Three-Party Controlled Authentication Semiquantum Key Agreement Protocol for Online Joint Consultation

In Wise Information Technology of Medicine, to ensure both confidentiality and integrity of the data created during online joint consultations, and to solve the problem that ordinary users cannot afford expensive quantum devices and are vulnerable to man-in-the-middle attacks during communication, this paper proposes a three-party controlled authentication semi-quantum key agreement protocol, leveraging the measurement retransmission operation and the entanglement properties of Cluster states. With the help of a trusted controller with full quantum capabilities, the identities of three semi-quantum parties are authenticated, and a shared key is negotiated fairly for subsequent communication. Since the semi-quantum participants only need to perform simple quantum state preparation, measurement and reflection operations, the protocol reduces the requirements for participants' capabilities and equipment. Moreover, the protocol prevents man-in-the-middle attacks by authenticating the identity of participants. The security evaluation demonstrates that the protocol is capable of effectively defending against both internal participant threats and external intrusions. Moreover, a comparison with existing semi-quantum key agreement protocols reveals that this protocol offers certain advantages when its functionality and performance are comprehensively evaluated.