Quantum Alice and Silent Bob: qubit-based quantum key recycling with almost no classical communication

We introduce a Quantum Key Recycling (QKR) protocol that needs no classical communication from Alice to Bob. Alice sends only a cipherstate, which consists of qubits that are individually measured by Bob. Bob merely has to respond with an authenticated one-bit accept/reject classical message. Compared to Quantum Key Distribution (QKD), QKR has reduced round complexity. Compared to other qubit-wise QKR protocols, our scheme has far less classical communication. We provide a security proof proof similar to [1] and find that the communication rate is asymptotically the same as for QKD with one-way postprocessing.