Securing Vehicle to Vehicle Communications using Blockchain through Visible Light and Acoustic Side-Channels

Abstract

Autonomous and self-driving vehicles are appearing on the public highways.\nThese vehicles commonly use wireless communication techniques for both\nvehicle-to-vehicle and vehicle-to-infrastructure communications. Manufacturers,\nregulators and the public are understandably concerned about large-scale\nsystems failure or malicious attack via these wireless vehicular networks. This\npaper explores the use of sensing and signalling devices that are commonly\nintegrated into modern vehicles for side-channel communication purposes.\nVisible light (using a CMOS camera) and acoustic (ultrasonic audio)\nside-channel encoding techniques are proposed, developed and evaluated in this\ncontext. The side-channels are examined both theoretically and experimentally\nand an upper bound on the line code modulation rate that is achievable with\nthese side channel schemes in the vehicular networking context is established.\nA novel inter-vehicle session key establishment protocol, leveraging both\nside-channels and a blockchain public key infrastructure, is then presented. In\nlight of the limited channel capacity and the interoperability/security\nrequirements for vehicular communications, techniques for constraining the\nthroughput requirement, providing device independence and validating the\nlocation of the intended recipient vehicle, are presented. These reduce the\nnecessary device handshake throughput to 176 bits for creating symmetric\nencryption and message authentication keys and in verifying a vehicle's\ncertificate with a recognised certification authority.\n