Group Secret Key Generation via Received Signal Strength: Protocols, Achievable Rates, and Implementation

Hongbo Liu, Jie Yang, Yan Wang, Yingying Jennifer Chen, Can Emre Koksal
2014 IEEE Transactions on Mobile Computing  
Secret key generation among wireless devices using physical layer information of radio channel has been an attractive alternative for ensuring security in mobile environments. Received signal strength (RSS) based secret key extraction gains much attention due to its easy accessibility in wireless infrastructure. However, the problem of using RSS to generate keys among multiple devices to ensure secure group communication in practice remains open. In this work, we propose a framework for
more » ... ative key generation among multiple wireless devices leveraging RSS. To deal with mobile devices not within each other's communication range, we employ relay nodes to achieve reliable key extraction. To enable secure group communication, two protocols are developed to perform collaborative group key generation via star and chain topologies respectively. We further provide the theoretic analysis on the achievable secrecy rate for both star and chain topologies in the presence of an eavesdropper. Our prototype development using MICAz motes and extensive experiments using fading trend based key extraction demonstrate the feasibility of using RSS for group key generation in both indoor and outdoor environments, and concurrently achieving a lower bit mismatch rate compared to existing studies. Index Terms-Collaborative secret key extraction, received signal strength, group key extraction, mobile wireless network Ç H. Liu is with the
doi:10.1109/tmc.2014.2310747 fatcat:mminsdmzzbemvayptzidfem72q