  This study proposes a new mediated asymmetric semi-quantum key distribution
(MASQKD) protocol. With the help of a dishonest third party, two classical
participants, who have only limited asymmetric quantum capabilities, can share
a secret key with each other. The proposed protocol is shown to be immune to
several well-known attacks. Furthermore, an improved MASQKD protocol is
proposed in which the quantum capabilities of one participant can be further
reduced.
