Configurable controlled teleportation using multipartite GHZ states

Abstract: We propose a controlled quantum teleportation protocol for securely transferring an unknown $n$-qubit state from a sender to a receiver, under the supervision of $m$ controller participants. The protocol uses $n$ copies of an $m$-qubit Greenberger-Horne-Zeilinger state as the quantum resource. Message qubits can be distributed among participants to enhance security against targeted external attacks. Each intermediate party may hold at most one resource qubit, reducing the total number of resource qubits required. The sender selects the end receiver during protocol execution, ensuring anonymity and minimizing the risk of interception by an external eavesdropper. We assess the protocol's performance by calculating teleportation fidelities for various $m$ and $n$ values and visualize the quantum states through Hinton diagrams. The results confirm the protocol's effectiveness for secure quantum communication in multi-party settings.