Side Channel Vulnerability in Parity Computation of Generic Key Reconciliation Process on QKD

Quantum key distribution (QKD) is a key exchange protocol based on quantum physics, and the key reconciliation process is a necessary process that should not be omitted from QKD in correcting discrepancies between the key sent and the one received. In this paper, we propose the single trace side channel attack on the parity sum, which is a common operation in general error-correcting algorithms. We show that one can fully recover the secret key using a power consumption trace captured when a processor computes the parity sum.