Multi-input functional encryption in the private-key setting: Stronger security from weaker assumptions

Zvika Brakerski, Ilan Komargodski*, Gil Segev

*Corresponding author for this work

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

31 Scopus citations

Abstract

We construct a general-purpose multi-input functional encryption scheme in the private-key setting. Namely, we construct a scheme where a functional key corresponding to a function f enables a user holding encryptions of x1,., xtto compute f(x1,., xt) but nothing else. This is achieved starting from any general-purpose private-key single-input scheme (without any additional assumptions), and is proven to be adaptively secure for any constant number of inputs t. Moreover, it can be extended to a super-constant number of inputs assuming that the underlying single-input scheme is sub-exponentially secure. Instantiating our construction with existing single-input schemes, we obtain multi-input schemes that are based on a variety of assumptions (such as indistinguishability obfuscation, multilinear maps, learning with errors, and even one-way functions), offering various trade-offs between security and efficiency. Previous and concurrent constructions of multi-input functional encryption schemes either rely on stronger assumptions and provided weaker security guarantees (Goldwasser et al. [EUROCRYPT’14], and Ananth and Jain [CRYPTO’15]), or relied on multilinear maps and could be proven secure only in an idealized generic model (Boneh et al. [EUROCRYPT’15]). In comparison, we present a general transformation that simultaneously relies on weaker assumptions and guarantees stronger security.

Original languageAmerican English
Title of host publicationAdvances in Cryptology - EUROCRYPT 2016 - 35th Annual International Conference on the Theory and Applications of Cryptographic Techniques, Proceedings
EditorsMarc Fischlin, Jean-Sebastien Coron
PublisherSpringer Verlag
Pages852-880
Number of pages29
ISBN (Print)9783662498958
DOIs
StatePublished - 2016
Event35th Annual International Conference on Theory and Applications of Cryptographic Techniques, EUROCRYPT 2016 - Vienna, Austria
Duration: 8 May 201612 May 2016

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume9666
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference35th Annual International Conference on Theory and Applications of Cryptographic Techniques, EUROCRYPT 2016
Country/TerritoryAustria
CityVienna
Period8/05/1612/05/16

Bibliographical note

Publisher Copyright:
© International Association for Cryptologic Research 2016.

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