Experimentally feasible protocol for semiquantum key distribution
This work addresses the challenge of implementing SQKD with current technology, enabling secure key distribution even when one party is classical, though it is incremental as it builds on existing SQKD frameworks.
The authors tackled the problem of experimental feasibility in semiquantum key distribution (SQKD) by proposing a new protocol called 'Classical Alice with a controllable mirror' that uses 4-level systems instead of qubits, and they proved it to be robust.
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.