Secure Route Planning Using Dynamic Games with Stopping States

TL;DR

This paper introduces a dynamic game framework for secure route planning that accounts for attacker threats and countermeasures, providing analytical solutions and a heuristic for optimal path selection.

Contribution

It models the motion planning problem as a zero-sum dynamic game with stopping states, deriving Nash equilibria and a heuristic for secure route planning.

Findings

Closed-form Nash equilibria for edge-games.

Analytic and approximate expressions for edge-game values.

A shortest path heuristic for secure route planning.

Abstract

We consider the classic motion planning problem defined over a roadmap in which a vehicle seeks to find an optimal path from a source to a destination in presence of an attacker who can launch attacks on the vehicle over any edge of the roadmap. The vehicle (defender) has the capability to switch on/off a countermeasure that can detect and permanently disable the attack if it occurs concurrently. We model the problem of traveling along en edge using the framework of a simultaneous zero-sum dynamic game (edge-game) with a stopping state played between an attacker and defender. We characterize the Nash equiliria of an edge-game and provide closed form expressions for two actions per player. We further provide an analytic and approximate expression on the value of an edge-game and characterize conditions under which it grows sub-linearly with the number of stages. We study the sensitivity of Nash equilibrium to the (i) cost of using the countermeasure, (ii) cost of motion and (iii) benefit of disabling the attack. The solution of an edge-game is used to formulate and solve for the secure planning problem known as a meta-game. We design an efficient heuristic by converting the problem to a shortest path problem using the edge cost as the solution of corresponding edge-games. We illustrate our findings through several insightful simulations.