Quantum Key Distribution Scheme with Key Recycling in Integrated Optical Network

Quantum Key Distribution (QKD) effectively solve the problem that optical network is vulnerable to wireless network attacks by using the principle of quantum mechanics. This paper uses the QKD as a service (QaaS, i.e., multiple users can obtain the required key rate from the same QKD network infrastructure without deploying a dedicated QKD network.) framework to integrate QKD into the optical network, and proposes A QKD-integrated four-layer optical network architecture. Two key virtualization steps, Key Pool (KP) and Virtual Key Pool (VKP), are also introduced at the key distribution layer, which can provide users with better key service while ensuring the security of key distribution. In a general way, the trusted relay schemes used in QKD networks achieve the purpose of extending security by consuming additional keys. However, key relay failures often occur in QKD systems, which greatly waste quantum key resources. Therefore, in this paper, we add the quantum key recycling (QKR) mechanism and introduce the hierarchical mechanism of reusing keys, which improves the use efficiency of keys in optical networks, saves key resources and improves the encryption capability of the system. In addition, the security and efficiency analysis show that our protocol can achieve ideal results under the existing quantum technology.