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Impossibility of VBB Obfuscation with Ideal Constant-Degree Graded Encodings

  • Rafael Pass
  • Abhi Shelat
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9562)

Abstract

A celebrated result by Barak et al. (Crypto’01) shows the impossibility of general-purpose virtual black-box (VBB) obfuscation in the plain model. A recent work by Canetti, Kalai, and Paneth (TCC’15) extends this impossibility result to the random oracle model (assuming trapdoor permutations).

In contrast, Brakerski-Rothblum (TCC’14) and Barak et al. (EuroCrypt’14) show that in idealized graded encoding models, general-purpose VBB obfuscation indeed is possible; these constructions require graded encoding schemes that enable evaluating high-degree (polynomial in the size of the circuit to be obfuscated) polynomials on encodings.

We show a complementary impossibility of general-purpose VBB obfuscation in idealized graded encoding models that enable only evaluation of constant-degree polynomials (assuming trapdoor permutations).

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Copyright information

© International Association for Cryptologic Research 2016

Authors and Affiliations

  1. 1.Cornell UniversityIthacaUSA
  2. 2.University of VirginiaCharlottesvilleUSA

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