There is a growing interest in physical layer security. Recent work has demonstrated that wireless devices can generate a shared secret key by exploiting variations in their channel. The rate at which the secret bits are generated, however, depends heavily on how fast the channel changes. As a result, existing schemes have a low secrecy rate and are mainly applicable to mobile environments. In contrast, this project presents a new physical-layer approach to secret key generation that is both fast and independent of channel variations. Our approach makes a receiver jam the signal in a manner that still allows it to decode the data, yet prevents other nodes from decoding. Results from a testbed implementation show that our method is significantly faster and more accurate than state of the art physical-layer secret key generation protocols. Specifically, while past work generates up to 44 secret bits/s with a 4% bit disagreement between the two devices, our design has a secrecy rate of 3–18 Kb/s with 0% bit disagreement.

Physical Layer Wireless Security Made Fast and Channel Independent
Shyamnath Gollakota and Dina Katabi
IEEE INFOMCOM, 2011. PDF

Shyamnath Gollakota
Massachusetts Institute of Technology

Dina Katabi
Massachusetts Institute of Technology