# Design and Performance Analysis of Secure Multicasting Cooperative Protocol for Wireless Sensor Network Applications

## TL;DR

This paper introduces a secure cooperative protocol for wireless sensor networks that enhances secrecy by sectoral transmission and beamforming, reducing eavesdropping risks in large relay-based networks.

## Contribution

It proposes a novel dual-phase amplify-and-forward protocol with sectoral transmission and analyzes its secrecy performance in the presence of untrusted relays.

## Key findings

- Secrecy outage probability decreases with more sectors.
- Distributed beamforming improves secure communication.
- Untrusted relays are less effective when cooperating aggressively.

## Abstract

This paper proposes a new security cooperative protocol, for dual phase amplify-and-forward large wireless sensor networks. In such a network, a portion of the K relays can be potential eavesdroppers. The source agrees to share with the destination a given channel state information (CSI) of a source-trusted relay-destination link to encode the message. Then, in the first hop, the source will use this CSI to map the right message to a certain sector while transmitting fake messages to the other sectors using sectoral transmission thanks to analog beamforming. In the second hop, the relays retransmit their received signals to the destination, using the distributed beamforming technique. We derived the secrecy outage probability and demonstrated that the probability of receiving the right encoded information by an untrustworthy relay is inversely proportional to the number of sectors. We also showed that the aggressive behavior of the cooperating untrusted relays is not effective compared to the case where each untrusted relay is trying to intercept the transmitted message individually.