Indistinguishability Obfuscation from Functional Encryption

Nir Bitansky, Vinod Vaikuntanathan

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

Abstract

Indistinguishability obfuscation (IO) is a tremendous notion, powerful enough to give rise to almost any known cryptographic object. So far, candidate IO constructions were based on specific assumptions on algebraic objects called multi-linear graded encodings. We present a generic construction of indistinguishability obfuscation from public-key functional encryption with succinct cipher texts and sub-exponential security. This shows the equivalence of indistinguishability obfuscation and public-key functional encryption, a primitive that has so far seemed to be much weaker, lacking the power and the staggering range of applications of indistinguishability obfuscation. As an application, we obtain a new candidate IO construction based on the functional encryption scheme of Garg, Gentry, Halevi, and Zhan dry [Eprint 14] under their assumptions on multi-linear graded encodings. We also show that, under the Learning with Errors assumptions, our techniques imply that any indistinguishability obfuscator can be converted to one where obfuscated circuits are of linear size in the size of the original circuit plus a polynomial overhead in its depth. Our reduction highlights the importance of cipher text succinctness in functional encryption schemes, which we hope will serve as a pathway to new IO constructions based on solid cryptographic foundations.

Original languageEnglish
Title of host publicationProceedings - 2015 IEEE 56th Annual Symposium on Foundations of Computer Science, FOCS 2015
PublisherIEEE Computer Society
Pages171-190
Number of pages20
ISBN (Electronic)9781467381918
DOIs
StatePublished - 11 Dec 2015
Externally publishedYes
Event56th IEEE Annual Symposium on Foundations of Computer Science, FOCS 2015 - Berkeley, United States
Duration: 17 Oct 201520 Oct 2015

Publication series

NameProceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS
Volume2015-December
ISSN (Print)0272-5428

Conference

Conference56th IEEE Annual Symposium on Foundations of Computer Science, FOCS 2015
Country/TerritoryUnited States
CityBerkeley
Period17/10/1520/10/15

Keywords

  • functional encryption
  • obfuscation

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