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An obfuscator $$\mathcal {O}$$ O is Virtual Grey Box (VGB) for a class $$\mathcal {C}$$ C of circuits if, for any $$C\in \mathcal {C}$$ C ∈ C and any predicate $$\pi $$ π , deducing $$\pi (C)$$ π ( C ) given $$\mathcal {O}(C)$$ O ( C ) is tantamount to deducing $$\pi (C)$$ π ( C ) given unbounded computational resources and polynomially many oracle queries(More)
The goal of general-purpose program obfuscation is to make an arbitrary computer program “unintelligible” while preserving its functionality. At least as far back as the work of Diffie and Hellman in 1976, researchers have contemplated applications of general-purpose obfuscation. However, until 2013, even heuristic constructions for general-purpose(More)
A function <i>f</i> is extractable if it is possible to algorithmically "extract," from any adversarial program that outputs a value <i>y</i> in the image of <i>f;</i> a preimage of <i>y</i>. When combined with hardness properties such as one-wayness or collision-resistance, extractability has proven to be a powerful tool. However, so far, extractability(More)
We construct 3-round proofs and arguments with negligible soundness error satisfying two relaxed notions of zero-knowledge (ZK): weak ZK and witness hiding (WH). At the heart of our constructions lie new techniques based on point obfuscation with auxiliary input (AIPO). It is known that such protocols cannot be proven secure using blackbox reductions (or(More)
We study the problem of verifiable delegation of computation over outsourced data, whereby a powerful worker maintains a large data structure for a weak client in a verifiable way. Compared to the well-studied problem of verifiable computation, this setting imposes additional difficulties since the verifier needs to verify consistency of updates succinctly(More)
Succinct non-interactive arguments (SNARGs) enable verifying NP statements with lower complexity than required for classical NP verification. Traditionally, the focus has been on minimizing the length of such arguments; nowadays researches have focused also on minimizing verification time, by drawing motivation from the problem of delegating computation. A(More)
We prove that finding a Nash equilibrium of a game is hard, assuming the existence of indistinguishability obfuscation and one-way functions with sub-exponential hardness. We do so by showing how these cryptographic primitives give rise to a hard computational problem that lies in the complexity class PPAD, for which finding Nash equilibrium is complete.(More)
Assuming trapdoor permutations, we show that there exist function families that cannot be VBBobfuscated even if both the obfuscator and the obfuscated program have access to a random oracle. Specifically, these families are the robust unobfuscatable families of [Bitansky-Paneth, STOC 13]. Our result stands in contrast to the general VBB obfuscation(More)
This work attempts to clarify to what extent simulationbased security (SIM-security) is achievable for functional encryption (FE) and its relation to the weaker indistinguishability-based security (INDsecurity). Our main result is a compiler that transforms any FE scheme for the general circuit functionality (which we denote by Circuit-FE) meeting(More)
In this paper we show that the existence of general indistinguishability obfuscators conjectured in a few recent works implies, somewhat counterintuitively, strong impossibility results for virtual black box obfuscation. In particular, we show that indistinguishability obfuscation for all circuits implies: • The impossibility of average-case virtual black(More)