Real-time wireless physical layer encryption

Abstract

In today's world where inexpensive, hobbyist grade devices can be used to infiltrate 802.11 networks, wireless security must be re-examined from the ground up. Current security schemes rely on pre-shared keys or some form of centralized key server. Both use cases are vulnerable to cheap man-in-the-middle and brute-force attacks as well as user error. Recently, physical (PHY) layer techniques have been proposed for the generation of encryption keys on the fly without the use of vulnerable key sharing. While these PHY layer techniques have been demonstrated to work in controlled settings with offline processing, little work has been done to integrate them into existing wireless standards. In this work, we present an integration of PHY layer channel state-based encryption key generation into a real-time 802.11 compliant software-defined radio. Our implementation samples application layer traffic to determine channel state information and produces keys for use in encrypting packets. Experimental results indicate that our system successfully samples application layer traffic to generate encryption keys in real-time.