An Algebraic Watchdog for Wireless Network Coding

TL;DR

This paper introduces an algebraic watchdog scheme for wireless network coding that enables nodes to probabilistically detect malicious behavior, enhancing network security through local overhearing and active downstream checking.

Contribution

It presents the first algebraic framework for probabilistic malicious node detection in wireless network coding, including a graphical model and exact probability formulas.

Findings

Probabilistic detection of malicious nodes is feasible.

The algebraic analysis provides exact false detection and misdetection probabilities.

The scheme improves security by enabling active, local monitoring of neighbors.

Abstract

In this paper, we propose a scheme, called the "algebraic watchdog" for wireless network coding, in which nodes can detect malicious behaviors probabilistically, police their downstream neighbors locally using overheard messages, and, thus, provide a secure global "self-checking network". Unlike traditional Byzantine detection protocols which are receiver-based, this protocol gives the senders an active role in checking the node downstream. This work is inspired by Marti et. al.'s watchdog-pathrater, which attempts to detect and mitigate the effects of routing misbehavior. As the first building block of a such system, we focus on a two-hop network. We present a graphical model to understand the inference process nodes execute to police their downstream neighbors; as well as to compute, analyze, and approximate the probabilities of misdetection and false detection. In addition, we present an algebraic analysis of the performance using an hypothesis testing framework, that provides exact formulae for probabilities of false detection and misdetection.