Single trace side-channel attack on key reconciliation in quantum key distribution system and its efficient countermeasures

Although quantum mechanics guarantees the security of the quantum key distribution system, it is crucial to examine whether the implementation flaws can lead to the disclosure of sensitive information. In this paper, we propose the side-channel attack on the key reconciliation in the quantum key distribution system. In this system, the sifted key and the syndrome are used to derive a shared secret key between two users. From our attack, these can be fully recovered through a single power consumption trace measured during the syndrome computation on the sender's side. Additionally, we propose efficient countermeasures to thwart such side-channel attacks.