A Three‐Party Lightweight Quantum Key Distribution Protocol in a Restricted Quantum Environment

ABSTRACT This study proposes a new lightweight quantum key distribution (LQKD) protocol based on the four‐particle cluster state within a quantum‐restricted environment. The protocol enables a quantum‐capable user to simultaneously establish two separate secret keys with two “classical” users, who are limited to performing only the Hadamard operation and measurements in the basis. By adopting a one‐way qubit transmission approach, the proposed protocol addresses several limitations of existing s