Abstract

The notion of obfuscation is a powerful idea in cryptography, but the most ideal variant – Virtual Black Box obfuscation – is impossible to achieve classically. Even though some other impossibility results in the quantum case have been found, whether it’s possible to use quantum information to obfuscate (classical) circuits is still an open question.

Fully homomorphic encryption is a key tool in many proposed constructions involving obfuscation in the classical world. For instance, it can boost obfuscation of log-depth circuits to polynomial-size ones. Having in mind recent progress in quantum homomorphic encryption (QHE), it’s natural to ask in what way QHE might help us in the quest to obfuscate quantum circuits.

In this talk, I will give an overview of a research line in progress: we try to find out whether QHE can boost the power of obfuscated classical circuits to the obfuscation of quantum circuits. I will sketch the progress we have made, and the technical obstacles that still remain to fully solve this question.

Joint work with Gorjan Alagic, Yfke Dulek, and Christian Schaffner.