An Observer-Based Key Agreement Scheme for Remotely Controlled Mobile Robots

Abstract

Remotely controlled mobile robots are important examples of Cyber–Physical Systems (CPSs) that are being deployed in many safety critical applications. Different control schemes that have been proposed to secure such systems against sophisticated cyber-attacks require the exchange of secret messages between their smart actuators and the remote controller. Thus, these schemes require pre-shared secret keys, or an established Public Key Infrastructure that allows for key agreement. Such cryptographic approaches might not always be suitable for the deployment environments of such remotely mobile robots. To address this problem, in this paper, we consider a control theoretic approach for establishing a secret key between the remotely controlled robot and the networked controller without resorting to traditional cryptographic techniques. Our key agreement scheme leverages a nonlinear unknown input observer and an error correction code mechanism to allow the robot to securely agree on a secret key with its remote controller. The effectiveness of the proposed solution is shown by mean of experimental results obtained using a Khepera-IV robot.