Paper 2018/244 Original: eprint.iacr.org/2018/244 ↗
Faster Homomorphic Linear Transformations in HElib
Abstract
HElib is a software library that implements homomorphic encryption (HE), with a focus on effective use of "packed" ciphertexts. An important operation (which is used in bootstrapping, as well as in other applications) is applying a known linear map to a vector of encrypted data. In this paper, we describe several algorithmic improvements that significantly speed up this operation: in our experiments, our new algorithms were 30-75 times faster than those currently implemented in HElib for typical parameters. Our techniques also reduce the size of the large public evaluation key, often using 33%-50% less space than the previous HElib implementation. We also implemented a new tradeoff that enables a drastic reduction in size, maybe a 25x factor or more for some parameters, paying only a 2-4x factor in runtime (and giving up some parallelization opportunities).
Metadata
- Available format(s)
PDF- Category
- Public-key cryptography
- Publication info
- Preprint.
- History
- 2019-05-11: last updated
- 2018-03-05: published
- Short URL
- https://ia.cr/2018/244
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2018/244,
author = {Shai Halevi and Victor Shoup},
title = {Faster Homomorphic Linear Transformations in HElib},
howpublished = {Cryptology {ePrint} Archive, Paper 2018/244},
year = {2018},
url = {https://eprint.iacr.org/2018/244}
}