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FINALLY: A Multi-Key FHE Scheme Based on NTRU and LWE

Authors:
Jeongeun Park , Norwegian University of Science and Technology
Barry van Leeuwen , KU Leuven
Oliver Zajonc , KU Leuven
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DOI: 10.62056/aebn-4c2h
URL: https://cic.iacr.org//p/1/3/15
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Abstract:

Multi-key fully homomorphic encryption (MKFHE), a generalization of fully homomorphic encryption (FHE), enables a computation over encrypted data under multiple keys. The first MKFHE schemes were based on the NTRU primitive, however these early NTRU based FHE schemes were found to be insecure due to the problem of over-stretched parameters. Recently, in the case of standard (non-multi key) FHE a secure version, called FINAL, of NTRU has been found. In this work we extend FINAL to an MKFHE scheme, this allows us to benefit from some of the performance advantages provided by NTRU based primitives. Thus, our scheme provides competitive performance against current state-of-the-art multi-key TFHE, in particular reducing the computational complexity from quadratic to linear in the number of keys.

BibTeX
@article{cic-2024-34826,
  title={FINALLY: A Multi-Key FHE Scheme Based on NTRU and LWE},
  journal={cic},
  publisher={International Association for Cryptologic Research},
  volume={1, Issue 3},
  url={https://cic.iacr.org//p/1/3/15},
  doi={10.62056/aebn-4c2h},
  author={Jeongeun Park and Barry van Leeuwen and Oliver Zajonc},
  year=2024
}