  Quantum key distribution (QKD) protocols make it possible for two quantum
parties to generate a secret shared key. Semiquantum key distribution (SQKD)
protocols, such as "QKD with classical Bob" and "QKD with classical Alice"
(that have both been proven robust), achieve this goal even if one of the
parties is classical. However, existing SQKD protocols are not experimentally
feasible with current technology. Here we suggest a new protocol, "Classical
Alice with a controllable mirror", that can be experimentally implemented with
current technology (using 4-level systems instead of qubits), and we prove it
to be robust.
