Dr. Frédéric Dupuis, Eidgenössische Technische Hochschule Zürich
Abstract
We describe how any two-party quantum computation, specified by a circuit which simultaneously acts on the registers of both parties, can be privately implemented against a quantum version of classical semi-honest adversaries that we call "specious". Our construction requires in general two ideal functionalities to garantee privacy: a private SWAP between registers held by the two parties, and a classical private AND-box equivalent to oblivious transfer. However, if the circuit to be evaluated is in the Clifford group, then only one call to SWAP is required for privacy, and the stronger AND-box is not required. SWAP can be built from a classical bit commitment scheme or an AND-box but an AND-box cannot be constructed from SWAP. We also show that SWAP cannot be implemented privately without any ideal functionalities, and hence that private circuit evaluation necessarily requires cryptographic assumptions. This is joint work with Jesper Buus Nielsen and Louis Salvail.
Part of a MITACS seminar series.