Breaking the Sub-Exponential Barrier in Obfustopia

Indistinguishability obfuscation (iO) has emerged as a surprisingly powerful notion. Almost all known cryptographic primitives can be constructed from general purpose iO and other minimalistic assumptions such as one-way functions. The primary challenge in this direction of research is to develop novel techniques for using iO since iO by itself offers virtually no protection to secret information in the underlying programs. When dealing with complex situations, often these techniques have to consider an exponential number of hybrids (usually one per input) in the security proof. This results in a sub-exponential loss in the security reduction. Unfortunately, this scenario is becoming more and more common and appears to be a fundamental barrier to current techniques. In this work, we explore the possibility of getting around this sub-exponential loss barrier in constructions based on iO as well as the weaker notion of functional encryption (FE). Towards this goal, we achieve the follo...

• Type: Journal
• Year: 2016
• Where: IACR
• Authors: Sanjam Garg, Omkant Pandey, Akshayaram Srinivasan, Mark Zhandry
• Keywords: Biometrics, IACR 2016