Quantum walk-based protocol for secure communication between any two directly connected nodes on a network

Abstract: The utilization of quantum entanglement as a cryptographic resource has superseded conventional approaches to secure communication. Security and fidelity of intranetwork communication between quantum devices is the backbone of a quantum network. This work presents an algorithm that generates entanglement between any two directly connected nodes of a quantum network to be used as a resource to enable quantum communication across that pair in the network. The algorithm is based on a directed discrete-time quantum walk and paves the way for private inter-node quantum communication channels in the network. We also present the simulation results of this algorithm on random networks generated from various models. We show that after implementation, the probability of the walker being at all nodes other than the source and target is negligible, and this holds independent of the random graph generation model. This constitutes a viable method for the practical realisation of secure communication over any random network topology.