Secure wireless communications: Secret keys through multipath

Secure wireless communications is a challenging problem due to the shared nature of the wireless medium. Most existing security protocols apply cryptographic techniques for bit scrambling at the application layer by exploiting a shared secret key between pairs of communicating nodes. However, more recent research argues that multipath propagation – a salient feature of wireless channels – provides a physical resource for secure communications. In this context, we propose a protocol that exploits the inherent randomness in multipath wireless channels for generating secret keys through channel estimation and quantization. Our approach is particularly attractive in wideband channels which exhibit a large number of statistically independent degrees of freedom (DoF), thereby enabling the generation of large, more-secure, keys. We show that the resulting keys are distinct for distinct pairwise links with a probability that increases exponentially with the key-size/channel DoF. We also c...

• Type: Conference
• Year: 2008
• Where: ICASSP
• Authors: Akbar M. Sayeed, Adrian Perrig
• Keywords: ICASSP 2008, Multipath Wireless Channels, Secret Key, Signal Processing, Wireless Channels