Authentication of Continuous-Variable Quantum Messages

Abstract: We introduce the first quantum authentication scheme for continuous-variable states. Our scheme is based on trap states, and is an adaptation of a discrete-variable scheme by Broadbent et al. (arXiv:1211.1080), but with more freedom in choosing the number of traps. We provide a security proof, mostly following the approach of Broadbent and Wainewright (arXiv:1607.03075). As a necessary ingredient for the proof we derive the continuous-variable analogue of the Pauli Twirl.