Unconditionally secure digital signatures implemented in an 8-user quantum network
This provides a solution for secure message authentication in quantum networks, addressing a critical need for verifiable origins in communications, though it is an incremental advance as it builds on existing quantum signature concepts.
The researchers tackled the problem of implementing unconditionally secure digital signatures in a quantum network, demonstrating for the first time a protocol that is secure against forging and repudiation on an 8-user network without trusted nodes, showing feasibility with bipartite entangled states.
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. Our USS protocol 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.