Paper 2024/314

Exploring the Advantages and Challenges of Fermat NTT in FHE Acceleration

Andrey Kim, Samsung Advanced Institute of Technology, Suwon, Republic of Korea
Ahmet Can Mert, Graz University of Technology, Graz, Austria
Anisha Mukherjee, Graz University of Technology, Graz, Austria
Aikata Aikata, Graz University of Technology, Graz, Austria
Maxim Deryabin, Samsung Advanced Institute of Technology, Suwon, Republic of Korea
Sunmin Kwon, Samsung Advanced Institute of Technology, Suwon, Republic of Korea
HyungChul Kang, Samsung Advanced Institute of Technology, Suwon, Republic of Korea
Sujoy Sinha Roy, Graz University of Technology, Graz, Austria
Abstract

Recognizing the importance of fast and resource-efficient polynomial multiplication in homomorphic encryption, in this paper, we introduce a novel method that enables integer multiplier-less Number Theoretic Transform (NTT) for computing polynomial multiplication. First, we use a Fermat number as an auxiliary modulus of NTT. However, this approach of using Fermat number scales poorly with the degree of polynomial. Hence, we propose a transformation of a large-degree univariate polynomial into small-degree multi-variable polynomials. After that, we compute these NTTs on small-degree polynomials with Fermat number as modulus. We design an accelerator architecture customized for the novel multivariate NTT and use it for benchmarking practical homomorphic encryption applications. The accelerator can achieve a 1,200× speed-up compared to software implementations. We further discuss the potential and limitations of the proposed polynomial multiplication method in the context of homomorphic encryption.

Metadata
Available format(s)
PDF
Category
Implementation
Publication info
Preprint.
Keywords
Fermat numberNTTPolynomial MultiplierFHEHardware Accelerator
Contact author(s)
andrey kim @ samsun com
ahmet mert @ iaik tugraz at
anisha mukherjee @ iaik tugraz at
aikata @ iaik tugraz at
max deriabin @ samsung com
sunmin7 kwon @ samsung com
hc1803 kang @ samsung com
sujoy sinharoy @ iaik tugraz at
History
2024-02-26: approved
2024-02-23: received
See all versions
Short URL
https://ia.cr/2024/314
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/314,
      author = {Andrey Kim and Ahmet Can Mert and Anisha Mukherjee and Aikata Aikata and Maxim Deryabin and Sunmin Kwon and HyungChul Kang and Sujoy Sinha Roy},
      title = {Exploring the Advantages and Challenges of Fermat NTT in FHE Acceleration},
      howpublished = {Cryptology ePrint Archive, Paper 2024/314},
      year = {2024},
      note = {\url{https://eprint.iacr.org/2024/314}},
      url = {https://eprint.iacr.org/2024/314}
}
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