Semi-device-independent security of one-way quantum key distribution

TL;DR

This paper demonstrates that semi-device-independent security can be achieved for one-way quantum key distribution by assuming bounded quantum system dimensions, enhancing security guarantees beyond traditional methods.

Contribution

It introduces a semi-device-independent security framework for one-way QKD, relying on dimension bounds and analogies with dimension witnesses and random-access codes.

Findings

Security guaranteed against individual attacks under dimension constraints

Framework extends security assurances beyond fully device-independent models

Relies on novel connections between QKD, dimension witnesses, and coding theory

Abstract

By testing nonlocality, the security of entanglement-based quantum key distribution (QKD) can be enhanced to being 'device-independent'. Here we ask whether such a strong form of security could also be established for one-way (prepare and measure) QKD. While fully device-independent security is impossible, we show that security can be guaranteed against individual attacks in a semi-device-independent scenario. In the latter, the devices used by the trusted parties are non-characterized, but the dimensionality of the quantum systems used in the protocol is assumed to be bounded. Our security proof relies on the analogies between one-way QKD, dimension witnesses and random-access codes.