Multipath Security In QKD Networks Using Trusted Nodes

Abstract

Quantum networks allow connecting users through open channels, with security based on laws of quantum mechanics Quantum key distribution (QKD) allows the distribution of secret keys through an open channel, where, unlike classical cryptography, the security is assured by the laws of Physics rather than computational complexity. Long-distance quantum communication requires quantum repeaters. Quantum repeaters are experimentally challenging to achieve. The most crucial ingredient is quantum memory, which is needed to store the qubit while preserving its entanglement. Using trusted nodes instead of a quantum repeater, quantum memories are not needed, however, security is compromised if any trusted node is compromised. Network topology decides the protection against compromised nodes. The more compromised nodes there are, the less secure communication will be. We propose a multi-path quantum network, whereby adding optimal edge to existing topology raises security. Also, check for the vulner ability of the network in the presence of compromised nodes. Results show that the level of protection increases as the number of paths increases. The topology tells us the number of max imum compromised nodes that the network can bear. In addition, we have thoroughly studied the quantum key distribution network, being an application of quantum networks.