Coherent one-way quantum conference key agreement based on twin field
This work addresses the challenge of secure key sharing among multiple users in quantum communication, though it appears incremental as it builds on existing QKD protocols.
The authors tackled the problem of low key rates in quantum conference key agreement (CKA) protocols, which are limited by total channel efficiency, by proposing a three-user protocol based on coherent one-way and twin-field quantum key distribution (QKD) that breaks this limit and simplifies experimental requirements.
Quantum conference key agreement (CKA) enables key sharing among multiple trusted users with information-theoretic security. Currently, the key rates of most quantum CKA protocols suffer from the limit of the total efficiency among quantum channels. Inspired by the coherent one-way and twin-field quantum key distribution (QKD) protocols, we propose a quantum CKA protocol of three users. Exploiting coherent states with intensity 0 and $μ$ to encode logic bits, our protocol can break the limit. Additionally, the requirements of phase randomization and multiple intensity modulation are removed in our protocol, making its experimental demonstration simple.