Experimental measurement-device-independent quantum digital signatures

G L Roberts,E Andersson,I V Puthoor,A W Sharpe,L C Comandar,Z L Yuan,M Lucamarini,A J Shields,J F Dynes,M Curty

doi:10.1038/s41467-017-01245-5

Abstract

The development of quantum networks will be paramount towards practical and secure telecommunications. These networks will need to sign and distribute information between many parties with information-theoretic security, requiring both quantum digital signatures (QDS) and quantum key distribution (QKD). Here, we introduce and experimentally realise a quantum network architecture, where the nodes are fully connected using a minimum amount of physical links. The central node of the network can act either as a totally untrusted relay, connecting the end users via the recently introduced measurement-device-independent (MDI)-QKD, or as a trusted recipient directly communicating with the end users via QKD. Using this network, we perform a proof-of-principle demonstration of QDS mediated by MDI-QKD. For that, we devised an efficient protocol to distil multiple signatures from the same block of data, thus reducing the statistical fluctuations in the sample and greatly enhancing the final QDS rate in the finite-size scenario.

Highlights

The development of quantum networks will be paramount towards practical and secure telecommunications
The security of these applications is largely based on public-key cryptography[2, 3], which is supposedly secure against an eavesdropper with limited computational power
Alice and Bob, are connected through a central node, Charlie, who normally acts as an untrusted relay between the users

Summary

Introduction

The development of quantum networks will be paramount towards practical and secure telecommunications. This allows us to extract the first QDS rates mediated by MDI-QKD. Hand V can be treated as in the original MDI-QKD scheme, whereas coincidence counts from detectors on different output ports of Charlie’s BS cannot be used to distil key bits, as they belong to different bases.

Results

Conclusion