  The quantum key distribution (QKD), guaranteed by the principle of quantum
physics, is a promising solution for future secure information and
communication technology. However, device imperfections compromise the security
of real-life QKD systems, restricting the wide deployment of QKD. This study
reports a decoy-state BB84 QKD experiment that considers both source and
detection imperfections. In particular, we achieved a rigorous finite-key
security bound over fiber links of up to 75 km by applying a systematic
performance analysis. Furthermore, our study considers more device
imperfections than most previous experiments, and the proposed theory can be
extended to other discrete-variable QKD systems. These features constitute a
crucial step toward securing QKD with imperfect practical devices.
