Unconditional security from noisy quantum storage

TL;DR

This paper introduces cryptographic protocols secure against adversaries with noisy quantum storage, enabling practical two-party cryptography with current quantum technology and no need for honest parties to have quantum memory.

Contribution

The authors develop new protocols for oblivious transfer and bit commitment that are unconditionally secure under realistic noise assumptions, extending the bounded-storage model.

Findings

Protocols are secure with realistic noise levels.

No quantum storage needed for honest parties.

Implementation feasible with current quantum hardware.

Abstract

We consider the implementation of two-party cryptographic primitives based on the sole assumption that no large-scale reliable quantum storage is available to the cheating party. We construct novel protocols for oblivious transfer and bit commitment, and prove that realistic noise levels provide security even against the most general attack. Such unconditional results were previously only known in the so-called bounded-storage model which is a special case of our setting. Our protocols can be implemented with present-day hardware used for quantum key distribution. In particular, no quantum storage is required for the honest parties.