Function-private subspace-membership encryption and its applications

Dan Boneh, Ananth Raghunathan, Gil Segev

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

36 Scopus citations

Abstract

Boneh, Raghunathan, and Segev (CRYPTO '13) have recently put forward the notion of function privacy and applied it to identity-based encryption, motivated by the need for providing predicate privacy in public-key searchable encryption. Intuitively, their notion asks that decryption keys reveal essentially no information on their corresponding identities, beyond the absolute minimum necessary. While Boneh et al. showed how to construct function-private identity-based encryption (which implies predicate-private encrypted keyword search), searchable encryption typically requires a richer set of predicates. In this paper we significantly extend the function privacy framework. First, we consider the notion of subspace-membership encryption, a generalization of inner-product encryption, and formalize a meaningful and realistic notion for capturing its function privacy. Then, we present a generic construction of a function-private subspace-membership encryption scheme based on any inner-product encryption scheme. This is the first generic construction that yields a function-private encryption scheme based on a non-function-private one. Finally, we present various applications of function-private subspacemembership encryption. Among our applications, we significantly improve the function privacy of the identity-based encryption schemes of Boneh et al.: whereas their schemes are function private only for identities that are highly unpredictable (with min-entropy of at least λ + ω(log λ) bits, where λ is the security parameter), we obtain functionprivate schemes assuming only the minimal required unpredictability (i.e., min-entropy of only ω(log λ) bits). This improvement offers a much more realistic function privacy guarantee.

Original languageAmerican English
Title of host publicationAdvances in Cryptology, ASIACRYPT 2013 - 19th International Conference on the Theory and Application of Cryptology and Information Security, Proceedings
Pages255-275
Number of pages21
EditionPART 1
DOIs
StatePublished - 2013
Event19th International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2013 - Bengaluru, India
Duration: 1 Dec 20135 Dec 2013

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
NumberPART 1
Volume8269 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference19th International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2013
Country/TerritoryIndia
CityBengaluru
Period1/12/135/12/13

Keywords

  • Function privacy
  • functional encryption

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