Paper 2024/634

NTRU-based FHE for Larger Key and Message Space

Robin Jadoul, COSIC, KU Leuven
Axel Mertens, COSIC, KU Leuven
Jeongeun Park, Norwegian University of Science and Technology (NTNU)
Hilder V. L. Pereira, Universidade Estadual de Campina
Abstract

The NTRU problem has proven a useful building block for efficient bootstrapping in Fully Homomorphic Encryption (FHE) schemes, and different such schemes have been proposed. FINAL (ASIACRYPT 2022) first constructed FHE using homomorphic multiplexer (CMux) gates for the blind rotation operation. Later, XZD+23 (CRYPTO 2023) gave an asymptotic optimization by changing the ciphertext format to enable ring automorphism evaluations. In this work, we examine an adaptation to FINAL to evaluate CMux gates of higher arity and the resulting tradeoff to running times and bootstrapping key sizes. In this setting, we can compare the time and space efficiency of both bootstrapping protocols with larger key space against each other and the state of the art.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Published elsewhere. ACISP 2024
Keywords
Fully Homomorphic EncryptionNTRUBootstrappingFINAL
Contact author(s)
robin jadoul @ esat kuleuven be
axel mertens @ esat kuleuven be
jeongeun park @ ntnu no
hilder @ unicamp br
History
2024-04-26: approved
2024-04-25: received
See all versions
Short URL
https://ia.cr/2024/634
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/634,
      author = {Robin Jadoul and Axel Mertens and Jeongeun Park and Hilder V. L. Pereira},
      title = {NTRU-based FHE for Larger Key and Message Space},
      howpublished = {Cryptology ePrint Archive, Paper 2024/634},
      year = {2024},
      note = {\url{https://eprint.iacr.org/2024/634}},
      url = {https://eprint.iacr.org/2024/634}
}
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