Paper 2020/172

Qubit-based Unclonable Encryption with Key Recycling

Daan Leermakers and Boris Skoric

Abstract

We re-visit Unclonable Encryption as introduced by Gottesman in 2003. We introduce two qubit-based prepare-and-measure Unclonable Encryption schemes with re-usable keys. In our first scheme there is no classical communication from Alice to Bob. Over a noisy channel its communication rate is lower than in Quantum Key Recycling schemes that lack unclonability. Our second scheme needs more rounds but has the advantage that it achieves the same rate as Quantum Key Distribution. We provide security proofs for both our schemes, based on the diamond norm distance, taking noise into account.