Efficient TFHE Bootstrapping in the Multiparty Setting

Jeongeun Park; Sergi Rovira

Paper 2023/759

Efficient TFHE Bootstrapping in the Multiparty Setting

Jeongeun Park

, KU Leuven

Sergi Rovira

, Pompeu Fabra University

Abstract

In this paper, we introduce a new approach to efficiently compute TFHE bootstrapping keys for (predefined) multiple users. Hence, a fixed number of users can enjoy the same level of efficiency as in the single key setting, keeping their individual input privacy. Our construction relies on a novel algorithm called homomorphic indicator, which can be of independent interest. We provide a detailed analysis of the noise growth and a set of secure parameters suitable to be used in practice. Moreover, we compare the complexity of our technique with other state-of-the-art constructions and show which method performs better in what parameter sets, based on our noise analysis. We also provide a prototype implementation of our technique. To the best of our knowledge, this is the first implementation of TFHE in the multiparty setting.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: TFHE Homomorphic Encryption Multiparty TFHE
Contact author(s): Jeongeun Park @ esat kuleuven be
sergi rovira @ upf edu
History: 2023-05-30: approved; 2023-05-25: received; See all versions
Short URL: https://ia.cr/2023/759
License: CC BY

BibTeX

@misc{cryptoeprint:2023/759,
      author = {Jeongeun Park and Sergi Rovira},
      title = {Efficient TFHE Bootstrapping in the Multiparty Setting},
      howpublished = {Cryptology ePrint Archive, Paper 2023/759},
      year = {2023},
      note = {\url{https://eprint.iacr.org/2023/759}},
      url = {https://eprint.iacr.org/2023/759}
}