Measurement-device-independent quantum key agreement based on entanglement swapping

Quantum key agreement (QKA) is an important cryptographic primitive that plays a pivotal role in private communications. However, in practical implementations of QKA, the flaws in participants' detectors may be exploited to compromise the security and fairness of the protocol. To address this issue, we propose a two-party measurement-device-independent QKA protocol, effectively eliminating all detector-side-channel loopholes. This protocol is based on quantum entanglement swapping and Bell-state measurements, making it feasible under current technological conditions. A thorough security analysis is conducted, demonstrating its ability to guarantee both security and fairness.