On adaptively secure multiparty computation with a short CRS

Ran Cohen, Chris Peikert

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

5 Scopus citations


In the setting of multiparty computation, a set of mutually distrusting parties wish to securely compute a joint function of their private inputs. A protocol is adaptively secure if honest parties might get corrupted after the protocol has started. Recently (TCC 2015) three constant-round adaptively secure protocols were presented [10,11,15]. All three constructions assume that the parties have access to a common reference string (CRS) whose size depends on the function to compute, even when facing semi-honest adversaries. It is unknown whether constantround adaptively secure protocols exist, without assuming access to such a CRS. In this work, we study adaptively secure protocols which only rely on a short CRS that is independent on the function to compute. – First, we raise a subtle issue relating to the usage of non-interactive non-committing encryption within security proofs in the UC framework, and explain how to overcome it. We demonstrate the problem in the security proof of the adaptively secure oblivious-transfer protocol from [8] and provide a complete proof of this protocol. – Next, we consider the two-party setting where one of the parties has a polynomial-size input domain, yet the other has no constraints on its input. We show that assuming the existence of adaptively secure oblivious transfer, every deterministic functionality can be computed with adaptive security in a constant number of rounds. – Finally, we present a new primitive called non-committing indistinguishability obfuscation, and show that this primitive is complete for constructing adaptively secure protocols with round complexity independent of the function.

Original languageEnglish
Title of host publicationSecurity and Cryptography for Networks - 10th International Conference, SCN 2016, Proceedings
EditorsRoberto De Prisco, Vassilis Zikas
PublisherSpringer Verlag
Number of pages18
ISBN (Print)9783319446172
StatePublished - 2016
Event10th International Conference on Security and Cryptography for Networks, SCN 2016 - Amalfi, Italy
Duration: 31 Aug 20162 Sep 2016

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume9841 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference10th International Conference on Security and Cryptography for Networks, SCN 2016

Bibliographical note

Publisher Copyright:
© Springer International Publishing Switzerland 2016.


C. Peikert—This material is based upon work supported by the National Science Foundation under CAREER Award CCF-1054495 and CNS-1606362, the Alfred P. Sloan Foundation, and by a Google Research Award. The views expressed are those of the authors and do not necessarily reflect the official policy or position of the National Science Foundation, the Sloan Foundation, or Google. R. Cohen—Work supported by the European Research Council under the ERC consolidators grant agreement n. 615172 (HIPS), by a grant from the Israel Ministry of Science, Technology and Space (grant 3-10883) and by the National Cyber Bureau of Israel.

FundersFunder number
National Cyber Bureau of Israel
National Science FoundationCCF-1054495, CNS-1606362
Alfred P. Sloan Foundation
European Research Council615172
Ministry of Science, Technology and Space3-10883


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