FINAL bootstrap acceleration on FPGA using DSP-free constant-multiplier NTTs

Jonas Bertels; Hilder V. L. Pereira; Ingrid Verbauwhede

Paper 2025/137

FINAL bootstrap acceleration on FPGA using DSP-free constant-multiplier NTTs

Jonas Bertels

, KU Leuven

Hilder V. L. Pereira

, State University of Campinas

Ingrid Verbauwhede

, KU Leuven

Abstract

This work showcases Quatorze-bis, a state-of-the-art Number Theoretic Transform circuit for TFHE-like cryptosystems on FPGAs. It contains a novel modular multiplication design for modular multiplication with a constant for a constant modulus. This modular multiplication design does not require any DSP units or any dedicated multiplier unit, nor does it require extra logic when compared to the state-of-the-art modular multipliers. Furthermore, we present an implementation of a constant multiplier Number Theoretic Transform design for TFHE-like schemes. Lastly, we use this Number Theoretic Transform design to implement a FINAL hardware accelerator for the AMD Alveo U55c which improves the Throughput metric of TFHE-like cryptosystems on FPGAs by a factor 9.28x over Li et al.'s NFP CHES 2024 accelerator and by 10-25% over the absolute state-of-the-art design FPT while using one third of FPTs DSPs.

Note: (The name Quatorze-bis is a reference to the speed of the design. Airplane speed in meters/hour = bootstrapping speed in bootstraps/second)

Metadata

Available format(s): PDF
Category: Implementation
Publication info: Preprint.
Keywords: NTT FHE Hardware Design FPGA TFHE
Contact author(s): jonas bertels @ esat kuleuven be
hilder @ unicamp br
ingrid verbauwhede @ esat kuleuven be
History: 2025-01-29: revised; 2025-01-28: received; See all versions
Short URL: https://ia.cr/2025/137
License: CC BY

BibTeX

@misc{cryptoeprint:2025/137,
      author = {Jonas Bertels and Hilder V. L. Pereira and Ingrid Verbauwhede},
      title = {{FINAL} bootstrap acceleration on {FPGA} using {DSP}-free constant-multiplier {NTTs}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/137},
      year = {2025},
      url = {https://eprint.iacr.org/2025/137}
}