Using TopGear in Overdrive: A more efficient ZKPoK for SPDZ

Carsten Baum; Daniele Cozzo; Nigel P.  Smart

Paper 2019/035 Original: eprint.iacr.org/2019/035 ↗

Using TopGear in Overdrive: A more efficient ZKPoK for SPDZ

Carsten Baum

Daniele Cozzo

Nigel P. Smart

Abstract

The HighGear protocol (Eurocrypt 2018) is the fastest currently known approach to preprocessing for the SPDZ Multi-Party Computation scheme. Its backbone is formed by an Ideal Lattice-based Somewhat Homomorphic Encryption Scheme and accompanying Zero-Knowledge proofs. Unfortunately, due to certain characteristics of HighGear such current implementations use far too low security parameters in a number of places. This is mainly due to memory and bandwidth consumption constraints. In this work we present a new approach to the ZKPoKs as introduced in the HighGear work. We rigorously formalize their approach and show how to improve upon it using a different proof strategy. This allows us to increase the security of the underlying protocols, all while maintaining roughly the same performance in terms of memory and bandwidth consumption.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
History: 2020-03-19: last updated; 2019-01-17: published
Short URL: https://ia.cr/2019/035
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2019/035,
      author = {Carsten Baum and Daniele Cozzo and Nigel P.  Smart},
      title = {Using TopGear in Overdrive: A more efficient ZKPoK for SPDZ},
      howpublished = {Cryptology {ePrint} Archive, Paper 2019/035},
      year = {2019},
      url = {https://eprint.iacr.org/2019/035}
}