  Semi-quantum inspired lightweight protocol is an important research issue in
realization of quantum protocols. However, the previous semi-quantum inspired
lightweight mediated quantum key distribution (SQIL-MQKD) protocols need to use
the Bell states or measure the Bell states. The generation and measurement of
Bell states are more difficult and expensive than those of single photons. To
solve this problem, a semi-quantum inspired lightweight mediated quantum key
distribution with limited resource protocol is proposed. In this protocol, an
untrusted third party (TP) only needs to perform the quantum operations related
to single photons and the participants only have to perform two quantum
operations: (1) reflecting qubits without disturbance (2) performing unitary
operations on single photons. In addition, this protocol is showed to be robust
under the collective attack.
