Ring packing and amortized FHEW bootstrapping

Daniele Micciancio; Jessica Sorrell

Paper 2018/532

Ring packing and amortized FHEW bootstrapping

Daniele Micciancio and Jessica Sorrell

Abstract

The FHEW fully homomorphic encryption scheme (Ducas and Micciancio, Eurocrypt 2015) offers very fast homomorphic NAND-gate computations (on encrypted data) and a relatively fast refreshing procedure that allows to homomorphically evaluate arbitrary NAND boolean circuits. Unfortunately, the refreshing procedure needs to be executed after every single NAND computation, and each refreshing operates on a single encrypted bit, greatly decreasing the overall throughput of the scheme. We give a new refreshing procedure that simultaneously refreshes $n$ FHEW ciphertexts, at a cost comparable to a single-bit FHEW refreshing operation. As a result, the cost of each refreshing is amortized over $n$ encrypted bits, improving the throughput for the homomorphic evaluation of boolean circuits roughly by a factor $n$.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Published elsewhere. Major revision. ICALP 2018
DOI: 10.4230/LIPIcs.ICALP.2018.100
Keywords: Fully Homomorphic Encryption Bootstrapping Lattice-based Cryptography
Contact author(s): jlsorrel @ eng ucsd edu
History: 2019-10-06: revised; 2018-06-04: received; See all versions
Short URL: https://ia.cr/2018/532
License: CC BY

BibTeX

@misc{cryptoeprint:2018/532,
      author = {Daniele Micciancio and Jessica Sorrell},
      title = {Ring packing and amortized {FHEW} bootstrapping},
      howpublished = {Cryptology {ePrint} Archive, Paper 2018/532},
      year = {2018},
      doi = {10.4230/LIPIcs.ICALP.2018.100},
      url = {https://eprint.iacr.org/2018/532}
}