Obfuscation combiners

Marc Fischlin, Amir Herzberg, Hod Bin-Noon, Haya Shulman

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

10 Scopus citations

Abstract

Obfuscation is challenging; we currently have practical candidates with rather vague security guarantees on the one side, and theoretical constructions which have recently experienced jeopardizing attacks against the underlying cryptographic assumptions on the other side. This motivates us to study and present robust combiners for obfuscators, which integrate several candidate obfuscators into a single obfuscator which is secure as long as a quorum of the candidates is indeed secure. We give several results about building obfuscation combiners, with matching upper and lower bounds for the precise quorum of secure candidates. Namely, we show that one can build 3-out-of-4 obfuscation combiners where at least three of the four combiners are secure, whereas 2- out-of-3 structural combiners (which combine the obfuscator candidates in a black-box sense) with only two secure candidates, are impossible. Our results generalize to (2γ + 1)-out-of-(3γ + 1) combiners for the positive result, and to 2γ-out-of-3γ results for the negative result, for any integer γ. To reduce overhead, we define detecting combiners, where the combined obfuscator may sometimes produce an error-indication instead of the desired output, indicating that some of the component obfuscators is faulty. We present a (γ +1)-out-of-(2γ +1) detecting combiner for any integer γ, bypassing the previous lower bound. We further show that γ- out-of-2γ structural detecting combiners are again impossible. Since our approach can be used for practical obfuscators, as well as for obfuscators proven secure (based on assumptions), we also briefly report on implementation results for some applied obfuscator programs.

Original languageEnglish
Title of host publicationAdvances in Cryptology - 36th Annual International Cryptology Conference, CRYPTO 2016, Proceedings
EditorsMatthew Robshaw, Jonathan Katz
PublisherSpringer Verlag
Pages521-550
Number of pages30
ISBN (Print)9783662530078
DOIs
StatePublished - 2016
Event36th Annual International Cryptology Conference, CRYPTO 2016 - Santa Barbara, United States
Duration: 14 Aug 201618 Aug 2016

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume9815
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference36th Annual International Cryptology Conference, CRYPTO 2016
Country/TerritoryUnited States
CitySanta Barbara
Period14/08/1618/08/16

Bibliographical note

Publisher Copyright:
© International Association for Cryptologic Research 2016.

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