Unconditionally secure digital signatures implemented in an eight-user quantum network

• Published in: New journal of physics Vol. 24; no. 9; p. 93038
• Main Authors: Pelet, Yoann, Puthoor, Ittoop Vergheese, Venkatachalam, Natarajan, Wengerowsky, Sören, Lončarić, Martin, Neumann, Sebastian Philipp, Liu, Bo, Samec, Željko, Stipčević, Mario, Ursin, Rupert, Andersson, Erika, Rarity, John G, Aktas, Djeylan, Joshi, Siddarth Koduru
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01-09-2022
• Subjects: Communication; digital signature; Digital signatures; Entangled states; Forging; Messages; Photonics; Physics; Protocol; quantum communication; quantum information; quantum networks; unconditionally secure signature
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/ac8e25

The ability to know and verifiably demonstrate the origins of messages can often be as important as encrypting the message itself. Here we present an experimental demonstration of an unconditionally secure digital signature (USS) protocol implemented for the first time, to the best of our knowledge, on a fully connected quantum network without trusted nodes. We choose a USS protocol which is secure against forging, repudiation and messages are transferrable. We show the feasibility of unconditionally secure signatures using only bi-partite entangled states distributed throughout the network and experimentally evaluate the performance of the protocol in real world scenarios with varying message lengths.