# Continuous-variable quantum authentication of physical unclonable keys

## TL;DR

This paper introduces a quantum authentication scheme for physical keys using optical scattering and homodyne detection, offering a practical, collision-resistant method with current technology.

## Contribution

It presents a novel continuous-variable quantum authentication method for physical unclonable keys based on optical scattering and wavefront shaping techniques.

## Key findings

- Scheme is implementable with current technology
- Offers collision resistance against cloning
- Robust authentication using homodyne detection

## Abstract

We propose a scheme for authentication of physical keys that are materialized by optical multiple-scattering media. The authentication relies on the optical response of the key when probed by randomly selected coherent states of light, and the use of standard wavefront-shaping techniques that direct the scattered photons coherently to a specific target mode at the output. The quadratures of the electromagnetic field of the scattered light at the target mode are analysed using a homodyne detection scheme, and the acceptance or rejection of the key is decided upon the outcomes of the measurements. The proposed scheme can be implemented with current technology and offers collision resistance and robustness against key cloning.