A flexible key-updating method for software-defined optical networks secured by quantum key distribution

Security threat is a challenging issue for data transmission in optical networks. Quantum key distribution (QKD) is a promising security solution to optical networks to provide secure keys. Meanwhile, key update is of importance to enhance the security of key in the networks. The previous update method is to provide a fixed key-updating period which has a strong regularity to be easily found. To enhance the security of data services, we proposed a quantum key-updating process by introducing the architecture of SDON secured by QKD. Then, a flexible quantum key-updating method (Flex-KUM) and a quantum key-updating algorithm based on Flex-KUM are designed in the comparison with the fixed method with different update periods. The results show that a higher level of security requires more updating keys, which leads to an increase in the blocking probability. Therefore, there is a trade-off between the enhanced security and resources.