# Secure Communication in Dynamic Wireless Ad hoc Networks

## TL;DR

This paper introduces a new secure communication scheme for wireless ad hoc networks with eavesdroppers, analyzing its connectivity properties and proposing methods to improve security and reduce delay.

## Contribution

A novel time-varying secure connectivity graph scheme for ad hoc networks, with analysis of connectivity metrics and strategies to enhance security and efficiency.

## Key findings

- Average incoming and outgoing edges are characterized.
- Secure connectivity time scales linearly with distance.
- Packet splitting and routing improve security and reduce delay.

## Abstract

We consider a wireless ad hoc network in the presence of eavesdroppers (EDs), where the nodes are distributed according to independent Poisson point processes (PPPs). The legitimate nodes follow the half-duplex mode of operation employing the slotted ALOHA protocol for transmission. For such a network, a novel communication scheme that induces a time-varying secure connectivity graph (SCG) is proposed, and the connectivity behavior of this induced SCG is studied. In particular, for a legitimate node in the network, we analyze (i) the average number of incoming edges and the average number of outgoing edges; (ii) the time to nearest-neighbor secure connectivity; and (iii) a condition on the EDs' density that allows information percolation, {\ie}, a condition for the existence of a `giant' component. The average time for secure connectivity among the nodes in this giant component is shown to scale linearly with the Euclidean distance. Further, we show that by splitting the packets into two sub-packets and routing each sub-packet along paths that are sufficiently far apart can (a) potentially improve secure connectivity and (b) reduce the overall delay incurred in exchanging packets between any two legitimate nodes in the giant component.