Key generation and distribution schemes classification for quantum key distribution networks of arbitrary topology

Quantum keys created during the quantum key distribution protocol have absolute secrecy due to physical laws and are not susceptible to breaking even with the unlimited computing power of the attacker. However, quantum key distribution systems have a range limit. Quantum key distribution networks based on trusted intermediate nodes are built to overcome the problem of the maximum range. This paper examines the connection of backbone networks with networks of arbitrary topology, introduces criteria for the classification of key generation and distribution schemes, and classifies some schemes according to the criteria introduced.