Quantum key distribution using unknown quantum states

This paper proposes a version of quantum key distribution (QKD) by leveraging unknown quantum states. The measurement made on the unknown quantum states is independent of them. As the number of copies of the unknown states increases, the key rate increases, and the disturbance caused by an eavesdropper also increases synchronously. If the unknown quantum states are orthogonal to each other, they cannot be completely distinguished. Our scheme is more efficient than the previous scenarios in QKD, where a set of known quantum states are leveraged. Our work offers a theoretical groundwork for constructing a highly effective QKD by exploiting unknown quantum states.