Publicly auditable secure multi-party computation

Carsten Baum, Ivan Damgård, Claudio Orlandi

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

71 Scopus citations

Abstract

In the last few years the efficiency of secure multi-party computation (MPC) increased in several orders of magnitudes. However, this alone might not be enough if we want MPC protocols to be used in practice. A crucial property that is needed in many applications is that everyone can check that a given (secure) computation was performed correctly – even in the extreme case where all the parties involved in the computation are corrupted, and even if the party who wants to verify the result was not participating. This is especially relevant in the clients-servers setting, where many clients provide input to a secure computation performed by a few servers. An obvious example of this is electronic voting, but also in many types of auctions one may want independent verification of the result. Traditionally, this is achieved by using non-interactive zero-knowledge proofs during the computation. A recent trend in MPC protocols is to have a more expensive preprocessing phase followed by a very efficient online phase, e.g., the recent so-called SPDZ protocol by Damgård et al. Applications such as voting and some auctions are perfect use-case for these protocols, as the parties usually know well in advance when the computation will take place, and using those protocols allows us to use only cheap information-theoretic primitives in the actual computation. Unfortunately no protocol of the SPDZ type supports an audit phase. In this paper, we show how to achieve efficient MPC with a public audit. We formalize the concept of publicly auditable secure computation and provide an enhanced version of the SPDZ protocol where, even if all the servers are corrupted, anyone with access to the transcript of the protocol can check that the output is indeed correct. Most importantly, we do so without significantly compromising the performance of SPDZ i.e. our online phase has complexity approximately twice that of SPDZ.

Original languageEnglish
Title of host publicationSecurity and Cryptography for Networks - 9th International Conference, SCN 2014, Proceedings
EditorsMichel Abdalla, Roberto de Prisco
PublisherSpringer Verlag
Pages175-196
Number of pages22
ISBN (Electronic)9783319108780
DOIs
StatePublished - 2014
Externally publishedYes
Event9th International Conference on Security and Cryptography for Networks, SCN 2014 - Amalfi, Italy
Duration: 3 Sep 20145 Sep 2014

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume8642
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference9th International Conference on Security and Cryptography for Networks, SCN 2014
Country/TerritoryItaly
CityAmalfi
Period3/09/145/09/14

Bibliographical note

Publisher Copyright:
© Springer International Publishing Switzerland 2014.

Keywords

  • Efficient Multi-Party Computation
  • Electronic Voting
  • Public Verifiability

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