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.

量子会议密钥协议 (CKA) 支持在具有信息论安全性的多个受信任用户之间共享密钥。目前，大多数量子 CKA 协议的关键速率都受到量子信道总效率的限制。受相干单向双场量子密钥分发（QKD）协议的启发，我们提出了一种三用户的量子CKA协议。利用强度为 0 和μ 的相干状态来编码逻辑位，我们的协议可以突破限制。此外，我们的协议中删除了相位随机化和多重强度调制的要求，使其实验演示变得简单。