Limits on the power of indistinguishability obfuscation and functional encryption

Recent breakthroughs in cryptography have positioned indistinguishability obfuscation as a "central hub" for almost all known cryptographic tasks, and as an extremely powerful building block for new cryptographic tasks resolving long-standing and foundational open problems. However, constructions based on indistinguishability obfuscation almost always rely on non-black-box techniques, and thus the extent to which it can be used as a building block has been completely unexplored so far. We present a framework for proving meaningful negative results on the power of indistinguishability obfuscation. By considering indistinguishability obfuscation for oracle-aided circuits, we capture the common techniques that have been used so far in constructions based on indis-tinguishability obfuscation. These include, in particular, non-black-box techniques such as the punctured programming approach of Sahai and Waters (STOC '14) and its variants, as well as sub-exponential security assumptions. Within our framework we prove the rst negative results on the power of indistinguishability obfuscation and of the tightly related notion of functional encryption. Our results are as follows