Talking to Strangers: Authentication in Ad-Hoc Wireless Networks.

TLDR

Bootstrapping trust between strangers makes secure communication in ad‑hoc wireless networks a difficult problem. The paper addresses secure communication and authentication in ad‑hoc wireless networks by presenting a user‑friendly solution that supports public‑key and hash‑based key exchange protocols. Devices exchange limited public information over a privileged side channel to enable authenticated key exchange over the wireless link, and the system is implemented in Java across various devices and media. The solution eliminates the need for a public key infrastructure, resists passive attacks on the privileged side channel and all wireless link attacks, and aligns with users’ intuition of communicating with nearby unknown devices.

Abstract

In this paper we address the problem of secure communication and authentication in ad-hoc wireless networks. This is a difficult problem, as it involves bootstrapping trust between strangers. We present a user-friendly solution, which provides secure authentication using almost any established public-key-based key exchange protocol, as well as inexpensive hash-based alternatives. In our approach, devices exchange a limited amount of public information over a privileged side channel, which will then allow them to complete an authenticated key exchange protocol over the wireless link. Our solution does not require a public key infrastructure, is secure against passive attacks on the privileged side channel and all attacks on the wireless link, and directly captures users’ intuitions that they want to talk to a particular previously unknown device in their physical proximity. We have implemented our system in Java for a variety of different devices, communication media, and key