Paper 2020/015 Original: eprint.iacr.org/2020/015 ↗

Efficient Homomorphic Conversion Between (Ring) LWE Ciphertexts

Hao Chen
Wei Dai
Miran Kim
Yongsoo Song
Abstract

In the past few years, significant progresses on homomorphic encryption (HE) have been made toward both theory and practice. The most promising HE schemes are based on the hardness of the Learning With Errors (LWE) problem or its ring variant (RLWE). In this work, we present new conversion algorithms which switch between different (R)LWE-based HE schemes to take advantages of them. Specifically, we present and combine three ideas to improve the key-switching procedure between LWE ciphertexts, transformation from LWE to RLWE, as well as packing of multiple LWE ciphertexts in a single RLWE encryption. Finally, we demonstrate an application of building a secure channel between a client and a cloud server with lightweight encryption, low communication cost, and capability of homomorphic computation.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
History
2020-12-04: last updated
2020-01-07: published
Short URL
https://ia.cr/2020/015
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2020/015,
      author = {Hao Chen and Wei Dai and Miran Kim and Yongsoo Song},
      title = {Efficient Homomorphic Conversion Between (Ring) LWE Ciphertexts},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/015},
      year = {2020},
      url = {https://eprint.iacr.org/2020/015}
}
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