Design of an OFDM Physical Layer Encryption Scheme

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

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41 Citations (Scopus)
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This paper presents a new encryption scheme implemented at the physical layer of wireless networks employing orthogonal frequency-division multiplexing (OFDM). The new scheme obfuscates the subcarriers by randomly reserving several subcarriers for dummy data and resequences the training symbol by a new secure sequence. Subcarrier obfuscation renders the OFDM transmission more secure and random, while training symbol resequencing protects the entire physical layer packet, but does not affect the normal functions of synchronization and channel estimation of legitimate users while preventing eavesdroppers from performing these functions. The security analysis shows the system is robust to various attacks by analyzing the search space using an exhaustive key search. Our scheme is shown to have a better performance in terms of search space, key rate and complexity in comparison with other OFDM physical layer encryption schemes. The scheme offers options for users to customize the security level and key rate according to the hardware resource. Its low complexity nature also makes the scheme suitable for resource limited devices. Details of practical design considerations are highlighted by applying the approach to an IEEE 802.11 OFDM system case study.
Original languageEnglish
Pages (from-to)2114 - 2127
Number of pages14
JournalIEEE Transactions on Vehicular Technology
Issue number3
Early online date20 May 2016
Publication statusPublished - Mar 2017


  • Communication system security
  • Wireless networks
  • OFDM
  • Physical layer
  • Cryptography


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