Single Trace Attack on Key Reconciliation Process for Quantum Key Distribution

In this paper, we propose the first single trace side-channel attack on the key reconciliation process for the quantum key distribution (QKD) system. Through a single power consumption trace measured during the syndrome computation of the key reconciliation process on the sender's side, we were able to fully recover the sifted key and the syndrome. The shared secret key between the two users can be directly obtained from the sifted key and the syndrome. The result of our work shows that the QKD system must consider side-channel attacks on the key reconciliation process for its practical use.