We study the asymptotic efficiency of indistinguishability obfuscation (iO) on two fronts: – Obfuscation size: Present constructions of indistinguishability obfuscation (iO) create obfuscated programs where the size of the obfuscated program is at least a multiplicative factor of security parameter larger than the size of the original program. In this work, we construct the first iO scheme for (bounded-input) Turing machines that achieves only a constant multiplicative overhead in size. The constant in our scheme is, in fact, 2. – Amortization: Suppose we want to obfuscate an arbitrary polynomial number of (bounded-input) Turing machines M1,…,Mn. We ask whether it is possible to obfuscate M1,…,Mn using a single application of an iO scheme for a circuit family where the size of any circuit is independent of n as well the size of any Turing machine Mi. In this work, we resolve this question in the affirmative, obtaining a new bootstrapping theorem for obfuscating arbitrarily many Turing machines. In order to obtain both of these results, we develop a new template for obfuscating Turing machines that is of independent interest and likely to find applications in future. The security of our results rely on the existence of sub-exponentially secure iO for circuits and re-randomizable encryption schemes.
CITATION STYLE
Ananth, P., Jain, A., & Sahai, A. (2017). Indistinguishability obfuscation for turing machines: Constant overhead and amortization. In Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) (Vol. 10402 LNCS, pp. 252–279). Springer Verlag. https://doi.org/10.1007/978-3-319-63715-0_9
Mendeley helps you to discover research relevant for your work.