ν-um is not secure. Specifically, it does not provide indistinguishability of encryptions. More critically, the scheme leaks the underlying private LWE keys. Source code for mounting the attacks is provided. The attacks were practically validated on the given parameter sets.

Metadata

Available format(s): PDF
Category: Attacks and cryptanalysis
Publication info: Published elsewhere. 2nd Annual FHE.org Conference (FHE.org 2023), Contributed talk, Tokyo, Japan, March 26, 2023
Keywords: NTRU-ν-um Fully homomorphic encryption Key recovery attack
Contact author(s): marc @ zama ai
History: 2023-04-08: revised; 2022-08-23: received; See all versions
Short URL: https://ia.cr/2022/1092
License: CC BY

BibTeX

@misc{cryptoeprint:2022/1092,
      author = {Marc Joye},
      title = {On {NTRU}-ν-um Modulo $X^N − 1$},
      howpublished = {Cryptology {ePrint} Archive, Paper 2022/1092},
      year = {2022},
      url = {https://eprint.iacr.org/2022/1092}
}