A Self-Synchronization Scheme of Quantum Key Transmission Based on Dual Key Pools

In a quantum key distribution (QKD) network based on trusted relays, quantum key fragments may be lost due to the unreliability of network transmission during the transmission of quantum keys for end-to-end cryptographic applications through these relays. Consequently, the keys at both ends are out of sync. A self-synchronization scheme of quantum key transmission is proposed to address this issue and to ensure consistent quantum keys between non-adjacent network nodes. In this scheme, each network node establishes two types of key pools: the neighbor pool (NP) and the cross pool (CP). The keys of the CP in the sending node are divided into key fragments, and each fragment is encrypted with the keys in the NP using the one-time pad (OTP) method before being transmitted to the receiving node. The receiving node only stores the key fragments that are correctly received in the corresponding locations of the CP, ensuring key consistency between the sending and receiving nodes through error handling mechanisms. Under this scheme, if the receiving node does not receive the key fragments due to errors or packet loss during the key transmission process, it will no longer initiate data retransmission and other operations, thereby avoiding multiple interactions between the sending and receiving nodes and improving the efficiency of key transmission.