iJam: Physical Layer Wireless Security Made Fast and Channel Independent


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


Shyamnath Gollakota
Massachusetts Institute of Technology

Dina Katabi
Massachusetts Institute of Technology

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