Secure Key Generation from OFDM Subcarriers’ Channel Response

Junqing Zhang, Alan Marshall, Roger Woods, Trung Q. Duong

Research output: Contribution to conferencePaperpeer-review

28 Citations (Scopus)
476 Downloads (Pure)


The ability to exchange keys between users is vital in any wireless based security system. A key generation technique exploits the randomness of the wireless channel is a promising alternative to existing key distribution techniques, e.g., public key cryptography. In this paper a secure key generation scheme based on the subcarriers’ channel responses in orthogonal frequencydivision multiplexing (OFDM) systems is proposed. We first implement a time-variant multipath channel with its channel impulse response modelled as a wide sense stationary (WSS) uncorrelated scattering random process and demonstrate that each subcarrier’s channel response is also a WSS random process. We then define the X% coherence time as the time required to produce an X% correlation coefficient in the autocorrelation function (ACF) of each channel tap, and find that when all the channel taps have the same Doppler power spectrum, all subcarriers’ channel responses has the same ACF as the channel taps. The subcarrier’s channel response is then sampled every X% coherence time and quantized into key bits. All the key sequences’ randomness is tested using National Institute of Standards and Technology (NIST) statistical test suite and the results indicate that the commonly used sampling interval as 50% coherence time cannot guarantee the randomness of the key sequence.
Original languageEnglish
Publication statusPublished - Dec 2014
EventIEEE Global Communications Conference 2014 - TX, Austin, United States
Duration: 08 Dec 201412 Dec 2014


ConferenceIEEE Global Communications Conference 2014
Abbreviated titleGLOBECOM 2014
Country/TerritoryUnited States


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