  Quantum key distribution (QKD) has been developed for decades and several
different QKD protocols have been proposed. But two difficulties limit the
implementation of most QKD protocols. First, the involved participants are
required to have heavy quantum capabilities, such as quantum joint operation,
quantum register, and so on. Second, a hypothetical authenticated classical
channel is used in most of the existing QKD protocols and this assumed channel
does not exist in reality. To solve both the above limitations at the same
time, this study proposes three lightweight authenticated QKD protocols with
key recycling and shows these proposed protocols are robust under the
collective attack.
