Paper 2015/1197 Original: eprint.iacr.org/2015/1197 ↗

On-the-fly Homomorphic Batching/Unbatching

Yarkın Doröz
Berk Sunar
Gizem S. Çetin
Abstract

We introduce a homomorphic batching technique that can be used to pack multiple ciphertext messages into one ciphertext for parallel processing. One is able to use the method to batch or unbatch messages homomorphically to further improve the flexibility of encrypted domain evaluations. In particular, we show various approaches to implement Number Theoretic Transform (NTT) homomorphically in FFT speed. Also, we present the limitations that we encounter in application of these methods. We implement homomorphic batching in various settings and present concrete performance figures. Finally, we present an implementation of a homomorphic NTT method which we process each element in an independent ciphertext. The advantage of this method is we are able to batch independent homomorphic NTT evaluations and achieve better amortized time.

Metadata
Available format(s)
PDF
Category
Applications
Publication info
Preprint.
History
2015-12-16: last updated
2015-12-16: published
Short URL
https://ia.cr/2015/1197
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2015/1197,
      author = {Yarkın Doröz and Berk Sunar and Gizem S.  Çetin},
      title = {On-the-fly Homomorphic Batching/Unbatching},
      howpublished = {Cryptology {ePrint} Archive, Paper 2015/1197},
      year = {2015},
      url = {https://eprint.iacr.org/2015/1197}
}
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