Paper 2021/1624 Original: eprint.iacr.org/2021/1624 ↗

On the IND-CCA1 Security of FHE Schemes

Prastudy Fauzi
Martha Norberg Hovd
Håvard Raddum
Abstract

Fully homomorphic encryption (FHE) is a powerful tool in cryptography that allows one to perform arbitrary computations on encrypted material without having to decrypt it first. There are numerous FHE schemes, all of which are expanded from somewhat homomorphic encryption (SHE) schemes, and some of which are considered viable in practice. However, while these FHE schemes are semantically (IND-CPA) secure, the question of their IND-CCA1 security is much less studied. In this paper, we group SHE schemes into broad categories based on their similarities and underlying hardness problems. For each category, we show that the SHE schemes are susceptible to either known adaptive key recovery attacks, a natural extension of known attacks, or our proposed attacks. Finally, we discuss the known techniques to achieve IND-CCA1 secure FHE and SHE schemes.

Metadata
Available format(s)
PDF
Publication info
Preprint.
History
2021-12-17: last updated
2021-12-17: published
Short URL
https://ia.cr/2021/1624
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2021/1624,
      author = {Prastudy Fauzi and Martha Norberg Hovd and Håvard Raddum},
      title = {On the IND-CCA1 Security of FHE Schemes},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/1624},
      year = {2021},
      url = {https://eprint.iacr.org/2021/1624}
}
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