Quantum Key Distribution (QKD) technology, based on laws of quantum physics, can generate unconditional security keys between two communication parties. QKD is nearly a commercial technology and can make it available to the public. In existing QKD networks and commercial QKD systems, classical network is an essential part of the implementation of QKD protocols. With security keys and encryption scheme (one-time pad), we can protect the security of various network applications. But the public classical channel in QKD network may suffers potential key consuming attacks. In this paper, we focus on how to detect the potential attacks during the security applications in the QKD network. Especially, we propose a Dynamic Key Consuming Detection scheme (DKode) in QKD-VoIP systems which encrypting VoIP streams with security keys from QKD systems.