MPC vs. SFE: Perfect security in a unified corruption model

Zuzana Beerliova-Trubiniova, Matthias Fitzi, Martin Hirt, Ueli Maurer, Vassilis Zikas

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Secure function evaluation (SFE) allows a set of players to compute an arbitrary agreed function of their private inputs, even if an adversary may corrupt some of the players. Secure multi-party computation (MPC) is a generalization allowing to perform an arbitrary on-going (also called reactive or stateful) computation during which players can receive outputs and provide new inputs at intermediate stages. At Crypto 2006, Ishai et al. considered mixed threshold adversaries that either passively corrupt some fixed number of players, or, alternatively, actively corrupt some (smaller) fixed number of players, and showed that for certain thresholds, cryptographic SFE is possible, whereas cryptographic MPC is not. However, this separation does not occur when one considers perfect security. Actually, past work suggests that no such separation exists, as all known general protocols for perfectly secure SFE can also be used for MPC. Also, such a separation does not show up with general adversaries, characterized by a collection of corruptible subsets of the players, when considering passive and active corruption. In this paper, we study the most general corruption model where the adversary is characterized by a collection of adversary classes, each specifying the subset of players that can be actively, passively, or fail-corrupted, respectively, and show that in this model, perfectly secure MPC separates from perfectly secure SFE. Furthermore, we derive the exact conditions on the adversary structure for the existence of perfectly secure SFE resp. MPC, and provide efficient protocols for both cases.

Original languageEnglish
Title of host publicationTheory of Cryptography
Subtitle of host publicationFifth Theory of Cryptography Conference, TCC 2008, Proceedings
EditorsRan Canetti
Place of PublicationBerlin, Heidelberg
PublisherSpringer
Pages231-250
Number of pages20
ISBN (Electronic)978-3-540-78524-8
ISBN (Print)978-3-540-78523-1
DOIs
Publication statusPublished - 10 Mar 2008
Event5th Theory of Cryptography Conference - New York, United States
Duration: 19 Mar 200821 Mar 2008
https://cs.nyu.edu/tcc08/

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
PublisherSpringer, Berlin, Heidelberg
Volume4948
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference5th Theory of Cryptography Conference
Abbreviated titleTCC 2008
CountryUnited States
CityNew York
Period19/03/0821/03/08
Internet address

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